Chemical Composition of Pinus roxburghii Bark Volatile Oil and Validation of Its Anti-Inflammatory Activity Using Molecular Modelling and Bleomycin-Induced Inflammation in Albino Mice

The chemical composition of Pinus roxburghii bark essential oil (PRO) was qualitatively and quantitatively determined using GC/FID and GC/MS. The anti-inflammatory activity was assessed in vitro by evaluating the binding percentages on the cannabinoids and opioids receptors. Bleomycin (BLM)-induced pulmonary inflammation in albino mice was adopted to assess PRO anti-inflammatory efficacy in vivo. In silico molecular modelling of its major components was performed on human glucocorticoids receptor (GR). Seventy-five components were identified in which longifolene (33.13%) and palmitic acid (9.34%) constituted the predominant components. No binding was observed on cannabinoid receptor type 1 (CB1), whereas mild binding was observed on cannabinoid receptor type 2 (CB2), delta, kappa, and mu receptors accounting for 2.9%, 6.9%, 10.9% and 22% binding. A significant in vivo activity was evidenced by reduction of the elevated malondialdehyde (MDA), nitric oxide (NO), myeloperoxidase (MPO), interleukin-6 (IL-6), and tumor necrosis factor-alpha (TNF-alpha) levels by 55.56%, 55.66%, 64.64%, 58.85% and 77.78% with concomitant elevation of superoxide dismutase (SOD) and catalase (CAT) activities comparable to BLM-treated group at 100 mg/kg body weight. In silico studies showed that palmitic acid exerted the fittest binding. PRO could serve as a potent anti-inflammatory natural candidate that should be supported by further clinical trials.