Abstract

Methanolic extracts (mg mL^-1) of Dicoma anomala (0.0625, 0.125, 0.25), Chenopodium album (0.078, 0.156, 0.313), used in traditional medicine in Lesotho, and Camellia sinensis (0.1094, 0.2085, 0.44) were assessed for cytotoxicity, genotoxicity and modulation of Cyclophosphamide (CP 1.25 mg mL^-1) - and EMS (0.25 mg mL^-1)-induced genotoxicity using the Allium cepa assay following 24 hours treatment. Cytotoxicity was measured by the mitotic index (MI). Genotoxicity (GT) was expressed as the number of aberrant mitotic cells per 100 mitotic cells. The MI and GT of test groups (triplicates), were compared with the negative (water) control group using t-test. Modulatory effect (ME) was calculated as, ME(%) = (1-(A-B)/(A-C) × 100) -1. A positive ME indicated an increase (synergism or potentiation) while a negative ME indicated a reduction (anti-genotoxicity) of mutagen-induced genotoxicity. The concentrations of D. anomala extract were cytotoxic and genotoxic. Mixtures of CP or EMS with the lower concentrations of D. anomala extract were more genotoxic than CP (250.50% increase) or EMS (149.74 and 157.37 % increase) or extracts alone. Only 0.313 mg mL^-1 of C. album extract was cytotoxic but none of the three concentrations was genotoxic. Mixtures of CP with extracts of C.album were cytotoxic. CP-induced genotoxicity was reduced (55.18, 68.36, 57.40 %) and EMS-induced genotoxicity was also reduced by low concentrations (50.72, 61.13 %) of C.album extract. However, 0.313 mg mL^-1 C. album extract increased (236.75%) EMS-induced genotoxicity. C. sinensis extracts and their mixtures with CP were not cytotoxic or genotoxic. CP-induced genotoxicity was reduced (63.61, 66.62, 78.64 %) but EMS-induced genotoxicity was increased (124.97, 4.48, 110.52 %) by C. sinensis extract.

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