Study of the Potential Toxicity and Side Effects Associated with the Long-term Consumption of Walnuts (Cola verticillata: Sterculiaceae): Anti-Meiosis in the Insect Assay

Cola verticillata (Sterculiaceae) is a plant that produces nuts renowned for their ceremonial, cultural, medicinal and above all economic value in Africa. The study consisted in evaluating the cytotoxic and genotoxic effects of the aqueous extract of the plant's nuts on the Zonocerus variegatus model. Male and adult locusts were treated with increasing concentrations of 5, 10, 20, 30 and 40 µg/ml. The 0.01 ml/mg extract was administered intraperitoneal and 96 h post-treatment the grasshoppers were killed, dissected and the testicular follicles removed for smear preparation. Chromosomal examinations revealed that the aqueous extract of C. verticillata induced a significant regression of the meiotic index, followed by a significant increase in the chiasmatic frequency in a concentration-dependent manner and in comparison with the control group. In addition to chromosome bridges, chromosome breaks, sticky chromosomes and leak chromosomes were observed mainly at 40 µg/ml. These results show that Cola extract is cytotoxic and genotoxic because it slowed down meiosis while also inducing multiple chromosomal abnormalities with clastogenic effects in the male Z. variegatus breeder. The results of this study call for populations to consume kola nuts (Cola verticillata) intermittently if the cytotoxic and genotoxic effects are not reversed.