Glycosidase inhibitory phenolic compounds from the seed of Psoralea corylifolia

The seeds of Psoralea corylifolia were extracted into five different polar solvents: chloroform, 50% ethanol in water, ethanol, methanol and water. All extracts were evaluated for glycosidase inhibitory activity. The chloroform extract (CE) showed the lowest IC₅₀ values against α-glucosidase (82.9 μg/ml) and α-mannosidase (132 μg/ml). Chromatography of CE yielded nine phenolic compounds which were identified as isovabachalcone (1), 4′-O-methylbavachalcone (2), isobavachromene (3), corylifolin (4), bavachinin (5), psoralidin (6), neobavaisoflavone (7), corylifol A (8), and bakuchiol (9). All isolated compounds, apart from compound 5, possessed α-glucosidase inhibitory activities. Among them, compounds 6–8 exhibited potent inhibition with IC₅₀s of 13.7, 27.7 and 11.3 μM, respectively. Furthermore, compounds 2 and 6 showed α-mannosidase inhibitory activity. Mechanistic analysis of their inhibition modes against α-glucosidase showed that compounds (6 and 7) were noncompetitive, whereas compound 8 was mixed. Furthermore, the most active glycosidase inhibitors (2, 6–8) were proven to be present in the native seed in high quantities by an HPLC chromatogram.     

Bioactive sesquiterpenoids from the solid culture of the edible mushroom Flammulina velutipes growing on cooked rice

The edible mushroom Flammulina velutipes was cultivated on cooked rice. Six new cuparene sesquiterpenes, enokipodins E-J (1-6), and two new sterpurane sesquiterpenes, sterpurols A (10) and B (11), with four known sesquiterpenes, 2,5-cuparadiene-1,4-dione (7), enokipodins B (8) and D (9), and sterpuric acid (12), were isolated from the solid culture of F. velutipes. The structures of new metabolites were elucidated by NMR experiments. The absolute configurations in new compounds were assigned by X-ray crystallographic analysis, the modified Mosher method, and CD data analysis. Bioactivity screening indicated that compounds 5-9 displayed weak antibacterial activity against Bacillus subtilis; 2, 3, and 5 showed weak antifungal activity against Aspergilus fumigatus; 6-9 showed both moderate cytotoxicity against the human tumor cell lines (HepG2, MCF-7, SGC7901, and A549) and antioxidant activity in DPPH scavenging assay. These results suggest that the solid culture of F. velutipes on cooked rice could be a good functional food.     

Antioxidant polyketide phenolic metabolites from the edible mushroom Cortinarius purpurascens

Phytochemical investigation of the ethyl acetate extract of the edible macrofungus, Cortinarius purpurascens, led to the isolation of nine anthraquinone-related pigments, citreorosein 6,8-dimethyl ether (1), physcione (2), rufoolivacin (3), rufoolivacin C (4), rufoolivacin D (5), leucorufoolivacin (6), verbindung cr11 (7), verbindung cr60 (8) and 1-Hydroxy-3-methyl-2-isopropanyl-6,8-dimethoxyanthraquinone (9). The structures of these isolated compounds were characterised by spectroscopic methods and comparison with published data. Among the tested compounds, 3–6 exhibited potent DPPH radical-scavenging activity with IC₅₀ values in the range of 3–8 μg/ml. The results indicated that the fungus is a possible source of natural products with potential antioxidant activity.     

Jasmonoid glucosides,sesquiterpenes and coumarins from the fruit of Clausena lansium

The fruit of Clausena lansium (wampee) is popular in southern China and warm areas of the world. Our chemical study on the fruit yielded three jasmonoid glucosides, 12-β-d-glucopyranosyloxy-6-epi-7-isocucurbic acid-1,6-lactone (1), 12-β-d-glucopyranosyloxyjasmonic acid (2) and 12-hydroxyjasmonic acid (3), two sesquiterpenes, (+)-curcumen-12-oic acid (4) and (+)-(E)-α-santalen-12-oic acid (5), two coumarins, xanthotoxol (6) and indicolactone (7), in addition to 3,4-dihydroxybenzoic acid (8), 5-hydroxymethylfuraldehyde (9), isopropyl β-d-glucopyranoside (10) and stigmasterol (11). Their structures were determined by spectroscopic methods. Compound 1 was a new metabolite and the others excluding 6 were reported from the species for the first time. Compounds 1–7 were evaluated for antioxidant and antibacterial activities. Among them, compound 6 showed antioxidant activity in ferric reducing antioxidant power (FRAP) and DPPH radical scavenging assays as well as antibacterial activity against Staphyloccocus aureus and Shigella dysenteriae, while compound 5 was active against Bacillus cereus.     

Antioxidants of therapeutic relevance in COPD from the neotropical blueberry Anthopterus wardii

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 100 μg/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.     

Eudesmane sesquiterpene glucosides from lychee seed and their cytotoxic activity

Two new sesquiterpene glucosides, litchiosides A (1) and B (2), were obtained along with pumilaside A (3) and funingensin A (4) from lychee (Litchi chinensis Sonn.) seed. Their structures were elucidated on the basis of spectroscopic and chemical evidence. The in vitro antitumour activity of compounds 1–4 against A549, LAC, Hela, and Hep-G2 cell lines was determined using the MTT colourimetric assay. Pumilaside A (3) exhibited significant activity against all the tested cell lines with IC₅₀ values of 0.012–6.29 μM, and funingensin A (4) showed moderate activity against Hep-G2 cells (IC₅₀ = 39.27 μM), while litchiosides A (1) and B (2) were found to be inactive.     

Biological activities of flavonoids from pathogenic-infected Astragalus adsurgens

The present study was aimed at the identification of biological components from pathogenic-infected Astragalus adsurgens with an activity-guided purification process. Fifteen flavonoids were obtained from the most active ethyl acetate fraction and identified as astradsurnin (1), a new chalcone derivative, together with fourteen known flavonoids (2-15). These compounds were tested for antibacterial activities against five bacteria and cytotoxic activities against two selected cancer cells. Within the series of flavonoids tested, compounds 4 and 15 were the most active against Escherichia coli, Bacillus cereus, Staphylococcus aureus, Erwinia carotovora and Bacillus subtilis with MICs ranging from 7.8 to 31.3 μg/ml. Moreover, compounds 4 and 5 exhibited moderate activity against HL-60 and SMMC-7721 cells with IC₅₀ values between 5 and 10 μg/ml. To our knowledge, this is the first time that it has been reported on the biological and chemical study of A. adsurgens infected by Embellisia astragali.     

Phenolic constituents from the flower buds of Lonicera japonica and their 5-lipoxygenase inhibitory activities

Thirteen phenolic constituents, luteolin (1), protocatechuic acid (2), caffeic acid (3), flavoyadorinin-B (4), 4,5-dicaffeoylquinic acid (5), luteolin 7-O-β-d-glucopyranoside (7), 3,5-dicaffeoylquinic acid methyl ester (8), methyl chlorogenate (9), quercetin 3-O-β-d-glucopyranoside (10), 3,5-dicaffeoylquinic acid (11), rhoifolin (12), chlorogenic acid (13), and a novel phenolic glucoside benzoate, vanillic acid 4-O-β-d-(6-O-benzoylglucopyranoside) (6), were isolated from the flower buds of Lonicera japonica. Flavoyadorinin-B (4) was isolated for the first time from a Caprifoliaceae plant. The structures of 1–13 were determined on the basis of chemical and spectroscopic evidence. These compounds were screened for their 5-lipoxygenase inhibitory activity. Only luteolin (1) showed significant inhibitory activity against 5-LOX-catalysed leukotriene production.     

Dicaffeoylquinic acid derivatives and flavonoid glucosides from glasswort (Salicornia herbacea L.) and their antioxidative activity

Two novel antioxidant compounds, isoquercitrin 6″-O-methyloxalate (6) and methyl 4-caffeoyl-3-dihydrocaffeoyl quinate (salicornate, 7), were isolated from Salicornia herbacea L.. Six known compounds were also identified as 3,5-dicaffeoylquinic acid (1), quercetin 3-O-β-d-glucopyranoside (2), 3-caffeoyl-4-dihydrocaffeoylquinic acid (3), methyl 3,5-dicaffeoyl quinate (4), 3,4-dicaffeoylquinic acid (5), and isorhamnetin 3-O-β-d-glucopyranoside (8). Their chemical structures were determined by spectroscopic data from ESI–MS and NMR. The isolated dicaffeoylquinic acid derivatives (1, 3, 4, 5, and 7) showed similar activities for scavenging 1,1-diphenyl-2-picrylhydrazyl radicals and inhibiting formation of cholesteryl ester hydroperoxide during copper ion-induced rat blood plasma oxidation. The two flavonol glucosides (2 and 6), which have no substitutions in the B ring of their aglycones, also had similar activity. However, compound 8, which has the same structure as 2 except for the presence of a methoxyl group in the C-3′ position of the B ring, showed predominantly lower antioxidant activity than the other isolated compounds.     

Secondary metabolites from the unripe pulp of Persea americana and their antimycobacterial activities

The fruits of Persea americana (Avocado) are nowadays used as healthy fruits in the world. Bioassay-guided fractionation of the active ethyl acetate soluble fraction has led to the isolation of five new fatty alcohol derivatives, avocadenols A–D (1–4) and avocadoin (5) from the unripe pulp of P. americana, along with 12 known compounds (6–17). These structures were elucidated by spectroscopic analysis. Among the isolates, avocadenol A (1), avocadenol B (2), (2R,4R)-1,2,4-trihydroxynonadecane (6), and (2R,4R)-1,2,4-trihydroxyheptadec-16-ene (7) showed antimycobacterial activity against Mycobacterium tuberculosis H₃₇R_Vin vitro, with MIC values of 24.0, 33.8, 24.9, and 35.7 μg/ml, respectively.     

Antioxidant activities of compounds isolated from Dalbergia odorifera T. Chen and their inhibition effects on the decrease of glutathione level of rat lens induced by UV irradiation

Four compounds were isolated from the root of Dalbergia odorifera T. Chen and identified by chemical and spectroscopic methods as 2′-O-methyl-isoliquiritigenin (1), odoriflavene (2), 5′-methoxy-vestitol (3) and formononetin (4). Their antioxidant activities were investigated in lard by the oxidative stability instrument; their inhibitory effects on the decrease of glutathione level of rat lens induced by UV irradiation were studied using a rat lens UV-damage model, and their in vitro cytotoxicity was measured on human SH-SY5Y neuroblastoma cells. Results indicated that all four compounds had obvious antioxidant effects, while none of them showed any synergistic effects on butylated hydroxytoluene or α-tocopherol. When FeCl₃ (4.0 μM) was added, the antioxidant activities of the four compounds markedly decreased. The inhibitory effects of compounds 1, 2 and 4 on the decrease of glutathione level of rat lens induced by UV irradiation were comparable to that of α-tocopherol. All four compounds showed cytotoxic activity when evaluated against a SH-SY5Y cell line in vitro.     

Phenolic-rich extract from the Costa Rican guava (Psidium friedrichsthalianum) pulp with antioxidant and anti-inflammatory activity. Potential for COPD therapy

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 100 μg/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.     

Pentadecyl ferulate,a potent antioxidant and antiproliferative agent from the halophyte Salicornia herbacea

An investigation of the chemical constituents of Salicornia herbacea has led to the isolation of one new natural product, pentadecyl ferulate (6), together with 11 known compounds, including phytol (1), stearolic acid (2), γ-linolenic acid (3), (3Z,6Z,9Z)-tricosa-3,6,9-triene (4), linoleic acid (5), stigmasterol (7), ergosterol (8), dioctyl phthalate (9), dibutyl phthalate (10), vanillic aldehyde (11), and scopoletin (12). The chemical structures of these materials were elucidated mainly by spectroscopic analysis. This work represents the first recorded example of the isolation of compounds 1, 2, 3, 4, 9, 10, and 11 from S. herbacea. The antioxidant experiments revealed that compound 6 possessed strong hydroxy radical and superoxide anion scavenging activities and was the principle antioxidant ingredient in the ethyl acetate extract. The antiproliferative results exhibited that compound 1 selectively inhibited HepG2 cells, whereas compounds 3 and 6 showed potent antiproliferative activities against HepG2 and A549 cells.     

New cytotoxic withanolides from Physalis peruviana

Investigation of the extracts of Physalis peruviana L. has led to the isolation of seven new withanolides, phyperunolide A (1), phyperunolide B (2), phyperunolide C (3), phyperunolide D (4), peruvianoxide (5), phyperunolide E (16), and phyperunolide F (17) together with ten known withanolides. The structure and absolute stereochemistry of all compounds were elucidated on the basis of CD and NMR spectral analysis, respectively. Compounds 1, 6, 7, and 9 showed cytotoxicity against lung cancer (A549), breast cancer (MDA-MB-231 and MCF7), and liver cancer (Hep G2 and Hep 3B) cancer cell lines. The presence of 5β,6β-epoxy-2-en-1-ones in withanolides is greatly helpful in cytotoxicity, it is a key known important factor to cytotoxicity; however, interestingly, the unusual 5-chloride withanolide, 9, displayed significant activity.     

Identification of flavonoids and flavonoid rhamnosides from Rhododendron mucronulatum for. albiflorum and their inhibitory activities against aldose reductase

To investigate the therapeutic potential of compounds from natural sources, Rhododendron mucronulatum for. albiflorum flowers (RMAF) and R. mucronulatum flowers (RMF) were tested for inhibition of aldose reductase (AR). The methanol extracts of RMAF and RMF exhibited AR inhibitory activities (IC₅₀ values 1.07 and 1.29 μg/mL, respectively). The stepwise polarity fractions of RMAF were tested for in vitro inhibition of AR from rat lenses. Of these, the ethyl acetate (EtOAc) fraction exhibited AR inhibitory activity (IC₅₀ 0.15 μg/mL). A chromatography of the active EtOAc fraction of RMAF led to the isolation of six flavonoids, which were identified by spectroscopic analysis as kaempferol (1), afzelin (2), quercetin (3), quercitrin (4), myricetin (5) and myricitrin (6). Compounds 1–6 exhibited high AR inhibitory activity, with IC₅₀ values of 0.79, 0.31, 0.48, 0.13, 11.92 and 2.67 μg/mL, respectively. HPLC/UV analysis revealed that the major flavonoids of RMAF and RMF are quercitrin (4) and myricitrin (6). Our results suggest that RMAF containing these six flavonoids could be a useful natural source in the development of a novel AR inhibitory agent against diabetic complications.     

Cytotoxic phenolics from Bulbophyllum odoratissimum

A phytochemical study of the whole plant of Bulbophyllum odoratissimum (J.E. Smith) Lindl (Orchidaceae) and cytotoxicity measurement of its isolated compounds have been carried out. The ethyl acetate extract yielded nine phenolics, identified as moscatin (1), 7-hydroxy-2,3,4-trimethoxy-9,10-dihydrophenanthrene (2), coelonin (3), densiflorol B (4), gigantol (5), batatasin III (6), tristin (7), vanillic acid (8) and syringaldehyde (9). Compounds 4 and 8 were discovered in the Bulbophyllum genus for the first time and all compounds, except for 9, have not been reported in this plant before. The isolated compounds were evaluated in vitro for their inhibitory ability against the growth of human leukaemia cell lines K562 and HL-60, human lung adenocarcinoma A549, human hepatoma BEL-7402 and human stomach cancer SGC-7901. Densiflorol B (4) the most active compound, exhibited IC₅₀ values of 0.08–3.52 μg/ml against the five tested cell lines.     

Schisarisanlactones A and B: A new class of nortriterpenoids from the fruits of Schisandra arisanensis

Two novel highly oxygenated nortriterpenoids, schisarisanlactones A (1) and B (2), have been isolated from the fruits of Schisandra arisanensis, an endemic plant of Taiwan. Compounds 1 and 2 possess an unprecedented 5/5/7/5/5-fused pentacyclic ring system. The structures of both compounds were determined on the basis of spectroscopic analyses, especially 2D NMR and MS. A plausible biogenetic pathway of 1 was proposed. Schisarisanlactone A (1) showed significant anti-HIV activity.     

Antioxidant abietane diterpenoids from Salvia barrelieri

The root extract of endemic Algerian Salvia species Salvia barrelieri Ettling and its diterpenoids were investigated for potential antioxidant activity. From its acetone extract, a new natural abietane diterpenoid 7-oxoroyleanone-12-methyl ether (1) and six known diterpenoids 7α-acetoxyroyleanone-12-methyl ether (2), royleanone (3), horminone (4), 7-acetylhorminone (5), cryptojaponol (6) and inuroyleanol (7) were isolated, and their structures were elucidated by spectroscopic means. Among the diterpenoids, the new diterpenoid 7-oxoroyleanone-12-methyl ether (1) showed highest superoxide anion scavenging activity while inuroyleanol (7) showed both the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) scavenging activity and inhibition of lipid peroxidation in β-carotene–linoleic acid system. These findings indicate that S. barrelieri extract as well as isolated abietane diterpenes, particularly inuroyleanol are promising antioxidants which can be used as food additives.     

Norditerpenoids from Agathis macrophylla

Three new norditerpenoids, (4S,5R,9S,10R)-methyl 19-hydroxy-15,16-dinorlabda-8(17),11E-dien-13-oxo-18-oate (1), (4R,5R,9R,10R,13S/R)-13-hydroxypodocarp-8(14)-en-19-oic acid (2/3) were isolated from Agathis macrophylla, together with 11 known diterpenoids. The structures of these compounds, 1-14, were established, mainly by spectroscopic analysis. The inactivation of protein tyrosine phosphatase 1B (PTP1B) by compounds 5-9 and 11-13 was tested and the cytotoxicity of compounds 1-14 against HL60 cell and SMMC-7721 cell were evaluated. Biological screening studies indicated that compounds 5, 7/8 and 9 were mild inactivators of PTP1B, whilst compounds 1, 4, 6, 7/8, and 10-12 exhibited moderate activity against both of the tested cell lines.