Ping Jiang, Jia Xiong, Fei Wang, Mary H. Grace, Mary Ann Lila, Rui Xu1 (2017). α-Amylase and α- Glucosidase Inhibitory Activities of Phenolic Extracts From Eucalyptus grandis x E. urophylla Bark.
1. College of Chemical Engineering, Nanjing Forestry University, Jiangsu Key Lab of Biomass-Based Green Fuels and
Chemicals, Nanjing, Jiangsu 210037, China;
2.Plants for Human Health Institute, Food Bioprocessing and Nutritional Sciences, North Carolina State University,
North Carolina Research Campus, Kannapolis, NC 28081 USA
This study evaluated the inhibitory effects of different extracts and fractions from Eucalyptus. grandis × urophylla bark (EB) against α-glucosidase and α amylase enzyme activities. The ethyl acetate extract (EB-E) showed the highest activity among others. Seven fractions were derived from EB-E, among them EB-E-7 showed the highest significant inhibition of both enzymes, with IC50 1.40 ± 0.18 and 1.72 ± 0.12 μg/mL, respectively, and significantly lower than that of acarbose. The total phenolic content of EB-E and its active fraction EB-E-7 showed highest contents of total phenolics: 178.79 ± 4.68 and 920.4 ± 5.46 mg GAEa
g-1, respectively. HPLC-MS analysis of EB-E-7 revealed the presence of ellagic acid ，quercetin-glucuronide, quercetin-3-α-rhamnopyranoside, and ellagic acid-rhamnoside as major compounds, together with smaller concentrations myricetin-rhamnoside, isorhamnetin-hexoside, myricetin-3-α-arabinofuranoside, and isorhamnetin. Therefore, the phenolic compounds from Eucalyptus grandis E. urograndis’ bark potently inhibited α-amylase and α-glucosidase activity have
potential in prevention of hyperglycemia.