In-vitro and in-vivo anti-inflammatory and antinociceptive effects of the methanol extract of the roots of Morinda officinalis

Abstract

Abstract The anti-inflammatory effects of the methanol extract of the roots of Morinda officinalis (MEMO) (Rubiaceae) were evaluated in-vitro and in-vivo. The effects of MEMO on lipopolysaccharide (LPS)-induced responses in the murine macrophage cell line RAW 264.7 were examined. MEMO potently inhibited the production of nitric oxide (NO), prostaglandin E2 and tumour necrosis factor-α (TNF-α) in LPS-stimulated RAW 264.7 macrophages. Consistent with these results, the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) at the protein level, and of iNOS, COX-2 and TNF-α at the mRNA level, was also inhibited by MEMO in a concentration-dependent manner. Furthermore, MEMO inhibited the nuclear factor kappa B (NF-κB) activation induced by LPS, and this was associated with the prevention of degradation of the inhibitor κB (IκB), and subsequently with attenuated p65 protein in the nucleus. The anti-inflammatory effect of MEMO was examined in rats using the carrageenan-induced oedema model. The antinociceptive effects of MEMO were assessed in mice using the acetic acid-induced abdominal constriction test and the hot-plate test. MEMO (100, 200 mg kg−1 per day, p.o.) exhibited anti-inflammatory and antinociceptive effects in these animal models. Taken together, the data demonstrate that MEMO has anti-inflammatory and antinociceptive activity, inhibiting iNOS, COX-2 and TNF-α expression by down-regulating NF-κB binding activity.