The hypoglycaemic activities of Opuntia ficus-indica, 0. lindheimeri and 0. robusta were investigated in streptozotocin-induced diabetic rats using enteral (oral) and parenteral (intraperitoneal and intravenous) routes of administration. When the aqueous extracts of the three Opunfriz species were administred intraveneously, they produced a hypoglycaemic effect. However, when the extracts were administered orally, only 0. lindheimeri produced a hypoglycaemic effect. A dilute aqueous (ammonium sulphate) solution of 0. lindheimeri dialysate also produced a hypoglycaemic effect when administered intravenously. Intraperitoneal administations of all Opuntia species extracts including 0. lindheimeri dialysate failed to produce hypoglycaemic effects. It appears that the concentration andor potency of the active hypoglycaemic principle in Opuntiu cacti is species-specific.

The hypoglycaemic activities of Opuntia ficus‐indica, O. lindheimeri and O. robusta were investigated in streptozotocin‐induced diabetic rats using enteral (oral) and parenteral (intraperitoneal and intravenous) routes of administration. When the aqueous extracts of the three Opuntia species were administred intraveneously, they produced a hypoglycaemic effect. However, when the extracts were administered orally, only O. lindheimeri produced a hypoglycaemic effect. A dilute aqueous (ammonium sulphate) solution of O. lindheimeri dialysate also produced a hypoglycaemic effect when administered intravenously. Intraperitoneal administations of all Opuntia species extracts including O. lindheimeri dialysate failed to produce hypoglycaemic effects. It appears that the concentration and/or potency of the active hypoglycaemic principle in Opuntia cacti is species‐specific.