Hyperglycaemic effect of Artocarpus communis Forst (Moraceae) root bark aqueous extract in Wistar rats

Decoctions and infusions of Artocarpus communis (Forst) (family: Moraceae) root bark are traditionally used among the Yoruba-speaking people of western Nigeria as folk remedies for the management, control and treatment of an array of human diseases, including type 2 diabetes mellitus. Although numerous bioactive prenylflavonoids have been isolated from the roots, stem bark and leaves of A communis, to the best of our knowledge, the effects of the plant's root bark extract on animal models of diabetes mellitus have hitherto not been reported in the biomedical literature. In our pilot study, we observed that A communis root bark aqueous extract (ACE) raised blood glucose concentrations in rats. In view of this finding, the present study was undertaken to investigate the glycaemic effect of ACE in comparison with that of streptozotocin (STZ) in Wistar rats. Four groups (A, B, C and D) of Wistar rats, each group consisting of 10 rats, were used in this study. Group A rats received distilled water in quantities equivalent to the volume of ACE administered. Diabetes mellitus was induced in the animals in groups B and C by intraperitoneal (ip) injections of STZ (75 mg/kg body weight). The rats in group C were additionally treated with ACE (50 mg/kg body weight ip) from the third to the tenth day following STZ treatment. Group D rats received ACE (12.5-100 mg/kg body weight ip) only. The effects of ACE were compared with those of STZ on blood glucose concentrations, serum and pancreatic insulin levels, hepatic hexokinase (HXK) and glucokinase (GCK) activities, and hepatic glycogen contents in the experimental animal paradigm used. The rats in treated groups B, C and D exhibited pronounced polyuria, hypo-insulinaemia and hyperglycaemia. Group D rats developed significant hyperglycaemia (p < 0.05) immediately after ACE administration, whereas groups B and C rats became hyperglycaemic 24 to 72 hours post STZ and STZ + ACE treatments, when compared with the control group A rats. Hepatic glycogen contents significantly increased (p < 0.05), while HXK and GCK activities significantly decreased (p < 0.05) in the treated groups B, C and D rats, when compared with the control group A rats. The findings of this laboratory animal study indicate that A communis root bark aqueous extract induced acute hyperglycaemia in Wistar rats, and that it disrupted the biochemical variables of the rat pancreas and liver.