Search

Strychnos peckii (Loganiaceae) is an important active ingredient in curare poisons in the Amazon rainforest. Although previous studies have identified this species as a promising source of monoterpene indole alkaloids (MIAs), knowledge about other natural products is still scarce. Thus, to detect and guide the isolation of unprecedented bioactive compounds from the leaves of S. peckii, an untargeted high-performance liquid chromatography coupled with mass spectrometry (HPLC-MS) analysis was performed with the leaf aqueous extract. The HPLCMS analysis allowed the detection of eleven compounds, including the alkaloids harman-3-carboxylic acid (5) and N,ß-glucopyranosyl vincosamide (6), and the flavonoids quercetin 3-O-rhamnopyranoside (9) and kaempferol 3-Orhamnopyranoside (10), all not previously reported in the Loganiaceae family. These compounds, along with strictosidine (3), 5-carboxystrictosidine (7), and desoxycordifoline (8) were isolated through modern chromatographic techniques and determined by using NMR spectroscopy in combination with MS. Overall, the untargeted HPLC-MS analysis proved to be a simple and effective approach to guide the isolation of substances not yet identified from S. peckii. [ABSTRACT FROM AUTHOR]

The essential oil (EO) from the leaves of Onychopetalum periquino, obtained by hydrodistillation, was analyzed by gas chromatography coupled with mass spectrometry (GC-MS), and also was investigated for its larvicidal activity against Aedes aegypti larvae. Thirteen compounds, representing 91.31% of the crude oil, were identified. Major compounds were sesquiterpenes, including β-elemene (53.16%), spathulenol (11.94%) and β-selinene (9.25%). The EO showed high larvicidal activity with a lethal concentration (LC50) of 63.75 μg/mL and 100% mortality at 200 μg/mL. These results represent the first report about the chemical composition of O. periquino and the first larvicidal evaluation with Onychopetalum species. [ABSTRACT FROM AUTHOR]

Abstract: Bacuri, ingá, and uchi are Amazon fruits consumed specially in the North region of Brazil. Due to their large consumption and the lack of knowledge regarding its chemical composition, these fruits were studied in relation to their Antioxidant chemical constitution. The total phenolic content ranged from 3.86 ± 0.47 to 33.38 ± 1.51 mg GAE/100 g, and the total flavonoid content ranged from 1.75 ± 0.22 to 19.44 ± 0.87 mg QUERE/100 g, where the contents showed a significant correlation with DPPH and ABTS antioxidant assays. Thus, UHPLC‐MS/MS was applied do quantify selected compounds, been citric acid the most abundant for all fruits. Furthermore, samples were screened for their α‐glycosidase and lipase inhibitory effects, in addition to their antimicrobial potentials. Bacuri showed the highest antioxidant and α‐glycosidase inhibitory capacity (IC50 15.20 μg/mL), whereas uchi and its main metabolite bergenin displayed moderate antimicrobial activities. The results shed light into the potentials of Amazonian fruit sources. Practical applications: Plant phenolics are essential components of functional foods, due to their antioxidant and enzyme inhibition activities, which are directly linked to several diseases prevention. This is the first study about the quantification of antioxidant compounds in the Amazonian fruits: bacuri, ingá, and uchi. Although they are quite consumed in the North region of Brazil, there are no bio‐products made from them. This study aimed to elucidate the knowledge about the chemical composition and potentialities within these fruits with the practical purpose of highlighting them to future commercial applications. In addition, once we indicate their capabilities, we contribute with local populations in respect to the production of such fruits, which still is a family activity. [ABSTRACT FROM AUTHOR]

(+)- N-formylnorglaucine ( 1), an aporphine alkaloid containing a formyl group linked to the heterocyclic nitrogen, was isolated from the leaves of Unonopsis stipitata, an Amazon medicinal plant. The chemical structure was characterized based on 1D- and 2D- NMR spectroscopy and HR-ESI-MS. NMR spectra revealed that 1 is composed of two rotamers ( 1a and 1b) in a ratio of approximately 2:1. In addition, the fragmentation behavior of 1 displayed an unusual fragmentation pattern compared to regular aporphine alkaloids. Thus, this compound is reported for the first time as a natural product in this study. [ABSTRACT FROM AUTHOR]

Introduction The Annonaceae family is known as a promising abundant source of secondary metabolites, especially annonaceous acetogenins, terpenoids and isoquinoline-derived alkaloids. Although widely investigated from the phytochemical viewpoint, this family still presents some largely unexplored genera, e.g. the Bocageopsis. Objective To investigate the alkaloid content of Bocageopsis pleiosperma Maas using direct infusion electrospray ionisation ion trap tandem mass spectrometry (ESI-IT-MS n) analysis. Methodology Dichloromethane extracts of aerial parts were subjected to acid-base partitioning to yield the alkaloidal fractions. These fractions were analysed by direct infusion into a (+)ESI-IT-MS n system. The alkaloidal fraction from the leaves was also obtained on a large scale and subjected to chromatographic separation. Results The tentative MS n-based identification of alkaloids in leaves, twigs and trunk bark showed that aporphine alkaloids were restricted to the leaves and twigs, tetrahydroprotoberberine alkaloids were only found in the twigs and trunk bark while benzylisoquinoline alkaloids were found in the leaves, twigs and trunk bark. Chromatographic separation of the leaf alkaloidal fraction yielded the aporphine alkaloids nornuciferine, asimilobine and isoboldine, the β-carboline alkaloid tetrahydroharman and some mixtures containing benzylisoquinoline and aporphine alkaloids, all described for the first time in the Bocageopsis genus. Furthermore, tetrahydroharman has not previously been reported in the Magnoliales order. Conclusion Direct infusion ESI-IT-MS n analysis of alkaloids allowed fast recognition of alkaloidal classes previously reported in the Annonaceae family, aiding the chromatographic step and allowing a selective isolation of compounds previously not identified in the Bocageopsis genus. Copyright © 2015 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

ABSTRACT Introduction The Unonopsis genus is a promising source of aporphinoid alkaloids, substances with great biological potential. These alkaloids have a well-defined mass spectrometry fragmentation pattern that, together with previous phytochemical knowledge, can guide the isolation of alkaloids not yet described for the genus. Objective Isolate substances not yet described in the Unonopsis genus, guided by alkaloidal profile analyses of stem barks, twigs and leaves of Unonopsis duckei using electrospray ionisation ion-trap tandem mass spectrometry (ESI-IT/MS n). Methods Methanolic extracts from stem barks, twigs and leaves were submitted to a liquid-liquid, acid-base partitioning treatment to obtain the alkaloidal fractions. These fractions were analysed by direct infusion into an ESI-IT/MS n system. The major alkaloids observed for each fraction were submitted to fragmentation analysis. Results The MS fragmentation patterns revealed the presence of alkaloids previously reported for Annonaceae, including nornuciferine, anonaine, asimilobine, liriodenine and lysicamine, known for the Unonopsis genus, as well as others that were not yet described for this genus. In this way, the proaporphine alkaloid glaziovine was isolated, as well as a mixture of the aporphine alkaloids glaucine and norglaucine, all described for the first time in the Unonopsis genus. Conclusion Mass spectrometry monitoring was fundamental to prioritise the isolation of substances not yet identified for the Unonopsis genus, dismissing known compounds and simplifying the phytochemical study. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

Twelve Unonopsis specimens, comprising five species commonly found at Amazonas state (Brazil) were collected in three different sites. The leaves of the specimens were extracted by hydrodistillation and analyzed by gas chromatography coupled to mass spectrometry (GC-MS). The data treated by chemometric analysis with the objective of verify the potential of their chemical profiles for chemotaxonomic approaches. Despite the essential oils presented spathulenol and caryophyllene oxide as a main constituent in most samples, the multivariate analysis showed significant differences between the species and their collection sites. The obtained results suggest high chemical similarity between U. floribunda and U. rufescens species and proved that U. guatterioides has a distinct chemistry when compared to the analyzed species. The chemical identification points to α-guaiene, α-calacorene and widdrol as possible chemical markers for U. floribunda and U. rufescens species. [ABSTRACT FROM AUTHOR]

Fruits are widely recognized as sources of biologically active metabolites, such as antioxidant compounds. In this context, fruits commonly consumed in the central Amazonia, especially in its biggest metropolis (Manaus - AM/Brazil), are attractive as potential sources of antioxidant compounds related to biological activities. Most of such fruits are still poorly studied and/or remain unknown outside the Amazon region. Therefore, this study aims to investigate nine fruits (abiu, cubiu, biribá, breadfruit, genipap, peach palm, murici, soursop, and umari) regarding their chemical composition (fixed and volatile), reducing capacity, antioxidant activity, enzyme inhibition, and cytotoxicity. Determination of small organic acids, hydroxycinnamic acids, flavan-3-ols and flavonoid aglycones was done by HPLC-MS/MS, whereas determination of volatile organic compounds (VOCs) was done by HS-SPME/GC-MS. Reducing capacity was determined by the Folin-Ciocalteu method, and antioxidant activities were evaluated by DPPH, ABTS, and H-ORAC FL assays. In vitro activities regarding inhibition of enzymes were tested for α-glucosidase, lipase, and α-amylase, and anti-glycation activities were evaluated for methylglyoxal and fructose. Cytotoxicity of fruit extracts was evaluated by cell viability of human fibroblast cell line (MRC-5). A total of 16 antioxidant compounds and 139 VOCs were determined, whose profiles were unique for each studied fruit. Total phenolic contents as well as antioxidant activities found herein were similar or even higher than those reported for several traditional fruits. Some of fruit extracts were able to inhibit α-glucosidase and glycation in methylglyoxal and fructose models, whereas none of them was active for lipase and α-amylase. All of the fruit extracts showed to be non-cytotoxic to MRC-5 cell line., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Rationale: Monoterpene indole alkaloids (MIAs) are a large group of biologically active compounds produced by hundreds of plant species in numerous plant families, such as Apocynaceae, Loganiaceae and Rubiaceae. Although this diversity is biosynthetically intermediated by strictosidine, there are no works focused on the fragmentation patterns under collision-induced dissociation of strictosidine-derived alkaloids., Methods: Initially, the alkaloid fingerprint of Strychnos peckii was established using leaf spray with tandem mass spectrometry (LS-MS/MS). Then, high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC/MS/MS) analyses were carried out to focus on the patterns of neutral losses in product ion scan experiments with the leaf aqueous extract. Finally, the product ion spectra from a set of presumable strictosidine-type derivatives were analyzed and organized via molecular networking (MN), and dereplicated by manual interpretation of MS/MS spectra., Results: LS-MS/MS allowed the tentative identification of strictosidine-derived alkaloids in the leaves of S. peckii, showing useful neutral losses for the dereplication of strictosidine analogues by HPLC/MS/MS experiments. The use of MN combined with manual interpretation of the fragmentation patterns highlighted characteristic fragmentation pathways, and allowed the tentative identification of strictosidine, desoxycordifoline, strictosidinic acid, 10-hydroxystrictosidine, 5-carboxystrictosidine, lyaloside, 3,4-dehydrostrictosidine and strictosidine lactam., Conclusions: The use of MN combined with the analysis of the fragmentation patterns proved to be a useful strategy for the dereplication of strictosidine-derived MIAs from S. peckii, highlighting known and unprecedented structures, as well as useful diagnostic product ions. Therefore, this workflow is an effective approach for the characterization of strictosidine-type alkaloids in future dereplication works., (© 2019 John Wiley & Sons, Ltd.)

Essential oils from the leaves, twigs and barks of Bocageopsis pleiosperma Maas were obtained by using hydrodistillation and analysed by using gas chromatography coupled to mass spectrometry. Several compounds (51) were detected and identified, being β-bisabolene the main component in all aerial parts of the plant, with higher concentration in the leaves (55.77%), followed by barks (38.53%) and twigs (34.37%). In order to increase the biological knowledge about the essential oil of Bocageopsis species, antimicrobial activities were evaluated against the microorganisms Escherichia coli, Staphylococcus epidermidis, Enterobacter aerogenes, Candida tropicalis, Candida dubliniensis, Candida glabrata and Candida albicans. The essential oil obtained from the barks exhibited a moderate effect against S. epidermidis ATCC 1228 (MIC = 250 μg/mL), while the other oils did not exhibit antimicrobial activity. These results represent the first report about the chemical composition of B. pleiosperma and the first antimicrobial evaluation with a Bocageopsis species.

Introduction: The Unonopsis genus is a promising source of aporphinoid alkaloids, substances with great biological potential. These alkaloids have a well-defined mass spectrometry fragmentation pattern that, together with previous phytochemical knowledge, can guide the isolation of alkaloids not yet described for the genus., Objective: Isolate substances not yet described in the Unonopsis genus, guided by alkaloidal profile analyses of stem barks, twigs and leaves of Unonopsis duckei using electrospray ionisation ion-trap tandem mass spectrometry (ESI-IT/MS(n) )., Methods: Methanolic extracts from stem barks, twigs and leaves were submitted to a liquid-liquid, acid-base partitioning treatment to obtain the alkaloidal fractions. These fractions were analysed by direct infusion into an ESI-IT/MS(n) system. The major alkaloids observed for each fraction were submitted to fragmentation analysis., Results: The MS fragmentation patterns revealed the presence of alkaloids previously reported for Annonaceae, including nornuciferine, anonaine, asimilobine, liriodenine and lysicamine, known for the Unonopsis genus, as well as others that were not yet described for this genus. In this way, the proaporphine alkaloid glaziovine was isolated, as well as a mixture of the aporphine alkaloids glaucine and norglaucine, all described for the first time in the Unonopsis genus., Conclusion: Mass spectrometry monitoring was fundamental to prioritise the isolation of substances not yet identified for the Unonopsis genus, dismissing known compounds and simplifying the phytochemical study., (Copyright © 2013 John Wiley & Sons, Ltd.)

A new dammarane triterpene named mauritic acid (1) was isolated from the roots of Mauritia flexuosa L.f. The complete structural assignment of this new compound was elucidated from spectroscopic methods. Moreover, this compound was evaluated for its cytotoxicity against human cancer cell lines (OVCAR-8, PCM3, NCIH358M and different leukaemia cell strains). The mauritic acid presented significant cytotoxicity against OVCAR-8, PCM3 and NCIH358M cell lines with IC50 3.02, 2.39 and 6.19 μM, respectively. The triterpenes 1 and 2 were also tested for their antimicrobial activity against 15 strains of microorganisms, including fungi and bacteria, with the best minimal inhibitory concentration values ranging from 50.8 to 203.5 μM.

Many isolated compounds from endophytic fungus have been useful to human beings, mainly those with medicinal applications and particularly those that can be used in inflammatory processes. Trichoderma fungi produce substances known as koninginins that have great structural similarity to compounds like flavonoids and vitamin E, which are able to inhibit the phospholipase A(2) (PLA(2)). In this work, koninginins A, E and F (KonA, KonE and KonF, respectivamente) isolated from Trichoderma koningii had their capabilities of inhibiting edema-inducing, myotoxic and enzymatic activities of the total venom of Bothrops jararacussu (jararacuçu) snake analyzed, as well as one of its homolog forms of phospholipases A(2) (bjPLA(2)-group IIB) and human secreted PLA(2) protein fusion (hsPLA(2)-group IIA). KonA was not efficient in inhibiting the three activities analyzed in all the tests performed. Nevertheless, KonE and KonF present great capability in inhibiting the effects provoked not only by the venom but also by both PLA(2). The activities inhibition shown by KonE and KonF over the enzymes is significantly higher than those obtained over the total venom. KonE and KonF were slightly more efficient in the inhibition of the group IIB (bjPLA(2)) PLA(2) effects than in the inhibition of the group IIA (hsPLA(2)) PLA(2) effects. KonE and KonF structures are similar to vitamin E and, possibly, the action mode of these molecules is similar to the one produced by the vitamin. These results, apparently, indicate that koninginins E and F, as well as vitamin E, present structural regions that might be used as start points in seeking for new and specific anti-inflammatory drugs against such enzymes.

Bioassay-guided fractionation of the bark extract of Annona foetida afforded a new antileishmanial pyrimidine-beta-carboline alkaloid, N-hydroxyannomontine (1), together with the previously reported annomontine (2), O-methylmoschatoline (3), and liriodenine (4). The structure of compound 1 was established on the basis of extensive 1D and 2D NMR and MS analyses. This is the third reported pyrimidine-beta-carboline-type alkaloid and is particularly important for Annona genus chemotaxonomy. In addition, all compounds exhibit in vitro antileishmanial activity against promastigote forms of Leishmania braziliensis. Compounds 2 and 4 showed better activity than compounds 1 and 3 against L. braziliensis. Compound 2 was not active against L. guyanensis.