Determination of major and minor capsaicinoids in different varieties of the Capsicum fruits using GC-MS and their inhibition effect of the chilliextract on α-amylase activity

The major and minor components of capsaicinoids were determined in seven main varieties of the Capsicum fruits grown in Northeast of Thailand. The methanol extract of capsaicinoids was cleaned up by C18 cartridge prior to qualitative and quantitative analysis by GC-MS. The chilli samples qualitatively comprised of nine identified compounds including nornordihydrocapsaicin, nordihydrocapsaicin, N-vanillyl-nonanamide, capsaicin, dihydrocapsaicin, N-vanillyl-decanamide, homocapsaicin, homodihydrocapsaicin isomer I and isomer II. Using full scan MS, the analytical figures of merit of the method had been validated and, based on the calibration curve of dihydrocapsaicin, both groups of the capsaicinoids could be quantitatively determined. It was found that the two major capsaicinoids consisting of 88.3 – 96.6% (capsaicin, 45.2 – 60.5% and dihydrocapsaicin, 32.2 – 44.0%) were found in higher contents in all studied samples, while some of the minor ones were still undetectable. The total contents of these capsaicinoids were ranged of 3,718.2 – 7,671.8 μg g-1 DW. Furthermore, an inhibition of α-amylase activity of the chilli extract was estimated by dinitrosalicylic acid method, resulted as a potent inhibitor (16 – 33% inhibition) against the amylase activity, potentially regarding to physiological response for a risk reduction of diabetes.