Phytochemical screening, heavy metals evaluation and acute toxicity studies of <i>Azadirachta indica</i> and <i>Mangifera indica</i> methanol leaves extract

Abstract

The present study was aimed to determine the phytochemical constituents, median lethal dose (LD₅₀) and levels of heavy metals in Azadirachta indica and Mangifera indica leaves obtained from Kano State, Nigeria. The preliminary phytochemical screening of Azadirachta indica and Mangifera indica leaves revealed the presence of Alkaloids, Flavonoids, Carbohydrate, Tannins, Saponins, Anthraquinones and Steroids while Cardiac Glycosides were absent in the methanol extracts. The results revealed that the concentrations of heavy metals in the leaves of Azadirachta indica were found to be 0.06± 0.01mg/kg, 0.05± 0.01 mg/kg and 0.07± 0.00mg/kg for Zn, As and Mn respectively and non-detectable concentrations of Cd, Cu, Ni, Co and Pb, and 0.02± 0.01mg/kg, 0.05±0.02mg/kg, 0.02±0.00mg/kg and 0.15±0.00mg/kg for Zn, As, Co and Mn respectively and non-detectable concentrations Cd, Cu, Ni and Pb in Mangifera indica. The LD₅₀ of the Azadirachta indica and Mangifera indica methanol leaves extract were was between 500-5000 mg/kg body weight using Lorke’s method, which showed that the extracts were slightly toxic. The levels of heavy metals detected were within the World Health Organization (WHO) permissible limits for metals in medicinal plant and herbal products. The findings of this study indicate the toxicity of the extracts as slightly toxic at LD₅₀ which might suggest their use with caution and the need for furtherstudies to assess their short and long-term cumulative risk with a view to improve their safety.