ABSTRACT
Phytochemical investigation of the ethanol extract of the stem bark of Hypericum lanceolatum Lam. (Guttifereae)afforded eight known compounds including 2,2ʹ,5,6ʹ-tetrahydroxybenzophenone (1), 5-hydroxy-3-methoxyxanthone(2), 3-hydroxy-5-methoxyxanthone (3), betulinic acid (4), hydroquinone (5) 6,7-dihydroxy-1,3-dimethoxyxanthone(6), calophyllumin A (7), and 1,3,5,6-tetrahydroxy-4-prenylxanthone (8). Compound 1 was submitted to acetylationreaction to give 5-acetoxy-2,2ʹ,6ʹ-trihydroxybenzophenone (9), a new hemisynthetic derivative. Compounds 5 and8 were isolated for the first time from this plant. The structures were established by extensive analysis of their massspectrometry and nuclear magnetic resonance (NMR) spectroscopic data and comparison with those from the literature.The isolated compounds (1, 2, 4, 5, and 8) and the derivative of benzophenone (9) were tested for their antipromastigoteand cytotoxic activities against visceral leishmaniasis parasite Leishmania donovani and macrophage RAW 264.7 cellline, respectively. Compound 9 was the most active with an IC50 value of 6.1 µg/ml, while compounds 1, 2, 4, and 8were moderately active with IC50 values ranging from 11.4 to 34.8 µg/ml against L. donovani and were not cytotoxicexcept compound 5 that was very toxic and not active. The findings of the present study suggested that compounds 1,2, 4, and 8 could be considered as a potential source of therapeutic medicine for the treatment of leishmaniasis.
ABSTRACT
Brillantaisia lamium is an erect branched herb, which grows to a height of 1.50 m in moist tropical areas, both in full sun and partial shade. In Cameroon, the aerial part of this plant is used in the treatment of various microbial infections such as skin diseases and infections of urinary tract. The aim of this study was to evaluate the antimicrobial activities of CH[2]Cl[2]: MeOH [1:1] extract, fractions and compounds from the aerial part of B. lamium. The plant was dried and extracted by maceration in CH[2]Cl[2]: MeOH [1:1 v/v]. Structures of the compounds from the CH[2]Cl[2]: MeOH [1:1] soluble fraction were determined by spectroscopic methods and compared with published data. The broth micro dilution method was used to evaluate the antimicrobial activities against bacteria and fungal species. Four known compounds: aurantiamide acetate [1], lupeol [2], lespedin [3], sitosterol 3-O-beta-D-glucopyranoside [4] and a mixture of sterols: campesterol [5], stigmasterol [6] and beta-sitosterol [7] were isolated from CH[2]Cl[2]: MeOH [1:1] extract of B. lamium aerial parts. The crude extract, fractions and isolated compounds exhibited both antibacterial and anti-fungal activities that varied with microorganism [MIC=6.25 - 1000 micro g/ml]. Compound 3 was the most active [MIC=6.25 - 100 micro g/ml] while Staphylococcus aureus, Enterococcus faecalis, Candida tropicalis and Cryptococcus neoformans were the most sensitive to all the tested compounds. The overall results of this study indicate that the CH[2]Cl[2]: MeOH [1:1] extract and some of isolated compounds have interesting antimicrobial properties and can be used for the treatment of fungal and bacterial infections