title: Neutralization of snake venom phospholipase A2 toxins by aqueous extract of Casearia sylvestris (Flacourtiaceae) in mouse neuromuscular preparation.
abstract: Aqueous extract of Casearia sylvestris (Flacourtiaceae) has been shown to inhibit enzymatic and biological properties of some Bothrops and Crotalus venoms and their purified phospholipase A(2) (PLA(2)) toxins. In this work we evaluated the influence of C. sylvestris aqueous extract upon neuromuscular blocking and muscle damaging activities of some PLA(2)s (crotoxin from C. durissus terrificus, bothropstoxin-I from B. jararacussu, piratoxin-I from B. pirajai and myotoxin-II from B. moojeni) in mouse phrenic-diaphragm preparations. Crotoxin (0.5 microM) and all other PLA(2) toxins (1.0 microM) induced irreversible and time-dependent blockade of twitches. Except for crotoxin, all PLA(2) toxins induced significant muscle damage indices, assessed by microscopic analysis. Preincubation of bothropstoxin-I, piratoxin-I or myotoxin-II with C. sylvestris extract (1:5 (w/w), 30 min, 37 degrees C) significantly prevented the neuromuscular blockade of preparations exposed to the mixtures for 90 min; the extent of protection ranged from 93% to 97%. The vegetal extract also neutralized the muscle damage (protection of 80-95%). Higher concentration of the C. sylvestris extract (1:10, w/w) was necessary to neutralize by 90% the neuromuscular blockade induced by crotoxin. These findings expanded the spectrum of C. sylvestris antivenom activities, evidencing that it may be a good source of potentially useful PLA(2) inhibitors.
authors.affiliation: Departamento de Farmacologia, Instituto de Biociências, Universidade Estadual Paulista, UNESP, Botucatu, SP, Brazil.
authors.forename: Walter L G
authors.initials: WL
authors.lastname: Cavalcante
authors.forename: Tayná O
authors.initials: TO
authors.lastname: Campos
authors.forename: Maeli
authors.initials: M
authors.lastname: Dal Pai-Silva
authors.forename: Paulo S
authors.initials: PS
authors.lastname: Pereira
authors.forename: Clayton Z
authors.initials: CZ
authors.lastname: Oliveira
authors.forename: Andreimar M
authors.initials: AM
authors.lastname: Soares
authors.forename: Márcia
authors.initials: M
authors.lastname: Gallacci
mesh_terms: D000818:Animals; D001938:Brazil; D037821:Casearia / Q000737:chemistry*; D003435:Crotalid Venoms / Q000037:antagonists & inhibitors / Q000633:toxicity; D003439:Crotoxin / Q000037:antagonists & inhibitors* / Q000633:toxicity; D003964:Diaphragm / Q000187:drug effects* / Q000294:innervation / Q000502:physiology; D054501:Group II Phospholipases A2 / Q000037:antagonists & inhibitors / Q000633:toxicity; D066298:In Vitro Techniques; D008297:Male; D051379:Mice; D008854:Microscopy, Electron; D008931:Mitochondria, Muscle / Q000187:drug effects / Q000648:ultrastructure; D009210:Myofibrils / Q000187:drug effects / Q000648:ultrastructure; D064801:Phospholipase A2 Inhibitors; D010791:Phrenic Nerve / Q000187:drug effects / Q000502:physiology; D010936:Plant Extracts / Q000737:chemistry / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry; D018517:Plant Roots / Q000737:chemistry; D018547:Plant Stems / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry; D030162:Reptilian Proteins / Q000037:antagonists & inhibitors / Q000633:toxicity; D013997:Time Factors; D014867:Water / Q000737:chemistry
chemical_list: D003435:Crotalid Venoms; D064801:Phospholipase A2 Inhibitors; D010936:Plant Extracts; D030162:Reptilian Proteins; D014867:Water; C078097:bothropstoxin; D003439:Crotoxin; C114085:piratoxin I; D054501:Group II Phospholipases A2; C061056:myotoxin II, Bothrops asper