Antinociceptive, anti-inflammatory and antidiabetic properties of Hypoxis hemerocallidea Fisch. & C.A. Mey. (Hypoxidaceae) corm [‘African Potato’] aqueous extract in mice and rats

In order to scientifically appraise some of the anecdotal, folkloric, ethnomedical uses of Hypoxis hemerocallidea Fisch. & C.A. Mey. (Hypoxidaceae) corm [‘African Potato’], the present study was undertaken to examine the antinociceptive, anti-inflammatory and antidiabetic properties of the corm's aqueous extract (APE) in mice and rats. The antinociceptive effect of APE was evaluated by ‘hot-plate’ and ‘acetic acid’ analgesic test methods in mice; while the anti-inflammatory and antidiabetic effects of the plant's extract were investigated in rats, using fresh egg albumin-induced pedal (paw) oedema, and streptozotocin (STZ)-induced diabetes mellitus models. Morphine (MPN, 10 mg/kg), diclofenac (DIC, 100 mg/kg) and chlorpropamide (250 mg/kg) were used as reference drugs for comparison. H. hemerocallidea corm aqueous extract (APE, 50–800 mg/kg i.p.) produced dose-dependent, significant (P < 0.05–0.001) antinociceptive effects against thermally- and chemically-induced nociceptive pain stimuli in mice. The plant extract (APE, 50–800 mg/kg p.o.) also significantly (P < 0.05–0.001) inhibited fresh egg albumin-induced acute inflammation, and caused dose-related, significant (P < 0.05–0.001) hypoglycaemia in normal (normoglycaemic) and diabetic rats. The results obtained in this study suggest that the antinociceptive effects of the plant's extract are peripherally- and centrally-mediated. The findings of this experimental animal study indicate that H. hemerocallidea corm aqueous extract (APE) possesses antinociceptive, anti-inflammatory and antidiabetic properties; and thus lend pharmacological support to folkloric, anecdotal uses of ‘African Potato’ in the treatment and/or management of painful, arthritic inflammatory conditions, as well as in the management and/or control of type-2 diabetes mellitus in some parts of southern Africa.