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.

Analgesic, Anti-Inflammatory and Antipyretic Effect of Mentha spicata (Spearmint).

Aim: Mentha spicata (L.) is popularly used as herbal remedy for various ailments. But the scientific basis for its medicinal use especially in pain and inflammation remains unknown. Therefore, the present study was aimed to investigate the analgesic, anti-inflammatory and antipyretic effects of whole plant of Mentha spicata in laboratory animals. Materials and Method: The methanol extract of Mentha spicata (MEMS) was used to investigate the acute effect on analgesia by Hot-plate test and acetic acid induced writhing method (By acetic acid) in mice and on inflammation in rats by carrageen induced paw edema method. Subcutaneous injection of 20% aqueous suspension of Brewer’s yeast in wistar rats leads to pyrexia. Results: The extract showed a significant (p<0.001) dose dependent increase in reaction time in mice in the hot-plate test at the doses of 250 mg/kg and 500 mg/kg body weight. The extract showed a significant (p<0.05) dose dependent increase in reaction time in mice in writhing method at the doses of 250 and 500 mg/kg body weight. The extract also exhibited promising anti-inflammatory effect as demonstrated by statistically significant (p<0.05) inhibition of paw volume by 42.58% at the dose of 250 mg/kg body weight and 45.10% at the dose of 500 mg/kg body weight at the sixth hour of study. Intraperitoneal administration of MEMS showed dose dependent decrease in body temperature in brewer’s yeast induced hyperthermia in rats at both doses. However, MEMS significantly decreased body temperature (p<0.05) at 500mg/kg compared to control. Conclusion: This study suggests that the methanol extract of Mentha spicata have analgesic, anti-inflammatory and antipyretic activity in a dose dependent manner which supports its use as an analgesic, anti-inflammatory and antipyretic drug in folk medicine.

Antinociceptive and Anti-inflammatory Activity of the Bark Extract of Plumeria rubra on Laboratory Animals.

Aims: To evaluate the analgesic and anti-inflammatory effects of ethanolic bark extract of Plumeria rubra on experimental animal models. Study Design: Assessment of antinociceptive and anti-inflammatory activity. Place and Duration of Study: Department of Pharmacy, North South University, Dhaka, Bangladesh, between January 2011 and June 2011. Methodology: The analgesic activity was evaluated by hot plate, acetic acid induced writhing and formalin 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 BW). The extract was also investigated for the anti-inflammatory effect on Long Evans rats using carrageenan induced rat paw edema method. For antiinflammatory study, 24 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 BW. Results: Phytochemical analysis of the extract revealed the presence of tannins, alkaloids, flavonoids and terpenoids. The extract elicited a highly significant (p<0.001) analgesic activity in a dose dependent manner on hot plate method, acetic acid induced writhing test and also on both the early and late phases of formalin test at the doses employed. In the hot plate method, the extract increased the reaction time of heat sensation to 60.81% and 66.52% at the doses of 250 and 500 mg/kg BW respectively while that of the standard drug was 57.40% at the 3rd hour of study. In acetic acid induced writhing test, the percent inhibition of writhing response by the extract was 62.87% and 70.66% at 250 and 500 mg/kg doses respectively (p<0.001) which were even better than the standard drug diclofenac sodium (50.30%). The extract also significantly inhibited the licking response at the dose of 500 mg/kg in both the early phase (55.11%, p<0.01) and the late phase (66.43%, p<0.01) of formalin test while the standard drug inhibited by 52.27% and 72.03%, respectively. The oral administration of the extract significantly (p<0.001) inhibited inflammatory response induced by carrageenan in a dose dependent fashion. The most prominent inhibition of 61.68% (250 mg/kg) and 73.65% (500 mg/kg) were observed at the 4th hour of study. Conclusion: The central and peripheral analgesic as well as anti-inflammatory effect of the ethanolic bark extract of P. rubra may be due to the presence of various chemical constituents specially flavonoids, tannins, alkaloids or terpenoids. These experimental findings would further establish the scientific basis of the traditional uses of the plant in the management and/or control of pain as well as inflammatory conditions.