ANALGESIC AND ANTI-INFLAMMATORY EFFECTS OF METHANOL EXTRACT AND FRACTIONS OF LAGGERA AURITA LINN F (COMPOSITAE) IN MICE AND RATS

ANALGESIC AND ANTI-INFLAMMATORY EFFECTS OF METHANOL EXTRACT AND FRACTIONS OF LAGGERA AURITA LINN F (COMPOSITAE) IN MICE AND RATS

Abstract:

The plant Laggera aurita is an annual or biennial herb of widespread in dry waste places from across Senegal to Southern Nigeria. The plant has been reportedly used for medicinal purposes including treatment of rheumatic pain, healing of cuts and bruises, and as a last resort to phagedenic and chronic ulcers. The present study investigated the analgesic and anti-inflammatory properties of the methanol extract, saponin and flavonoid fractions of the plant in mice and rats. Acetic acid induced writhes test, thermally induced pain and formalin induced inflammation models in rodents were used to evaluate the antinociceptive properties of the extracts. Phytochemical and acute toxicological screenings were also conducted. The median lethal dose was above 5000 mg/kg in mice and rats for both the methanol extract and the fractions. The histological changes at 5000 mg/kg were slight glomerular necrosis and tubular damage in the kidney, slight vascular congestion, kupfer cell hyperplasia and lymphocyte hyperplasia in liver, lymphocyte hyperplasia on spleen, slight alveolar congestion on lungs and moderate erosion of stomach epithelium on stomach. The methanol extract, saponin and flavonoid fractions at doses of 200, 400 and 800 mg/kg significantly (p<0.05) inhibited the acetic acid induced abdominal writhes in mice dose dependently. Both the extract and fractions at 800 mg/kg showed better activity than 20 mg/kg piroxicam. The methanol extract, saponin and flavonoid fractions of Laggera aurita also significantly (p<0.05) and dose dependently increased the reaction time in the thermally induced pain model. The methanol extract (800 mg/kg) and saponin fraction (400 and 800 mg/kg) showed better activity when compared to the standard morphine (5 mg/kg) at 60, 90 and 120 minutes. Naloxone, a non specific opioid antagonoist blocked the analgesic effect observed with the thermally induced pain model in mice for both the methanol and viii fractions. The methanol extract and saponin fraction of Laggera aurita significantly (p<0.05) decreased formalin induced paw edema in a dose dependent manner. The saponin fraction (800 mg/kg) exhibited better anti-inflammatory effects than ketoprofen (10 mg/kg), the standard anti-inflammatory drug used. These findings suggest that the methanol extract, saponin and flavonoid fractions of the plant Laggera aurita possess analgesic and anti-inflammatory activities that justify the ethnomedical use in the treatment of painful and inflammatory conditions by the herbal practitioners.

ANALGESIC AND ANTI-INFLAMMATORY EFFECTS OF METHANOL EXTRACT AND FRACTIONS OF LAGGERA AURITA LINN F (COMPOSITAE) IN MICE AND RATS