Fine structure and hypoglycemic effect of a galactoglucan from the bulbs of Lanzhou lily.

The present research aimed to further identify the fine structure, morphology, and thermal behaviors of a galactoglucan BHP-2 derived from Lanzhou lily bulbs through partial acid hydrolysis, methylation, 2D NMR (1H 1H COSY, HSQC, and HMBC), scanning electron microscopy (SEM) and thermogravimetric-differential thermal analysis (TG-DTA). Additionally, the study assessed the potential in vitro hypoglycemic effect of BHP-2 by examining its inhibitory effect on α -glucosidase and α -amylase. The results indicated that the main backbone composition of BHP-2 consisted of →4)- α -D-Glc p -(1→, →3)- β -D-Glc p -(1 → and →6)- β -D-Gal p -(1→, while the side chain composition predominantly featured →4)- α -D-Glc p -(1→, →3,5)- α -L-Ara f -(1 → and →3)- β -D-Gal p -(1→, attached to the C-2 and/or C-3 positions of →4)- α -D-Glc p -(1→. Terminal residues consisted of α -D-Glc p -(1 → and β -L-Ara f -(1→. BHP-2 exhibited excellent thermal stability, with a microscopic surface characterized by tightly packed sheets and numerous spiral depressions, which might contribute to its remarkable in vitro hypoglycemic effect. BHP-2 showed competitive inhibition of α -amylase and mixed non-competitive inhibition of α -glucosidase, with respective IC50 values of 0.31 and 0.18 mg/mL, closely resembling to those of acarbose (0.27 and 0.12 mg/mL). These findings suggested that BHP-2 had potential as an additive for glycemic intervention. [ABSTRACT FROM AUTHOR]