Phytochemical studies of extracts from Aloe succotrina

Abstract

Global climate change and geographical differences are two major parameters known to have, either, direct or indirect influence on the production of secondary metabolites in plants, which in-turn may affect the quality and/or quantity of the overall metabolites. The primary purpose of this thesis was to evaluate the phytochemistry of the whole leaf of Aloe succotrina Lam. spp. - a South African native plant - through a chromatographic spectroscopic approach-against available data accumulated for the cultivated population. Preliminary screening of the crude extracts i.e. HEX, DCM and EtOAc on TLC aluminium plates precoated with silica gel 60 F254 followed by various chromatographic separation, led to the isolation of five known compounds: ?-sitosterol (1) and two anthrone-C-glycosides (2 and 5), including two coumarin derivatives-the aglycone (3) and glycoside derivative (4). Notably, apart from 5 and 2, the accumulation of 1, 3 and 4 in A. succotrina Lam. spp. is reported for the first time. Structural elucidation of the individual compounds was achieved by extensive spectroscopic analysis i.e. MS, IR, 1H and 13C-NMR spectroscopy and in some cases comparison to the literature. A comparative HPLC chromatogram of the crude MeOH extract of the leaves of A. succotrina Lam. was developed for qualitative (and quantitative) identification of the active metabolites, which could be realized by VWD with detection at 290 nm.