Investigations of activities of alkaloid of trifoliate yam (<i>dioscorea dumetorum</i>, (kunth) pax.

Abstract

Alkaloid was extracted from the tubers of Dioscorea dumetorum by a procedure that consisted of acidification with dilute HCl, basification with dilute ammonia solution and extraction with chloroform. It was investigated for its cytotoxic, genotoxic and allelopathic activities on Allium cepa roots, tomato seeds and bean seedlings with a view to studying its safety or otherwise as famine food. The allelopathic, cytotoxic and genotoxic activities of the alkaloid were investigated using tomato seeds, bean seedlings and A. cepa assay techniques. The thin layer chromatography (tlc) of the alkaloid on pre-coated silica gel 60 F₂₅₄ gave only one spot implying that alkaloid  contained in trifoliate yam was chromatographically pure. The allelopathic studies revealed that the alkaloid did not have any significant effect on tomato seed germination, and root and shoot lengths of bean seedlings. The alkaloid caused slight reduction in the amount of chlorophyll a, chlorophyll b and total chlorophyll and elevated the levels of total proteins, soluble sugars and proline in bean seedlings. Mitotic Index decreased with increased alkaloid concentrations but no chromosomal aberration was observed. It is concluded from this study that alkaloid from D. dumetorum was cytotoxic but not genotoxic.

Key words: Cytotoxic, Genotoxic, Allelopathic, Dioscorea dumetorum, Chromosomal aberration, Mitotic index.