Analgesic and anti-inflammatory properties of extracts from the bulbils of Dioscorea bulbifera L. var sativa (Dioscoreaceae) in mice and rats

The aqueous (Adb) and methanol (Mdb) extracts of the dry bulbils of Dioscorea bulbifera were evaluated against pain induced by acetic acid, formalin or pressure and for anti-inflammatory properties in carrageenan-, histamine-, serotonin- and formalin- animal models. Oral administration of these extracts at the doses of 150, 300 and 600mg/kg induced a dose dependant inhibition of pain and inflammation. At the dose of 600mg/kg, Adb produced a maximum effect of 56.38%, 73.06% and 42.79%, respectively on pain induced by acetic acid, formalin and pressure while Mdb produced an inhibition of 62.70% on acetic acid induced-pain, 84.54% on formalin induced-pain and 47.70% on pain induced by pressure. The oral administration of Adb and Mdb (600mg/kg) caused a maximum inhibition of 60.63% and 80.00%, respectively, in paw oedema induced by carrageenan. Adb (600mg/kg) also exhibited acute anti-inflammatory activity on paw oedema induced by histamine, serotonin and formalin, inhibiting this by 42.37%, 42.04% and 45.02%, respectively. A respective inhibition of 34.39, 46.92% and 32.06%, was observed after administration of Mdb at the dose of 600mg/kg. In the chronic inflammation model, the extracts showed maximum inhibition of 50.43% (Adb) and 40.84% (Mdb), respectively on the 3^rd and 5^th days of treatment.

In conclusion, the bulbils of Dioscorea bulbifera have central and peripheral analgesic properties as well as antiinflammatory activities. So, they constitute a potent source of new analgesic and anti-inflammatory principles.