Screening of plants from new caledonia and vanuatu for inhibitory activity of xanthine oxidase and elastase.

A series of 38 plants (55 plant extracts) from New Caledonia and 22 plants (40 plant extracts) from Vanuatu (Efate and Erromango islands) were screened for xan-thine oxidase (XOD) and elastase inhibitory activity. Of the crude extracts 82% were found to possess xanthine oxidase inhibitory activity, and 23% were active against elastase, at a concentration of 50 µg/ml. The methanol extracts of Cunonia montana Schlechter (Cunoniaceae) and Amyema scandens Danser (Loranthaceae), bark and leaves, respectively, exhibited the highest activity in both the assays. C. montana bark extract at 50 µg/ml exhibited 85 and 84% inhibition of XOD and elastase, respectively. IC 50 values were 23 ± 0.82 and 41 ± 3 µg/ml, respectively, for XOD and elastase. A. scandens leaf extract, at 50 µg/ml, exhibited 88 and 71% inhibition of XOD and elastase, respectively. IC 50 values were 13 ± 0.48 and 44 ± 2.2 µg/ml respectively, for XOD and elastase.

LC-UV-electrospray-MS-MS mass spectrometry analysis of plant constituents inhibiting xanthine oxidase.

PURPOSE: A previous screening showed that Amyema scandensi [corrected] Danser (Loranthaceae) efficiently inhibited XOD. The aim of this study was to identify the compounds with anti-XOD properties. For this purpose, Electrospray Tandem Mass Spectrometry (ESI-MS-MS) coupled with UV and Diode Array LC techniques were employed. METHODS: Leaves were delipidized with petroleum ether and extracted with acetone:water 70:30, v:v. The extract was fractionated into the ethyl acetate and water soluble phases. Chemical investigation was performed following the bioactivity guided fractionation. Two fractions with anti-XOD activity were isolated by silica gel column chromatography of the ethyl acetate phase and analyzed by LC-UV-ESI-MS-MS. RESULTS: The compounds identified with authentic standards were: catechin, epicatechin, epicatechin-3-gallate, quercetin-3-O-glucoside, quercetin-3-O-rhamnoside, and isorhamnetin-3-O-glucoside. Other constituents, only partially characterized, were a procyanidin dimer, a procyanidin trimer, three dimers epi/catechine-epi/catechine gallate and isorhamnetin-O-deoxyhexose. The anti-XOD activity was mainly due to galloyl-containing oligomeric proanthocyanidins. CONCLUSIONS: The coupling of UV Diode Array-HPLC with ESI-MS-MS represents a versatile tool for the rapid characterization of compounds in complex mixtures, avoiding time-consuming previous isolation.

Guiera senegalensis J. F. Gmelin (Combretaceae): Biological activities and chemical investigation.

Guiera senegalensis J. F. Gmelin (Combretaceae) leaves are used in African traditional medicine for gastrointestinal disorders, cough and topically for wound healing. This paper regards the evaluation of antiradical, antielastase, antimicrobial, genotoxic and antimutagenic activities of the leaf extracts and the determination of chemical structure of the elastase inhibitors. Antimicrobial activity was tested against Gram positive and negative bacteria, moulds and yeasts. Genotoxic potential was assayed with Bacillus subtilis rec -assay and Salmonella-microsome test. The latter was used also for determining antimutagenic activity. Antiradical properties were evaluated as inhibition of ADP-Fe(2+) induced lipoperoxidation in rat liver microsomes. Porcine pancreatic elastase was used to test enzyme inhibition. The methanolic extract was fractionated with dichloromethane, w-butanol and water and these fractions were tested for the above mentioned activities. The crude extract possessed a mild antimicrobial effect only on Gram positive bacteria (MIC 0.8-1.5 mg/ml) and the effect was associated to dichloromethane and n-butanol fractions. The crude extract and the dichloromethane and n-butanol fractions were weakly genotoxic but showed also a significant antimutagenicity. Inhibition of lipoperoxidation was assignable mainly to the n-butanol fraction. Elastase was inhibited (IC(50) 181 µg/ml) and the inhibition was retained in the water soluble fraction (IC(50) 37µg/ml). The compounds responsible for the enzyme inhibition were a mixture of proanthocyanidins constituted predominantly by (-)-epicatechin and (-)-epigallocatechin units. The mean degree of polymerization was 2-6.