Chemical constituents from the roots of Acanthus ilicifolius var. xiamenensis

Chemical investigation of Acanthus ilicifolius var. xiamenensis led to the isolation of eleven compounds, and their structures were identified to be 2-benzoxazolinone (1), 2-hydroxy-2H-1,4-benzoxazin-3(4H)-one (2), (2R)-2-O-β-d-glucopyranosyl-2H-1,4-benzox azin-3(4H)-one (3), (2R)-2-O-β-d-glucopyranosyl-4-hydroxy-2H-1,4-benzoxazin-3(4H)-one (4), (2R)-2-O-β-d-glucopyranosyl-7-hydroxy-2H-1,4-benzoxazin-3(4H)-one (5), lyoniside (6), 3′-methoxy-luteolin-7-O-β-d-glucopyranoside (7), β-sitosterol-3-O-β-d-glucopyranoside (8), stigmasterol octadecanoate (9), β-sitosterol octadecanoate (10), stigmasterol-3-O-β-d-glucopyranoside (11) on the basis of mass and NMR spectra. This is the first report on the occurrence of compound 6 and 7 in Acanthaceae. This work also represents the first phytochemical work on the roots of A. ilicifolius var. xiamenensis.     

New steroid and other compounds from non-polar extracts of Clusia burle-marxii and their chemotaxonomic significance

Phytochemical investigation of the non-polar extract of Clusia burle-marxii led to the identification of a new steroid (1), along with friedelinol (2), β-sitosterol (3), friedelin (4), stigmast-5-en-3β,7β-diol (5), stigmast-5-en-3β,7α-diol (6), stigmasterol (7), sitostenone (8), betulinic acid (9), butyrospermol (10), euphol (11), betulin aldehyde (12), 2,2-dimethyl-5-hydroxy-7-phenyl-chromane (13), 6-deoxyisojacareubin (14), padiaxanthone (15) and betulonic acid (16). This is the first report of the identification of compounds 5, 6 and 10 in the family, the first report of compounds 14 and 15 in the genus, and the first report of compounds 2, 3, 7, 8, 12, 16 in the species. Chemotaxonomic significance of these compounds is described herein.     

Thiophenes,polyacetylenes and terpenes from the aerial parts of Eclipata prostrata

One new bithiophenes, 5-(but-3-yne-1,2-diol)-5′-hydroxy-methyl-2,2′-bithiophene (2), two new polyacetylenic glucosides, 3-O-β-d-glucopyranosyloxy-1-hydroxy-4E,6E-tetradecene-8,10,12-triyne (8), (5E)-trideca-1,5-dien-7,9,11-triyne-3,4-diol-4-O-β-d-glucopyranoside (9), six new terpenoid glycosides, rel-(1S,2S,3S,4R,6R)-1,6-epoxy-menthane-2,3-diol-3-O-β-d-glucopyranoside (10), rel-(1S,2S,3S,4R,6R)-3-O-(6-O-caffeoyl-β-d-glucopyranosyl)-1,6-epoxy menthane-2,3-diol (11), (2E,6E)-2,6,10-trimethyl-2,6,11-dodecatriene-1,10-diol-1-O-β-d-glucopyranoside (12), 3β,16β,29-trihydroxy oleanane-12-ene-3-O-β-d-glucopyranoside (13), 3,28-di-O-β-d-glucopyranosyl-3β,16β-dihydroxy oleanane-12-ene-28-oleanlic acid (14), 3-O-β-d-glucopyranosyl-(1→2)-β-d-glucopyranosyl oleanlic-18-ene acid-28-O-β-d-glucopyranoside (15), along with fifteen known compounds (1, 3–7, and 16–24), were isolated from the aerial parts of Eclipta prostrata. Their structures were established by analysis of the spectroscopic data. The isolated compounds 1–9 were tested for activities against dipeptidyl peptidase IV (DPP-IV), compound 7 showed significant antihyperglycemic activities by inhibitory effects on DPP-IV in human plasma in vitro, with IC₅₀ value of 0.51 μM. Compounds 10–24 were tested in vitro against NF-κB-luc 293 cell line induced by LPS. Compounds 12, 15, 16, 19, 21, and 23 exhibited moderate anti-inflammatory activities.     

Further constituents of Galianthe thalictroides (Rubiaceae) and inhibition of DNA topoisomerases I and IIα by its cytotoxic β-carboline alkaloids

A new cytotoxic β-carboline alkaloid, 1-methyl-3-(2-hydroxypropan-2-yl)-2-(5-methoxy-9H-β-carbolin-1-yl)-cyclopentanol (1), was isolated from roots of Galianthe thalictroides, together with the alkaloid 1-(hydroxymethyl)-3-(2-hydroxypropan-2-yl)-2-(5-methoxy-9H-β-carbolin-1-yl)-cyclopentanol (2), the anthraquinones 1-methyl-alizarin and morindaparvin-A, the coumarin scopoletin, homovanillic alcohol, (−)-epicatechin, and the steroids stigmast-4-en-3-one, 4,22-stigmastadien-3-one, campest-4-en-3-one, stigmast-4-en-3,6-dione, 6-β-hydroxy-stigmast-4-en-3-one, stigmasterol, campesterol, β-sitosterol, and β-sitosterol-3-O-β-d-glucopyranoside. Among the previously known compounds, homovanillic alcohol is a novel finding in Rubiaceae, while 1-methyl-alizarin, morindaparvin-A, scopoletin, stigmast-4-en-3-one, 4,22-stigmastadien-3-one, campest-4-en-3-one, stigmast-4-en-3,6-dione, and 6-β-hydroxy-stigmast-4-en-3-one is reported for the first time in the genus Galianthe. The cytotoxic β-carboline alkaloids 1 and 2 exhibited potent antitopoisomerase I and IIα activities and strong evidence is provided for their action as topoisomerase IIα poisons and redox-independent inhibitors.     

Unusual lipids and acylglucosylsterols from the roots of Livistona chinensis

A 70% ethanol extract from the roots of Livistona chinensis has been investigated, led to the isolation of 18 compounds, including two new 6′-O-acyl-β-d-glucosyl-β-sitosterols, 6′-O-(2″-hydroxyheptadecanoyl)-β-d-glucosyl-β-sitosterol (1) and 6′-O-(icosa-9″Z,12″Z-dienoyl)-β-d-glucosyl-β-sitosterol (2), two new keto esters, ethyl 16-(dodeca-4″′Z,7″′Z-dienyl)-29-oxo-15-(tetradeca-5″Z,8″Z,11″Z-trienyl) triacontanoate (7), and 16-hydroxy-8-oxohexadecyl tetradecanoate (9), a new unsaturated fatty acid, tetracosa-(11Z,14Z,18Z)-trienoic acid (8), as well as a new fatty alcohol, 10-decylnonadecane-1,19-diol (10). The structures of new compounds were elucidated, based on spectroscopic and chemical methods. The antiproliferative activity against four human tumor cell lines (K562, HL-60, HepG2, and CNE-1) was evaluated. Four compounds (1–3, 5) showed potent antiproliferative effects with the IC₅₀ of 10–100 μM. To our knowledge, this is the first report of the occurrence of 6′-O-acyl-β-d-glucosyl-β-sitosterol and 3-O-acyl-β-sitosterol in the genus Livistona. Keto fatty acids and their esters are also rare in higher plant.     

α-Glucosidase inhibitory constituents from Chrozophora plicata

Five new secondary metabolites have been isolated from Chrozophora plicata including an acacetin derivative (1), three pyrrole alkaloids plicatanins A–C (2–4, resp.) and the bilactone plicatanone (5). Together with these compounds, the known compounds, β-sitosterol (6), methyl p-coumarate (7), 4-hydroxyphenylacetic acid (8), succinic acid (9), speranberculatine A (10), β-sitosterol-3-O-β-d-glucopyranoside (11) and apigenin-5-O-β-d-glucopyranoside (12) have also been isolated. The structures of isolates 1–12 were established by 1D (¹H, ¹³C) and 2D NMR (HMQC, HMBC, COSY) spectroscopy and mass spectrometry (EIMS, HREIMS, FABMS, HRFABMS). The structure of plicatanin A (3) was further confirmed through single crystal X-ray technique. Compounds 1–12 were evaluated for their inhibitory activity against the enzyme yeast α-glucosidase. The compound 4 was found to be most potent with IC₅₀ value 27.8 μM.     

Microbial metabolism of prenylated apigenin derivatives by Mucor hiemalis

6-Prenylapigenin (1) and 8-prenylapegenin (2) were semi-synthesized from apigenin by nuclear prenylation. Morusin (3) was isolated from the root bark of Morus alba L. The microbial transformation studies of these three bioactive prenylated apigenin derivatives were performed using eighteen cell cultures in order to select microorganisms capable of transforming them. It was identified that Mucor hiemalis (KCTC 26779) showed the ability to metabolize the parent compounds (1–3) into three new (4–6) and one known (7) glucosylated derivatives with high efficiency. Their structures were established as 6-prenylapigenin 7-O-β-d-glucopyranoside (4), 8-prenylapigenin 7-O-β-d-glucopyranoside (5), morusin 5-O-β-d-glucopyranoside (6), and morusin 4′-O-β-d-glucopyranoside (7) by the spectroscopic methods.     

Biotransformation of naringin and naringenin by cultured Eucalyptus perriniana cells

The biotransformation of naringin and naringenin was investigated using cultured cells of Eucalyptus perriniana. Naringin (1) was converted into naringenin 7-O-β-d-glucopyranoside (2, 15%), naringenin (3, 1%), naringenin 5,7-O-β-d-diglucopyranoside (4, 15%), naringenin 4′,7-O-β-d-diglucopyranoside (5, 26%), naringenin 7-O-[6-O-(β-d-glucopyranosyl)]-β-d-glucopyranoside (6, β-gentiobioside, 5%), naringenin 7-O-[6-O-(α-l-rhamnopyranosyl)]-β-d-glucopyranoside (7, β-rutinoside, 3%), and 7-O-β-d-gentiobiosyl-4′-O-β-d-glucopyranosylnaringenin (8, 1%) by cultured cells of E. perriniana. On the other hand, 2 (14%), 4 (7%), 5 (13%), 6 (2%), 7 (1%), naringenin 4′-O-β-d-glucopyranoside (9, 4%), naringenin 5-O-β-d-glucopyranoside (10, 2%), and naringenin 4′,5-O-β-d-diglucopyranoside (11, 5%) were isolated from cultured E. perriniana cells, that had been treated with naringenin (3). Products, 7-O-β-d-gentiobiosyl-4′-O-β-d-glucopyranosylnaringenin (8) and naringenin 4′,5-O-β-d-diglucopyranoside (11), were hitherto unknown.     

Gout prophylactic constituents from the flower buds of Lonicera japonica

Two new sesquiterpene glycosides (R)-dehydroxyabscisic alcohol β-d-apiofuranosyl-(1″ → 6′)-β-d-glucopyranoside (1) and (−)-(1S,2R,6R,7R)-1,2,6-trimethyl-8-hydroxy methyltricyclic[5.3.1.0^2,6]-undec-8-en-10-one β-d-apiofuranosyl-(1″ → 6′)-β-d-glucopyranoside (2), were isolated from the flower buds of Lonicera japonica. Their structures were determined by spectroscopic and chemical methods. Compound 2 could significantly decrease monosodium urate-mediated cytokine production from activated macrophage through lowering IL-1β and TNFα.     

Two new guaiane sesquiterpenes from Datura metel L. with anti-inflammatory activity

Chemical investigation of an acidic methanol extract of the whole plants of Datura metel resulted in the isolation of two new guainane sesquiterpenes, 1β,5α,7β-guaiane-4β,10α,11-triol (1) and 1α,5α,7α-11-guaiene-2α,3β,4α,10α,13-pentaol (2), along with eight known compounds: pterodontriol B (3), disciferitriol (4), scopolamine (5), kaempferol 3-O-β-d-glucosyl(1 → 2)-β-d-galactoside 7-O-β-d-glucoside (6), kaempferol 3-O-β-glucopyranosyl(1 → 2)-β-glucopyranoside-7-O-α-rhamnopyranoside (7), pinoresinol 4′′-O-β-d-glucopyranoside (8), (7R,8S,7′S,8′R)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxy-lignan-4-O-β-d-glucopyranoside (9), and (7S,8R,7′S,8′S)-4,9,4′,7′-tetrahydroxy-3,3′-dimethoxy-7,9′-epoxylignan-4-O-β-d-glucopyranoside (10). Their structures were elucidated by extensive spectroscopic methods, including 1D and 2D NMR and MS spectra. Compounds 2-4 and 6-10 were shown to have modest anti-inflammatory effects through inhibition of NO production in LPS-stimulated BV cells.     

Two new antioxidant flavones from the twigs of Eriosema robustum (Fabaceae)

Phytochemical study of the ethanol extract of the twigs of Eriosema robustum, a Cameroonian medicinal plant resulted to the isolation of two new flavones, 2′,3′,5′,5,7-pentahydroxy-3,4′-dimethoxyflavone (1) and 2′,3,5′,5,7-pentahydroxy-4′-methoxyflavone (2), along with five known compounds: 6-prenylpinocembrin (3), 1-O-heptatriacontanoyl glycerol (4), β-sitosterol (5), stigmasterol (6) and 3-O-β-d-glucopyranoside of sitosterol (7). The structure of the isolated compounds were elucidated on the basis of their NMR, UV and MS data, and by comparison with those reported in the literature. The ethanol crude extract, fractions and some isolated compounds (1–4) were evaluated for their radical scavenging capacity using 2,2-diphenyl-1-picryhydrazyl (DPPH). The crude extract, fraction II, the new compounds namely robusflavones A (1) and B (2) exhibited significant antioxidant activity.     

A new phenylpropanoid and an alkylglycoside from Piper retrofractum leaves with their antioxidant and α-glucosidase inhibitory activity

Two new compounds, piperoside (1) and isoheptanol 2(S)-O-β-d-xylopyranosyl (1→6)-O-β-d-glucopyranoside (11), along with 10 known compounds 3,4-dihydroxyallylbenzene (2), 1,2-di-O-β-d-glucopyranosyl-4-allylbenzene (3), tachioside (4), benzyl-O-β-d-glucopyranoside (5), icariside F₂ (6), dihydrovomifoliol-3′-O-β-d-glucopyranoside (7), isopropyl O-β-d-glucopyranoside (8), isopropyl primeveroside (9), n-butyl O-β-d-glucopyranoside (10), isoheptanol 2(S)-O-β-d-apiofuranosyl-(1→6)-O-β-d-glucopyranoside (12), were isolated from the leaves of Piper retrofractum. Their structures were determined from 1D-NMR, 2D-NMR, and HR-ESI-MS spectral, a modified Mosher’s method, and comparisons with previous reports. All of the isolated compounds showed modest α-glucosidase inhibitory (4.60 ± 1.74% to 11.97 ± 3.30%) and antioxidant activities under the tested conditions.     

Vernoguinamide: A new ceramide and other compounds from the root of Vernonia guineensis Benth. and their chemophenetic significance

The chemical investigation of the roots of Vernonia guineensis Benth. (Asteraceae) resulted in the isolation of a new ceramide, named vernoguinamide (1), together with fifteen known compounds, including three anthraquinones, physion (2), erythroglaucin (3) and emodin (4), three triterpenoids, hop-17(21)-en-3β-yl acetate (5), lupeol (6) and betulinic acid (7), six steroids, vernoguinoside A (8), vernoguinoside (9), β-sitosterol 3-O-β-D-glucoside (10), stigmasterol 3-O-β-D-glucoside (11), stigmasterol (12) and β-sitosterol (13) and three fatty acid derivatives, tetracosanoic acid (14), tricosanic acid (15) and arachidic acid glycerol ester (16). The structure of the new compound as well as those of the known compounds were established by spectrometric analysis including HRESI-MS, 1D and 2D-NMR and by comparison with the previously reported data. Among these compounds, the anthraquinones 2–4 and the triterpene 5 were isolated for the first time from Vernonia genus and compounds 6, 7 and 14–16 were extracted for the first time from the species. The isolated compounds were tested for their antibacterial activity and 3, 8 and 9 were the most active compounds against the tested bacteria. Furthermore, the chemophenetic relationships of the isolated compounds and their significance were also discussed.     

Three new neolignan glucosides from the stems of Dendrobium aurantiacum var. denneanum

Three new neolignan glucosides (1–3), together with four known analogs (4–7), have been isolated from the stems of Dendrobium aurantiacum var. denneanum. Structures of the new compounds including the absolute configurations were determined by spectroscopic and chemical methods as (−)-(8R,7′E)-4-hydroxy-3,3′,5,5′-tetramethoxy-8,4′-oxyneolign-7′-ene-9,9′-diol 4,9-bis-O-β-d-glucopyranoside (1), (−)-(8S,7′E)-4-hydroxy-3,3′,5,5′-tetramethoxy-8,4′-oxyneolign-7′-ene-9,9′-diol 4,9-bis-O-β-d-glucopyranoside (2), and (−)-(8R,7′E)-4-hydroxy-3,3′,5,5′,9′-pentamethoxy-8,4′-oxyneolign-7′-ene-9-ol 4,9-bis-O-β-d-glucopyranoside (3), respectively.     

New 19α-hydroxyursane-type triterpenes from the leaves of Meyna spinosa (= Vangueria spinosa), Rubiaceae

Two new 19α-hydroxyursane-type triterpenes, 2α,3α,19α,24,28-pentahydroxyurs-12-ene (1) and meyanthic acid, 3β-acetoxy-2β,19α,23-trihydroxyurs-12-en-28-oic acid (2) along with one new aliphatic ester, myricyl pentadecanoate (3) and five known compounds, 19α-hydroxyasiatic acid (4), oleanolic acid (5), myricyl alcohol (6), β-sitosterol (7) and its glycoside (8) were isolated from the methanolic leaf extract of Meyna spinosa Roxb. ex Link (= Vangueria spinosa Roxb., Rubiaceae). The structures of the new compounds were elucidated on the basis of extensive spectroscopic (including 2D NMR) analysis and comparison with literature. Except oleanolic acid, isolation of known compounds was reported for the first time from this plant.     

Lignan glycosides from the Rhizomes of Smilax trinervula and their Biological activities

Phytochemical investigation of the rhizomes of Smilax trinervula led to isolation and structure elucidation of eight lignan glycosides, including five new lignans, namely, (7S, 8R, 8′R)-4, 4′, 9-trihydroxy-3, 3′, 5, 5′-tetramethoxy-7, 9′-epoxylignan-7′-one 4′-O-β-d-glucopyranoside (1), (7S, 8R, 8′R)-4, 4′, 9-trihydroxy-3, 3′, 5, 5′-tetramethoxy-7, 9′-epoxylignan-7′-one 4-O-β-d- glucopyranoside (2) (7S, 8R)-4, 9, 9′-trihydroxy-3, 3′, 5-trimethoxy-4′, 7-epoxy-8, 5′-neolignan 9′-O-β-d-glucopyranoside (3), (7R, 8R)-4, 9, 9′-trihydroxy-3, 5-dimethoxy-7.O.4′, 8.O.3′- neolignan 9′-O-β-d-glucopyranoside (4), and (7S, 8R)-4, 9, 9′-trihydroxy-3, 3′, 5-trimethoxy-8, 4′-oxy-neolignan 4-O-β-d-glucopyranoside (5), along with three known compounds (6-8). Their structures were established mainly on the basis of 1D and 2D NMR spectral data, ESI–MS and comparison with the literature. Compounds 1-8 were tested in vitro for their cytotoxic activity against four human tumor cell lines (SH-SY5Y, SGC-7901, HCT-116, Lovo). Compounds 3 and 5 exhibited cytotoxic activity against Lovo cells, with IC₅₀ value of 10.4 μM and 8.5 μM, respectively.     

Ulmosides A and B: Flavonoid 6-C-glycosides from Ulmus wallichiana,stimulating osteoblast differentiation assessed by alkaline phosphatase

Chemical investigation of Ulmus wallichiana stem bark resulted in isolation and identification of three new compounds (2S,3S)-(+)-3′,4′,5,7-tetrahydroxydihydroflavonol-6-C-β-d-glucopyranoside (1), (2S,3S)-(+)-4′,5,7-trihydroxydihydroflavonol-6-C-β-d-glucopyranoside (3) and 3-C-β-d-glucopyranoside-2,4,6-trihydroxymethylbenzoate (8), together with five known flavonoid-6-C-glucosides (2, 4–7). Their structures were elucidated using 1D and 2D NMR spectroscopic analysis. The absolute stereochemistry in compounds 1 and 3 were established with the help of CD data analysis and comparison with the literature data analysis. All the isolated compounds (1–8) were assessed for promoting the osteoblast differentiation using primary culture of rat osteoblast as an in vitro system. Compounds 1–3 and 5 significantly increased osteoblast differentiation as assessed by alkaline phosphatase activity.     

Monoterpene glycosides from the seeds of Paeonia suffruticosa protect HEK 293 cells from irradiation-induced DNA damage

Three monoterpene glycosides, β-gentiobiosylpaeoniflorin (1), pyridylpaeoniflorin (2) and (8R)-piperitone-4-en-9-O-β-d-glucopyranoside (3), together with eight known compounds, which were 6′-O-β-glucopyranosylalbiflorin (4), paeoniflorin (5), debenzoyl albiflorin (6), albiflorin (7), oxypaeoniflorin (8), 8-debenzoylpaeoniflorin (9), 8-debenzoylpaeonidanin (10) and 1-O-β-d-glucopyranosylpaeonisuffrone (11), respectively, were isolated from the seeds of Paeonia suffruticosa. The structures of these compounds were elucidated based on spectral analysis, including 1D, 2D NMR and CD spectrum. In the in vitro cell culture system, compounds 1, 2, 4, 6, 7, 8, 10 and 11 at concentrations of 10 and 20 μM protected HEK293 cells against ⁶⁰Co γ-rays irradiation induced cell death efficiently, with compounds 2 and 7 showing the greatest potential; Compounds 1, 2, 4, 6, 7 and 11 brought about a significant reduction in the population of apoptotic cells. Furthermore, the irradiation induced formation of γ-H2AX foci, an important marker of ionizing radiation-induced DNA double-strand breaks (DSBs), was significantly inhibited by compound 2 and 7 too, suggesting a protective effect of these compounds on irradiation-induced cell damage.     

Chemical constituents from Psychotria arborea Hiern (Rubiaceae)

The chemical study of the stems extract of Psychotria arborea Hiern led to the isolation of thirteen compounds, including four anthraquinones: 2-methylanthracene-9,10-dione (1), 2-methoxyanthracene-9,10-dione (2), 2-hydroxy-3-methylanthracene-9,10-dione (3) and 3-hydroxy-1-methoxy-2-methylanthracene-9,10-dione (4); two diterpenes: ent-kaur-16-en-19-oic acid (5) and 15-acetoxy-ent-kaur-16-en-19-oic acid (6); two triterpenes, β-amyrin (8) and oleanolic acid (9), one flavonoid: Quercetin (7), three sterols: A mixture of stigmasterol (10) and β-sitosterol (11) and β-sitosterol-3-O-β-D-glucopyranoside (12) and one fatty acid (13). The structures of these compounds were elucidated based on NMR and HR-ESIMS analysis, further supported by comparison with previously reported spectral data. Compounds 1–4 and compounds 10–12 were tested for their antibacterial activity against three bacteria strains Escherichia coli, Staphylococcus aureus and Salmonella enterica. All these tested compounds were found to be inactive. Furthermore, the chemotaxonomic significance of the obtained compounds was discussed in detail.