Flavonol glycosides from whole cottonseed by-product

Cottonseeds are fed to high-producing dairy cows as a source of fat and highly-digestible fibre. Seven flavonol glycosides have been identified from whole cottonseed by-product. Their structures were established as quercetin 3-O-{β-d-apiofuranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside} (1), kaempferol 3-O-{β-d-apiofuranosyl-(1 → 2)-[α-l-rhamnopyranosyl-(1 → 6)]-β-d-glucopyranoside} (2), quercetin 3-O-[β-d-apiofuranosyl-(1 → 2)-β-d-glucopyranoside] (3), quercetin 3-O-β-d-glucopyranoside (4), kaempferol 3-O-[α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside] (5), quercetin 3-O-[α-l-rhamnopyranosyl-(1 → 6)-β-d-glucopyranoside] (6), and kaempferol 3-O-α-l-rhamnopyranoside (7). Gallic acid (8) and 3,4-dihydroxybenzoic acid (9) were also found. All structures were elucidated by ESI-MS and NMR spectroscopic methods. Total polyphenols were assayed by the Folin–Ciocalteu method.     

Kaempferol acetylated glycosides from the seed cake of Camellia oleifera

The seed cake is a big by-product after crushing cooking oil from the seeds of Camellia oleifera Abel. Chemical investigation on the seed cake of C. oleifera led to the isolation of two new kaempferol acetylated glycosides (1 and 2). In addition, five kaempferol glycosides (3–7) and their aglycone, kaempferol (8), were also obtained, in addition to gallic acid (9). Their structures were determined by the detailed spectroscopic analysis and acidic hydrolysis. The new compounds were characterised as kaempferol-3-O-[4′′′′-O-acetyl-α-l-rhamnopyranosyl-(1→6)]-[β-d-glucopyranosyl-(1→2)]-β-d-glucopyranoside (1) and kaempferol-3-O-[4′′′′-O-acetyl-α-l-rhamnopyranosyl-(1→6)]-[β-d-xylopyranosyl-(1→2)]-β-d-gluco-pyranoside (2), respectively. The DPPH radical scavenging activity of all the isolated compounds was described.     

Two new saponins from tetraploid jiaogulan (Gynostemma pentaphyllum), and their anti-inflammatory and α-glucosidase inhibitory activities

Jiaogulan tea has been commercialised globally. This study investigated the chemical components and health properties of a new jiaogulan genotype, tetraploid Gynostemma pentaphyllum. Two new saponins, (23S)-21β-O-methyl-3β,20ξ-dihydroxy-12-oxo-21,23-epoxydammar-24-ene-3-O-[α-l-rhamnopyranosyl(1→2)][β-d-glucopyranosyl(1→3)]-α-l-arabinopyranoside (4) and 23β-H-3β,20ξ-dihydroxy-19-oxo-21,23-epoxydammar-24-ene-3-O-[α-l-rhamnopyranosyl(1→2)][β-d-xylopyranosyl(1→3)]-α-l-arabinopyranoside (5), together with one lactone, 3,5-dihydroxyfuran-2(5H)-one (1), and two flavonoids, rutin (2) and kaempferol 3-O-rutinoside (3), were characterised in the aerial parts of tetraploid jiaogulan. The chemical structures of the five isolated compounds were elucidated by NMR, HR-MS spectra and chemical degradation. The five compounds were also examined and compared with the methanol extract and n-butanol soluble fraction of the jiaogulan for their inhibitory activities on lipopolysaccharide (LPS)-induced IL-1β, IL-6 and COX-2 mRNA expression in RAW 264.7 mouse macrophages, and their in vitro α-glucosidase suppressing capacities. The results from this study may be used to promote the potential application of jiaogulan in functional foods.     

Spirostane and cholestane glycosides from the bulbs of Allium nigrum L

A phytochemical investigation of the fresh bulbs of Allium nigrum L. led to the isolation of new spirostane-type glycosides as two inseparable isomer mixtures, nigrosides A1/A2 (1a/1b) and nigrosides B1/B2 (2a/2b), two new cholestane-type glycosides, nigrosides C and D (3 and 4), together with the known compounds, 25(R,S)-5α-spirostan-2α,3β,6β-trio1-3-O-β-d-glucopyranosyl-(1 → 2)-O-[β-d-xylopyranosyl-(1 → 3)]-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (5a/5b) and 25(R,S)-5α-spirostan-2α,3β,6β-trio1 3-O-β-d-glucopyranosyl-(1 → 2)-O-[4-O-(3S)-3-hydroxy-3-methylglutaryl-β-d-xylopyranosyl-(1 → 3)]-O-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (6a/6b), isolated from this plant for the first time. All structures were elucidated mainly by spectroscopic analysis (1D and 2D NMR experiments, FABMS, HRESIMS) and by comparison with literature data. Cytotoxicity of the isolated compounds was assessed against human colon carcinoma (HT-29 and HCT 116) cell lines. Compounds 5a/5b and 6a/6b were found to be the most active with IC₅₀ values 1.09 and 2.82 μM against HT-29 and 1.59 and 3.45 μM against HCT 116, respectively.     

Identification of phenolic antioxidants from Sword Brake fern (Pteris ensiformis Burm.)

Sword Brake fern (Pteris ensiformis Burm.) is one of the most common ingredients of traditional herbal drinks in Taiwan. In an effort to identify antioxidants from the aqueous extract of Sword Brake fern (SBF), the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity-guided isolation was employed. Three new compounds, kaempferol 3-O-α-l-rhamnopyranoside-7-O-[α-d-apiofuranosyl-(1-2)-β-d-glucopyranoside] (1), 7-O-caffeoylhydroxymaltol 3-O-β-d-glucopyranoside (3) and hispidin 4-O-β-d-glucopyranoside (4), together with five known compounds, kaempferol 3-O-α-l-rhamnopyranosid-7-O-β-d-glucopyranoside (2), caffeic acid (5), 5-O-caffeoylquinic acid (6), 3,5-di-O-caffeoylquinic acid (7) and 4,5-di-O-caffeoylquinic acid (8) were isolated and determined on the basis of spectroscopic analyses. HPLC with UV detector was further employed to analyze the content of each compound in SBF based on the retention time by comparison with isolated pure compounds. It was found that the most abundant phenolic compound was compound 3, followed by compounds 7 and 4. The di-O-caffeoylquinic acids (7 and 8) have the strongest DPPH scavenging potential with IC₅₀ around 10 μM and the highest Trolox equivalent antioxidant capacity (TEAC) about 2 mM. This data indicates that SBF is rich in phenolic antioxidants.     

Spirostane,furostane and cholestane saponins from Persian leek with antifungal activity

A phytochemical investigation of the seeds of Persian leek afforded the isolation of two new spirostane glycosides, persicosides A (1) and B (2), four new furostane glycosides, isolated as a couple of inseparable mixture, persicosides C1/C2 (3a/3b) and D1/D2 (4a/4b), one cholestane glycoside, persicoside E (5), together with the furostane glycosides ceposides A1/A2 and C1/C2 (6a/6b and 7a/7b), tropeosides A1/A2 and B1/B2 (8a/8b and 9a/9b), and ascalonicoside A1/A2 (10a/10b), already described in white onion, red Tropea onion, and shallot, respectively. Structure elucidation of the compounds was carried out by comprehensive spectroscopic analyses, including 2D NMR spectroscopy and MS spectrometry, and by chemical evidences. The chemical structure of new compounds were identified as (25S)-spirostan-2α,3β,6β-triol 3-O-[β-d-glucopyranosyl-(1 → 3)] [β-d-xylopyranosyl-(1 → 2)]-β-d-glucopyranosyl-(1 → 4)-β-d-galactopyranoside (1), (25S)-spirostan-2α,3β,6β-triol 3-O-[β-d-xylopyranosyl-(1 → 3)] [α-l-rhamnopyranosyl-(1 → 2)]-β-d-glucopyranosyl-(1 → 4)-O-β-d-galactopyranoside (2), furosta-1β,3β,22ξ,26-tetraol 5-en 1-O-β-d-glucopyranosyl (1 → 3)-β-d-glucopyranosyl (1 → 2)-β-d-galactopyranosyl 26-O-α-l-rhamnopyranosyl (1 → 2)-β-d-galactopyranoside (3a,3b), furosta-2α,3β,22ξ,26-tetraol 3-O-β-d-glucopyranosyl (1 → 3)-β-d-glucopyranosyl (1 → 2)-β-d-galactopyranosyl 26-O-β-d-glucopyranoside (4a,4b), (22S)-cholesta-1β,3β,16β,22β-tetraol 5-en 1-O-α-l-rhamnopyranosyl 16-O-α-l-rhamnopyranosyl (1 → 2)-β-d-galactopyranoside (5).     

New flavonol glycosides from Barbeya oleoides Schweinfurth

Three new flavonol glycosides, 3′,5′ dimethoxymyricetin-4″-O-α-l-rhamnopyranosyl (1–4) β-d-glucopyranoside (1), 3′-methoxyquercetin-4″-O-α-l-rhamnopyranosyl (1–4) β-d-glucopyranoside (2) and 3′-methoxyqurecetin-6″-O-α-l-rhamnopyranosyl (1–6) β-d-glucopyranoside (3), have been isolated from the aerial part of Barbeya oleoides Schweinf., along with twelve known compounds, uvaol (4), ursolic acid (5), corosolic acid (6), arjunolic acid (7), β-sitosterol-3-O-β-d-glucoside (8), (+)–catechin (9), (-)-epicatechin (10), isorhamnetin-4′-O-glucoside (11), arjunglucoside I (12), d-(-)-bornesitol (13), gallocatechin (14) and epigallocatechin (15). Compounds 4–15 were isolated for the first time from Barbeyaceae. Structure elucidation of compounds 1–3 was based on MS and NMR data. The ethyl acetate extract of the stems as well as compounds 5, 6, 14 and 15 showed significant antimicrobial activity, while the ethanol extracts of leaves, stems and compounds 4, 7, 8, 13–15 have dose-dependent spasmolytic action.     

Isolation and structure elucidation of novel phenolic constituents from Sorbus domestica fruits

In the framework of the detailed phytochemical analysis of Sorbus domestica fruits at several maturity stages and additively to the phenolic compounds elucidated by LC-DAD-MS (ESI+), ten more, novel phenolic compounds were isolated after preparative work and their structure elucidation was achieved with UV–vis, NMR (¹H, ¹³C, COSY, HSQC, HMBC, NOESY, TOCSY, ROESY), LC-DAD-MS (ESI+) and HR-NanoESI-QqTOF-MS/MS. The novel compounds belong to the categories of hydroxybenzoic acid derivatives (Compounds 1, 2, 3), polyphenolic phenylpropanoid derivative (Compound 4), quercetin glycosides (Compounds 5, 6), flavanol glycoside (Compound 7), quercetin dimmer (Compound 8) and biphenyls (Compounds 9, 10). Their structures were established as: Vannilic acid 4-O-α-L-rhamnoside (1), protocatechuic acid anhydrite (2), trivanilloyl-(1,3,4-trihydroxybenzol) ester (3), 3-{4-(bis[4-hydroxy-3-(5-hydroxypentanoyloxy) phenyl) methoxy]-3,5-dihydroxy phenyl} propanoic acid (4), quercetin 3-O-β-D-glucopyranosyl(1′′′→2′′)-α-L-rhamnosyl(1′′′′→3′′′)-α-L-rhamnosyl(1′′′′′→3′′′′)-α-L-arabinofuranoside, quercetin 3-O-α-L-rhamnosyl(1′′′→3′′)-β-D-glucopyranoside (6), 5,7,3′,6′-tetrahydroxyflavanol 7-O-β-D-glucopyranoside (7), (7-O-4′′′, 4′O-7′′) quercetin dimmer (8), [2,2′-dihydroxy, 4-(propionic acid hexyl ester), 4′-(propionic acid heptyl ester)] biphenyl (9) and [2,6,2′,6′-tetrahydroxy, 4,4′-bis-(propionic acid hexyl ester)] biphenyl (10).     

Identification,quantification and antioxidant activity of acylated flavonol glycosides from sea buckthorn (Hippophae rhamnoides ssp. sinensis)

A novel acylated flavonol glycoside: isorhamnetin (3-O-[(6-O-E-sinapoyl)-β-d-glucopyranosyl-(1 → 2)]-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside) (1), together with two known acylated flavonol glycosides: quercetin (3-O-[(6-O-E-sinapoyl)-β-d-glucopyranosyl-(1 → 2)]-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside) (2) and kaempferol (3-O-[(6-O-E-sinapoyl)-β-d-glucopyranosyl-(1 → 2)]-β-d-glucopyranosyl-7-O-α-l-rhamnopyranoside) (3) were isolated from the n-butanol fraction of sea buckthorn (Hippophae rhamnoides ssp. sinensis) berries for the first time by chromatographic methods, and their structures were elucidated using UV, MS, ¹H and ¹³C NMR, and 2D NMR. Compounds 1–3 showed good scavenging activities, with respective IC₅₀ values of 8.91, 4.26 and 30.90 μM toward the 2,2′-diphenyl-1-picrylhydrazyl (DPPH) radical; respective Trolox equivalent antioxidant capacities of 2.89, 4.04 and 2.44 μM μM⁻¹ toward 2,2′-azino-bis-3-ethyl-benzothiazoline-6-sulphonate (ABTS) radical. The quantitative analysis of the isolated acylated flavonol glycosides was performed by HPLC–DAD method. The contents of compounds 1–3 were in the range of 12.2–31.4, 4.0–25.3, 7.5–59.7 mg/100 g dried berries and 9.1–34.5, 75.1–182.1, 29.2–113.4 mg/100 g dried leaves, respectively.     

Antioxidative properties and flavonoid composition of Chenopodium quinoa seeds cultivated in Japan

To evaluate the nutritional advantages of quinoa seeds (Chenopodium quinoa Willd.) cultivated in Japan, antioxidative properties and flavonoid composition were determined and compared to corresponding data for conventionally-used cereals and pseudo-cereals, including quinoa seeds from South America. The antioxidant activities of these grains against DPPH radicals were strongly associated with the total phenolic content of the tested samples. The crude extracts of quinoa seeds cultivated in Japan exhibited higher antioxidative effects than those from South America and other cereals, excluding buckwheat. Four flavonol glycosides were isolated and identified from the Japanese quinoa seeds, and the chemical composition of the flavonoids – quercetin and kaempferol 3-O-(2″,6″-di-O-α-rhamnopyranosyl)-β-galactopyranosides (1 and 4), quercetin 3-O-(2″,6″-di-O-α-rhamnopyranosyl)-β-glucopyranoside (2), and quercetin 3-O-(2″-O-β-apiofuranosyl-6″-O-α-rhamnopyranosyl)-β-galactopyranoside (3) – was evaluated through quantitative determination. Trioside 2 was isolated for the first time from quinoa seeds. These glycosides were not detected in extracts from any of the tested grains except quinoa. The aglycone quercetin content of the Japanese quinoa seeds is higher than in the seeds from South America and buckwheat. The amounts of quercetin and kaempferol formed via acidic hydrolysis in quinoa are much higher than those of conventionally-used edible plants. The quinoa seeds cultivated in Japan are the most effective functional foodstuff – in terms of being a source of antioxidative and bioactive flavonoids – among cereals and pseudo-cereals.     

Terpenoids and hexenes from the leaves of Crataegus pinnatifida

Crataegus pinnatifida have long been used in traditional Chinese medicine and European herbal medicine, and are widely consumed as food, in the form of juice, drink, jam and canned fruit. Four new compounds, a sesquiterpene and its glycoside (1–2), two monoterpene glycosides (3–4), together with eight known compounds (5–12), were isolated from the leaves of C. pinnatifida. Their structures were elucidated as (5Z)-6-[5-(2-hydroxypropan-2-yl)-2-methyltetrahydrofuran-2-yl]-3-methylhexa-1,5-dien-3-ol (1), (5Z)-6-[5-(2-O-β-d-glucopyranosyl-propan-2-yl)-2-methyl tetrahydrofuran-2-yl]-3-methylhexa-1,5-dien-3-ol (2), 5-ethenyl-2-[2-O-β-d-glucopyranosyl-(1″ → 6′)-β-d-glucopyranosyl-propan-2-yl]-5-methyltetrahydrofuran-2-ol (3), 4-[4β-O-β-d-xylopyranosyl-(1″ → 6′)-β-d-glucopyranosyl-2,6,6-trimethyl-1-cyclohexen-1-yl]-butan-2-one (4), (Z)-3-hexenyl O-β-d-glucopyranosyl-(1″ → 6′)-β-d-glucopyranoside (5), (Z)-3-hexenyl O-β-d-xylopyranosyl-(1″ → 6′)-β-d-glucopyranoside (6), (Z)-3-hexenyl O-β-d-rhamnopyranosyl-(1″ → 6′)-β-d-glucopyranoside (7), (3R,5S,6S,7E,9S)-megastiman-7-ene-3,5,6,9-tetrol (8), (3R,5S,6S,7E,9S)-megastigman-7-ene-3,5,6,9-tetrol9-O-β-d-glucopyranoside (9), (6S,7E,9R)-6,9-dihydroxy-4,7-megastigmadien-3-one 9-O-[β-d-xylopyranosyl-(1″ → 6′)-β-d-glucopyranoside] (10), Linarionoside C (11), and (3S,9R)-3,9-dihydroxy-megastigman-5-ene 3-O-primeveroside (12), using a combination of mass spectroscopy, 1D and 2D NMR spectroscopy and chemical analysis. Cytotoxicity of the new compounds was assayed against selected human glioma (U87) cell lines.     

Characterization of the components present in the active fractions of health gingers (Curcuma xanthorrhiza and Zingiber zerumbet) by HPLC–DAD–ESIMS

Curcuma xanthorrhiza and Zingiber zerumbet are two of the most commonly used ingredients in Indo-Malaysian traditional medicines, health supplements and tonics. Recently, a number of products derived from the aqueous extracts of these species have appeared in the market in the form of spray-dried powder packed in sachet or bottle. On-line high performance liquid chromatography, coupled with diode array detection and electrospray ion trap tandem mass spectroscopy (HPLC–DAD–ESI–MSⁿ), was used to analyze the components in the antioxidant-active fractions from the rhizomes of these species. Three components were identified from C. xanthorrhiza, including bisdemethoxycurcumin (1), demethoxycurcumin (2) and curcumin (3). The active fraction from Z. zerumbet consisted of five components, including kaempferol 3-O-rhamnoside (4), compound 5 [kaempferol 3-O-(2″-O-acetyl)rhamnoside (5a) or kaempferol 3-O-(3″-O-acetyl)rhamnoside (5b)], kaempferol 3-O-(4″-O-acetyl)rhamnoside (6), kaempferol 3-O-(3″,4″-O-diacetyl)rhamnoside (7) and kaempferol 3-O-(2″,4″-O-diacetyl)rhamnoside (8). To confirm their identities, the components from Z. zerumbet were isolated conventionally and were analyzed by spectroscopic techniques as well as by comparison with literature data.     

Chemical constituents with antioxidant activities from litchi (Litchi chinensis Sonn.) seeds

Litchi (Litchi chinensis Sonn.) is widely accepted as a delicious fruit in China and its seeds have been commonly used in traditional Chinese medicine to relieve neuralgic pain. In the present study, chemical investigation of the 95% ethanol extract of Litchi chinensis seeds led to the isolation of four new compounds, 2α,3α-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4β-8-catechin) (5), 2β,3β-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4α-8-epicatechin) (7), litchiol A (9) and litchiol B (12), together with 11 known ones, 2,5-dihydroxy-hexanoic acid (1), soscopoletin (2), coumaric acid (3), protocatechuic acid (4), 2α,3α-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4β−8)-epicatechin (6), pterodontriol d-6-O-β-d-glucopyranoside (8), Narirutin (10), naringin (11), dihydrocharcone-4′-O-β-d-glucopyranoside (13), pinocembrin-7-rutinoside (14), pinocembrin-7-neohesperidoside (15). Their structures were mainly elucidated on the basis of NMR, MS, IR, CD and UV spectral evidences. Antioxidant activities of 14 compounds were determined by DPPH radical-scavenging assay and Trolox equivalent antioxidant capacity assay, and the results showed that four compounds, protocatechuic acid (4), 2α,3α-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4β-8-catechin (5), 2α,3α-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4β−8)-epicatechin (6), 2β,3β-epoxy-5,7,3′,4′-tetrahydroxyflavan-(4α-8)-epicatechin (7), exhibited moderate antioxidant activities.     

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.     

Isolation and structural determination of a novel flavonol triglycoside and 7 compounds from the leaves of oriental raisin tree (Hovenia dulcis) and their antioxidative activity

The hot water and ethanol extracts of oriental raisin tree (Hovenia dulcis Thunb) leaves showed DPPH radical scavenging activities. Antioxidants were purified and isolated from hot water and ethanol extracts by various column chromatographic procedures with the guided assay of DPPH radical scavenging. The structure of a novel flavonol triglycoside was determined to kaempferol 3-O-α-l-rhamnopyranoside-7-O-[α-d-glucopyranosyl(1→3)-α-l-rhamnopyranoside] (4). In addition, 7 known compounds were identified as caffeine (1), kaempferol 3,7-O-α-l-dirhamnopyranoside (2), kaempferol 3-O-α-l-rhamnopyranosyl( 1→6)-O-β-d-glucopyranosyl(1→2)-O-β-d-glucopyranoside (3), E-3-carboxy-2-petenedioate 5-methyl ester (5), quercetin 3-O-α-l-rhamnopyranoside (6), kaempferol 3-O-α-l-rhamnopyranoside (7), and quercetin 3-O-β-d-glucopyranoside (8). Compound 1–3 and 5–8 were newly identified in this plant. Quercetin glycosides (5, 7) showed higher DPPH radical scavenging activity than other compounds.     

Two unusual minor 18,19-seco-ursane glycosides from leaves of Ilex cornuta

The leaves of Ilex cornuta is traditionally used as a functional tea in China. Two new minor 18,19-seco-ursane glycosides, named cornutaoside A (1) and B (2), were isolated from leaves of I. cornuta, along with two known compounds (3 and 4). Their structures were elucidated as (3β,12β)-3-[β-d-glucopyranosyl-(1 → 2)-α-l-arabinopyranosyl]-12,21-dihydroxy-19-oxo-18,19-secours-13(18)-en-28-oic acid (1) and (3β,12β)-3-[β-d-glucopyranosyl-(1 → 2)-α-l-arabinopyranosyl]-12,19,21-trihydroxy-18,19-secours-13(18)-en-28-oic acid (2), by chemical methods, 1D and 2D NMR experiments, and by comparison with known analogues. This is the first report of E-seco triterpenoids and diterpene skeletons (4) from this plant. In a preliminary cytotoxic test against U937, L1210, and B16 cell lines, 1 and 2 had no significant activities as compared to controls, with concentrations up to 443.61 and 346.25 μM/plate, for 1 and 2, respectively.     

Three new flavanonol glycosides from leaves of Engelhardtia roxburghiana, and their anti-inflammation, antiproliferative and antioxidant properties

The ethyl acetate fraction of the leaves of Engelhardia roxburghiana Wall exhibited strong anti-inflammatory, anti-proliferative, and antioxidant activities. From this fraction, three new flavanonol glycosides: (2R, 3R)-3,5,7,4′-tetrahydroxyflavanonol-3-O-(3″-O-galloyl)-α-l-rhamnopyranoside (1), (2R, 3R)-3,5,7,3′,4′-pentahydroxyflavanonol-3-O-(3″-O-galloyl)-α-l-rhamnopyranoside (2), (2R, 3R)-3,5,7,3′,4′-pentahydroxyflavanonol-3-O-(3″-O- p-(E)-coumaroyl)-α-l-rhamnopyranoside (3), were isolated. The structures of these compounds were elucidated based on spectroscopic, and chemical analyses. The anti-inflammatory activities of 1-3 were examined as their inhibitory abilities on the expression of IL-1β, TNF-α, MCP-1, and COX-2 mRNA, in lipopolysaccharide-stimulated mouse J774A.1 macrophage cells. At the concentration of 50 μM, 2 and 3 significantly reduced the IL-1β expression, while 1 induced its expression contrarily. Meanwhile, 1 and 3 exhibited significant inhibition of TNF-α expression at the concentration of 10 μM, while 2 could achieve weak but significant inhibition at 50 μM. Furthermore, 1-3 did not suppress the mRNA expression of MCP-1 and COX-2. Compounds 1-3 showed significant anti-proliferative effect in Hep G2 cells. 3 showed the most potent anti-proliferative effect in HT-29 human colon cancer cells, while 1 and 2 had no inhibition. In addition, 1 and 2 exhibited antioxidant activities. The ORAC values of 1 and 2 were 12.8 and 17.0 mmol TE/g and the HOSC values of 1 and 2 were 14.4 and 16.0 mmol TE/g, respectively.     

Separation and structure analysis of trisaccharide isomers produced from lactose by Lactobacillus bulgaricus L3 β-galactosidase

Using lactose as the substrate, galacto-oligosaccharides containing β-d-galactose residues were synthesised with β-galactosidase from Lactobacillus bulgaricus L3. The reaction mixture was fermented by yeast cells to consume the monosaccharides and disaccharides, and then it was fully acetylated in the presence of acetic anhydride under I₂ catalysis. Column chromatography of the resulting products, using ethyl acetate: petroleum ether as the eluent, generated two isomers of trisaccharide derivatives (I and II) in gram scale for the first time. Their structure characteristics were investigated by ESI-MS and NMR spectra. They were identified as (2,3,4,6-tetra-O-acetyl-d-galactopyranosyl)-β-(1 → 6)-(2,3,4-tri-O-acetyl-d-galactopyranosyl)-β-(1 → 4)-1,2,3,6-tetra-O-acetyl-α-d-glucopyranose (I) and (2,3,4,6-tetra-O-acetyl-d-galactopyranosyl)-β-(1 → 3)-(2,4,6-tri-O-acetyl-d-galactopyranosyl)-β-(1 → 4)-1,2,3,6-tetra-O-acetyl-α-d-glucopyranose (II), respectively. ESI-MS analysis of both deacetylated products of the two trisaccharide derivatives I and II revealed molecular ion peaks of free trisaccharides, which were structurally identified as Gal-β-(1 → 6)-Gal-β-(1 → 4)-Glc and Gal-β-(1 → 3)-Gal-β-(1 → 4)-Glc, respectively.     

Polyphenols from longan seeds and their radical-scavenging activity

Five previously uncharacterised polyphenols, ethyl gallate (2), 1-β-O-galloyl-d-glucopyranose (3), methyl brevifolin carboxylate (4), brevifolin (5) and 4-O-α-l-rhamnopyranosyl-ellagic acid (8), and three previously identified polyphenols, gallic acid (1), corilagin (6) and ellagic acid (7), were isolated from longan seeds. Their structures were identified by spectroscopic and chemical methods including HRESIMS and NMR. Eight polyphenols exhibited scavenging activity towards DPPH radicals with SC₅₀ values of 0.80–5.91 μg/ml and towards superoxide radicals with SC₅₀ values of 1.04–7.03 μg/ml. The radical-scavenging activity of the newly characterised polyphenols was comparable to that of gallic acid, corilagin and ellagic acid.     

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.