Evaluation of the bio-toxicity and cytogenetic effects of methanolic leaf extract of <i>Heliotropium indicum</i> L.

Abstract

Heliotropium indicum L. has been shown to be very important in traditional healing medicine. However, many reports have indicated that the toxicity is not unconnected with pharmaceutical properties. This study therefore investigated the cytotoxic, genotoxic and biotoxic activities of methanolic leaf extract of H. indicum using Brine Shrimp lethality assay. The results revealed that the leaf extract of H. indicum showed lethality against the Brine Shrimps nauplii. The highest mortality was recorded at a concentration of 1000 μg/ml. The LC50 value of the Brine Shrimps mortality of the extract was recorded to be 461.04±10.02 μg/ml. In addition, the extract inhibited mitotic division in A. cepa root meristematic cells. The mitotic index was reduced from 59.99% in the control to 2.2% at 1000 μg/ml of the leaf extract. Chromosomal aberrations were observed at different concentrations. These include sticky chromosomes at metaphase and anaphase, chromosome breakage, degenerated and disoriented chromosomes at metaphase plate. It can be concluded from this present study that methanolic leaf extract of H. indicum was cytotoxic and genotoxic to Brine Shrimps and A. cepa cells respectively. Hence, caution should be exercised with respect to the consumption of H. indicum leaf in any form.

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Keywords: Mitotic index, chromosome aberrations, Brine Shrimps Lethality assay, Allium cepa assay, leaf extract