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Walnut yield and quality are often affected by beetle infestations, particularly those caused by Carpophilus truncatus (Murray) (Nitidulidae) and Oryzaephilus mercator (L.) (Silvanidae). Beetle damage exposes walnuts to microbial food spoilers such as Fusarium species. Insecticides currently used for beetle control are environmentally unfriendly. This work explored a green synthesis approach for copper oxide nanoparticles (CuO-NPs) in a basic medium at 30 °C by hydrolates, aqueous extracts obtained from Lippia integrifolia and Pimpinella anisum, denoted as CuO-I and CuO-A, respectively. Characterization through XRD, FT-IR, Raman, UV-visible absorbance, and AFM techniques indicated that CuO-A and CuO-I have a size ranging from 2-10 nm in height. The antifungal assay showed that both have a similar efficacy (MID=320 μg), 3-fold stronger than CuO- NPs obtained in absence of hydrolates (denoted CuO-W) (MID=960 μg), with the broadest inhibitory halos (ID=126-128 mm) observed for CuO-A. Insecticidal activity of CuO-NPs showed a concentration-dependent behavior, with CuO-I showing an effect comparable to that of diatomaceous earth. SEM images confirmed the adhesion of nanoparticles to insect surfaces, which could induce oxygen deprivation and disruption of metabolic processes. Both CuO-A and CuO-I are promising for their use in integrated pest control in walnut storage., (© 2024 Wiley-VHCA AG, Zurich, Switzerland.)

Carpophilus dimidiatus (Fabricius) (Nitidulidae) and Oryzaephilus mercator (L.) (Silvanidae) are insect pests that cause severe damage in important walnut growing regions in the northwest of Argentina. The current management approaches for these pests involve the use of unsafe phosphorus pesticides whose overuse have led to farmworker poisoning, pest resistance issues, and environmental contamination. Plant extracts, particularly essential oils, are an alternative source of insect control agents. Excito-repellent essential oils can be used to develop ecofriendly tools for managing the pest population without affecting quality and visual appearance of the stored walnuts. Laboratory studies were conducted to assess the excito-repellent effects of C. dimidiatus and O. mercator of 12 essential oils derived from aromatic plants used as food additives and traditional medicine in Argentina: Aloysia citrodora (AC), Aloysia gratissima (AG), Aloysia gratissima var. Gratissima (AGG), Blepharocalyx salicipholius (BS), Hyptis mutabilis (HM), Lippia junelliana (LJ), Lippia turbinata (LT), Mentha x piperita (MP), Minthostachys mollis (MM), Minthostachys verticillata (MV), Origanum vulgare (OV), and Rosmarinus officinalis (RO). The most bioactive EOs (ER ijk ≥ 70%) were Aloysia gratissima var. Gratissima (AGG), Minthostachys verticillata , and Lippia junelliana . Their bioactivity profile and chemical space, characterized from GC-MS measures, Generalized Estimating Equations, and Hierarchical Cluster Analysis, revealed that they are mixtures of very functionalized molecules with physicochemical properties similar to those of insecticides with low residual property that enter the insect body through the respiratory system by inhalation. The AGG, MV, and LJ oils are promising as protective agents of walnut products. In our laboratory, studies of their formulations for use in integrated pest management programs are still ongoing.

Fusarium graminearum causes destructive ear rot diseases in maize and wheat. New antifungals are essential to combat this pathogen, and aerial parts of Justicia species (Acanthaceae) are a potential source. We investigated the antifungal activity of extracts from stems and leaves of five Justicia species native to Northwest Argentina. The aerial parts were subjected to sequential extractions with dichloromethane, ethyl acetate, and methanol. The resulting extracts were tested by the disc diffusion method against F. graminearum strains. Only the leaf and stem extracts from J. xylosteoides displayed inhibitory effects, with the dichloromethane leaf extract as the most active. The compounds involved were identified as the lignans hinokinin, savinin, and isohibalactone. Both the dichloromethane extract and hinokinin synergised with tebuconazole, and inhibited deoxynivalenol biosynthesis. The identified compounds warrant further research as additives to azole fungicides for F. graminearum control.

Essential oils from aerial parts of six aromatic plants were analysed by GC-MS. The major compounds identified were γ -terpinene (11.5%), cuminaldehyde (26.6%) and γ -terpinen-7-al (40.6%) in Cuminum cyminum , trans -anethol (95.2%) in Pimpinella anisum , α-pinene (11.6%), limonene (21.0%), β-caryophyllene (22.3%) and α-humulene (16.7%) in Lippia integrifolia , limonene (40.8%) and artemisia ketone (19.3%) in Lippia junelliana , trans -β-ocimene (15.6%), 4-ethyl-4-methyl-1-hexene (24.5%), trans -tagetone (20.5%) and verbenone (27.2%) in Tagetes minuta , 1,8-cineole (17.9%),elixene (10.3%) and spathulenol (13.8%) in Aloysia gratissima . Oils with strong insecticidal activity on Carpophilus dimidiatus and Oryzaephilus mercator were from P. anisum (LC 50 = 4 µl/L; LC 100 = 10 µl/L) and T. minuta (LC 50 =10.19-12.57 µl/L; LC 100 =20 µl/L). Scents of C. cyminum and L. junelliana were strong insecticides on O. mercator (LC 50 =7.02-7.17 µl/L; LC 100 =10.00-20.00 µl/L). The insecticidal activity was associated to the whole content of C10 molecules and oxygenated constituents. The P. anisum oil is promising as protective agent of nut products.

A fraction enriched in triterpenoid saponins (F4) from Anagallis arvensis L. was chemically characterized by UHPLC-ESI-QTOF-MS/MS and NMR analyses. The results proposed the presence of nine monodesmosidic saponins derived from oleanolic acid, including two reported for the first time for this species, 3 : 3-O-{β-D-glucopyranosyl (1→4)-[β-D-xylopyranosyl (1→2)]-β-D-glucopyranosyl (1→4)-[β-D-glucopyranosyl (1→2)]-α-L-arabinopyranosyl}-13β, 28-epoxy- 22 acetyl- 28 methoxy-16α, 24-oleananediol and 4 : 3-O-{β-D-glucopyranosyl (1→4)-β-D-glucopyranosyl (1→4)-[β-D-xylopyranosyl (1→2)]-β-D-glucopyranosyl (1→4)-[β-D-glucopyranosyl (1→2)]-α-L-arabinopyranosyl}-13β, 28-epoxy- 16α, 30-oleananediol. Furthermore, haemolytic activity was determined by dot-blot autography, and cytotoxicity on human lymphocyte cultures was analysed according to metabolic activity (MTT assay) and membrane integrity (Trypan blue exclusion test). F4 showed mild cytotoxicity (%V > 50% at 100 μg/mL) on human lymphocytes under conditions of activation or not by LPS; moreover, showed haemolytic activity between 50 and 500 μg. This work contributed to phytochemical knowledge of the triterpenoid saponins from A. arvensis , and its cytotoxic effects on normal human cells.

Fungal co-culture has several biotechnological applications including the discovery or the enhanced production of secondary metabolites. It is also a powerful tool aiding to elucidate the involvement of secondary metabolism in fungus-fungus interactions. The aim of this work was to investigate secondary metabolites produced when Fusarium verticillioides is co-cultured with Gliocladium roseum. Secreted metabolites were analyzed by HPLC-MS, and fusaric acid (FA) was quantified by HPLC-DAD. Four FA derivatives were identified only in the F. verticillioides-G. roseum co-culture. Mass spectrometry and one- and two-dimensional NMR spectra indicated that they were 5-butylpyridine-2-carboxylic acid methyl ester (5B2CAM), 4-(5-butylpicolinamido) butanoic acid (45BBA), methyl 4-(5-butylpicolinamido) butanoate (M45BBA), and bis(5-butyl-2-pyridinecarboxylate-N1,O2)-copper (B52P). 45BBA and M45BBA are reported for the first time and were FA biotransformation products generated by G. roseum. The antifungal activity of 5B2CAM, 45BBA, and M45BBA was evaluated in vitro against Botrytis cinerea and Aspergillus niger. They were less fungitoxic than FA, with 45BBA as the least toxic. Our results suggest that the effective antagonism exerted by G. roseum against F. verticillioides is due, at least in part, to its detoxifying ability against FA., (© 2021. The Author(s) under exclusive licence to Society for Mycotoxin (Research Gesellschaft für Mykotoxinforschung e.V.) and Springer-Verlag GmbH Germany, part of Springer Nature.)

Orobanche and Striga are parasitic weeds extremely well adapted to the life cycle of their host plants. They cannot be eliminated by conventional weed control methods. Suicidal germination induced by strigolactones (SLs) analogs is an option to control these weeds. Here, we reported two new halogenated (+)-GR24 analogs, named 7-bromo-GR24 (7BrGR24) and 7-fluoro-GR24 (7FGR24), which were synthesized using commercially available materials following simple steps. Both compounds strongly promoted seed germination of Orobanche cumana . Their EC 50 values of 2.3±0.28×10 -8 M (7BrGR24) and 0.97±0.29×10 -8 M (7FGR24) were 3- and 5-fold lower, respectively, than those of (+)-GR24 and rac -GR24 (EC 50 =5.1±1.32-5.3±1.44×10 -8 ; p <0.05). The 7FGR24 was the strongest seed germination promoter tested, with a stimulation percentage of 62.0±9.1% at 1.0×10 -8 M and 90.9±3.8% at 1.0×10 -6 M. It showed higher binding affinity (IC 50 =0.189±0.012μM) for the SL receptor ShHTL7 than (+)-GR24 (IC 50 =0.248±0.032μM), rac -GR24 (IC 50 =0.319±0.032μM), and 7BrGR24 (IC 50 =0.521±0.087μM). Molecular docking experiments indicated that the binding affinity of both halogenated analogs to the strigolactone receptor OsD14 was similar to that of (+)-GR24. Our results indicate that 7FGR24 is a promising agent for the control of parasitic weeds., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Chen, Kuang, Shi, Wang, Fu, Xie, Yang, Sampietro, Huang and Yuan.)

Aims: This work aimed to identify secondary metabolites from aerial parts of Euphorbia species functional for control of toxigenic Fusarium species responsible of cereal grain rots., Methods and Results: Aerial parts of Euphorbia serpens, Euphorbia schickendantzii and Euphorbia collina were sequentially extracted with hexane, ethyl acetate and methanol. The extracts were tested against strains of Fusarium verticillioides and Fusarium graminearum by microdilution tests. The hexane extract of E. collina provided the lowest IC 50 s on both fungal species. Further fractionation showed that cycloartenol (CA) and 24-methylenecycloartanol are associated to the moderate inhibitory effect of the hexane extract on fungal growth.Sublethal concentrations of CA and 24MCA blocked deoxynivalenol (DON) and fumonisins production.CA and 24MCA co-applied with potassium sorbate, a food preservative used for Fusarium control, synergized the growth inhibition of fungi. The mixtures reduced mycotoxins accumulation when applied at sublethal concentrations., Conclusions: CA and 24MCA inhibited both fungal growth and mycotoxins production. This fact is an advantage respect to potassium sorbate which increased the mycotoxins accumulation at sublethal concentrations., Significance and Impact of the Study: CA and 24MCA synergized potassium sorbate and their mixtures offer a lower mycotoxigenic risk than potassium sorbate for control of the Fusarium species., (© 2020 The Society for Applied Microbiology.)

Extracts from aerial parts of Prosopis ruscifolia , Bidens pilosa , Cercidium praecox and Phoradendron liga were assayed against toxigenic Aspergillus species. They were obtained by sequential extraction of the aerial parts with hexane (fHex), dichloromethane (fDCM), ethyl acetate (fEtOAc) and methanol (fMeOH). The fMeOH from P. ruscifolia showed the highest antifungal spectrum (MIC = 750-1500 µg mL -1 ; MID = 50-200 µg; DI = 1.7-3.0 mm). Indolizidine alkaloids (juliflorine and juliprosine) and tryptamine were identified with strong (MIC = 188 µg mL -1 ) and moderate antifungal activities (MIC = 750 µg mL -1 ), respectively, towards A. parasiticus and A. flavus . The fMeOH, the indolizidine alkaloids and tryptamine synergized the fungitoxic effect of potassium sorbate and propiconazole. They completely suppressed the biosynthesis of aflatoxins at concentrations of 47, 94 and 375 µg mL -1 , respectively. Our results indicate that fMeOH and its identified alkaloids are promisory additives of commercial antifungals and are antiaflatoxigenic agents at concentrations below of those required for complete suppression of fungal growth.

Tessaria dodoneifolia [Asteraceae] is traditionally employed in Northwestern Argentina for fungal infections treatment. We report the antifungal activity guided isolation and identification of substances from aerial parts of this species, both individually and in combination with fluconazole (FLU), against Candida albicans strains. Two antifungal flavanones were identified as naringenin (NAR) and pinocembrin (PIN). These compounds could individually inhibit the growth of C. albicans strains. Combinations of NAR and PIN with FLU were synergistic against the FLU resistant and sensitive C. albicans strains. Genotoxic and cytotoxic evaluations were also performed. NAR, PIN and their combinations with FLU did not have a genotoxic effect on Bacillus subtilis rec strains. Finally, these compounds did not show cytotoxicity at concentrations below 80 μg/mL., (© 2020 Published by Elsevier Ltd.)

Twenty four extracts from Bignoniaceae plants of northwest Argentina were tested for antifungal activity against Aspergillus species responsible of the grape black rot. Stems and leaves of Amphilophium cynanchoides, Macfadyena cynanchoides, Tecoma stans and Jacaranda mimosifolia were separately extracted with solvents of increasing polarity to obtain the dichloromethane (fCH 2 Cl 2 ), ethyl acetate (fEtOAc) and methanol extracts (fMeOH). The fCH 2 Cl 2 from stem of M. cynanchoides had the lowest IC 50 (1.0-1.2 mg/mL) and MID values (0.6-1.2 mg) and the highest ID values (5.0-6.8 mm) on A. niger and A. carbonarius. The main contributors of the antifungal activity of fCH 2 Cl 2 were identified as lapachol (MIC = 0.25-1.00 mg/ml) and 1-hydroxy-4-methylanthraquinone (MIC = 0.0625-0.125 mg/mL). These compounds synergized the antifungal activity of sodium metabisulfite and showed an additive effect in mixtures with propiconazol. They might be used as additives of commercial antifungals to protect grapes against A. niger and A. carbonarius .

Background: Erwinia carotovora subsp. cause the potato soft rot, which is a major disease in agriculture. Antibacterial agents currently applied on potato soft rot often offer a restricted control and have several disadvantages. Propolis has shown a wide range of antimicrobial activity, although its effect has not been investigated on E. carotovora subsp. In this work, we tested extracts from propolis samples of Northwest Argentina against E. carotovora subsp., Results: Ethanolic propolis extracts (EPEs) from samples of Santiago del Estero province, particularly from sample 4 (EPE4), showed the highest antibacterial activity, which was associated with the highest content of flavonoids. 2',4'-Dihydroxychalcone, 2',4'-dihydroxy-3'-methoxychalcone, galangin, and pinocembrin were identified as antibacterial constituents of EPE4. 2',4'-Dihydroxychalcone showed an antibacterial activity (minimum inhibitory concentration, MIC = 0.3-1.2 μg gallic acid equivalents (GAE) mL -1 ; minimum bactericidal concentration, MBC = 0.6-4.8 μg GAE mL -1 ) lower than that of bacterimycin (MIC = 2.4-9.6 μg mL -1 ; MBC = 19.2-38.4 μg GAE mL -1 ) and streptocycline (MIC = 19.2-38.4 μg mL -1 ; MBC = 38.4-76.8 μg mL -1 ). Preventive assays on unwounded and wounded potatoes showed that their immersion in EPE4 containing 87.5 μg GAE mL -1 or streptocycline containing 40 μg mL -1 was equally effective in controlling potato soft rot, reducing the disease incidence by 64.6-67.0% (unwounded tubers) and 88.0-86.0% (wounded tubers) and the disease severity by 49.8-49.8% (unwounded tubers) and 54.5-68.5% (wounded tubers)., Conclusions: Flavonoid-rich propolis extracts from Northwest Argentina efficiently reduced in vivo the incidence and severity of potato soft rot caused by E. carotovora subsp., (© 2020 Society of Chemical Industry.)

Extracts from aerial parts of medicinal plants from northwest Argentina were screened for antibacterial activity against the phytopathogenic strains namely CECT 124 ( Pseudomonas corrugata ), CECT 126 ( P. syringae pv. tomato ), CECT 225 ( Erwinia carotovora var. carotovora ), CECT 472 ( Agrobacterium tumefaciens ) and CECT 792 ( Xanthomonas campestres pv. vesicatoria ). Leaves and stems of Aspidosperma quebracho-blanco , Schinus fasciculatus , S. gracilipes , Amphilophium cynanchoides and Tecoma stans were separately extracted with solvents of increasing polarity to obtain the dichloromethane (fCH 2 Cl 2 ), ethyl acetate (fEtAc) and methanol extracts (fMeOH), respectively. Among the thirty extracts tested, only fEtAc from leaves and stems of S. fasciculatus reached the IC 50 against the five bacterial strains tested (IC 50  = 0.9 mg/ml). The fEtAc from the leaves contained kaempferol, quercetin and agathisflavone which had moderate to strong antibacterial activity. This extract and its identified flavonoids showed synergic (CECT 124,126 and 792) or additive effects (CECT 472 and 225) in mixtures with Kocide 3000.

Essential oils from aerial parts of the herbs Peganum harmala and Nepeta cataria , and leaves of the tree Phellodendron amurense were analyzed by GC-FID and GC-MS, and their larvicidal activities were assayed on the early fourth instar larvae of Aedes aegypti . The major constituents of the oils were limonene (14.5%) and thymol (11.5%) in P. harmala , thymol (46.5%), 4aα,7α,7aβ-nepetalactone (18.3%) and 4aα,7β,7aα-neptalactone (19.7%) in N. cataria , eugenol (14.5%) andγ-eudesmol (9.5%) in P. amurense .The oil of N. cataria had a strong larvicidal activity (LC 50  < 50 µg/mL; LC 90  < 86.8 µg/mL) on A. aegypti while the remaining oils showed a moderated killing effect. The larvicidal activity of N. cataria oil was associated to the contents of 1,8-cineol, camphor, 4aα,7α,7aβ-Nepetalactone, 4aα,7β,7aα-Nepetalactone and thymol. Our results indicate that the oil of N. cataria deserves to be used as a source of larvicidal agents against A. aegypti ., Competing Interests: We have no conflicts of interest concerning the work reported in this article, (© 2020 The Authors.)

Essential oils from aerial parts of Senecio nutans, Senecio viridis, Tagetes terniflora and Aloysia gratissima were analysed by GC-MS and their antifungal activities were assayed on toxigenic Fusarium and Aspergillus species. Sabinene (27.6 ± 0.1%), α-phellandrene (15.7 ± 0.3%), o -cymene (9.6 ± 0.2%) and β-pinene (6.1 ± 0.2%) in S. nutans , 9,10-dehydrofukinone (92.7 ± 0.2%) in S. viridis , β-thujone (36.1 ± 0.1%), α-thujone (32.2 ± 0.2%), 1,8-cineol (10.7 ± 0.1%) and sabinene (6.2 ± 0.2%) in A. gratissima , and cis -tagetone (33.6 ± 0.2%), cis -β-ocimene (17.1 ± 0.2%), trans -tagetone (17.0 ± 0.1%), cis -ocimenone (8.0 ± 0.2%) and trans -ocimenone (8.2 ± 0.1%) in T. terniflora . The oils showed moderate antifungal activity (1.2 mg/mL > MIC >0.6 mg/mL) on the Fusarium species and a weak effect on Aspergillus species. The antifungal activity was associated on F. verticillioides to the high content of cis -tagetone, trans -tagetone, cis -β-ocimene, cis -ocimenone, trans -ocimenone and on F. graminearum due to the total content of oxygenated sesquiterpenes and 9,10- dehydrofukinone. The oil of S. viridis synergized the effect of fungicides and food preservatives on F. verticillioides .[Formula: see text].

Fusarium meridionale and F. boothii cause Gibberella Ear Rot (GER) in maize. This study determined the effects of temperature (5-35 °C) and water activity (0.90-0.995 a w ) on the growth, and deoxynivalenol (DON) and nivalenol (NIV) production of F. meridionale and F. boothii strains in maize grains. Fusarium graminearum sensu stricto strains from wheat were also tested. The three Fusarium species grew best at 0.995 a w and 25 °C. Growth was absent or marginal at 0.90 a w regardless of temperature. F. meridionale and F. boothii were sensitive to 30 °C and more affected by water stress than F. graminearum sensu stricto. The highest DON levels were at 0.995-0.97 a w and 30 °C and at 0.97 a w and 20 °C for F. graminearum sensu stricto, and at 0.995-0.97 a w and 20 °C for F. boothii. Fusarium meridionale reached maximum NIV accumulation at 0.995 a w and 20 °C. This produced DON at negligible levels compared to the other two Fusarium species. Growth of F. meridionale and F. boothii was well adapted to the usual autumn high humidity and mild temperatures associated with GER in northwest Argentina. Control strategies during grain development should be taken into account to reduce the risk of the presence of DON and NIV in the harvested grains., (Copyright © 2019 Elsevier B.V. All rights reserved.)

An antifungal activity-directed fractionation of leaf constituents from Schinopsis balansae on Fusarium graminearum yielded a fraction mainly made of a mixture of four 3-n-heptadec(en)ylcatechols (PALK). The PALK fraction showed on macroconidia germination a MIC 100 value of 500 μg/mL which was twofold higher than that required for prothioconazole (MIC 100  = 250 μg/mL). Sublethal concentrations of PALK modify the morphogenesis in germinating macroconidia, and decreased fungal production of H 2 O 2 and deoxynivalenol biosynthesis at early fungal growth. Mixes of PALK and prothioconazole showed a synergic interaction. Our findings suggest that PALK constituents might restrict the adherence of F. graminearum to the surface of its hosts and its virulence on susceptible cereals. They deserve further research as additives of azole fungicides against F. graminearum.

The composition of essential oils from leaves of Kazakhstan medicinal plants was analysed by GC-MS. The major compounds identified were 1,8-cineole (34.2%), myrcene (19.1%) and α-pinene (9.4%) in Ajania fruticulosa; 1,8-cineole (21.0%), β-thujone (11.0%), camphor (8.5%), borneol (7.3%) and α-thujone (6.5%), in Achillea nobilis; camphor (47.3%), 1,8-cineole (23.9%), camphene (9.8%) and β-thujone (6.0%) in Artemisia terrae-albae; 1,8-cineole(55.8%) and β-pinene (6.2%) in Hyssopus ambiguus; α-thuyene(46.3%) and δ-cadinene(6.3%) in Juniperus sibirica; sabinene (64%) in Juniperus sabina; and α-pinene (51.5%), β-phellandrene (11.2%) and δ-cadinene (6.3%) in Pinus sibirica. The essential oils did not show antifungal effect (MIC > 1.20 mg/mL) on Aspergillus carbonarius and Aspergillus niger, while the oils from A. nobilis, A. terrae-albae, H. ambiguus and J. sabina exhibited moderate and moderate to weak antimicrobial activities on Fusarium verticillioides (MIC = 0.60 mg/mL) and Fusarium graminearum (MIC = 0.60-1.20 mg/mL), respectively. A principal component analysis associated the antifungal activity (r 2  > 0.80, p = 0.05) with the presence of borneol, camphor, camphene, 1,8-cineole,α- and β-thujone, and of the oxygenated monoterpenes.

Ethnopharmacological Relevance: Anagallis arvensis L. (Primulaceae) is used in argentinean northwestern traditional medicine to treat fungal infections. We are reporting the isolation and identification of compounds with antifungal activity against human pathogenic yeast Candida albicans, and toxicity evaluation., Aim of the Study: to study the antifungal activity of extracts and purified compounds obtained form A. arvensis aerial parts, alone and in combinations with fluconazole (FLU), and to study the toxicity of the active compounds., Materials and Methods: Disk diffusion assays were used to perform an activity-guided isolation of antifungal compounds from the aerial parts of A. arvensis. Broth dilution checkerboard and viable cell count assays were employed to determine the effects of samples and combinations of FLU + samples against Candida albicans. The chemical structures of active compounds were elucidated by spectroscopic analysis. Genotoxic and haemolytic effects of the isolated compounds were determined., Results: Four triterpenoid saponins (1-4) were identified. Anagallisin C (AnC), exerted the highest inhibitory activity among the assayed compounds against C. albicans reference strain (ATCC 10231), with MIC-0 =1µg/mL. The Fractional Inhibitory Concentration Index (FICI=0.129) indicated a synergistic effect between AnC (0.125µg/mL) and FLU (0.031µg/mL) against C. albicans ATCC 10231. AnC inhibited C. albicans 12-99 FLU resistant strain (MIC-0 =1µg/mL), and the FICI=0.188 indicated a synergistic effect between AnC (0.125µg/mL) and fluconazole (16µg/mL). The combination AnC+ FLU exerted fungicidal activity against both C. albicans strains. AnC exerted inhibitory activity against C. albicans ATCC 10231 sessile cells (MIC 5 0=0.5µg/mL and MIC 80 =1µg/mL) and against C. albicans 12-99 sessile cells (MIC 5 0=0.75µg/mL and MIC 80 =1.25µg/mL). AnC exerted haemolytic effect against human red blood cells at 15µg/mL and did not exerted genotoxic effect on Bacillus subtilis rec strains., Conclusions: The antifungal activity and lack of genotoxic effects of AnC give support to the traditional use of A. arvensis as antifungal and makes AnC a compound of interest to expand the available antifungal drugs., (Copyright © 2017 Elsevier Ireland Ltd. All rights reserved.)

Essential oils from aerial parts of Acantholippia deserticola, Artemisia proceriformis, Achillea micrantha and Libanotis buchtormensis were analysed by GC-MS. The major compounds identified were β-thujone (66.5 ± 0.2%), and trans-sabinyl acetate (12.1 ± 0.2%) in A. deserticola; α-thujone (66.9 ± 0.4%) in A. proceriformis; 1,8-cineole (26.9 ± 0.5%), and camphor (17.7 ± 0.3%) in A. micrantha and cis-β-ocimene (23.3 ± 0.3%), and trans-β-ocimene (18.4 ± 0.2%) in L. buchtormensis. The oils showed a weak antimicrobial effect (MIC100 > 1.5 mg/ml) on most phytopathogens tested. A moderate antimicrobial activity (MIC100 between 0.5 and 1.5 mg/ml) was displayed by the oils of A. deserticola, A. micrantha and L. buchtormensis on Septoria tritici and by the oil of A. deserticola on Septoria glycine. The antimicrobial activity was associated to the contents of β-thujone, trans-sabinyl acetate and trans-sabinol. Our results indicate that the tested essential oils have little inhibitory potency not suitable for use as plant protection products against the phytopathogens assayed.

The main secondary metabolite of Senecio nutans is 4-hydroxy-3-(3-methyl-2-butenyl)acetophenone (4HMBA). The antifungal activity of this compound and three derivatives was assessed using Candida albicans. 4HMBA exhibited the highest antifungal activity among the assayed compounds. The Fractional Inhibitory Concentration (FIC = 0.133) indicated a synergistic fungicidal effect of 4HMBA (5 mg L(-1)) and fluconazole (FLU) (0.5 mg L(-1)) against the C. albicans reference strain (ATCC 10231). Microscopy showed that 4HMBA inhibits filamentation and reduces cell wall thickness. Our findings suggest that 4HMBA is an interesting compound to diminish resistance to commercial fungistatic drugs such as fluconazole.

Six plant extracts prepared from Ligaria cuneifolia and Jodina rhombifolia were screened for their potential antimicrobial activities against phytopathogens and clinically standard reference bacterial strains. Bioautography and broth microdilution methods were used to study samples antibacterial activities against 7 bacterial strains. The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of samples were attained. An antibacterial activity guided isolation and identification of active compounds was carried out for L. cuneifolia methanolic extract (LCME). Both methanolic and aqueous extracts from L. cuneifolia showed inhibitory activities against phytopathogenic bacteria, with MICs ranging from 2.5 to 156 μg mL(-1) for LCME and 5 mg mL(-1) for the aqueous extract. None of the three J. rhombifolia extracts showed significant antibacterial activities against phytopathogenic strains (MIC > 5 mg mL(-1)), except for the aqueous extracts against Pseudomonas syringae (MIC = 312 μg mL(-1)). Only LCME showed bactericidal activities against phytopathogenic strains (MBCs = 78 μg mL(-1)). The LCME exhibited significant inhibitory activity against reference clinical strains: Escherichia coli (MIC = 156 μg mL(-1)) and Staphylococcus aureus (MIC = 78 μg mL(-1), MBC = 312 μg mL(-1)). LCME active compounds were identified as flavonol mono and diglycosides, and gallic acid. The antibacterial activity of purified compounds was also evaluated. A synergistic effect against S. aureus was found between gallic acid and a quercetin glycoside. Hence, anti-phytopathogenic bacteria potential compounds isolated from L. cuneifolia could be used as an effective source against bacterial diseases in plants., (Copyright © 2014 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.)

Infusion, tincture and decoction of leaves of Zuccagnia punctata Cav. were assayed on growth of Fusarium verticillioides, F. graminearum sensu stricto, F. boothii, F. meridionale, F. subglutinans and F. thapsinum. The tincture showed the lowest IC50 on mycelial growth. A diethyl ether fraction of the tincture showed the highest antifungal activity in microdilution assays on F. verticillioides and F. graminearum. The antifungal constituents were separated by silica gel chromatography and identified as 2',4'-dihydroxychalcone, 2',4'-dihydroxy-3'-methoxychalcone and 7-hydroxy-3',4'-dimethoxyflavone. These chalcones had the lowest MIC and MFC values on F. verticillioides and F. graminearum sensu stricto. 2',4'-Dihydroxychalcone was mildly toxic and the remaining identified compounds were non-toxic in the brine shrimp assay. 2',4'-Dihydroxychalcone in mixtures with commercial food preservatives showed additive effects on F. graminearum sensu stricto and synergistic ones on F. verticillioides. 2',4'-Dihydroxy-3'-methoxychalcone showed synergistic effects in mixtures. Our results suggest that addition of chalcones to food preservatives allows reduction in the doses of the preservatives required for control of Fusarium species.

The composition of the essential oils from leaves (Sal) and fruits of S. areira (Saf), and fruits of S. fasciculatus (Sff) and S. gracilipes (Sgf) were analyzed by GC/MS. The major compounds identified were sabinene (26.0 +/- 0.5%), bicyclogermacrene (14.5 +/- 0.4%), and E-citral (6.7+/- 0.2%) in Sal oil, limonene (27.7 +/- 0.7%), sabinene (16.0+/- 0.5%), beta-phellandrene (14.6 +/- 0.8%) and bicyclogermacrene (8.1 +/- 0.2%) in Saf oil, sabinene (22.7 +/- 0.6%), alpha-phellandrene (18.7 +/- 0.3%), beta-phellandrene (15.7 +/- 0.4%), and bicyclogermacrene (8.1 +/- 0.2%) in Sff oil and beta-pinene (25.4 +/- 0.8%), alpha-pinene (24.7 +/- 0.7%), and sabinene (13.6 +/- 0.4%) in Sgf oil.The antifungal activity of the four oils was evaluated on strains of Fusarium verticillioides and F. graminearum, and the results compared with the effect of epoxyconazole, pyraclostrobin and thyme oil. The Sff oil had the highest antifungal activity among the Schinus oils tested, with MIC100 (F. graminearum) = 6 per thousand and MIC100 (F. verticillioides) = 12 per thousand. A principal component analysis suggests that 9 constituents (alpha-thujene, alpha-terpinene, p-cymene, gamma-terpinene, terpinolene, 1-terpineol, alpha-calacorene, alpha-phellandrene, and terpinen-4-ol) explain the higher antifungal effect of Sff. The MIC100s of Schinus oils were on average 30-60 and 8.5-17 fold lower than those obtained for thyme oil on F. verticillioides and F. graminearum, respectively. In the case of commercial fungicides, their MIC100s were three orders of magnitude lower than those of Schinus oils. The last ones showed an additive interaction when assayed in mixtures with the commecial fungicides and thyme oil. The results suggest that the doses of fungicides required for control of the Fusarium species can be reduced when they are assayed in mixtures with the Schinus oils.

Aims: The purpose of this research was to identify antifungal compounds from leaves of Schinus and Schinopsis species useful for the control of toxigenic Fusarium species responsible of ear rot diseases., Methods and Results: Leaves of Schinopsis (S. lorentzii and S. haenkeana) and Schinus (S. areira, S. gracilipes and S. fasciculatus) were sequentially extracted with dichloromethane, ethyl acetate and methanol. The antifungal activity of the fraction soluble in methanol of these extracts (fCH2Cl2, fAcEt and fMeOH, respectively) was determined by the broth microdilution method and the disc-diffusion method. The minimum inhibitory dose (MID), the diameter of growth inhibition (DGI) and the minimum concentration for 50% inhibition of fungal growth (MIC50) were calculated. The fCH2Cl2 and fAcEt of the Schinopsis species had the lowest MID and MIC50 values and the highest DGI. The antifungal compounds were identified as lupeol and a mix of phenolic lipids. The last one had the highest antifungal activity with MIC50 31-28 μg g(-1) and 165-150 μg g(-1) on Fusarium graminearum and Fusarium verticillioides, respectively. The identified metabolites completely inhibited fumonisin and deoxynivalenol production at lower concentrations than ferulic acid, a natural antimycotoxigenic compound., Conclusions: It was proven that lupeol and phenolic lipids were inhibitors of both fungal growth and mycotoxin production of toxigenic Fusarium species. This fact is specially interesting in the control of the toxigenic Fusarium species because several commercial antifungals showed to stimulate mycotoxin biosynthesis at sublethal concentrations., Significance and Impact of the Study: Control of toxigenic Fusarium species requires compounds able to inhibit both fungal growth and mycotoxin production. Our results suggest that the use of lupeol as food preservative and the phenolic lipids as fungal growth inhibitors of F. verticillioides and F. graminearum did not imply an increase in mycotoxin accumulation., (© 2014 The Society for Applied Microbiology.)

A 96-well plate micromethod was developed to measure 5-n-alkylresorcinols (5nARs) in cereal grains and food derived products. The 5nARs reacted in alkaline alcoholic medium with Fast Blue RR ½ZnCl2 salt to yield coloured azo-derivatives. The highest sensitivity for 5nARs was obtained at 490 nm with 0.025% ethanolic Fast Blue RR and 5% K2CO3. This reaction showed good linearity for olivetol (0.05-0.20 μg). Contents of 5nARs determined in cereal grains and derived products by the new Fast Blue RR micromethod were highly correlated (R(2)=0.9944) with those obtained by a Fast Blue B method currently used. A Bland-Altman analysis indicated a small positive bias near to zero (R(2)=0.0401), suggesting that the methods can be interchangeably used. The new reaction is completed in 15 min and the coloured products are read within the 15 min after completion. The micromethod offers a fast analysis of 5nARs in cereal grains and derived products with low consumption of reagents and solvents., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

Twenty six isolates of Fusarium graminearum from grains of maize hybrids harvested in ±west Argentina were grown on autoclaved rice grain to assess their ability to produce type B trichothecenes. Chemical analysis indicated that 38% of isolates were nivalenol (NIV) producers only, 31% were major NIV producers with high DON(deoxynivalenol)/NIV ratios, 8% were major DON producers with minor NIV production, and 23% were DON producers only. Isolates showed a high variability in their toxigenic potential which was not related to fungal biomass. The distribution of the different chemotypes as well as the high and the low trichothecene-producing Fusarium isolates could not be associated to a geographical origin. Our results confirmed for the first time that isolates of Fusarium graminearum from maize of northwest Argentina are able to produce DON and NIV. A substancial contamination with both NIV and DON is likely in maize from northwest Argentina. Their contents should be quantified in regional surveillances for mycotoxin contamination.

Ethnopharmacological Relevance: Caesalpinia paraguariensis (D. Parodi) Burkart stem bark infusion (CPBI) is traditionally used in Argentina because their "vulnerary" properties., Aim of the Study: CPBI was studied throughout bio-guided purification procedures conducted by in vitro biological assays in order to isolate the main bioactive compounds., Material and Methods: Anti-inflammatory activity was assessed by enzyme inhibition assays of Hyaluronidase (Hyal) and inducible Nitric Oxide Synthase (iNOS). The antioxidant properties were evaluated by DPPH free radical scavenging assay, lipid peroxidation inhibition assay on erythrocyte membranes, and a cell-based assay that included the fluorescent probe (DCFH-DA) for indicating reactive oxygen species (ROS) generation. Bioactive compounds were purified by chromatographic methods and their structures elucidated using spectroscopic methods (ESI-MS and 1D/2D-(1)H/(13)C-NMR)., Results: Four main bioactive compounds were isolated from CPBI: ellagic acid (1), 3-O-methylellagic acid (2), 3,3'-di-O-methylellagic acid (3) and 3,3'-di-O-methylellagic-4-β-D-xylopyranoside (4). These were bioactive at concentrations in which are present in CPBI, being compounds 2 and 3 the best enzyme inhibitors of Hyal and iNOS, reaching the 90% inhibitory concentration (IC90) values ranging from 2.8 to 16.4 μM, that are better than that of the positive controls, aspirin (IC90: no reached) and aminoguanidine (IC90: 20.2 μM) respectively. Compounds 2 and 3 were also better scavengers for lipoperoxides than butylated hydroxytoluene (BHT), reaching the 90% effective concentration (EC90) at 1.2-4.5 μg/ml, and for DPPH radical (2.5-7.3 μg/ml); moreover compounds were able to exert its scavenging action on intracellular ROS. Structural features relevant to the biological activities are discussed., Conclusions: This work provides scientific validity to the popular usage of CPBI., (Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.)

Members of the Fusarium graminearum species complex (Fg complex) cause Gibberella ear rot in maize from northwest Argentina. The potential of these pathogens to contaminate maize grains with type B trichothecenes is a health risk for both humans and animals. We evaluated the reliability of multiplex PCR assays based on TRI3 and TRI12 genes, and single PCR assays based on TRI7 and TRI13 genes to infer trichothecene chemotypes of 112 strains of Fg complex collected from northwest Argentina, checking trichothecene production by chemical analysis. Single and multiplex PCR assays indicated that strains belonging to F. meridionale (87/112) had a NIV genotype. The remainder strains (25/112), which belonged to F. boothii, had a DON genotype (based on single PCR assays) or 15ADON genotype (based on multiplex PCR assays). No strains tested were incorrectly diagnosed with a DON/NIV genotype. Chemical analysis indicated that the F. meridionale strains were NIV producers only (44/87), major NIV producers with unexpected high DON/NIV ratios (36/87), or unexpected major DON producers with minor NIV production (7/87). Strains with atypical DON/NIV production seem to be new phenotypes under a putative NIV genotype, since PCR assays do not provide evidences of a new trichothecene genotype. DON production and absence of its acetylated forms were shown for strains of F. boothii. The inconsistencies between genetic and chemical data highlight the risk of inferring the trichothecenes potentially contaminating food and feedstuffs based only on PCR assays. This study confirms for the first time that strains of Fg complex from maize of northwest Argentina are DON and NIV producers. In addition, dominance of NIV producers in the Fg complex population isolated from maize is unprecedented in Argentina, and of significant concern to food safety and animal production., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Members of the Fusarium graminearum species complex (Fg complex) are the causal agents of ear rot in maize and Fusarium head blight of wheat and other small grain cereals. The potential of these pathogens to contaminate cereals with trichothecene mycotoxins is a health risk for both humans and animals. A survey of ear rot isolates from maize collected in northwest Argentina recovered 66 isolates belonging to the Fg complex. A multilocus genotyping (MLGT) assay for determination of Fg complex species and trichothecene chemotypes was used to identify 56 of these isolates as F. meridionale and 10 isolates as F. boothii. F. meridionale was fixed for the nivalenol (NIV) chemotype, and all of the F. boothii isolates had the 15-acetyldeoxynivalenol (15ADON) chemotype. The results of genetic diversity analysis based on nine variable number tandem repeat (VNTR) loci supported the hypothesis of genetic isolation between F. meridionale and F. boothii, and provided little evidence of geographic substructure among populations of the dominant pathogen species, F. meridionale. This is the first study to indicate that F. meridionale and F. boothii may play a substantial role in the infection and trichothecene contamination of maize in Argentina. In addition, dominance of the NIV chemotype among Fg complex isolates from Argentina is unprecedented, and of significant concern to food safety and animal production., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Ethnopharmacological Relevance: Leaf extracts from Tripodanthus acutifolius (Ruiz and Pavón) Van Tieghem have long been used in Argentinean traditional medicine as anti-inflammatory, however, there is no scientific evidence which supports this use in the literature., Aim of the Study: The present study was conducted to evaluate the ability of five phenolic compounds purified from infusion prepared from Tripodanthus acutifolius leaves to inhibit key enzymes in inflammatory processes. As anti-inflammatory compounds frequently possess free radical scavenging activities, purified substances were comparatively evaluated to asses their free radical scavenging properties. Genotoxic effects were also evaluated., Materials and Methods: Compounds were evaluated on their ability to inhibit hyaluronidase and cyclooxygenase-2 (COX-2) activities to assess their anti-inflammatory capacities. Free radical scavenging activity was assessed by: 1,1-diphenyl-2-picryl-hydrazyl radical (DPPH), superoxide anion assay and the inhibition on lipid peroxidation. Genotoxicity was evaluated by Bacillus subtilis rec assay., Results: Fractionation of Tripodanthus acutifolius infusion yielded a novel phenylbutanoid derivative (tripodantoside) and four known flavonoid glycosides (rutin, nicotiflorin, hyperoside and isoquercitrin). Flavonoids produced higher inhibition on hyluronidase activity (IC(50) approximately 1.7 mM) than tripodantoside (IC(50)=27.90 mM). A similar COX-2 inhibition activity was exerted by tripodantoside and monoglycosilated flavonoids (IC(50) approximately 50 microM). Compounds were strong radical scavengers, with effective concentration 50 (EC(50)) values for DPPH in the range of 2.7-6.3 microg/mL, and for superoxide anion in the range of 3.9-8.7 microg/mL. All compounds scavenged peroxyl radicals in the lipid peroxidation assay. The substances showed no genotoxic effects., Conclusions: The anti-inflammatory effects, free radical scavenging activities and lack of genotoxicity of purified compounds may support the folk use of infusion from Tripodanthus acutifolius leaves as anti-inflammatory., (Copyright 2010 Elsevier Ireland Ltd. All rights reserved.)

Aims: To perform an activity-guided purification, identification and quantification of antibacterial compounds from Tripodanthus acutifolius infusion. To validate the antibacterial activity of purified substances., Methods and Results: Bioautographic methods were employed as screening assays for purifying bioactive substances. Purification procedures included sephadex LH-20 column chromatography and reverse phase HPLC. Identification was achieved by spectroscopic methods (UV-Vis, MS, NMR and polarimetry) and chromatographic assays (paper chromatography and HPLC). Antibacterial activity was studied by microdilution, colony count and photometric assays, Sytox green stain and transmission electron microscopy (TEM). Four glycoflavonoids (rutin, nicotiflorin, hyperoside and isoquercitrin) and an unusual phenylbutanoid glycoside (tripodantoside) were purified and identified. Tripodantoside was found at 6.59 +/- 0.82 g per 100 g of dry leaves. The flavonoids showed bactericidal effect at a concentration of 4 mg ml(-1) against Staphylococcus aureus and Pseudomonas aeruginosa strains from American Type Culture Collection, while tripodantoside was almost four times more active than those compounds, with a minimum bactericidal concentration = 1.024 mg ml(-1) against these strains. Tripodantoside aglycone showed bacteriolytic effects on the assayed strains, causing evident damages on cell wall and membrane, while tripodantoside did not exhibit those effects., Conclusions: The antibacterial activity of T. acutifolius infusion would be partially attributed to the purified glycoflavonoids and mainly to tripodantoside., Significance and Impact: The high extraction yield and the antibacterial activity exhibited by tripodantoside makes this chemical structure of interest to support further studies dealing with chemical modifications to increase the antibacterial activity or to seek another activities.

Fusarium species are worldwide causal agents of ear rot in cereals. Their toxigenic potential is a health risk for both humans and animals. In Argentina, most identification of these fungi has been based on morphological and cross-fertility criteria which are time consuming and require considerable expertise in Fusarium taxonomy and physiology. DNA based approaches have been reported as rapid, sensitive and specific alternatives to identify the main fumonisin and trichothecene-producing Fusarium species. In this work, we used PCR assays and the partial sequence of TEF1-alpha gene (Translation Elongation Factor-1 alpha) to identify the fumonisin and trichothecene-producing species in Fusarium isolates from diverse regions of Argentina. The relative efficiency and reliability of those methods to improve mycotoxin risk prediction in this country were also assessed. Species-specific PCR assays were targeted toward multicopy IGS (Intergenic Spacer of rDNA units) and on the toxin biosynthetic genes FUM1 (fumonisins) and TRI13 and TRI7 genes (trichothecenes). PCR assays based on FUM1 gene and IGS sequences allowed detection and discrimination of the fumonisin producers Fusarium proliferatum and Fusarium verticillioides. Molecular identification of nonfumonisin producers from Gibberella fujikuroi species complex was possible after determination of TEF1-alplha gene sequences, which indicated the presence of Fusarium subglutinans, Fusarium andiyazi and Fusarium thapsinum. TEF-1 alpha gene sequences also allowed discrimination of the different species of the Fusarium graminearum complex (F. graminearum sensu lato) as F. graminearum sensu stricto, Fusarium meridionale and Fusarium boothii. The last two species belonged to NIV chemotype and were detected for the first time in the subtropical region of Argentina while F. graminearum sensu stricto was DON producer only, which was also confirmed by specific PCR assays based on TRI137/TRI7 genes. Our results indicated that the PCR assays evaluated in this work are reliable diagnostic tools to detect the main toxigenic Fusarium species associated to cereal grains in Argentina. An extensive epidemiological survey based on the approach presented in this work is currently in progress to know the mycotoxigenic hazard of Fusarium species in cereal grains from the subtropical region of Argentina., (Copyright © 2009 The British Mycological Society. Published by Elsevier Ltd. All rights reserved.)

The present work describes the purification and characterization of a novel extracellular polygalacturonase, PGase I, produced by Pycnoporus sanguineus when grown on citrus fruit pectin. This substrate gave enhanced enzyme production as compared to sucrose and lactose. PGase I is an exocellular enzyme releasing galacturonic acid as its principal hydrolysis product as determined by TLC and orcinol-sulphuric acid staining. Its capacity to hydrolyze digalacturonate identified PGase I as an exo-polygalacturonase. SDS-PAGE showed that PGase I is an N-glycosidated monomer. The enzyme has a molecular mass of 42kDa, optimum pH 4.8 and stability between pH 3.8 and 8.0. A temperature optimum was observed at 50-60 degrees C, with some enzyme activity retained up to 80 degrees C. Its activation energy was 5.352calmol(-1). PGase I showed a higher affinity towards PGA than citric pectin (Km=0.55+/-0.02 and 0.72+/-0.02mgml(-1), respectively). Consequently, PGase I is an exo-PGase, EC 3.2.1.82.

The antifungal activity of the ethanolic extract (EE), (3R)-5,7,2',3'-tetrahydroxy-4'-methoxy-5'-prenylisoflavanone (1) and (3R)-7-2'-3'-trihydroxy-4'-methoxy-5'-prenylisoflavanone (2) isolated from Geoffroea decorticans was evaluated against four different species of Aspergillus. Their effect was compared with that displayed by synthetic products. The antifungal activity was assayed by bioautography, hyphal radial growth, hyphal extent and microdilution in liquid medium. The percentage of hyphal radial growth inhibition produced by EE varied between 18.4+/-0.1 and 39.6+/-0.2 for Aspergillus nomius VSC23 and Aspergillus nomius 13137, respectively; and the same value for 1 and 2 were between 31.2+/-0.1-60.8+/-1.5 and 28.9+/-0.7-57.2+/-0.6 for Aspergillus flavus (IEV 018) and Aspergillus nomius 13137, respectively. The values of MIC/MFC determined for EE, 1 and 2 were compared with the actions of ascorbic and sorbic acids, and clotrimazole. The sequence of antifungal potency was clotrimazole>1>2>ascorbic acid>sorbic acid>EE. Consequently, EE as well as the purified substances from Geoffroea decorticans would be used as biopesticides against Aspergillus species. The cytotoxicity was evaluated.

Aims: To determine the antibacterial and cytotoxic activities of aqueous and ethanolic extracts of northwestern Argentinian plants used in folk medicine. To compare the mentioned activities with those of five commercial antibiotics. To identify the compounds responsible for the antibacterial activity., Methods and Results: Plant extracts were prepared according to traditional uses in northwestern Argentina. Antibacterial activity was assayed by agar dilution in Petri dishes and broth dilution in 96-well plates. Lethal dose 50 (LD(50)) was determined by the Artemia salina assay. Phytochemical analysis was performed by sample adsorption on silica gel, thin-layer chromatography (TLC), bioautography and UV-visible spectra. The results showed that Tripodanthus acutifolius aqueous extracts have lower minimal inhibitory concentrations (MIC) (502 and 506 microg of extracted material (EM) per ml for infusion and decoction, respectively) than cefotaxim MIC (640 microg ml(-1)) against Acinetobacterfreundii (303). These data were lower than their LD(50). Tripodanthus acutifolius tincture showed lower MIC (110 microg of EM per ml) and minimal bactericidal concentration (MBC) (220 microg of EM per ml) than cefotaxim (MIC and MBC of 320 microg ml(-1)) for Pseudomonasaeruginosa. This extract also showed a MIC/MBC of 110/220 microg of EM per ml, lower than oxacillin (MIC/MBC of 160/220 microg ml(-1)) for Staphylococcus aureus (ATCC 25923). The cytotoxicity of all extracts were compared with that of commercial antibiotics. Rutin (3,3',4',5,7-pentahydroxyflavone 3-beta-rhamnosilglucoside), iso-quercitrin (3,3',4',5,7-pentahydroxyflavone 3-beta-glucoside) and a terpene would be partially responsible for the antibacterial activity of T. acutifolius infusion., Conclusions: Tripodanthus acutifolius extracts had the ability to inhibit bacterial growth. The antibacterial activity differs with the applied extractive method, and it could be partially attributed to glycoflavonoids. This paper contributes to the knowledge of antibacterial capacity of plants from northwestern Argentina., Significance and Impact of the Study: These antibacterial activities support further studies to discover new chemical structures that can contribute to alleviate or cure some illnesses.

Several compounds related with plant defense and pharmacological activities have been isolated from sugarcane. Straw phytotoxins and their possible mechanisms of growth inhibition are largely unknown. A bioassay-guided fractionation of the phytotoxic constituents leachated from a sugarcane straw led to the isolation of trans-ferulic (trans-FA), cis-ferulic (cis-FA), vanillic (VA) and syringic (SA) acids. The straw leachates and their identified constituents significantly inhibited root growth of lettuce and four weeds. VA was more phytotoxic to root elongation than FA and SA. The identified phenolic compounds significantly increased leakage of root cell constituents, inhibited dehydrogenase activity and reduced chlorophyll content in lettuce. VA and FA inhibited mitotic index while SA increased cell division. Additive (VA-FA and FA-SA) and synergistic (VA-SA) interactions on root growth were observed at the response level of EC(25). Although the isolated compounds differed in their relative phytotoxic activities, the observed physiological responses suggest that they have a common mode of action. HPLC analysis indicated that sugarcane straw can potentially release 1.43 (ratio 2:1, trans:cis), 1.14 and 0.14mmolkg(-1) (straw dry weight) of FA, VA and SA, respectively. As phenolic acids are often found spatially concentrated in the top soil layers under plant straws, further studies are needed to establish the impact of these compounds in natural settings.

Aims: To determine the antimycotic and cytotoxic activities of partially purified propolis extract on yeasts, xylophagous and phytopathogenic fungi. To compare these activities with pinocembrin and galangin isolated from this propolis and with the synthetic drugs ketoconazole and clortrimazole., Methods and Results: Ethanolic propolis extract was partially purified by cooling at -20 degrees C. Two of its components were isolated by HPLC and identified as pinocembrin and galangin. The antifungal activity was assayed by bioautography, hyphal radial growth, hyphal extent and microdilution in liquid medium. Cytotoxicity was studied with the lethality assay of Artemia salina. The obtained results were compared with the actions of ketoconazole and clortrimazole. The results showed that the antifungal potency of ketoconazole and clortrimazole is higher than pinocembrin, galangin and the partially purified propolis extract in this order. Otherwise, the cytotoxicity of the synthetic drugs is also the highest., Conclusions: Partially purified propolis extract inhibits fungal growth. The comparison of its relative biocide potency and cytotoxicity with synthetic drugs and two components of this propolis (pinocembrin and galangin) showed that the propolis from 'El Siambón', Tucumán, Argentina, is a suitable source of antifungal products., Significance and Impact of the Study: The partially purified propolis extract and its isolated compounds, pinocembrin and galangin, have the capacity of being used as antifungals without detriment to the equilibrium of agroecosystems. The impact of this study is that the preparation of agrochemicals with reduced economic costs using a partially purified preparation as the active principle is possible.