Fig. 2

α-Amylase and α-glucosidase inhibition of corn silk–lemon and commercial tea infusion. A (α)-amylase inhibitory activity. Absorbance of the mixture of infusion dilution, sodium phosphate buffer (pH 6.9 with 0.006 M NaCl) containing Hog pancreatic α-amylase and 1% starch solution in 0.02 M sodium phosphate buffer (pH 6.9 with 0.006 M NaCl) was read at 540 nm using a spectrophotometer. The percent α-amylase inhibition was plotted against five samples extract concentration (ug/ml). The percentage (%) enzyme inhibitory activity of the phenolic extracts was calculated as described by Worthington et al. (2003). B (α)-glucosidase inhibitory activity: The infusion dilution, α-glucosidase solution, phosphate buffer (pH 6.9). The mixtures were incubated at 25 °C for 5 min, and absorbance read at 405 nm in the spectrophotometer. The α-glucosidase inhibitory activity expressed as percentage inhibition and plotted against five samples extract concentration (ug/ml). The percentage (%) enzyme inhibitory activity of the phenolic extracts was calculated (Apostilidis et al. 2007). A: 100% CSF; B: 95% CSF and 5% LF; F: top tea; L: lipton tea; G: green tea; CSF: corn silk flour; LF: lemon flour