Hypoglycemic effects of <i>Rhodiola crenulata</i> (HK. f. et. Thoms) H. Ohba <i>in vitro</i> and <i>in vivo</i> and its ingredient identification by UPLC-triple-TOF/MS

Abstract

<i>Rhodiola crenulata</i> (HK. f. et. Thoms) H. Ohba (RC), mainly distributed in the highly cold region of China, has long been used as a medicine/healthy food for eliminating fatigue and increasing blood circulation. This study aimed to evaluate the inhibitory effects of the RCRS extract on α-amylase and α-glucosidase (sucrase and maltase) <i>in vitro</i> and <i>in vivo</i>, and tentatively analyze and identify its chemical ingredients using UPLC-Triple-TOF/MS. The <i>Rhodiola crenulata</i> RCRS extract had strong inhibitory activities against α-amylase, sucrase and maltase with an IC₅₀ of 0.031 mg mL^-1, 0.142 mg mL^-1 and 0.214 mg mL^-1, respectively. Furthermore, the RCRS extract could significantly decrease the postprandial blood glucose (PBG) level of normal mice in a starch tolerance test, and reduce the PBG levels of diabetic mice in a starch/maltose/sucrose tolerance test. UHPLC-Triple-TOF-MS/MS analysis indicated that hydroxybenzoic acids, hydroxycinnamic acids, alcohol glycosides, flavonols and their derivatives were the main active ingredients in the RCRS extract. The results demonstrate that the RCRS extract of <i>Rhodiola crenulata</i> could be employed as a healthy food or medicine for controlling postprandial blood glucose levels.