Determination of Acute Toxicity and Anti-Anxiety Activity of Hydroalcoholic Leaf Extracts of Selected Medicinal Plant Extracts

The acute toxicity and anxiolytic effects of hydroalcoholic Tapinanthus dodoneifolius, Bryophyllum pinnatum, and Terminalia catappa leaf extracts were examined. Limit dose acute toxicity testing in mice was used to assess acute toxicity. The open-field paradigm (OFT) was used to assess anxiolytic activity after 1 hour of single oral administration of distilled water, extracts (at three dose levels), and diazepam (0. 5 mg/kg) using the behavioral indices of mean centre zone time (CZT), centre zone re-entry (CZR), and defeaction/urination frequency (D/UF). Acute toxicity testing reveals that the extracts are safe, with an LD50 of 5g/kg. On the OFT paradigm, single acute T. dodoneifolius and B.pinnatum extract treatments demonstrated consistent dose-dependency in anxiolytic activity across the three parameters of mean CTZ, mean CZR, and mean MD/UF, with T. catappa extract exhibiting dose-dependent anxiolytic effect only on the first parameter. At the maximum dosage level of 500 mg/kg, however, all plant extract treatments had anxiolytic effects equivalent to 0.5 mg/kg diazepam treatments. The findings of this study justify the traditional use of medicinal plant extracts in the treatment of neuropsychiatric illnesses.