Effect of Adansonia digitata L. fruit on postprandial glycaemia in non-diabetic adults

Abstract

Introduction: Diabetes mellitus is a chronic disease that affect 13% of the Portuguese population, which is estimated to increase to 15.8% in 2035 [1]. Adansonia digitata L. (Baobab) fruit is considered an important nutritional and medicinal resource [2], which is commonly consumed in the African continent. Previous studies have found postprandial hypoglycaemic activity attributed to fruit polyphenol content [3]. This study aimed to verify the effect of Adansonia digitata L. (Baobab) fruit on postprandial glycaemia levels on non-diabetics adults and evaluate compounds related with antioxidant activity.

Materials and methods: Following Cooperativa Egas Moniz ethical committee approval 31 nondiabetic adults, with ages between 18 and 40 years, were recruited from the local community. A written informed consent was obtained from volunteers that were randomly allocated in a control group (n = 16), subjected to an oral glucose tolerance test (OGTT), or in an intervention group (n = 15), subjected to OGTT followed by administration of 250 mL Baobab aqueous extract (BAE). Repeated Measures ANOVA of mixed type was used to access the difference between the 2 groups for postprandial BGL at different times. Independent samples t-test was used to access the difference between the 2 groups for AUC, ΔC_max and C_max. BAE content of total phenols, proanthocyanidins and hydrolysable tannins, as well as its antioxidant activity (FRAP, DPPH, ABTS and inhibition of O₂^•− and NO^• methods) were quantified.

Results: Results revealed that there is no interaction between the independent and repeated measures factors, thus is not possible to infer about differences in PBG in different moments. Results showed higher (C_máx) PBG in the control group compared with the intervention group (p = 0,029), although no significant variation (ΔC_max) was observed (p = 0.054). PBG area under the curve (AUC) was significantly lower (p = 0.012) on the intervention group. Total phenols, proanthocyanidins and hydrolysable tannins concentrations from BAE were 702.39 ± 11.85, 336.33±10.85 and 237.63±4.71 mg EAT/100g FW, respectively. Antioxidant activity was high, being the reducing power given by the FRAP method 1289.58 ± 34.44 mg ET/100 g FW, the scavenging activities of the DPPH and ABTS radicals 1269.72 ± 129.23 and 1004.42 ± 41.65 mg ET/100g FW, respectively. O₂^•− and NO^• IC50 were respectively 57.86 ± 2.57 and 29.48 ± 5.17 mg EAG/100g FW.

Discussion and conclusions: Results obtained suggest that the BAE could act beneficially for postprandial glycaemic control, as previously stated [3] and a possible correlation with its antioxidant properties.