Inhibitory Effects of Various Ratios of Polysaccharides/Alkaloids from Rhizome of Coptis chinensis Franch on α-Glucosidase

Purpose: To investigate the inhibitory effects of various ratios of polysaccharides/ alkaloids from the rhizome of Coptis chinensis Franch (RCC) on α-glucosidase.Methods: The polysaccharides (PSD) and alkaloids (ALK) from RCC were prepared using the water extraction and alcohol precipitation method and Reinecke’s salt precipitation method, respectively. Subsequently, the α glucosidase inhibitory effects of PSD, ALK, and PSD/ALK at various ratios were evaluated spectrophotometrically in vitro.Results: With a half maximal inhibitory concentration (IC50) value of 171.67 μg/mL, ALK showed higher α-glucosidase inhibitory activity than PSD (IC50 = 296.89 μg/mL). In addition, the polysaccharides/alkaloids (PSD/ALK) at the ratio of 3:1 exhibited stronger α-glucosidase inhibitory activity (IC50 = 160.9 μg/mL) than PSD, ALK and PSD/ALK at ratios of 1:3 (IC50 = 394.78 μg/mL), 1:2 (IC50 = 185.18 μg/mL), 1:1 (IC50 = 350.51 μg/mL), and 2:1 (IC50 = 229.16 μg/mL).Conclusion: The results obtained suggest that PSD/ALK (3:1) possesses the strongest α-glucosidase inhibitory effect and may be considered as a candidate agent in future anti-diabetes drug development.Keywords: Coptis chinensis, Polysaccharides, Alkaloids, α-Glucosidase, Antidiabetic