Inhibitory effect of macabarterin, a polyoxygenated ellagitannin from Macaranga barteri, on human neutrophil respiratory burst activity.

An ellagitannin with a 2,4-acyl group, named macabarterin (1), and a new ellagic acid glycoside, 3-O-methylellagic acid 4-O-β-d-xylopyranoside (2), were isolated from the stem bark extract of Macaranga barteri along with five known phenolic compounds, ellagic acid (3), 3-O-methylellagic acid (4), gallic acid (5), methyl gallate (6), and scopoletin (7). The structures of 1 and 2, as well as those of the known compounds, were elucidated on the basis of spectroscopic data and by comparison with reported data. Compounds 1-5 and 7 were tested for their anti-inflammatory potential in a cell-based respiratory burst assay, compound 1 being found an inhibitor of the superoxides produced in the cellular system.

Antimalarial compounds from the root bark of Garcinia polyantha Olv.

Eight compounds were isolated from the roots of Garcinia polyantha, and identified. Two of them, the xanthone garciniaxanthone I (1), and the triterpene, named garcinane (2), are reported as new natural products. The structures of the new compounds were elucidated on the basis of 1D and 2D NMR spectroscopic studies.

Polyanxanthone A, B and C, three xanthones from the wood trunk of Garcinia polyantha Oliv.

Three xanthones, polyanxanthone A (1), B (2) and C (3) have been isolated from the methanol extract of the wood trunk of Garcinia polyantha, along with five known xanthones: 1,3,5-trihydroxyxanthone (4); 1,5-dihydroxyxanthone (5); 1,3,6,7-tetrahydroxyxanthone (6); 1,6-dihydroxy-5-methoxyxanthone (7) and 1,3,5,6-tetrahydroxyxanthone (8). Their structures were determined by means of 1D- and 2D-NMR techniques. Some of the above compounds were screened for their anticholinesterase activity on acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes.

Antibacterial activities of the extracts and conessine from Holarrhena floribunda G. Don. (Apocynaceae).

The methanolic extract and conessine isolated from the stem bark of Holarrhena floribunda (Hf) were tested for their antibacterial activities on Bacillus: Bacillus cereus, Bacillus subtilis, Bacillus megaterium and Bacillus stearothermophilus using the disc diffusion method. Phytochemical analysis of the crude extract and fractions was also conducted. The inhibition parameters of the crude methanol extract and the total alkaloid fraction were determined using the macrodilution method.

Bafoudiosbulbins A, and B, two anti-salmonellal clerodane diterpenoids from Dioscorea bulbifera L. var sativa.

Two clerodane diterpenoids, Bafoudiosbulbins A 1, and B 2, together with five known compounds: tetracosanoic acid, 1-(tetracosanoyl)-glycerol, trans-tetracosanylferulate, beta-sitosterol and 3-O-beta-D-glucopyranosyl-beta-sitosterol were isolated from the tubers of Dioscorea bulbifera L. var sativa. Their structures were established by spectroscopic methods (1D and 2D-NMR, MS) and X-ray crystallographic diffraction analysis of compound 1.

Xanthones from Garcinia smeathmannii (Oliver) and their antimicrobial activity.

Two new xanthones, smeathxanthone A (1) (2-(3,7-dimethyl-2,6-octadienyl)-1,3,5,8-tetrahydroxyxanthone) and smeathxanthone B (2) (5,7,10-trihydroxy-2-methyl-2-(4-methylpent-3-enyl)[2H, 6H]pyrano[3,2-b]xanthen-6-one), have been isolated from the stem bark of Garcinia smeathmannii, and their structures elucidated on the basis of 1D and 2D NMR experiments. 1,3,5-Trihydroxyxanthone and 1,5-dihydroxyxanthone were also obtained. The compounds showed only modest activity against a range of bacteria and yeasts.

Triterpenes from Maesopsis eminii.

Two pentacyclic triterpenes, 1alpha,3beta-dihydroxybauer-7-en-28-oic acid (1) and 3beta-hydroxybauer-7-en-28-oic acid (2), together with sitosterol-3-beta-O-d-glucopyranoside and stigmasterol have been isolated from the bark of the plant Maesopsis eminii. Their structures have been elucidated by spectroscopic methods. One of the triterpenes (1) is new, and its structure was confirmed by X-ray crystallographic analysis.

In vitro anti-inflammatory activity of 23-hydroxyursolic acid isolated from Cussonia bancoensis in murine macrophage RAW 264.7 cells.

In the present study, the effects of various triterpenoids isolated from the stem bark of Cussonia bancoensis, namely, ursolic acid ( 1), 23-hydroxyursolic acid ( 2), 3-O-alpha- L-arabinopyranosyl-23-hydroxyursolic acid (3), and 3-O-beta-D-glucopyranosyl-23-hydroxyursolic acid ( 4) were evaluated on lipopolysaccharide (LPS)-induced nitric oxide (NO) and prostaglandin E (2) (PGE (2)) release by the macrophage cell line RAW 264.7. Of the tested triterpenoids, 23-hydroxyursolic acid ( 2) was found to be the most potent inhibitor of NO production, and also significantly reduced PGE (2) release.

Saponins from Cussonia bancoensis and their inhibitory effects on nitric oxide production.

Two new triterpenoid saponins (1 and 2) were isolated from the stem bark of Cussonia bancoensis together with the known stigmasterol, ursolic acid, 23-hydroxyursolic acid (3), and 3beta-hydroxylup-20(29)-en-28-oic acid. On the basis of their spectroscopic data and on chemical transformations, the structures of the new saponins have been established as 3-O-(alpha-Ll-arabinopyranosyl)-23-hydroxyursolic acid (1) and 3-O-(beta-D-glucopyranosyl)-23-hydroxyursolic acid (2). In a nitric oxide (NO)-production bioassay, compound 3 exhibited significant NO inhibitory activity, while compounds 1 and 2 were less potent than 3.

In vivo anti-nociceptive and anti-inflammatory effect of the two triterpenes, ursolic acid and 23-hydroxyursolic acid, from Cussonia bancoensis.

Triterpenoids, ursolic acid (1) and 23-hydroxyursolic acid (2) were obtained from the hydrolysis of BuOH fraction of Cussonia bancoensis extract to test antinociceptive and anti-inflammatory effect of C. bancoensis (Araliaceae). Compound 1 and 2 exhibited anti-nociceptive effects, which were determined by acetic acid-induced writhing test and hot plate test.

Quinovic acid glycosides from Mitragyna stipulosa--first examples of natural inhibitors of snake venom phosphodiesterase I.

Phytochemical investigations on the non-alkaloidal extracts of Mitragyna stipulosa bark has led to the isolation of a series of triterpenoids mainly consisting of quinovic acid ([structure: see text]) and its glycoside derivatives [structure: see text] and [structure: see text]. The other constituents isolated include alpha-amyrin, 3beta-acetyl ursolic acid and a mixture of oleanolic and ursolic acid and beta-sitosterol glucopyranoside. Their structures were identified by spectral and chemical studies and compounds [structure: see text] and [structure: see text] were, respectively, identified as quinovic acid 3-O-[beta-D-glucopyranoside] (quinovin glycoside C) and quinovic acid 3-O-[beta-D-quinovopyranoside]-27-O-[beta-D-glucopyranosyl] ester.

Structure-activity relationship of triterpenoids isolated from Mitragyna stipulosa on cytotoxicity.

Chromatographic separation of the stem bark extract of Mitragyna stipulosa afforded triterpene derivatives ursolic acid (1), quinovic acid (2), quinivic acid 3-O-beta-D-glucopyranoside (3, quinovin glycoside C), quinovic acid 3-O-[(2-O-sulfo)-beta-D-quinovopyranoside] (4, zygophyloside D) and quinovic acid 3-O-beta-D-quinovopyranosyl-27-O-beta-D-glucopyranosyl ester (5, zygophyloside B). These five compounds were subjected to the cytotoxicity on MTT assay system. Compound 1 among tested showed the most potent cytotoxicity.