Alpha glucosidase

Ultrapure water (˂5 µg/L TOC) obtained by a water purification system (Mili-Q Merck Millipore, Chile) was used. For mass spectrometry analysis, HPLC-grade methanol and MS-grade formic acid were used, obtained from J.T. Baker (Phillipsburg, NJ, USA). Gallic acid, Folin Ciocalteu commercial reagent, 2,4,6-tris(2-pyridyl)-s-triazine, sodium carbonate, acetic acid, ferric chloride hexahydrate, sodium acetate, Trolox, hydrochloric acid, 2,2′-Azobis(2-amidinopropane) dihydrochloride, absolute ethanol, fluorescein solution, phosphate buffer, acetylcholinesterase enzyme (AChE), butyrylcholinesterase enzyme (BChE), galantamine, Tris-HCl buffer, Ellman’s reagent (DTNB), acetylcholine, butyrylcholine, magnesium chloride, sodium chloride, alpha-glucosidase, 4-nitrophenyl α-d-glucopyranoside, acarbose, orlistat, pancreatic lipase, 4-nitrophenyl-dodecanoate, dimethyl sulfoxide (DMSO) and HPLC standard with a purity greater than 95% (usnic acid and atranorin) were obtained from Sigma (Sigma, St. Louis, MO, USA).

GA (purity ≥ 99%), glutaric acid (purity ≥ 98%) and succinimide (purity ≥ 98%) were purchased from J&K chemicals Ltd (Beijing, China). Alpha-glucosidase and sodium hydroxymethyl cellulose were purchased from Sigma (ALDRICH, Shanghai). p-Nitrophenol-α-d-glucoside (pNPG) was purchased from ACROS ORGANICS (Geel, Belgium). Acetonitrile (LC grade) was purchased from Fisher Chemical Ltd (Waltham, MA, USA). Double distilled water was used for all experiments. Male spraque-dawley rats (SD, 220 ± 10 g) were supplied by Animal Experiment Center of Hebei Medical University (SCXK 1711175, Shijiazhuang, China). The animals were performed in accordance with the Principles of Laboratory Animal Care, and approved by the Animal Care Committee of Hebei Medical University in China.

Alpha-glucosidase (Saccharomyces cerevisiae) and 3,5-dinitro salicylic acid (DNS) were purchased from Sigma-Aldrich, Saint Louis, Missouri, USA, while P-nitrophenyl-α–D-glucopyranoside (p-NPG), sodium carbonate (Na₂CO₃), sodium dihydrogen phosphate, and di-sodium hydrogen phosphate were purchased from Hi-Media, Pennsylvania, USA.

Millipore-grade water was obtained from a LC-Pak™ Millex system (Millipore Corporation, Billerica, MA, USA). Formic acid, methanol, alpha-amylase, sodium chloride, sodium phosphate dibasic, sodium phosphate monobasic, starch, dinitrosalicylic acid, acarbose, alpha-glucosidase, 4-nitrophenyl-α-d-glucopyranoside, trichloroacetic acid, tris HCl, HMG-CoAR inhibition assay kit, ACE, N-[3-(2-Furyl)acryloyl]-l-phenylalanyl-glycyl-glycine, captopril, porcine pancreatic lipase, p-NPB, dimethylformamide, orlistat, and (3-(N-morpholino) propanesulfonic acid were purchased from Sigma-Aldrich, St. Louis, MO, USA.

Trolox (6-hydroxyl-2,5,7,8-tetramethylchroman-2-carboxylicacid), EGCG (epigallocatechin gallate), and other reagents such as ABTS (2,2-azino-bis (3-ethylbenzo thiazoline-6-sulfonic acid) diammonium salt), TPTZ (2,4,6-tri[2 -pyridyl]-s-triazine), iron (III) chloride hexahydrate, AAPH (2,2-Azobis(2-methylpropionamidine) dihydrochloride), fluorescein sodium salt, potassium peroxodisulfate, copper sulfate, hydrogen peroxide, perchloric acid, alpha-glucosidase (Saccharomyces cerevisiae), alpha-amylase (procaine pancreas), and 3,5,di-nitro salicylic acid (DNS), sodium carbonate (Na₂CO₃), 4-nitro-phenyl-α-D-glucopyranoside (pNPG), di-sodium hydrogen phosphate, and sodium dihydrogen phosphate were purchased from Sigma-Aldrich, Cape Town, South Africa. The organic solvents used in this study were supplied by Merck, Cape Town, South Africa. The NMR spectra were carried out on an Avance 400 MHz spectrometer (Bruker, Rheinstetten, Germany) using deuterated chloroform. Preparative HPLC was utilized for the purification of compounds using HPLC-grade methanol and distilled water.