Quinolizidine alkaloids: the bioactive principles in Cnestis ferruginea (de Candolle) with male antifertility activities

Abstract

Objectives: The reproductive activities of purified fractions from the root extract of Cnestis ferruginea was evaluated in rats. Phytochemical screening of the extract revealed the presence of alkaloids, tannins and anthraquinones. Materials and Methods: Column chromatography produced 20 fractions which were reduced to 6 by thin layer chromatography. Nuclear magnetic resonance spectroscopy revealed quinolizidine alkaloids (fractions 3 and 4) as the active principles in the extract of Cnestis ferruginea. Each fraction of Cnestis ferruginea (0.1, 1 and 2 mgkg 'bw) was administered to rats by gavages for 60 days. Results: All fractions caused significant reduction (p<0.05) in sperm counts, motility, viability, morphology and plasma levels of testosterone, luteinizing hormone and follicle stimulating hormone. Fractions 3 and 4 caused the highest reduction (p<0.001) in fertility, FSH and LH levels comparable to those of quinine sulphate. There was recovery after 60 days of withdrawal from the extracts. Conclusion: T h e results suggest that Cnestis ferruginea possesses reversible male antifertility effects. The active principles with these activities appear to be quinolizidine alkaloids