Analgesic and anti-inflammatory activities of the 2,8-dihydroxy-1,6-dimethoxyxanthone from Haploclathra paniculata (Mart) Benth (Guttiferae)

Abstract

In the present study, the pharmacological effects of 2,8-dihydroxy-1,6-dimethoxyxanthone from the bark of Haploclathra paniculata were investigated in mice using in vivo inflammation and nociception models. Acetic acid-induced writhing, paw licking induced by formalin, hot plate, and carrageenan-induced paw edema tests were used to investigate the anti-inflammatory and antinociceptive activities of the xanthone compound. Xanthone, at both doses, inhibited abdominal writhing and the formalin test. At a dose of 20 mg/kg, the time of reaction to the hot plate increased, and significant effects were observed after 30, 60 and 90 min of treatment. At doses of 10 and 20 mg/kg p.o., the 2,8-dihydroxy-1,6-dimethoxyxanthone significantly reduced paw edema at 3 h after the stimulus. The tests also showed no acute toxicity of the xanthone compound in mice. 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability was also studied and confirmed the antioxidant activity of the xanthone. To propose the mechanism of action of anti-inflammatory activity of the xanthone, a molecular docking was performed using the isoenzymes cyclooxygenase 1 and 2 and the results indicate that the molecule is capable of inhibiting both the enzymes. Therefore, it can be concluded that 2,8-dihydroxy-1,6-dimethoxyxanthone from H. paniculata demonstrates analgesic, anti-inflammatory, and antioxidant activities.

Keywords: DPPH; analgesic effect; anti-inflammatory activity; edema; inflammation; oxygenated xanthone.