Impairing Efficacy of Nigella sativa Linn. (Ranunculaceae) Seed Extracts on Phosphatase Activity in Haemolymph and Fat Bodies of Schistocerca gregaria (Forskal) (Acrididae: Orthoptera)
Karem Ghoneim, Khalid Hamadah, Atif El-Hela
The present study aimed to investigate the disturbing effects of sublethal concentrations (15.0% and 7.5%) of methanol, petroleum ether and n-butanol extracts of Nigella sativa seeds on acid (ACP) and alkaline (ALP) phosphatases in haemolymph and fat bodies of last instar nymphs and newly emerged adult females of the economically dangerous desert locust Schistocerca gregaria. Both methanol and petroleum ether extracts of N. sativa exhibited remarkably enhancing effects on ACP activity in haemolymphof nymphs and adults, while n-butanol extract exerted an inhibitory action on the enzyme activity in early- and mid-aged nymphs as well as in adults. With regard to ACP activity in fat bodies, all extracts generally promoted it in both nymphs and adults with few exceptions. Various degrees of disturbance of ALP activity in haemolymph of nymphs and adults were exhibited by N. sativa extracts. As most prominent findings, prohibited enzyme activity was detected only in haemolymph of early-aged nymphs, regardless to the extract and concentration. On the contrary, all extracts enhanced the enzyme activity, generally in late-aged nymphs and adults. Concerning the mid-aged nymphs, only methanol extract exhibited a promoting effect on ALP activity while both petroleum ether and n-butanol extracts exhibited reducing effects on it. In fat bodies, methanol extract of N. sativa prohibited the ALP activity in early- and mid-aged nymphs but induced it in late-aged congeners. Regarding the newly emerged adult females, ALP activity increased, irrespective of the extract and concentration.