Abstract
Glyphosate is a non-selective herbicide that has adverse effects on non-target organisms. This present study investigated the toxic effects of glyphosate on earthworms and the potential of antioxidant-rich plants, Ocimum gratissimum and Telfairia occidentalis remediate these effects. Earthworms (Eisenia fetida) were placed into four groups and treated with concentrations of 1, 2 and 3% glyphosate in soil. The last group was a control group. The worms were collected on the 3rd, 7th and 14th, days post-exposure. During these intervals, the weight of the worms and activities of antioxidant enzyme - superoxide dismutase (SOD), catalase (CAT), glutathione (GSH), malondialdehyde (MDA) were measured to determine the level of antioxidant responses. Furthermore, the percentage of DNA fragmentation was measured to assess the level of DNA damage. Compared with the control group, earthworms exposed to glyphosate and fed with Ocimum gratissimum and Telfairia occidentalis showed varying responses, with increased activities of CAT, SOD, GSH and reduced levels of MDA. Also, decreased fragmented DNA was observed in earthworm groups fed with Ocimum gratissimum and Telfairia occidentalis in comparison with the group treated exclusively with the herbicide. These results suggest that toxicity from glyphosate exposure significantly reduced oxidative damage, lipid peroxidation and DNA damage in Eisenia fetida by the antioxidant-rich plants. It is conceivable that soil organisms could suffer a significant mortality when exposed to high concentrations of glyphosate. The cultivation of these plants should be encouraged while caution should be exercised in the use of the herbicides.
Ethanolic extract of Casearia sylvestris and its clerodane diterpen (caseargrewiin F) protect against DNA damage at low concentrations and cause DNA damage at high concentrations in mice's blood cells