Pesticides are used in agriculture and in domestic pest control. Dichlorvos, an organophosphate, is a predominant pesticide used in domestic insect control in developing countries. Acute and prolonged exposure may lead to death, genotoxic, neurological, reproductive, carcinogenic, immunological, hepatic, renal, respiratory, metabolic, dermal and other systemic effects. Its toxicity is due to the ability of the compound to inhibit acetyl cholinesterase at cholinergic junction of the nervous system. This study is a review of the toxicological effects of dichlorvos in a public health perspective.

Vernonia calvoana is an indigenous green leafy vegetable that grows around the Cameroons and the southern part of Nigeria. This study was designed to evaluate the phytochemical and antioxidant activity of V. calvoana inflorescents using the following methods: 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH), Ferric reducing/antioxidant power (FRAP), 2, 2-azobis-3-ethyl benzothiolin-6-sulphonic acid (ABTS), anti-lipid, superoxide, phosphomolybdate and ascorbic acid assay. The result showed significantly high saponins, alkaloids and polyphenols at (p<0.05). Oxalates, cyanates, phytates, tannins, terpenoids, steroids, anthraquinones, flavonoids and sesquiterpene lactones were found in trace amounts. The assay indicated strong free radical scavenging activity, including ABTS, anti-lipid, superoxide, phosphomolybdate activities of the inflorescents. However, the percentage antioxidant capacity was low in the inflorescents using FRAP, whereas the antioxidant capacity increased with increase in concentration compared to the ascorbic acid standard. Moreover, the inflorescents were found to show stronger antioxidant activity (137.0+6.86) compared to ascorbic acid (79.44%).We therefore conclude that V. calvoana inflorescents could serve as source strong diatary antioxidants.

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This study is aimed at evaluating the biochemical effects and antioxidants activity of extracts of Vernoia calvoana Hook. f (V.C) on STZ induced diabetic rats. Thirty-six rats weighing (100 to 150 g), were divided into 6 groups of 6 animals each. Groups 1 and 2 representing normal and diabetic controls (NC and DC), respectively, receiving placebo, while groups 3 to 6 represented diabetic treated, receiving 500 mg/kg body weight (b.w.) metformin, 400 mg/kg b.w. crude, n-hexane and methanol fractions of V.C, respectively. Treament with drug and extracts of V.C showed a decrease in fasting blood glucose (FBG) in all experimental groups and was significant (p<0.05) on the 7th day of the experimental period, compared to diabetic control. Progressive increase in body weight was observed in all experimental groups compared to DC group. A significant (p<0.05) increase in glutathione peroxidase (GPX) and catalase (CAT) activities were recorded in all experimental treated animal compared to DC and NC. Malondialdehyde (MDA) concentration was observed to decrease significant (p<0.05) in all experimental groups compared to DC. Histopathologically, the changes in pancreatic integrity were consistent with that of biochemical findings. It may be concluded that, extracts of V.C possess potent ameliorative activity against STZ-induced diabetes, via a potential free radical mopping activity.