Antioxidant lignans from the leaves of ficus exasperata

No Abstract.Nigerian Journal of Natural Products and Medicine Vol. 10 () 2006: pp.111-11

Isolation of two flavonoids from Bauhinia Monandra (KURZ) leaves and their antioxidative effects

Bauhinia monandra (Kurz), traditionally use in the treatment of diabetes with established significant anti-diabetic activity was investigated for its antioxidant constituents since the activity demonstrated can be linked to the presence of antioxidant compounds. Bioassay directed fractionation of the ethyl acetate soluble leaves extract has led to isolation of two active compounds identified as: Quercetin-3-O-rutinoside (1) and Quercetin (2). The molecular structures elucidations of both compounds were carried out using spectroscopic studies (1H NMR, 13C NMR and MS). These compounds are reported from this species for the first time. A DPPH spectrophotometric assay was used to evaluate the antioxidant potential of the compounds. Compound 2 had higher antioxidant activity while Compound 1 had lower activity than L-ascorbic acid which was used as standard. African Journal of Traditional, Complementary and Alternative Medicines Vol. 3(4) 2006: 59-6

6-C-METHYLQUERCETIN-3, 3', 4'-TRIMETHYL ETHER FROM THE LEAVES EXTRACT OF PILIOSTIGMA RETICULATUM

From the leaves of Piliostigma reticulatum, three C-methylflavonols: 6-C-methylquercetin-3, 3', 4'-trimethyl ether, a new natural product; 6-C-methylkaempferol-3-methyl ether, 6,8-di-C-methylkaempferol-3,7-dimethyl ether and a 2-phenoxychromone ( Piliostigmin) and were isolated along with quercetin, quercetrin and quercetin-3-O-glucoside. The chemotaxonomic significance of the findings is briefly discussed. Key Words: Piliostigma reticulatum; Caesalpinaceae; leaves; 2-phenoxychromone; C- methylflavonols; chemotaxonomy. Nigerian Journal of Natural Products and Medicine Vol.7 2003: 37-3

ANTIMICROBIAL CONSTITUENTS OF CHRYSOPHYLLUM ALBIDUM SEED COTYLEDONS

Cotyledons from the seeds of Chrysophyllum albidum G. Don-Holl. (Sapotaceae), are used in ointments in the treatment of vaginal and dermatological infections in Western Nigeria. Activity directed chemical analysis of the methanolic extract of the cotyledons from the seeds of Chrysophyllum albidum led to the isolation and characterisation of eleagnine (1,2,3,4-tetrahydro-1-methyl-β-carboline), tetrahydro-2-methylharman (1,2,3,4-tetrahydro-1, 2 -dimethyl-β-carboline) and skatole (3-methylindole). Eleagnine was the main antimicrobial compound with activity against Candida albicans (MIC 1250μg/ml) and Candida pseudotropicalis (MIC 250mg/ml). It was also active against Escherichia coli (MIC 500mg/ml), Staphylococcus aureus (MIC 62.5μg/ml), Pseudomonas aeruginosa (MIC 500μg/ml) and Bacillus subtilis (MIC 250μg/ml). 1,2,3,4-tetrahydro-1, 2 -dimethyl-β-carboline also showed activity against these organisms while skatole had little activity. Key Words: Chrysophyllum albidum; Sapotaceae; eleagnine; tetrahydro-2-methylharman; skatole; antimicrobial activity. Nigerian Journal of Natural Products and Medicine Vol.7 2003: 33-3

Cytotoxicity Study Of Antioxidant Flavonoids From Bauhinia Tomentosa Leaf Extract

A 1, 1-diphenyl-2-picrylhydrazyl (DPPH) activity-guided fractionation procedure was used to isolate the antioxidant constituents of a 50% ethanol dried leaf extract of Bauhinia tomentosa. Four flavonol glycosides: kaempferol-7-O-rhamnoside (1), kaempferol-3-O-glucoside (2), quercetin-3-O-glucoside (3) and quercetin-3-Orutinoside (4) were isolated by accelerated gradient chromatography (AGC) and Sephadex LH-20 column chromatography. Compounds 1-3 are reported for the first time from this species. The structures of the compounds were established by spectroscopic methods (1H NMR, 13C NMR and MS). A DPPH spectrophotometric assay was employed to evaluate the antioxidant activity of the isolated compounds. Compound 3 had higher antioxidant activity than L-ascorbic acid while 1 and 4 similarand 2 lower activities. Compounds 2-4 were non-cytotoxic, but kaempferol-7-O-rhamnoside (compound 1) displayed slight cytotoxicity to bovine dermal cells (LC50 = 116.58 μg/ml) in the tetrazolium (MTT) based assa

ANTIMICROBIAL STUDIES ON NIGERIAN HIGHER FUNGI

The 18 fungi fruit bodies showed varied antibacterial activity. None of the fungi showed anticandidal activity. Key Words: Nigerian fungi, antimicrobial activity, Pyonoporus sanguineus Nig. J. Nat Prod. And Med. Vol.3 1999: 64-6