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The need for safe, effective preservatives is a prominent issue in the food and drug industries, reflecting demand for natural alternatives to synthetic chemicals viewed as harmful to consumers and the environment. Thus, this study determined the identities and scavenging capacities of antioxidant metabolites produced as a response to potato tuber wounding, using activity-guided fractionation of polar extracts from a Yukon Gold cultivar that had previously exhibited exceptionally high radical-scavenging activity. Activity-guided fractionation using the ABTS(+) radical scavenging assay and LC-MS with TOF-MS for compositional analysis of the most potent antioxidant fractions yielded identification of nine constituents: coumaroylputrescine; feruloylquinic acid; isoferuloylputrescine; ferulic acid; 22,25-dimethoxy-3-[[2,3,4-tri-O-methyl-6-O-(2,3,4,6-tetra-O-methyl-β-d-glucopyranosyl)-β-d-glucopyranosyl]oxy]-(3β)-lanost-9(11)-en-24-one; 4-(2Z)-2-decen-1-yl-5-[1-(4-hydroxyphenyl)decyl]-1,2-benzenediol; 8-[(2E)-3,7-dimethyl-2,6-octadien-1-yl]-5-hydroxy-2,8-dimethyl-6-(3-methyl-2-buten-1-yl)-2H-1-benzopyran-4,7(3H,8H)-dione; 3-[(2-O-β-d-glucopyranosyl-β-d-glucopyranosyl)oxy]-20-[(6-O-β-d-xylopyranosyl-β-d-glucopyranosyl)oxy]-dammar-24-en-19-al; (3β)-28-oxo-28-(phenylmethoxy)oleanan-3-yl 2-O-β-d-galactopyranosyl-3-O-(phenylmethyl)-, butyl ester β-d-glucopyranosiduronic acid. A positive correlation was observed between the scavenging activities and the polarities of the active fractions. The antioxidant capacities of the fractions were also characterised by monitoring the activity throughout a 45-minute assay period., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

The cultivation, storage, and distribution of potato tubers are compromised by mechanical damage and suboptimal healing. To investigate wound-healing progress in cultivars with contrasting russeting patterns, metabolite profiles reported previously for polar tissue extracts were complemented by GC/MS measurements for nonpolar extracts and quantitative (13)C NMR of interfacial solid suspensions. Potential marker compounds that distinguish cultivar type and wound-healing time point included fatty acids, fatty alcohols, alkanes, glyceryl esters, α,ω-fatty diacids, and hydroxyfatty acids. The abundant long-chain fatty acids in nonpolar extracts and solids from the smooth-skinned Yukon Gold cultivar suggested extensive suberin biopolymer formation; this hypothesis was supported by high proportions of arenes, alkenes, and carbonyl groups in the solid and among the polar markers. The absence of many potential marker classes in nonpolar Atlantic extracts and interfacial solids suggested a limited extent of suberization. Modest scavenging activities of all nonpolar extracts indicate that the majority of antioxidants produced in response to wounding are polar.

Potato (Solanum tuberosum L.) is a worldwide food staple, but substantial waste accompanies the cultivation of this crop due to wounding of the outer skin and subsequent unfavorable healing conditions. Motivated by both economic and nutritional considerations, this metabolite profiling study aims to improve understanding of closing layer and wound periderm formation and guide the development of new methods to ensure faster and more complete healing after skin breakage. The polar metabolites of wound-healing tissues from four potato cultivars with differing patterns of tuber skin russeting (Norkotah Russet, Atlantic, Chipeta, and Yukon Gold) were analyzed at three and seven days after wounding, during suberized closing layer formation and nascent wound periderm development, respectively. The polar extracts were assessed using LC-MS and NMR spectroscopic methods, including multivariate analysis and tentative identification of 22 of the 24 biomarkers that discriminate among the cultivars at a given wound-healing time point or between developmental stages. Differences among the metabolites that could be identified from NMR- and MS-derived biomarkers highlight the strengths and limitations of each method, also demonstrating the complementarity of these approaches in terms of assembling a complete molecular picture of the tissue extracts. Both methods revealed that differences among the cultivar metabolite profiles diminish as healing proceeds during the period following wounding. The biomarkers included polyphenolic amines, flavonoid glycosides, phenolic acids and glycoalkaloids. Because wound healing is associated with oxidative stress, the free radical scavenging activities of the extracts from different cultivars were measured at each wounding time point, revealing significantly higher scavenging activity of the Yukon Gold periderm especially after 7 days of wounding.

The potential therapeutic effects of Costa Rican guava (Psidium friedrichsthalianum) extracts for chronic obstructive pulmonary disease were examined. The ethyl acetate fraction displayed the highest antioxidant activity, as compared to the hexane, chloroform, and n-butanol fractions, as well as the crude extract. This fraction was evaluated for its anti-inflammatory activity response relationship against interleukin-8 (IL-8) and inhibition of matrix metalloproteinase-1 (MMP-1) expression before and after treatment with cigarette smoke. The ethyl acetate fraction exhibited inhibitory activity against IL-8 production and MMP-1 expression, showing the most potent inhibitory activities in both assays at 100μg/mL, and nine compounds (1-9) were found. Phenolic compounds 1-O-trans-cinnamoyl-β-d-glucopyranose (2), ellagic acid (3), myricetin (4), quercitrin (7), and quercetin (9) were identified using standard compounds or literature reports from related species. Compounds 1, 5, 6, and 8 were tentatively identified as 1,5-dimethyl citrate (1), sinapic aldehyde 4-O-β-d-glucopyranose (5), 3,3',4-tri-O-methylellagic acid-4'-O-d-glucopyranoside (6), and 1,3-O-diferuloylglycerol (8), All nine compounds are reported for the first time in Costa Rican guava., (Copyright © 2013 Elsevier Ltd. All rights reserved.)

There are many neotropical blueberries, and recent studies have shown that some have even stronger antioxidant activity than the well-known edible North American blueberries. Antioxidant marker compounds were predicted by applying multivariate statistics to data from LC-TOF-MS analysis and antioxidant assays of 3 North American blueberry species (Vaccinium corymbosum, Vaccinium angustifolium, and a defined mixture of Vaccinium virgatum with V. corymbosum) and 12 neotropical blueberry species (Anthopterus wardii, Cavendishia grandifolia, Cavendishia isernii, Ceratostema silvicola, Disterigma rimbachii, Macleania coccoloboides, Macleania cordifolia, Macleania rupestris, Satyria boliviana, Sphyrospermum buxifolium, Sphyrospermum cordifolium, and Sphyrospermum ellipticum). Fourteen antioxidant markers were detected, and 12 of these, including 7 anthocyanins, 3 flavonols, 1 hydroxycinnamic acid, and 1 iridoid glycoside, were identified. This application of multivariate analysis to bioactivity and mass data can be used for identification of pharmacologically active natural products and may help to determine which neotropical blueberry species will be prioritized for agricultural development. Also, the compositional differences between North American and neotropical blueberries were determined by chemometric analysis, and 44 marker compounds including 16 anthocyanins, 15 flavonoids, 7 hydroxycinnamic acid derivatives, 5 triterpene glycosides, and 1 iridoid glycoside were identified.

Fruits of the cultivated eggplant species Solanum melongena and its wild relative Solanum incanum have a high content of hydroxycinnamic acid conjugates, which are implicated in the human health benefits of various fruits and vegetables. Monocaffeoylquinic acid esters, in particular 5-O-(E)-caffeoylquinic acid, are usually predominant in solanaceous fruits and tubers. Two closely related caffeoylquinic acid derivatives with longer C(18) HPLC retention times than those of monocaffeoylquinic acids are minor constituents in cultivated eggplant fruit. In a prior study, the two compounds were tentatively identified as 3-O-acetyl- and 4-O-acetyl-5-O-(E)-caffeoylquinic acids and composed ≤2% of the total hydroxycinnamic acid conjugates in fruit of most S. melongena accessions. It was recently found that the pair of these caffeoylquinic acid derivatives can compose 15-25% of the total hydroxycinnamic acid conjugates in fruits of S. incanum and wild S. melongena. This facilitated C(18) HPLC isolation and structural elucidation using (1)H and (13)C NMR techniques and HR-ToF-MS. The isomeric compounds were identified as 3-O-malonyl-5-O-(E)-caffeoylquinic acid (isomer 1) and 4-O-(E)-caffeoyl-5-O-malonylquinic acid (isomer 2). Both exhibited free radical scavenging activity, albeit about 4-fold lower than that of the flavonol quercetin dihydrate. By contrast, the iron chelation activities of isomers 1 and 2, respectively, were about 3- and 6-fold greater than that of quercetin dihydrate. Reports of malonylhydroxycinnamoylquinic acids are rare, and only a few of these compounds have been structurally elucidated using both NMR and MS techniques. To the authors' knowledge, these two malonylcaffeoylquinic acid isomers have not previously been reported.

Edible blueberry species are well recognized for their potential health benefits. Ericaceae fruits including the North American highbush blueberry (Vaccinium corymbosum L.) and five less common edible blueberry relatives from the New World tropics, Anthopterus wardii Ball, Cavendishia grandifolia Hoerold, Macleania coccoloboides A. C. Smith, Sphyrospermum buxifolium Poeppig & Endlicher, and Sphyrospermum cordifolium Benth, were investigated for their antioxidant properties and phenolic profiles. The neotropical berries C. grandifolia and A. wardii exhibited significantly higher 1,1-diphenyl-2-picrylhydrazyl (DPPH(•)) and 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonate) (ABTS(• +)) free radical scavenging and iron chelation activities than V. corymbosum. Total phenolic content and high-performance liquid chromatography with photodiode array detection (HPLC-PDA) compositional fingerprint analyses were also carried out. Significant correlations were observed among total phenolic contents, DPPH(•) and ABTS(• +) scavenging, and iron chelation activities. By use of HPLC-PDA, the phenolic constituents in the berries were identified as chlorogenic acid, p-coumaric acid, hyperoside, quercetin-3-O-glucoside, isoorientin, isovitexin, orientin and vitexin. Principal component analysis reduced the dimensions of antioxidant and total phenolic data to two components, which accounted for 95% of total variation among the six fruits. Each fruit species formed its own cluster, and therefore the antioxidant profile of each species was shown to be distinct.

The plant Melissa officinalis L. has been used traditionally in the treatment of cognitive dysfunction. Based on its traditional medicinal use, it was assessed for its clinical efficacy in mild to moderate Alzheimer's patients. The plant was effective in the management of the disease. Therefore, based on this result, a similar plant extract was prepared in order to be screened for bioactivities which are relevant in Alzheimer's disease therapy. The extract was recently screened for antioxidant activity and it showed a wide range of antioxidant properties. Another important bioactivity is acetylcholinesterase inhibition, which the extract was screened for in the current investigation. The extract was capable of inhibiting the enzyme in a time and dose-dependent manner. Activity of the extract at 10 min was estimated as 1.72+/-0.16 microg equivalents of physostigmine/mg of the extract. Acetylcholinesterase inhibitory guided fractionation of the extract was then carried out. Most of the fractions showed inhibitory activity and were more potent than the extract. The contents of the most potent fraction were identified as cis- and trans-rosmarinic acid isomers and a rosmarinic acid derivative using LC-DAD-ESI-MS and NMR methods.

Abstract: Four flavone C-glycosides, isoorientin (1), orientin (2), vitexin (3), and isovitexin (4), were isolated from the neotropical blueberry of Anthopterus wardii, a so-called “superfruit”, using antioxidant activity-guided fractionation. A dose–response relationship of compounds 1–4 was determined for their anti-inflammatory activity against interleukin-8 (IL-8) and for the inhibition of matrix metalloproteinase-1 (MMP-1) expression, an inflammatory marker for chronic obstructive pulmonary disease. The four flavone C-glycosides exhibited inhibitory activity against IL-8 production and MMP-1 expression, with compounds 1, 3, and 4 having the most potent inhibitory activities in both assays at 100μg/ml. The structures of compounds 1–4 were determined by spectroscopic methods. These flavone C-glycosides are reported for the first time in the Anthopterus genus. [Copyright &y& Elsevier]

Abstract: The leaf material of lemon balm (Melissa officinalis L.) was extracted with 450ml/l aqueous ethanol by medium pressure liquid–solid extraction. The total phenolic content of the extract was estimated as gallic acid equivalents by Folin–Ciocalteu reagent method and a qualitative–quantitative compositional analysis was carried out using high performance liquid chromatography coupled with photodiode array detection. The lemon balm extract contained hydroxycinnamic acid derivatives and flavonoids with caffeic acid, m-coumaric acid, eriodictyol-7-O-glucoside, naringin, hesperidin, rosmarinic acid, naringenin, hesperetin being identified based on their chromatographic behaviour and spectral characteristics. The extract was also investigated for potential in vitro antioxidant properties in iron(III) reduction, iron(II) chelation, 1,1-diphenyl-2-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulphonate), superoxide anion and nitric oxide free-radical scavenging, and inhibition of β-carotene–linoleic acid bleaching assays. The extract demonstrated antioxidant activity in all the assays. However, it was not as potent as the positive controls except in the β-carotene–linoleic acid bleaching assay, where its activity was superior to that of gallic and caffeic acids and statistically indistinguishable from quercetin and BHA. The exceptionally high antioxidant activity and the fact that this assay is of biological relevance warrants further investigation of lemon balm extract in ex vivo and in vivo models of oxidative stress. [Copyright &y& Elsevier]

Abstract: The chemical composition and antioxidant properties of a water-soluble extract of Moldavian balm (Dracocephalum moldavica L., syn. Moldavian dragonhead) prepared by hydrodistillation are presented in this study. The total phenol content was estimated as gallic acid equivalents by the Folin-Ciocalteu reagent method, while the qualitative–quantitative composition of the extract was determined by high performance liquid chromatography coupled with photodiode array detection. The antioxidant properties assessed included iron(III) reduction and iron(II) chelation and 1,1-diphenyl-2-picrylhydrazyl, 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonate) and superoxide anion free radical scavenging. In addition, the ability of the extract to protect 2-deoxy-d-ribose and bovine brain-derived phospholipids against hydroxyl radical-mediated degradation was assessed. The extract principally contained polar compounds including hydroxycinnamic acids and flavonoids, with caffeic and ferulic acids, luteolin-7-O-glucoside, rosmarinic acid, luteolin and apigenin being identified from their chromatographic behavior and spectral characteristics. The Moldavian balm extract demonstrated activity in all the antioxidant assays; however, it was not as potent as the positive control except in the phospholipid-based assay where its hydroxyl radical scavenging activity was statistically indistinguishable from that demonstrated by Pycnogenol. [Copyright &y& Elsevier]