Atrazine in fish feed and African catfish (Clarias gariepinus) from aquaculture farms in Southwestern Nigeria

Extensive use of atrazine as herbicide in crop farming in Nigeria may lead to its accumulation in fish feed ingredients or aquatic ecosystem from aerosol or by runoff resulting in its residue in aquatic animals. Atrazine residues were determined in fish feed and catfish (Clarias gariepinus) fillets from commercial aquaculture farms in Southwestern Nigeria by matrix solvent particle dispersion and quantification using an ELISA kit. The mean atrazine concentrations in feed and fish were about 1.3–1.5 μg/kg and 1.4–1.8 μg/kg respectively. Atrazine was mostly detected in catfish from Ogun State (91.3%) and feed from Lagos State (80.0%) with mean concentrations of 1.4 � 0.4 μg/kg and 1.5 � 0.5 μg/kg, respectively. Mean atrazine concentration in catfish samples from Lagos State was significantly higher (P < 0.05) than the mean concentration in catfish samples from Ogun State. This study showed that the Estimated Average Daily Intake (EADI) of atrazine in fish samples from the selected states were below the Acceptable Daily Intake (ADI) value of 6 μg/kg for herbicide residues and thus within safe limit but their presence in fish is a cause for concern

Knowledge, attitude and perception of related toxicity of pesticide exposure in humans and animals in Ibadan, Nigeria

This study reported knowledge, attitude and perception of pesticide use among farmers to determine the level of farmers’ education on use and handling of pesticides. Data on pesticide types purchased were collected from pet-shops and agro-allied stores in three states in Nigeria. Questionnaires were administered to 100 farmers within Ibadan (Oyo State) to determine specific pesticides used, handling procedures adopted by farmers, protective measures employed and perception of toxic potentials of pesticides to human handlers and exposed animal. Survey reports showed majority used DDVP, 34% of farmers were uneducated, while 42%, 18% and 6% had primary, secondary and tertiary education, respectively. About 63.5% had been farming for 11-20years, 75% kept poultry while others kept sheep/goat and cattle. About 75% sought information from extension agents on pesticide use. The farmers were aware pesticides pose health hazards to animals but only 75% knew it could affect humans, 40% knew of pesticide withdrawal period with diverse opinions on route of pesticide poisoning. The study concluded that farmers and pet-owners in Southwest Nigeria use pesticides unethically and majority are unaware of toxicity and hazards of misuse and handling of pesticides, consequently exposing themselves and animals to hazardous and toxic pesticide levels. Legislations on pesticides enacted to prevent pesticide abuse should be enforced and awareness campaigns intensified to enlighten farmers and pet-owners on potential hazard pesticides pose to themselves, animals and environment. This would eventually prevent unnecessary exposure through misuse/mishandling of pesticides and create a safer ecosystem at large. Keywords: Attitude, Knowledge, Perception, Pesticide, Toxicit

Pharmacological reactivity of isolated guinea pig ileum to ethanol leaf extracts of Amaranthus caudatus and Solanum melongena

The pharmacological reactivity of guinea pig ileum to ethanol leaf extract of Amaranthus caudatus and Solanum melongena were determined in vitro. Parameters evaluated include the threshold value and the concentration ratio (CR). The potency of the plant extracts as expressed by EC50, the Emax (maximum response) and its corresponding concentration were determined from the concentration response curve in the absence or presence of 2X10-7 M atropine or 2X10-7 M mepyramine. The study showed that the extract of Amaranthus caudatus or Solanum melongena produced a dose-dependent contraction of the smooth muscle of the guinea pig ileum with threshold values at 80 or 100mg/ml respectively. 2X10-7 M atropine or 2X10-7 M mepyramine individually caused a right shift on the cumulative concentration-response curve for each plant extract. The potencies of the plant extracts were significantly (p<0.05) decreased, and the concentration producing Emax was significantly (p<0.05) increased in the presence of the antagonists. The ileal contraction produced by A. caudatus was more sensitive to mepyramine antagonism. The EC50 (373.80±51.56mg/ml) and the concentration producing Emax (855.00±75.00mg/ml) for A. caudatus extract increased significantly (p<0.05) to 849.00±29.16 mg/ml and 875.00±25 respectively in the presence of atropine, indicating that the extract interacted with muscarinic receptors. The mean EC50 and the concentration eliciting the Emax for S. melongena extract increased significantly (p<0.05) from 288.91±32.46mg/ml and 600.00±22.00mg/ml to 385.21±19.20mg/ml and 800±0.00 mg/ml respectively in the presence of mepyramine thus indicating stimulation of the histaminergic H1 receptors of the gastrointestinal tract. Taken together, this study demonstrated that A. caudatus predominantly stimulates muscarinic receptors to produce contraction of the gastrointestinal smooth muscle, while S. melongena predominantly stimulates histaminergic H1 receptors

Anti-Inflammatory and Analgesic Activities of Ethanolic Leaf Extract of Calotropis procera

Ethanolic extract of the leaf of Calotropis procera was investigated for its anti-inflammatory and analgesic activities. The extract was evaluated using formalin-induced paw lick, carragenaan-induced paw oedema in Wistar rats, acetic acid-induced writhing and tail flick tests in mice. Each experiment consisted of thirty animals randomly, but equally divided into groups of 100mg/kg, 200mg/kg or 400mg/kg body weight (b.w) of extract, Indomethacin (10 mg/kg b.w) or aspirin (15mg/kg b.w) pre-treated animals and a control group administered with distilled water (10ml/kg b.w). The administration of the extract was repeated for formalin-induced paw lick and acetic-acid induced writhing models in the presence of an opioid antagonist, naloxone. The data were analyzed using one way ANOVA and difference of means were considered significant at p <0.05. The ethanolic extract exhibited potent anti-inflammatory or analgesic effect in this study. Inhibition of formation of paw oedema by the extract (100mg/kg b.w) was significantly higher than for Indomethacin. Itching was significantly reduced in rats administered with extract in the early phase of formalin response, and was comparable to Indomethacin (10mg/kg b.w). 100 mg/kg body weight of the extract also inhibited the writhing movement comparably with aspirin (15mg/kg b.w). Same pattern was also observed with tail flick model in mice. The study showed that the mechanism of action of the analgesic or anti-inflammatory action of the leaf extract is mediated both centrally and peripherally. The analgesic or anti-inflammatory effect of the extract was not attenuated by opioid antagonist, naloxone, thus ruling out the involvement of opioid receptors in the central mechanism of action of the extract. It was therefore concluded that these activities are mediated via interaction with other nociceptive pathways

Anti-inflammatory and analgesic effects of methanol extract of Stellaria media (L.) Vill leaf

The anti-inflammatory and analgesic effect of the methanolic extract of Stellaria media (L.) Vill leaf was studied using albumen-induced paw oedema and formalin-induced paw lick in rats as the anti-inflammatory test models; acetic acid-induced writhing, hot plate and tail flick tests in mice as the analgesic models. Three groups of five rats or mice each were administered orally with the leaf extract of S. media at 100mg/kg, 300mg/kg or 500mg/kg body weight respectively. A fourth group was administered with Indomethacin (5mg/kg b.w) and distilled water (10mls/kg b.w) for the control group. The extract of S. media dose-dependently, significantly (p<0.05) inhibited egg albumen-induced paw oedema as effectively as Indomethacin. The late phase of the formalin response was also inhibited. The extract at 300mg/kg body weight produced a significant (p<0.05) inhibition of the acetic acid-induced abdominal constrictions in mice compared to the control group and mice administered with indomethacin. The analgesic property of the extract was also exhibited in the tail flick test as the extract significantly (p<0.05) increased the tolerance of the mice to pain relative to indomethacin-treated mice. The methanolic extract of S. media showed potent peripherally and centrally mediated anti-inflammatory and analgesic properties. The analgesic effect appears mediated through inhibition of release of histamine, serotonin and kinins, prostaglandin, cyclooxygenase and slow reacting substance