Tinospora cordifolia ameliorates paclitaxel-induced neuropathic pain in albino rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Tinospora cordifolia (T. cordifolia) (Willd.) Miers, a member of the Menispermaceae, family documented in the ancient textbooks of the Ayurveda System of Medicine, has been used in the management of sciatica pain and diabetic neuropathy. AIM: The study has been designed to evaluate the antinociceptive potential of various extracts of T. cordifolia stem in Paclitaxel (PT)-generated neuropathic pain model in albino rats and explore its possible mechanism employing molecular docking studies. METHODS: Stems of T. cordifolia were shade dried, grinded in fine powder, and extracted separately with different solvents viz. ethanol, water & hydro-alcoholic and characterized using LCMS/MS. The antinociceptive property of T. cordifolia stem (200 and 400 mg/kg) was examined in albino rats using a PT-induced neuropathic pain model. Further, the effect of these extracts was also observed using different behavioral assays viz. cold allodynia, mechanical hyperalgesia (pin-prick test), locomotor activity test, walking track test, and Sciatic Functional Index (SFI) in rats. Tissue lysate of the sciatic nerve was used to determine various biochemical markers such as GSH, SOD, TBARS, tissue protein, and nitrite. Further to explore the possible mechanism of action, the most abundant and therapeutically active compounds available in aqueous extract were analyzed for binding affinity towards soluble epoxide hydrolase (sEH) enzyme (PDB ID: 3wk4) employing molecular docking studies. RESULTS: The results of the LCMS/MS study of different extracts of T. cordifolia indicated presence of alkaloids, glycosides, terpenoids, sterols and sugars such as amritoside A, tinocordin, magnoflorine, N-methylcoclaurine, coridine, 20ß-hydroxyecdysone and menaquinone-7 palmatin, cordifolioside A and tinosporine etc. Among all the three extracts, the hydroalcoholic extract (400 mg/kg) showed the highest response followed by aqueous and ethanolic extracts as evident in in vivo behavioral and biochemical evaluations. Furthermore, docking studies also exposed that these compounds viz. N-methylcoclaurine tinosporin, palmatine, tinocordin, 20ß-hydroxyecdysone, and coridine exhibited well to excellent affinity towards target sEH protein. CONCLUSION: T. cordifolia stem could alleviate neuropathic pain via soluble epoxide hydrolase inhibitory activity.