Nematicidal Activities of Two Phytoalexins from Taverniera abyssinica

Abstract

The traditional analgesic and antipyretic Ethiopian drug “Dingetegna” is made of dried root material of Taverniera abyssinica A. Rich (Leguminosae). In a screening for nematicidal natural products, “Dingetegna” extracts showed strong nematicidal activities towards C. elegans. In the following, medicarpin and 4-hydroxymedicarpin were isolated as nematicidal constituents from the extracts. In a micro well plate assay for nematicidal activity, both compounds exhibited an LD₅₀ of 25 µg/ml towards C. elegans. Beside these nematicidal effects, weak cytotoxic and antimicrobial activities were observed. In addition, both compounds inhibited oxygen consumption of axenically grown C. elegans, L 1210 cells, and filamentous fungi. Respiration in sensitive bacteria was not affected. In L1210 cells, the incorporation of precursors into macromolecules was affected in the presence of glucose, indicating that inhibition of respiration is not the only target site of the compounds.

Key words

Taverniera abyssinica - Leguminosae - nematicidal activity - antimicrobial activity - cytotoxic activity - medicarpin - 4-hydroxymedicarpin