Role of catalytic function in the antiplatelet activity of phospholipase A(2) cobra (Naja naja naja) venom

Three acidic phospholipases A(2) from Indian cobra (Naja naja naja) venom inhibited platelet aggregation in platelet rich plasma induced separately by ADP, collagen and epinephrine with different potencies. The order of inhibition was epinephrine > collagen > ADP. They did not inhibit platelet aggregation induced by arachidonic acid (10 muM). The inhibition was dependent on concentration of the protein and the time of incubation of the phospholipases A(2) with platelet rich plasma. Parabromophenacyl bromide modified PLA(2) enzymes lost their enzymatic activity as well as platelet aggregation inhibition activity suggesting the involvement of catalytic function in platelet aggregation inhibitory activity

Antimicrobial properties of a non-toxic glycoprotein (WSG) from Withania somnifera (Ashwagandha)

Abstract A monomeric glycoprotein with a molecular mass of 28 kDa in SDS-PAGE was isolated from the Withania somnifera root tubers. The protein designated WSG (Withania somnifera glycoprotein) demonstrated potent antimicrobial activity against the phytopathogenic fungi and bacteria tested. Antifungal effect has been demonstrated in that WSG exerts a fungistastic effect by inhibiting spore germination and hyphal growth in the tested fungi. WSG showed potent antifungal activity against Aspergillus flavus, Fusarium oxysporum, F. verticilloides and antibacterial activity against Clvibacter michiganensis subsp. michiganensis. WSG is an acidic, non-toxic (trypsin-chymotrypsin) protease inhibitor. These results encourage further studies of WSG as a potential therapeutic agent for its antifungal activity. (© 2006 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

The anti-snake venom properties of Tamarindus indica (leguminosae) seed extract

Abstract In Indian traditional medicine, various plants have been used widely as a remedy for treating snakebites. The aim of this study was to evaluate the effect of Tamarindus indica seed extract on the pharmacological as well as the enzymatic effects induced by V. russelli venom. Tamarind seed extract inhibited the PLA2, protease, hyaluronidase, l-amino acid oxidase and 5′-nucleotidase enzyme activities of venom in a dose-dependent manner. These are the major hydrolytic enzymes responsible for the early effects of envenomation, such as local tissue damage, inflammation and hypotension. Furthermore, the extract neutralized the degradation of the Bβ chain of human fibrinogen and indirect hemolysis caused by venom. It was also observed that the extract exerted a moderate effect on the clotting time, prolonging it only to a small extent. Edema, hemorrhage and myotoxic effects including lethality, induced by venom were neutralized significantly when different doses of the extract were preincubated with venom before the assays. On the other hand, animals that received extract 10 min after the injection of venom were protected from venom induced toxicity. Since it inhibits hydrolytic enzymes and pharmacological effects, it may be used as an alternative treatment to serum therapy and, in addition, as a rich source of potential inhibitors of PLA2, metalloproteinases, serine proteases, hyaluronidases and 5¢-nucleotidases, the enzymes involved in several physiopathological human and animal diseases. Copyright © 2006 John Wiley & Sons, Ltd