Asian Journal of Biochemistry, Genetics and Molecular Biology

The growing use of plant-derived preparations worldwide has increased the importance of evaluating their safety. Jatropha tanjorensis, a leafy vegetable also employed in traditional medicine, has received relatively little investigation regarding the cytotoxic and genotoxic activity of its ethanolic leaf extract. We therefore examined these effects in the Allium cepa root meristem assay. Onion bulbs were treated for 72 hours with 1.25, 2.5 or 5.0 mg/mL extract; tap water was the negative control and methotrexate (0.1 mg/mL) the positive control. Measurements comprised root number and length, the mitotic index and chromosomal aberrations. One-way analysis of variance and the Tukey–Kramer multiple comparison test were used to analyse the data. Relative to the negative control, root length was significantly lower at every extract concentration (p < 0.05), falling from 4.22 ± 0.10 cm to 0.08 ± 0.02 cm at 5.0 mg/mL. A significant decrease in root number occurred only at 5.0 mg/mL. At the highest concentration, the mitotic index was 36.40 ± 3.76%, compared with 77.60 ± 5.48% for the negative control. Chromosome stickiness became more frequent as concentration increased, and aberrant cells accounted for 20.33 ± 3.26% at 5.0 mg/mL. No micronuclei or chromosomal breaks were detected in extract-treated groups. Under the conditions examined, the extract thus produced concentration-related effects on root growth, cell division and chromosomal characteristics in Allium cepa. Studies in mammalian models are needed before its safety for human use can be established.