title: Neutralization of local toxicity induced by vipera russelli phospholipase A2 by lipophilic derivative of ascorbic acid.
abstract: L-ascorbic acid upon condensation with palmitic acid in the presence of sulphuric acid results in L-ascorbic acid-6-palmitate (AP). The effect of L-ascorbic acid derivative, AP on the pharmacological activities of purified basic multi-toxic PLA2 enzyme, VRV-PL-VIIIa from Vipera russelli snake venom along with in vitro activities is described. AP inhibited VRV-PL-VIIIa enzyme activity in a concentration dependent manner with IC50 value of 48.85 μM and the inhibition is found to be independent of substrate and calcium concentration. Upon investigating the in vivo pharmacological activities, it has been found that AP inhibited VRV-PL-VIIIa induced mouse paw edematogenic activity in a dose dependant manner. Intramuscular co-injection of AP with VRV-PL-VIIIa (1:10 w:w) neutralized the VRV-PL-VIIIa induced myotoxocity. Sections of mouse thigh muscle showed normal intact musculature with normal levels of serum creatine kinase and lactate dehydrogenase. Histopathological studies showed that administration of VRV-PL-VIIIa (i.p) along with AP mixture inhibited VRV-PL-VIIIa induced lung haemorrhage in mouse indicated that enzyme activity is responsible for all these observed pathological and pharmacological activities. The biophysical interaction studies showed that AP interacted directly with the enzyme and decreased the relative intrinsic fluorescence intensity. CD spectral analysis showed an apparent shift in the far UV-CD spectra of VRV-PL-VIIIa with AP. Docking study also confirmed the interaction of AP with enzyme directly. These results demonstrate that AP neutralizes VRV-PL-VIIIa induced pharmacological activities by inhibiting the enzyme with direct interactions. This compound along with other inhibitors of snake venom hydrolytic enzymes might be of use to neutralize local toxicity of V. russelli venom where antivenoms have failed.
authors.affiliation: Department of Studies in Biochemistry, University of Mysore, India.
authors.forename: Riyaz
authors.initials: R
authors.lastname: Mohamed
authors.forename: Holenarasipura V
authors.initials: HV
authors.lastname: Shivaprasad
authors.forename: Noor M
authors.initials: NM
authors.lastname: Jameel
authors.forename: Mysore A
authors.initials: MA
authors.lastname: Shekar
authors.forename: Bannikuppe S
authors.initials: BS
authors.lastname: Vishwanath
mesh_terms: D000818:Animals; D000997:Antivenins / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D001205:Ascorbic Acid / Q000031:analogs & derivatives / Q000494:pharmacology*; D002942:Circular Dichroism; D003402:Creatine Kinase / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D004487:Edema / Q000188:drug therapy* / Q000473:pathology / Q000517:prevention & control; D054501:Group II Phospholipases A2 / Q000037:antagonists & inhibitors* / Q000378:metabolism / Q000633:toxicity; D006470:Hemorrhage / Q000188:drug therapy* / Q000473:pathology / Q000517:prevention & control; D020128:Inhibitory Concentration 50; D007770:L-Lactate Dehydrogenase / Q000032:analysis; D008168:Lung / Q000187:drug effects / Q000473:pathology; D051379:Mice; D008958:Models, Molecular; D009132:Muscles / Q000187:drug effects / Q000473:pathology; D010168:Palmitates / Q000737:chemistry / Q000494:pharmacology*; D017840:Daboia / Q000502:physiology*; D012909:Snake Bites; D013050:Spectrometry, Fluorescence; D014757:Viper Venoms / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000201:enzymology
chemical_list: D000997:Antivenins; D010168:Palmitates; D014757:Viper Venoms; D007770:L-Lactate Dehydrogenase; D003402:Creatine Kinase; D054501:Group II Phospholipases A2; C408444:VRV-PL-VIIIa phospholipase A2, Vipera russelli; D001205:Ascorbic Acid