Estudo de validação da espécie de Eleutherine bulbosa (Mill.) Urb. (Iridaceae): Aspectos de farmacobotânica, química e biologia.

Abstract

Neuropathic pain represents a heterogeneous group of diseases with different etiologies that differ in relation to the location, representing one of the main chronic pain conditions, with high world prevalence, requiring pharmacological treatment with a multidisciplinary approach, constituting a serious public health problem; which has led to the search for new alternatives and / or therapeutic supplements, mainly from natural products. In the real perspective of obtaining new therapeutic agents of plant origin, validation studies of plant species should be stimulated to define parameters of efficacy, safety and quality. In this sense, the objective of this study is to contribute with the validation of Eleutherine bulbosa (Mill.) Urb. (Iridaceae) (vernacular names: coquinho,), native species of Tropical America, of great occurrence in the state of Maranhão, Brazil and wide therapeutic use in the local population; aiming to evaluate pharmacobotanical, chemical and biological parameters in neuropathic pain model; contributing to quality control of authenticity and standardization of the extracts of the species. Leaves of Eleutherine bulbosa were collected in natural habitat, submitted to drying and milling, obtaining hydroalcohol extracts by maceration (EbMac) and Soxhlet apparatus (EbSox), in the hydromodule ratios of 1:18 and 1:14, respectively; (chemical screening, determination of total polyphenol content, determination of flavonoid content and chromatographic profile by high performance chromatography / mass spectrometer coupled to mass spectrometer / MS) and investigation of the analgesic potential in a model of neuropathic pain in rats (behavioral analysis: forced deambulation, mechanical allodynia and thermal hyperalgesia; biochemical analysis: determination of the activity of catalase and superoxide dismutase enzymes) and in vitro assay (determination of cyclooxygenase 1 and cyclooxygenase 2). Sample of fresh plant material was submitted to the pharmacochemical analysis (morphology and anatomy) that allow the definition of parameters for the evaluation of authenticity of the plant species, using conventional pharmacognostic research. The chemical analyzes showed that EbMac and EbSox present important classes of secondary metabolites, with expressive contents of total phenomena and flavonoids; showing in the chromatograms various compounds, especially anthraquinones, naphthoquinones and flavonoids; especially in EbSox. The extracts presented antinociceptive activity in neuropathic pain induced by sciatic nerve compression (sciatica model) in rats when administered orally for 15 days of treatment, with more expressive results in EbSox. The animals treated with EbMac and EbSox reduced the concentrations of catalase and superoxide dismutase, demonstrating antioxidant effect in neuropathic pain; (COX-1) and cyclooxygenase-2 (COX-2), with greater COX-2 potential, signaling the inhibitory action of extracts by synthesis of inflammatory mediators; results best evidenced in EbSox. Extraction of the leaves of Eleutherine bulbosa in Soxhlet apparatus demonstrated more expressive results in chemical and biological analyzes in neuropathic pain model; thus, to infer better extraction capacity to the procedure performed in Soxhlet apparatus, effectively contributing to the study of standardization of this species.