Chemical composition and anti-arthritic activity of the essential oil from Litsea cubeba against Type II collagen rheumatoid arthritis in rat collagen

Abstract

Purpose: To study the curative effect of the volatile oil from Litsea cubeba (EOL) on type II collagen (CII) induced arthritic (CIA) rat. Methods: The chemical constituents of EOL were analyzed by gas chromatography-mass spectrometry (GC-MS). The analgesic effect of the oil was assessed by acetic acid-stimulated torsion and hot plate methods, while antiinflammatory potential was further assessed by in an ear oedema model induced by dimethylbenzene in mice. The anti-rheumatoid arthritis (RA) activity of EOL in mice was evaluated in terms of paw volume, arthritis index, thymus and spleen index, and serum inflammatory factor levels. Results: GC-MS showed that α-citral (26.42 %), β-citral (21.94 %), and limonene (12.79 %) were the main components of EOL. Different doses of EOL (50, 100, 200 mg/kg) exerted varying inhibitory effects on torsion in mice induced by acetic acid (p < 0.01) but had no significant effect on thermal stimulation-induced pain. EOL reduced ear oedema in mice (p < 0.01). In addition, EOL (50, 100, 200 mg/kg) reduced the mouse paw volume, arthritis index, and thymus and spleen index (p < 0.01). Furthermore, EOL reduced proinflammatory cytokines in serum but increased antiinflammatory cytokines (p < 0.01). Conclusion: EOL ameliorates symptoms of inflammation in CIA rats by inhibiting inflammatory reactions, suggesting it could be further developed as an anti-arthritic drug. Keywords: Litsea cubeba, Essential oil, Rrheumatoid arthritis, Pro-inflammatory cytokines