Structure characterization, antioxidant and hypoglycemic activity of an arabinogalactoglucan from Scutellaria baicalensis Georgi

An arabinogalactoglucan SBP-1 was purified from Scutellaria baicalensis by DEAE-52 and Sephadex G-100 column chromatography. The structure of SBP-1 was characterized using HPLC, IR, GC-MS, 1-D and 2-D NMR. The antioxidant and hypoglycemic activity of SBP-1 was investigated by vitro evaluation. The results showed that SBP-1 was composed of arabinose, glucose and galactose in a molar ratio of 1.0:5.9:1.1 and its M-w were 91,156. The backbone of SBP-1 was mainly composed of repeating -> 1)-alpha-D-Glcp-(4 -> 1)-alpha-D-Glcp-(3 -> 1)-alpha-D-Galp- (4 ->. The braches were composed of -> 2)-alpha-L-Araf-(1 ->, -> 3)-beta-D-Glcp-(1 -> and alpha-D-Glcp-(1 ->, which mainly substituted at O-6 of Glc, while terminal residue was alpha-L-Araf-(1 -> and alpha-D-Glcp-(1 ->. Vitro bioactivity showed that SBP-1 had dose-dependent antioxidant and hypoglycemic activity. The scavenging rate on ABTS, DPPH, hydroxyl and superoxide radicals was all beyond 60% as SBP-1 concentration reached 4 mg/mL, and the inhibition rate on alpha-glucosidase and alpha-amylase was both more than 80%, which was closely to that of acarbose.

Automated summary

In this study, an arabinogalactoglucan SBP-1 was purified from Scutellaria baicalensis and its structure was characterized. SBP-1 showed antioxidant and hypoglycemic activities, indicating its potential therapeutic value.