Adicionar comentário

Ticli FK (1), Hage LIS (1), Cambraia RS (2), Pereira PS (2), Magro AJ, Fontes MRM (3), Stábeli RG (4), Giglio JR (5), França SC (2), Soares AM (1), Sampaio SV (1)

(1)Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, FCFRP, Universidade de São Paulo, USP, Ribeirão Preto-SP, Brazil;
(2)Unidade de Biotecnologia, Universidade de Ribeirão Preto, UNAERP, Ribeirão Preto-SP, Brazil;
(3)Departamento de Física e Biofísica, IB, Universidade Estadual Paulista, UNESP, Botucatu-SP, Brazil;
(4)Laboratório de Bioquímica do Instituto de Pesquisas em Patologias Tropicais (IPEPATRO), FioCruz; UNIR, Porto Velho-RO, Brazil;
(5)Departamento de Bioquímica e Imunologia, FMRP, Universidade de São Paulo, USP, Ribeirão Preto-SP, Brazil

Rosmarinic acid, a new snake venom phospholipase A₂ inhibitor from Cordia verbenacea (Boraginaceae): antiserum action potentiation and molecular interaction.

Many plants are used in traditional medicine as active agents against various effects induced by snakebite. The methanolic extract from Cordia verbenacea (Cv) significantly inhibited paw edema induced by Bothrops jararacussu snake venom and by its main basic phospholipase A₂ homologs, namely bothropstoxins I and II (BthTXs). The active component was isolated by chromatography on Sephadex LH-20 and by RP-HPLC on a C18 column and identified as rosmarinic acid (Cv-RA). Rosmarinic acid is an ester of caffeic acid and 3,4-dihydroxyphenyllactic acid [2-O-cafeoil-3-(3,4-di-hydroxy-phenyl)-R-lactic acid]. This is the first report of RA in the species C. verbenacea (‘baleeira’, ‘whaler’) and of its anti-inflammatory and antimyotoxic properties against snake venoms and isolated toxins. RA inhibited the edema and myotoxic activity induced by the basic PLA2s BthTX-I and BthTX-II. It was, however, less efficient to inhibit the PLA2 activity of BthTX-II and, still less, the PLA2 and edema-inducing activities of the acidic isoform BthA-I-PLA2 from the same venom, showing therefore a higher inhibitory activity upon basic PLA2s. RA also inhibited most of the myotoxic and partially the edema-inducing effects of both basic PLA2s, thus reinforcing the idea of dissociation between the catalytic and pharmacological domains. The pure compound potentiated the ability of the commercial equine polyvalent antivenom in neutralizing lethal and myotoxic effects of the crude venom and of isolated PLA_2s in experimental models. CD data presented here suggest that, after binding, no significant conformation changes occur either in the Cv-RA or in the target PL_A2. A possible model for the interaction of rosmarinic acid with Lys49-PL_A2 BthTX-I is proposed.

Abbreviations: Cv-ME, Cordia verbenacea methanolic extract; Cv-RA, rosmarinic acid from Cordia verbenacea; PLA2, phospholipase A2; PLIs, phospholipase A₂ inhibitors; BthTX-I, B. jararacussu bothropstoxin-I; BthTX-II, B. jararacussu bothropstoxin-II; BthA-I-PLA2, B. jararacussu acidic phospholipase A2; COSY, Correlation SpectroscopY; HMQC, heteronuclear multiple quantum coherence; HMBC, heteronuclear multiple bond coherence; CD, circular dichroism