Metal analysis, phytotoxic, insecticidal and cytotoxic activities of selected medicinal plants of Khyber Pakhtunkhwa.

In the present study four medicinal plants traditionally used in Pakistan for treatment of various ailments were evaluated for their heavy metals content, insecticidal, cytotoxic and phytotoxic actions. The metals like Cr, Cu, Zn, Mn, Ni, Pb, Fe and Co were determined in crude extract and various fractions. Soil samples were also tested for heavy metals to determine assimilation of any metal by the plant. Lead, Chromium, copper, nickel and cobalt exceeded the permissible limit in most of the tested samples while the concentration of zinc, manganese and iron was within the permissible limit. Chloroform fraction from Achyranthes aspera and ethyl acetate fraction from Duchesnea indica showed significant phytotoxic activities. Crude extract and chloroform fraction from Xanthium strumarium showed insecticidal activity comparable to that of permethrin and thus could be a significant source of natural insecticide. The butanol fraction from X. strumarium showed significant cytotoxicity with LC(50) 1.9306 μg/ml, having mortality rate 93% at highest dose, while the crude extract from Valeriana wallichii showed 90% mortality rate (LC(50) 4.9730 μg/ml) at highest dose. However, the extracts from other plants were not effective against the brine shrimps tested.