Can extracts of the tubers and leaves of some species of yam be used to beat cancer, diabetes, pain, arthritis, bone loss and premenopausal syndrome?
Researchers say the tuber of yam (Dioscorea esculenta) may provide a possible source for the discovery of anti-inflammatory agents (painkillers) without the adverse effects associated with the use of aspirin and other non-steroidal anti-inflammatory drugs.
The study published in African Journal of Biotechnology entitled “Anti-inflammatory studies of yam (Dioscorea esculenta) extract on wistar rats.”
The researchers from the Department of Pharmacognosy, University of Ibadan, Ibadan, Oyo State, led by J. O. Olayemi and E. O. Ajaiyeoba, evaluated the defatted methanol extract of Dioscorea esculenta tuber for anti-inflammatory properties in animal model using Wistar rats.
The study was done using the cotton thread method in measuring the right hind paw oedema and granuloma tissue formation in rats. The extract was tested at doses between 100-200 mg/kg body weight of rats.
Preliminary phytochemical screening confirmed the presence of saponins, disgenin, -sistosterol, stigmasterol, cardiac glycosides, fat and starch.
The extract exhibited significant inhibition of the carrageenan-induced oedema that was dose-dependent with a good initial effect in one hour and two hour at doses of 100 mg/kg and 150 mg/kg, respectively.
The observed activity was comparable to that of 150 mg/kg acetylsalicylic acid that was used as a reference drug in the study. Dioscorea esculenta tuber methanol extract supports the folkloric use for management of inflammation.
The researchers concluded, “This result indicated that the yam species has anti- inflammatory activity. It seems the anti-inflammatory property is shortlived and one may suggest this action is quickly metabolized and removed from the system after reaching its peak in two hours. This activity is optimally active at doses between 100 mg/kg and 150 mg/kg in the present study.
“A number of adverse effects have been associated with the use of aspirin and other non-steroidal anti- inflammatory drugs. This necessitates the need to source newer compounds from natural products with less or no adverse effects. The tuber of D. esculenta may provide a possible source for the discovery of anti-inflammatory agents.”
Commonly called English lesser yam, Chinese yam, Lagos yam and Hausa potato, Dioscorea esculenta belongs to the plant family Dioscoreaceae.
The Yoruba call it igu àlùbọ́sà and odunkun.