In vitro and in vivo anti-inflammatory activity of Cupressus torulosa D.DON needles extract and its chemical characterization

Abstract

Ethnopharmacological relevanceCupressus torulosa (family Cupressaceae), widely distributed in the north western Himalayan region of India, is a coniferous aromatic tree with various traditional uses of its aerial parts. Its needles have been used for anti-inflammatory, anticonvulsant, antimicrobial, and wound-healing properties. Aim of the studyThe study aimed at investigating the previously unknown anti-inflammatory activity of the hydromethanolic extract of the needles employing in vitro and in vivo assays and scientifically validate traditional claim of their use in treatment of inflammation. Chemical characterization of the extract with the aid of UPLCQTOFMS was also of interest. Materials and methodsC. torulosa needles were first defatted with hexane and sequentially extracted with chloroform and 25% aqueous methanol (AM). Since the presence of phenolics (TPCs, 208.21 ± 0.95 mg GAE/g needles) and flavonoids (TFCs, 84.61 ± 1.21 mg QE/g needles) was observed in the AM extract only, it was chosen for biological and chemical examinations. Acute toxicity of the AM extract on female mice was evaluated following the OECD guideline 423. In vitro anti-inflammatory activity of the AM extract was examined using egg albumin denaturation assay while carrageenan-induced paw edema and formalin-induced paw edema models at doses of 100, 200 and 400 mg/kg po were used to determine the in vivo activity of the AM extract on Wistar rats of either sex. The components of the AM extract were analyzed by UPLC-QTOF-MS method using non-targeted metabolomics approach. ResultsAM extract was found to be non-toxic at 2000 mg/kg b.w. with no signs of abnormal locomotion, seizures and writhing. The extract demonstrated promising in vitro anti-inflammatory activity (IC50 160.01 μg/mL) compared to standard diclofenac sodium (IC50 73.94 μg/mL) in egg albumin denaturation assay. In carrageenan-induced paw edema and formalin-induced paw edema tests the extract showed significant anti- inflammatory activity (57.28% and 51.04% inhibition of paw edema, respectively) at the dose of 400 mg/kg p.o. after 4 h in comparison to the standard diclofenac sodium which displayed 61.39% and 52.90% inhibition, respectively, at the dose of 10 mg/kg p.o. after 4 h in these models. A total of 63 chemical constituents, majority of them being phenolics, were found in the AM extract of the needles. Two compounds namely monotropein (iridoid glycoside), (±)12-HETE (eicosanoid) and fraxin (coumarin glycoside) were reported to have anti-inflammatory effect. ConclusionsFor the first time our study demonstrated that hydro-methanolic extract of C. torulosa needles exhibit anti-inflammatory activity thereby supporting their traditional use in the treatment of inflammatory disorders. UPLCQTOFMS assisted chemical profile of the extract was also unveiled.