Cytotoxic, anti-mitotic and cytogenetic effects of the leaves and stems of Olax subscorpioidea Oliv. (Olacaceae) against Artemia salina nauplii and Allium cepa meristematic cells

The search for novel, safe and effective anticancer agents has been a continuous and recurring objective in cancer research. Olax subscorpioidea is a medicinal plant used for ethnomedicinal treatment of cancer in Nigeria. In this study, we investigated the cytotoxic, anti-mitotic and cytogenetic effects of methanol extracts of the leaves and stems of O. subscorpioidea. The cytotoxic activities were evaluated against brine shrimps (Artemia salina) nauplii and Allium cepa roots, while anti-mitotic and cytogenetic effects were assessed on Allium cepa meristematic cells. Cytotoxicity assays showed that the extracts demonstrated potent cytotoxic activities, having LC50 values of 10.7 and 45.2 µg/mL against brine shrimps and IC50 values in the range of 47.03 – 81.93 µg/mL on A. cepa roots. These activities were comparable to that of potassium dichromate and methotrexate used as positive control in each of the assays. Anti-mitotic results indicated that at a concentration of 10 µg/mL, the extracts demonstrated percentage mitotic inhibition (% M.I) of 35.95 – 70.12%, with greater or similar anti-mitotic effects to methotrexate at a concentration of 125 µg/mL, % M.I of 39.04 – 40.64%. Cytogenetic investigation revealed that the extracts showed chromosomal aberrations that were not considerably different from those observed in the negative control group. The current findings suggest that the plant extracts may contain cytotoxic and anti-mitotic compounds. Further research to investigate these extracts in more sophisticated test systems and to isolate and characterize their active principles is ongoing.