Anti-inflammatory and Analgesic Activities of Alpinia nigra Fruit Extract in Laboratory Animals

Aim: This study was aimed to evaluate the possible anti-inflammatory and analgesic properties of the ethanol extract of fruit of Alpinia nigra (Zingiberaceae).

Study Design: Assessment of anti-inflammatory and analgesic activity.

Place and Duration of Study: Department of Pharmacy, North South University, Dhaka, Bangladesh, between June 2012 and February 2013.

Methodology: The crude extract was investigated for anti-inflammatory effect on Long Evans rats using carrageenan induced paw edema method. For anti-inflammatory study, 20 rats were divided into 4 different groups each receiving either distilled water, standard drug or the extract at the doses of 250 and 500 mg/kg body weight. The analgesic activity was evaluated by hot plate; acetic acid induced writhing method in Swiss Albino mice divided into 4 different groups (control, standard diclofenac sodium and extract at two different doses of 250 and 500 mg/kg body weight).

Results: The results of preliminary phytochemical analysis revealed the presence of alkaloids, flavonoids, tannins, glycosides in significant amounts. The present study assessed anti-inflammatory activity of its fruit extracts at a dose of 250 mg/kg and 500 mg/kg against carrageenan induced paw edema in long Evans rats. Both the extracts were able to show a dose dependent anti-inflammatory activity as compared to diclofenac sodium used as a standard. The extract elicited a highly significant (p<0.001) analgesic activity in a dose dependent manner on hot plate and acetic acid induced writhing methods.

Conclusion: The anti-inflammatory and analgesic effect of the ethanol fruit extract of A. nigra may be due to the presence of various chemical constituents especially flavonoids, tannins, alkaloids or terpenoids. These experimental findings would further establish the scientific basis of the traditional uses of the plant in the management of inflammatory conditions as well as control of pain.