Isolation of new flavan-3-ol and lignan glucoside from Loropetalum chinense and their antimicrobial activities

Phytochemical and antimicrobial activity study on the ethanol extract of the leaves and stems of Loropetalum chinense led to the isolation of a new flavan-3-ol compounds, 8-[1-(3,4-dihydroxyphenyl)-3-methoxy-3-oxopropyl]-catechin (loropetaliside A) (1) and a new lignan glucoside, 1-(5-hydroxy-3-methoxyphenyl)-2-(2-β-glucopyranosyl-4-hydroxy-5-(1-(E)propen-3-ol)-phenyl)-propane-3-ol (loropetaliside B) (3) and several known compounds manglieside D (2), quercetin (4), kaempferol-3-O-D-glucopyranoside (5), quercetin-3-O-β-L-rhamnoside (6) and tiliroside (7). Their structures were elucidated on the basis of extensive spectroscopic analysis.     

New triterpenoid saponins from Leontice smirnowii

Three new triterpene saponins, leonticins I (1), J (2) and L (3) were isolated from the tubers of Leontice smirnowii. On the basis of spectroscopic methods, including 2D NMR experiments (DEPT, gs-COSY, gs-HMQC, gs-HMBC and gs-HSQC-TOCSY), mass spectrometry (HR-ESI-MS) and chemical degradation, the structures of the new compounds were elucidated as 3-O-β-D-glucopyranosyl-(1 → 3)-[β-D-xylopyranosyl-1 → 2)]-α-L-arabinopyranosyl-28-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]-3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid (1), 3-O-[β-D-xylopyranosyl-(1 → 3)-β-D-galactopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)-α-L-arabinopyranosyl]-28-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]-3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid (2) and 3-O-[β-D-xylopyranosyl-(1 → 3)-β-D-galactopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 3)]-[β-D-xylopyranosyl-(1 → 2)]-α-L-arabinopyranosyl]-28-O-[α-L-rhamnopyranosyl-(1 → 4)-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosyl]-3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid (3), respectively. The aglycone 3β-hydroxy-30-norolean-12,20(29)-dien-28-oic acid was observed for the first time in Leontice species.     

Homoisoflavanones from Ledebouria floribunda

The bulbs of Ledebouria floribunda (Baker) Jessop have yielded two novel compounds, 7-O-[α-rhamnopyranosyl-(1→6)-β-glucopiranosyl]-5-hydroxy-3-(4-methoxybenzyl)-chroman-4-one (1) and 7-O-[α-rhamnopyranosyl-(1→6)-β-glucopiranosyl]-5-hydroxy-3-(4′-hydroxybenzyl)-chroman-4-one (2) along with five other known compounds, 5,7-dihydroxy-3-(4′-methoxybenzyl)-chroman-4-one or 3,9-dihidroeucomin (3), 5,7-dihidroxy-6-methoxy-3-(4′-methoxybenzyl)-chroman-4-one (4), 5,7-dihidroxy 3-(4′-hydroxybenzyl)-chroman-4-one or 4,4′-demethyl-3,9-dihydropuctatin (5), 5,7-dihidroxy-3-(4′-hydroxybenzyl)-6-methoxy-chroman-4-one or 3,9-dihydroeucomnalin (6) and 7-hydroxy-3-(4′-hydroxybenzyl)-5-methoxy-chroman-4-one (7). Their structures were elucidated by spectra analysis. The seven homoisoflavanones were found to be antioxidant against DPPH radical and β-carotene/linoleic acid system.     

Antioxidant neolignan and phenolic glucosides from the fruit of Euterpe oleracea

Three new glucosides, namely, (–)-7R8S-7′,8′-dihydroxy-dihydrodehydroconiferyl alcohol-9-O-β-d-glucopyranoside (1), (+)-7S8R-7′,8′-dihydroxy-dihydrodehydroconiferyl alcohol-9-O-β-d-glucopyranoside (2) and 4-hydroxy-2-methoxyphenyl 1-O-[6-(hydrogen 3-hydroxy-3-methylpentanedioate)]-β-d-glucopyranoside (3), along with 6 known compounds were isolated from the fruit of Euterpe oleracea Mart. Their structures were elucidated based on spectroscopic analyses including NMR, HR-ESI-MS and CD. All the isolated compounds demonstrated significant antioxidant activity and 2 displayed moderate cytotoxicity against HL-60 cells.     

Isolation and structural characterization of glycosides from an anti-angiogenic extract of Monnina obtusifolia H.B.K.

Angiogenesis, the growth of new blood vessels from the pre-existing vasculature is of physiological and pathological importance. Substantial data over the last decade has implicated uncontrolled angiogenesis with various pathological states. Vascular endothelial growth factors (VEGFs) play a critical role in its regulation, and have become one of the most interesting anti-angiogenesis targets. We have investigated the anti-angiogenic potential of plant extracts in a preliminary ELISA screening. The n-BuOH extract obtained from the leaves of Monnina obtusifolia (Polygalaceae) demonstrated an inhibition of VEGF-A or Placental Growth Factor interaction with Flt-1 (VEGF receptor 1), with an inhibition over 50% in particular for VEGF-A/Flt-1 interaction at a concentration of 500 μg/mL. Successively fractionation of the bioactive n-BuOH extracts of M. obtusifolia aerial parts led to the isolation of six new compounds, 1-O-(4-hydroxy-2-methylene-butanoic acid)-6-O-β-d-(4-hydroxy-2-methylene-butanoyl)-glucopyranose (1), 1-O-(isopentenyl)-6-O-β-d-(4-hydroxy-2-methylene-butanoyl)-glucopyranose (2), 1-O-(4-hydroxy-2-methylene-butanoic acid)-6-O-β-d-(isovaleroyl)-glucopyranose (3), 1-O-(3-methylbut-3enyl)-6-O-β-d-(isovaleroyl)-glucopyranose (4), two new sucrose esters, 3,4-O-β-d-di-feruloyl-fructofuranosyl-6-O-α-d-(p-coumaroyl)-glucopyranoside (5), and 3,4-O-β-d-di-feruloyl-fructofuranosyl-6-O-α-d-(caffeoyl)-glucopyranoside (6), together with known flavonoids. Their structures were established on the basis of detailed spectral analysis. Since none of the isolated compounds showed a relevant inhibition of VEGFs, the biological activity observed for the butanolic extract might be due to the presence of a combination of compounds acting synergistically.     

Cytotoxic taraxerane triterpenoids from Saussurea graminea

Four new taraxerane triterpenoids, 1β,3β-dihydroxy-11α,12α-oxidotaraxerane (1), 28-hydroxy-11α,12α-oxidotaraxerane-3-one (2), 3β-hydroxy-11α,12α-oxidotaraxerane-28-al (3), and 3-O-acetyl-11α,12α-oxidotaraxerane-28-al (4), together with three known compounds 3β-hydroxy-11α,12α-oxidotaraxerane (5), 3β,28-dihydroxy-11α,12α-oxidotaraxerane (6), and 11α,12α-oxidotaraxerane-3-one (7), were isolated from the 70% EtOH extract of Saussurea graminea. Their structures were elucidated on the basis of extensive 1D and 2D NMR (COSY, HMQC, HMBC and NOESY) analyses. The isolated compounds were evaluated in vitro for cytotoxic properties against eight tumor cell lines (A-549, BGC-823, HCT15, HeLa, HepG2, MCF-7, SGC-7901 and SK-MEL-2).     

A new dihydrodibenzodioxinone from Hypericum x ‘Hidcote’

One new compound, 4-hydroxy-4a,7-dimethoxy-4,4a-dihydrodibenzo-p-dioxin-2(3H)-one (1), was isolated from the aerial parts of the hybrid Hypericum x ‘Hidcote’, together with 8 known compounds: caryophyllene-4,5-epoxide, quercetin, quercitrin, quercetin-3-O-β-D-galactopyranoside, epicatechin, betulinic acid methyl ester, β-sitosterol and β-sitosterol glucoside. The structure of the new compound, as well as its absolute configuration, was established by means of spectroscopic data analyses, including 2D NMR spectroscopy and X-ray structural analysis.     

Monoterpenes with antibacterial activities from a Cameroonian medicinal plant Canthium Multiflorum (Rubiaceae)

Investigation of the crude extract obtained from the aerial parts of Canthium multiflorum led to the isolation of a new iridoid (1) together with twelve known compounds. The structures of these compounds were elucidated by interpretation of 1D and 2D NMR spectroscopic data, accurate mass measurements and comparison with analytical data of previously known analogues. Most of the isolated compounds have been reported for the first time from C. multiflorium. The antimicrobial activities of the isolated compounds were evaluated on five different bacterial strains using agar diffusion technique. The Gram-positive bacterium Staphylococcus aureus subsp. aureus (DSM 799), and the Gram-negative bacteria Actinobacter calco-aceticus (DSM 30006), Serratia plymuthica (DSM 4540), Pseudomonas stutzeri (DSM 4166) and Escherichia coli (DSM 1116) were employed for this purpose. The new iridoid, named 6-oxo-genipin (1), demonstrated significant inhibitory activity against all microbial strains tested, especially the pathogen Staphylococcus aureus. In addition, the compounds 3, 4 and 9 exhibited antiplasmodial activity against Plasmodium falciparum strain K1 and weak cytotoxicity against L6 cell lines.     

A new triterpene saponin from Androsace integra

A new triterpene saponin, androsacin (1), along with two known compounds, ardisiacrispin A (2) and saxifragifolin A (3), were isolated from the whole plants of Androsace integra. The chemical structure of the new compound was elucidated as 3β-O-{β-D-glucopyranosyl-(1 → 4)-O-β-D-xylopyranosyl-(1 → 2)-O-β-D-glucopyranosyl-(1 → 4)-[O-β-D-glucopyranosyl-(1 → 2)]-α-L-arabinopyranosyl}-16α-hydroxy-13β,28-epoxy-olean-30-al on the basis of spectral evidence. Ardisiacrispin A (2) was cytotoxic toward HepG2 cancer cell with the GI₅₀ value of 1.56 μM.     

Progress of oxidation of non-phenolic lignin moiety in an oxygen bleaching process via the conversion of non-phenolic into phenolic lignin moiety

To examine whether non-phenolic lignin moiety is converted into the new phenolic counterpart by the participation of active oxygen species (AOS) under oxygen bleaching conditions, a β-O-4 type dimeric lignin model compound, 2-(2-methoxyphenoxy)-1-(3,4-dimethoxyphenyl)propane-1,3-diol (I), 2-(3,5-difluorophenoxy)-1-(4-hydroxy-3-methoxyphenyl)propane-1,3-diol (III), or 2-(3,5-difluorophenoxy)-1-(3,4-dimethoxyphenyl)propane-1,3-diol (IV), was treated under conditions similar to those for oxygen bleaching. A phenolic compound, 4-hydroxy-3-methoxybenzyl alcohol, was added together to generate AOS in the reaction of compound I or IV. The results obtained suggested that AOS attack the side chains of compounds I, III, and IV accompanied by the β-O-4 bond cleavages and the liberations of the corresponding phenolic compounds, 2-methoxyphenol (II), 3,5-difluorophenol (V), and compound V, respectively. However, the rapid liberation of compound V in the oxygen-alkali treatment of compound III may mainly be caused by alkaline-induced reactions and/or some oxidation reactions of the primary degradation product of compound III, a muconic acid derivative.     

Antibacterial triterpenes from the threatened wood-decay fungus Fomitopsis rosea

From a biologically active extract from the fungus Fomitopsis rosea, two new lanostane triterpenes were isolated, 3α-(3′-butylcarboxyacetoxy)oxepanoquercinic acid C 1 and 3α-hydroxy-24-methylene-23-oxolanost-8-en-26-carboxylic acid 2, along with three known triterpenes, 3–5, and the epidioxy sterol derivative 6. The structures of the compounds were elucidated based on their spectral properties. All triterpenes demonstrated antibacterial activity against S. aureus but possessed no antiradical activity against DPPH radicals.     

Bioactive phenolics from the fruits of Livistona chinensis

This study investigated the antioxidant and cytotoxic activity of the phenolics isolated from the fruits of Livistona chinensis. Four new compounds, 1-{ω-isoferul[6- (4-hydroxybutyl)pentadecanoic acid]}-glycerol (1), E-[6′-(5″-hydroxypentyl)tricosyl]-4-hydroxy-3-methoxycinnamate (2), 2-(3′-hydroxy-5′-methoxyphenyl)-3-hydroxylmethyl-7-methoxy-2,3-dihydrobenzofuran-5- carboxylic acid (3), 7-hydroxy-5,4′-dimethoxy-2-arylbenzofuran (4), together with eleven known phenolics (5-15), were isolated and identified. Among these compounds, 1-4, 5-O-caffeoylshikimic acid (5), caffeic acid (7), and 3-O-caffeoylshikimic acid (8) showed potent antioxidant activity. 1-5, and 8 showed potent antiproliferative activities with IC₅₀ values among 5-150 μM against HepG2 human liver cancer, HL-60 human myeloid leukemia, K562 human myeloid leukemia, and CNE-1 human nasopharyngeal carcinoma cell lines. On the basis of these findings, it could be proposed that the fruits of L. chinensis may serve as attractive mines of powerful anticancer and antioxidant agents for various purposes.     

Chemical constituents from endophytic fungus Fusarium oxysporum

A new oxysporidinone analogue (1) and a new 3-hydroxyl-2-piperidinone derivative (2), along with the known compounds (−)-4,6′-anhydrooxysporidinone (3), (+)-fusarinolic acid (4), gibepyrone D (5), beauvercin (6),cerevisterol (7), fusaruside (8), and (2S,2′R,3R,3′E,4E,8E)-1-O-D-glucopyranosyl-2-N-(2′-hydroxy-3′-octadecenoyl)-3-hydroxy-9-methyl-4,8-sphingadienine (9) were isolated from Fusarium oxysporum. Compounds 1-9 were evaluated for cytotoxicity using the MTT method against cancer cell lines, PC-3, PANC-1, and A549. Beauvericin showed cytotoxicity against PC-3, PANC-1, and A549 with IC₅₀ value of 49.5 ± 3.8, 47.2 ± 2.9, and 10.4 ± 1.6 μM, respectively. Beauvericin also exhibited anti-bacterial activity towards methicillin-resistant Staphylococcus aureus (MIC = 3.125 μg/mL) and Bacillus subtilis (MIC = 3.125 μg/mL).     

New anthraquinone glycosides from the roots of Morinda citrifolia

Six new anthraquinone glycosides: digiferruginol-1-methylether-11-O-β-gentiobioside (1); digiferruginol-11-O-β-primeveroside (2); damnacanthol-11-O-β-primeveroside (3); 1-methoxy-2-primeverosyloxymethyl-anthraquinone-3-olate (4); 1-hydroxy-2-primeverosyloxymethyl-anthraquinone-3-olate (5); and 1-hydroxy-5,6-dimethoxy-2-methyl-7-primeverosyloxyanthraquinone (6) were isolated from Morinda citrifolia (Rubiaceae) roots together with four known anthraquinone glycosides. The structures of the new compounds were established using spectral methods. For five of the new compounds, the sugar is attached via the hydroxymethyl group of the anthraquinone C-2 carbon. This type of bond is rarely found for anthraquinone glycosides isolated from natural sources.     

Three new triterpenoid saponins from root of Gardenia jasminoides Ellis

Three new compounds (Gardeniside A–C), 11α,12α-epoxy-3β-[(O-β-D-glucuronopyranoside-6′-O-methly ester)oxy]olean-28,13-olide (1), siaresinolic acid 3-O-β-D-glucuronopyranoside-6′-O-methly ester (2), and 3-O-β-D- glucuronopyranoside-6′-O-methly ester-siaresinolic acid-28-O-β-D- glucopyranoside (3), with seven known compounds oleanolic acid 3-O-β-D- glucuronopyranoside-6′-O-methly ester (4), oleanolic acid 3-O-β-D- glucuropyranoside (5), hederagenin 3-O-β-D- glucuronopyranoside-6′-O- methly ester (6), chikusetsusaponin IVa methyl ester (7), chikusetsusaponin (8), chikusetsusaponin IVa butyl ester (9), siaresinolic acid 28-o-β-d-glucopyranosyl ester (10) were isolated from the root of Gardenia jasminoides Ellis. Six compounds (1, 4–7, and 9) showed cytotoxic activities against HeLa, A549, MCF-7 and A354-S2 cell lines.     

Protection against neurodegenerative diseases of Iris pseudopumila extracts and their constituents

The present study describes for the first time the in vitro properties of Iris pseudopumila flowers and rhizomes extracts and their constituents. The methanolic extract of rhizomes showed significant anti-inflammatory activity through inhibition of NO production in the murine monocytic macrophage cell line RAW 264.7. Among the isolated compounds, those which most effectively inhibited LPS-induced NO production were irisolidone and 7-methyl-tectorigenin-4′-O-[β-D-glucopyranosyl-(1→6)-β-D-glucopyranoside], with IC₅₀ values of 23.6 μM and 29.4 μM respectively. Isoorientin and isovitexin exhibited the most promising activity against AChE with IC₅₀ of 26.8 μM and 36.4 μM, respectively. The same compounds exhibited also the higher activity against BChE.     

Glycyrrhetinic acid protects mice from Staphylococcus aureus pneumonia

In the present study, the antimicrobial activity of glycyrrhetinic acid (GA) against Staphylococcus aureus, and its influence on the production of S. aureus alpha-haemolysin (Hla) were investigated, along with the in vivo activity of GA against S. aureus-induced pneumonia. GA could not inhibit the growth of S. aureus, but the secretion of Hla by S. aureus was significantly inhibited by low concentrations of GA in a dose-dependent manner. Furthermore, in vivo data show that GA provides protection against staphylococcal pneumonia in a murine model system.     

Bioactive cis-stilbenoids from the tubers of Scirpus yagara

Two new cis-stilbenoids, sciryagarol I (1) and II (2) were isolated from the EtOAc extract of the tubers of Scirpus yagara, together with four known compounds. The structures of all compounds were determined by comprehensive analyses of their spectroscopic data and comparison with literature information. The compounds 3, 4 and 6 were isolated for the first time from this genus. Some compounds were tested for their cytotoxicity against human tumor cell lines and antimicrobial activity. Compounds 1–4 showed significant cytotoxicity against the Hela cell lines with IC₅₀ values ranging from 7.21 to 61.21 μM. 1 and 2 exhibited some antimicrobial activity against Staphylococcus aureus and Candida albicans with uniform MICs of 79.3 μl/ml for 2, and 152 μl/ml for 1, respectively.     

Two new tryptophan derivatives from the seed kernels of Entada rheedei: Effects on cell viability and HIV infectivity

Two new tryptophan derivatives, N-sulfonyl-L-tryptophan (tryptorheedei A) (1) and 3-(N-sulfonylindolyl)-D-lactic acid (tryptorheedei B) (2) together with the known 5-O-β-D-glucopyranosyl-2-hydroxyphenylacetic acid (3), 1-O-methylglucopyranoside, entadamide A, homogentisic acid and 3-O-β-D-glucopyranosyl-β-sitosterol, were isolated from the seed kernels of Entada rheedei (Mimosaceae). Their structures were established using 1D and 2D NMR spectroscopy, mass spectrometry and by comparison with spectroscopic data reported in the literature. Compounds 1 and 2 showed no toxicity to TZM and Human PBMC cells. Both compounds 1 and 2 were found to promote early infection events in HIV, likely by inhibiting the enzyme indolamine 2,3-dioxygenase (IDO) and preventing tryptophan depletion. Inhibition of IDO acutely in HIV infection inhibits viral replication, but chronic activation of IDO leads to immune impairment in AIDS. IDO is also the gatekeeper enzyme for kynurenine metabolism, a pathway involved in serotonin and melatonin biosynthesis and the regulation of glutamate and dopamine levels in the brain. Therefore inhibition of IDO might explain both the reported medicinal and neuropsychiatric effects of E. rheedei.     

Cytotoxic triterpene saponins from the leaves of Aralia elata

Phytochemical investigation of the leaves of Aralia elata has led to the isolation of four new compounds, 3-O-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl oleanolic acid (1), 3-O-[β-D-glucopyranosyl (1→3)-β-D-glucopyranosyl (1→3)]-[β-D-glucopyranosyl (1→2)]-β-d-glucopyranosyl hederagenin 28-O-β-D-glucopyranoside (2), 3-O-{[β-D-glucopyranosyl (1→2)]-[β-d-glucopyranosyl (1→3)-β-d-glucopyranosyl (1→3)]-β-D-glucopyranosyl} oleanolic acid 28-O-β-D-glucopyranosyl ester (3) and 3-O-[β-D-glucopyranosyl (1→2)]-[β-D-glucopyranosyl (1→3)]-β-d-glucopyranosyl caulophyllogenin (4) and two known compounds, 3-O-[β-D-glucopyranosyl (1→3)-α-l-arabinopyranosyl]-echinocystic acid (5) and 3-O-α-L-arabinopyranosyl echinocystic acid (6). The structural determination was accomplished with spectroscopic analysis, in particular (13)C-NMR, 2D-NMR and HR-ESI-MS techniques. Compounds 1-6 were tested for their inhibition of the growth of HL60, A549 and DU145 cancer cells. Compound 1 showed significant cytotoxic activity against HL60 and A549 cancer cells with IC(50) values of 6.99μM and 7.93μM respectively. In addition, compounds 5 and 6 showed significant cytotoxic activity against HL60 cancer cells with IC(50) values of 5.75μM and 7.51μM, respectively.