Inhibition of enzymatic activities of Bothrops asper snake venom and docking analysis of compounds from plants used in Central America to treat snakebite envenoming.

ETHNOPHARMACOLOGICAL RELEVANCE: Snakebite envenoming is a public health problem of high impact in Central America. Bothrops asper, known as barba amarilla, terciopelo, and equis, is the snake species responsible for most snakebites in Central America. In this region, there is a long-standing tradition on the use of plants in the management of snakebites, especially in indigenous communities. Ethnomedical use of Eryngium foetidum L., Neurolaena lobata (L.) Cass. and Pimenta dioica (L.) Merr. to treat snakebite envenoming has been reported in Belice, Guatemala, Nicaragua, and Costa Rica. Extracts of the leaves of these plants have shown anti-venom activities in in vitro assays in previous studies. AIM OF THE STUDY: To assess the ability of organic fractions from these three plants to inhibit enzymatic activities associated with toxicity of the venom of B. asper, and to study, by docking analysis, the interaction of metalloproteinase and phospholipases A2 (PLA2) from B. asper venom with secondary metabolites previously described in these plants. MATERIALS AND METHODS: Organic fractions were obtained from these three plant species and their ability to neutralize proteolytic, PLA2 and in vitro coagulant activities of B. asper venom was assessed. A phytochemical analysis was carried out in these fractions. The interaction of secondary metabolites previously described in these plants with three toxins from B. asper venom (a metalloproteinase, a PLA2 and a PLA2 homologue) was investigated by docking analysis. RESULTS: The inhibitory activity of plants was mainly concentrated in their polar fractions. Acetonic fraction from P. dioica was the most active against PLA2 activity, while the acetonic fraction of E. foetidum completely inhibited the proteolytic activity of the venom. Coagulant activity was partially inhibited only by the acetone and ethyl acetate fractions of P. dioica. Phytochemical analysis of the most bioactive fractions identified flavonoids, saponins, essential oils, coumarins, alkaloids, tannins and sesquiterpene lactones. Docking analysis revealed high affinity interactions of several secondary metabolites of these plants with residues in the vicinity of the catalytic site of these enzymes and, in the case of PLA2 homologue myotoxin II, in the hydrophobic channel. CONCLUSIONS: Various fractions from these plants have inhibitory activity against enzymatic actions of B. asper venom which are directly associated with toxicological effects. Docking analysis showed structural evidence of the interaction of secondary metabolites with three toxins. These observations provide support to the potential of these plants to inhibit relevant toxic components of this snake venom.

Inhibición de los efectos coagulante, fosfolipasa A2 y proteolítico del veneno de Bothrops asper por plantas usadas tradicionalmente en Centroamérica / Inhibition of the coagulant, phospholipase A2 and proteolytic effects of Bothrops asper venom by plants traditionally used in Central America

Existen pocos estudios científicos que demuestren el valor terapéutico de las plantas usadas en la medicina tradicional centroamericana para tratar el envenenamiento ofídico. En este estudio se evaluó la capacidad de los extractos etanólicos de nueve plantas de uso etnomédico en Centroamérica (Acacia hindsii, Aristolochia maxima, Bursera simaruba, Cissampelos pareira, Eryngium foetidum, Hamelia patens, Pimenta dioica, Piper peltatum y Sansevieria hyacinthoides) para inhibir el efecto coagulante del veneno de Bothrops asper. Tres de ellas (B. simaruba, E. foetidum y P. dioica) también fueron evaluadas en cuanto a su capacidad inhibitoria de los efectos fosfolipasa A2 (PLA2) y proteolítico del veneno. Las plantas fueron colectadas en Guatemala, secadas, extraídas con etanol y los efectos inhibitorios evaluados in vitro después de preincubar concentraciones variables de extracto con concentraciones fijas de veneno. Los resultados demostraron que ninguno de los extractos logró inhibir los efectos coagulante y PLA2, pero los extractos clorofilados de P. dioica y E. foetidum inhibieron efectivamente la actividad proteolítica del veneno. El tamizaje fitoquímico, mediante ensayos macro y semimicrométricos de cromatografía en capa fina, demostró la presencia de metabolitos secundarios reportados con actividad antiproteolítica (flavonoides, antocianinas, catequinas y taninos) en la composición química de los extractos de E. foetidum y P. dioica. Su efecto sobre el veneno se evaluó mediante electroforesis SDS-PAGE, demostrándose que no está mediado por degradación proteolítica de los componentes del veneno. El aislamiento y caracterización específica de sus metabolitos secundarios en futuros estudios, permitirá determinar el mecanismo de acción inhibitoria ejercido por estos extractos.

Medicinal plants have been traditionally used in Central America to treat snakebite envenomations, however, very few scientific studies aimed to demonstrate their efficacy and safety have been performed. In this study, ethanolic extracts of nine plants used in the region by traditional healers in snakebite cases (Acacia hindsii, Aristolochia maxima, Bursera simaruba, Cissampelos pareira, Eryngium foetidum, Hamelia patens, Pimenta dioica, Piper peltatum and Sansevieria hyacinthoides) were evaluated for their ability to inhibit the coagulant effect induced by the venom of the snake Bothrops asper. Three of these extracts (B. simaruba, E. foetidum and P. dioica) were also evaluated for their inhibitory effect on the phospholipase A2 (PLA2) and proteolytic activities of the venom. Plants were collected in Guatemala, dried, extracted with ethanol, and their inhibitory effects were evaluated in vitro after pre-incubation of several amounts of each extract with a challenge concentration of venom. Results showed that none of the extracts inhibited the coagulant and PLA2 effects; however, chlorophyllated extracts of E. foetidum and P. dioica effectively inhibited the proteolytic activity of the venom. Phytochemical analysis of these extracts, conducted by macrometric assays and semimicroanalysis by thin layer chromatography, identified secondary metabolites (flavones, anthocyanins, catequines and tannins) whose anti-proteolytic activities have been widely reported. SDS-PAGE analysis demonstrated that the mechanism of inhibition is not related to proteolytic degradation of the venom proteins by the plant extracts. Further studies are needed to isolate and identify the active venom inhibitory compounds of these plants, aimed to understand their mechanism of action.

Síndrome de Sweet: estudio de un caso / Sweet's syndrome: study of a case

Se presenta un caso con diagnóstico clínico e histopatológico de Síndrome de Sweet, cuyas lesiones dermatológicas se iniciaron días antes de su ingreso al hospital, las cuales estaban caracterizadas por placas eritematosas con nódulos milimétricos blandos, rojo violáceos tensos y brillantes, de resolución espontánea. El diagnóstico clínico guardó los criterios mayores y menores de inclusión de este síndrome, lo cual fue corroborado por el estudio histopatológico