Structural Insight into Binding Mode of 9-Hydroxy Aristolochic Acid, Diclofenac and Indomethacin to PLA2

Isolation and structural characterization of bioactive compound from Aristolochia sprucei aqueous extract with anti-myotoxic activity

A bioactive compound isolated from the stem extract of Aristolochia sprucei through High Performance Liquid Chromatography (HPLC) was identified via Nuclear Magnetic Resonance (NMR) as the aristolochic acid (AA). This compound showed an inhibitory effect over the myotoxic activity of Bothrops jararacussu and Bothrops asper venoms, being also effective against the indirect hemolytic activity of B. asper venom. Besides, AA also inhibited the myotoxic activity of BthTX-I and MTX-II with an efficiency greater than 60% against both myotoxins. Docking predictions revealed an interesting mechanism, through which the AA displays an interaction profile consistent with its inhibiting abilities, binding to both active and putative sites of svPLA₂. Overall, the present findings indicate that AA may bind to critical regions of myotoxic Asp 49 and Lys49-PLA₂s from snake venoms, highlighting the relevance of domains comprising the active and putative sites to inhibit these toxins.

Health risk associated with the oral consumption of "Chiniy-tref", a traditional medicinal preparation used in Martinique (French West Indies): Qualitative and quantitative analyses of aristolochic acids contained therein

"Chiniy-tref" (CT) is a traditional preparation used in folk medicine in Martinique Island (French West Indies) that is nowadays mainly taken orally to prevent or act against any "manifestation of evil". CT is easily prepared at home by macerating larvae of the endemic swallowtail Battus polydamas (ssp.) cebriones (Dalman, 1823), sometimes accompanied by a leaf of its host-plant Aristolochia trilobata L., in commercial rum. We have previously reported the detection of nephrotoxic and carcinogenic aristolochic acids (AAs) I and II in CT, leading the Regional Health Agency (ARS) of Martinique to issue an alert regarding the potential risks associated with its consumption in 2015. In order to complete the toxicity risk assessment for oral consumption of CT, a full qualitative analysis of AAs and their analogues (AAAs) was performed, as well as a quantitative determination of the major AAs, namely AAs I and II. The phytochemical profiling of AAAs present in CT, that also corresponds to that of B. polydamas cebriones larvae feeding on A. trilobata, has been established for the first time by ultra-high performance liquid chromatography/electrospray ionization quadrupole time of-flight tandem mass spectrometry. AAs I and II were quantified in a small panel of tinctures by using a validated UHPLC/UV method, allowing us to estimate the probable daily intakes of these toxins by CT consumers. The results proved the existence of a real risk of renal toxicity and carcinogenicity associated with the chronic oral consumption of CT in Martinique, and more generally of similar "snake bottles" throughout the Caribbean.

Molecular docking and dynamic studies of crepiside E beta glucopyranoside as an inhibitor of snake venom PLA2

Alternative treatments from plant-derived small molecules for neutralizing the venom lethality in snake envenomation are prevalent now. Elephantopus scaber, a tropical plant species has been recognized for its various pharmacological activities and especially anti-snake venom property; however, the molecular basis for this property is not understood. It is reported that snake venom PLA2 is a toxic factor with pharmacological effects independent of their catalytic activity. Here we report the inhibition of catalytic property of Cobra and Viper (group I and group II) snake venom PLA2 by the phytocompounds from E. scaber through molecular docking and dynamics studies. Initially, Lipinski's rule, ADMET, and molecular docking studies were carried out. Our results show that among 124 phytocompounds, crepiside E (deacylcynaropicrin-3' beta-glucopyranoside) has shown interactions with the conserved catalytic active site residues, His 48 and Asp 49, in both the PLA2s. Further, molecular dynamic simulations for 60 ns confirmed the stability of crepiside E in the active site of PLA2s and were found to be stable throughout the simulation. In order to understand the drug-likeness of crepiside E, pIC50 and MMGBSA scores were correlated by performing a linear regression analysis. Crepiside E was found to have similar chemical features to that of doxycycline, a known PLA2 inhibitor as indicated by a similarity score of 64.15%. Hence, it is concluded that crepiside E beta glucopyranoside present in Elephantopus scaber contributes to neutralizing the snake venom.