Contraceptive and Phytochemical Profile of Lime-Yellow Pea (Macrotyloma axillare, E. Mey) Verdc: A Tropical Climber

Abstract

Background: Rising human population has detrimental effects on quality of life and lead to increased cases of pollution and poverty. Modern forms of contraceptives also have severe side effects and result in high cases of unwanted pregnancies. As a result, several cases of illegal abortion, leading to serious health complications have been reported, and more than 30 million US dollars are used to treat post-abortion complications in Kenya annually. Herbal contraceptives offer alternatives to health problems, and this study was novel with significant findings, since little information exists about the pharmacological properties of M. axillare, unlike its closely related species, M. uniflorum, which has been extensively studied and established to have great pharmacological potential. Aims: To establish and validate the use of M. axillare extracts as traditional contraceptives and also to profile the phytochemicals responsible for its contraceptive activity. Place and Duration of Study: Department of Veterinary Anatomy and Physiology, University of Nairobi, Kenya. Methodology: The contraceptive effects were investigated by in vivo studies using Virgin Wistar female rats (Rattus norvegicus) with regular oestrus cycle. Qualitative and quantitative phytochemical profiling was carried out using standard procedures while GC-MS analysis was employed in the identification of compounds present in the methanolic extracts. Results: Macroscopic and microscopic examination of female reproductive tract revealed reduced ovary size, involuted uterus and persistent corpus luteum in the ovary and no births were recorded in groups treated with higher doses of the plant extracts. The presence of saponins, alkaloids, steroids and terpenoids, as well as phenolic compounds like tannins and flavonoids, which could be responsible for the contraceptive activity observed, either acting independently or synergistically, was confirmed through qualitative phytochemical analysis. GC-MS profile also led to the identification of compounds that included sitosterol, stigmasterol, stigmasta-3,5-dien-7-one, stigmastan-3,5-diene and campesterol that have structural similarities to known reproductive hormones and conventional contraceptives and could, therefore, be responsible for the observed contraceptive activity of the plant extract. Conclusion: The tested methanolic extracts have a potential contraceptive activity that warrants further investigations towards the development of novel plant-based contraceptives.