Sclerocarya birrea (Anacardiaceae) stem-bark extract corrects glycaemia in diabetic rats and acts on β-cells by enhancing glucose-stimulated insulin secretion

Abstract

Sclerocarya birrea is a plant widely used as traditional medication for the treatment of diabetes in sub-Saharan regions. However, the mechanism of action is unknown and only hypoglycaemic effects of S. birrea extract (SBE) in diabetic rats have been reported to date. Here, we tested aqueous extracts of S. birrea on insulin-secreting INS-1E cells and isolated rat islets. Following 24 h of treatment at 5 mg/ml, the extract markedly potentiated glucose-stimulated insulin secretion. Neither basal insulin release nor non-nutrient stimulation was affected. The potentiation of the secretory response at stimulatory glucose appeared after 12 h of treatment. No acute effects were observed and, at the effective concentration, SBE was safe regarding cell integrity and differentiation. The mechanism of action of the SBE was related to glucose metabolism as both ATP generation and glucose oxidation were enhanced following the 24-h treatment. In streptozotocin-induced diabetic rats, SBE administration corrected glycaemia and restored plasma insulin levels after 2 weeks of treatment. These data show direct action of S. birrea on insulin-secreting cells and favour further delineation for use of the plant in the management of diabetes.

Inhibitory potentials and kinetics of the inhibition of carbohydrate-hydrolysing enzymes by the pod and seed extracts of Lessertia montana (Fabaceae) E. Phillips & R.A. Dyer

“…A methanol/methylene chloride extract (150 and 300 mg/kg) has been found to cause a reduction in blood glucose levels and increase plasma insulin levels in diabetic rats 217 . A similar hypoglycaemic effect with increased plasma insulin, was reported in diabetic rats treated with aqueous stem-bark extracts (300 mg/ml) 206 . Contradictory findings were reported in diabetic rats treated with ethanol stem-bark extracts (60, 120 and 240 mg/kg), where a reduction in blood glucose levels, without significantly affecting pancreatic insulin secretion was observed 104 .…”

“…In the present study, glucose uptake was monitored in C2C12, HepG2 and 3T3-L1 cells birrea were found to enhance glucose utilization in Chang liver, C2C12 and 3T3-L1 cells (12 and 50 µg/ml) 30 , findings that support the results of the present study. The glucose-lowering effects of S. birrea using in vivo models is known 104,206,208,217 .…”

Profiling of Phytochemicals in Tissues from Sclerocarya birrea by HPLC-MS and Their Link with Antioxidant Activity

“…The bark, leaves, and roots of Sclerocarya birrea (S. birrea)have attracted attention because they have been traditionally used to treat an assortment of human ailments such as dysentery, fevers, malaria, diarrhea, stomach ailments, rheumatism, sore eyes, gangrenous rectitis, infertility, headaches, toothache, and body pains [6,7]. As a result, extracts of this plant have been reported to possess antioxidant, antibacterial, antifungal, astringent anticonvulsant [8][9][10], antihyperglycemic, anti-inflammatory [11], and antiatherogenic properties [12]. Several of these properties could be attributed to the high content of polyphenols and its antioxidant activity [13][14][15][16].…”

RP-HPLC–ESI–QTOF/MS2 based strategy for the comprehensive metabolite profiling of Sclerocarya birrea (marula) bark

“…Extract 1 was obtained by maceration of 1 kg powdered stem bark in 3 L of distilled water for 48 h (Ndifossap et al, 2010); extract 2 by maceration of 500 g powdered stem bark in 2 L distilled water for 1 h (Fotio et al, 2009); extract 3 by maceration of 2 kg powdered stem bark in methanol for 72 h (Fotio et al, 2009); extract 4 by maceration of 2 kg powdered stem bark in a mixture methanol:dicloromethane (1:1) for one week (Dimo et al, 2007). All extracts were centrifuged for 15 min at 3500 rpm and the supernatant was collected.…”