Phytochemical analyses, anxiolytic and anti-amnesic effect of methanol stem bark extract of Vitex doniana (sweet) in mice

This study investigated the oral acute toxicity (LD50), anxiolytic and anti-amnesic effects of the methanol stem bark extract of Vitex doniana (MSVD) in mice. The anxiolytic and anti-amnesic effects were assessed using standard protocols. The phytoconstituents in MSVD was quantified. The MSVD was further analysed using Ultraviolet-visible (UV-VIS) and Fourier Transform Infra red (FTIR) fingerprints. The LD50 was > 5000 mg/kg suggesting its safety. The MSVD (125, 250 and 500 mg/kg, p.o.) showed significant (p<0.05) increase in the percentage open arm entry and duration on elevated plus maze as well as reduced the anxiety index as indexed from the open arm avoidance index indicating an anti-anxiety effect. Subsequently, MSVD significantly (p<0.05) increased the percentage alternation reduced by scopolamine consistent with anti-amnesic effect. The phytoconstituents estimation of MSVD showed abundance of flavonoids. The UV-VIS spectra corresponded to the presence of flavonoid, phenolic acid derivatives and terpenoids while the FTIR revealed the presence of amine, hydroxyl, alkane, carboxylic, amide, ether, aromatic and carbonyl functional groups among others in MSVD. This study therefore, concluded that flavonoids, either in synergy or additive with other phytocompounds in MSVB may be responsible for the observed anxiolytic and anti-amnesic effects elicited by MSVD in this study.