Bioassay-guided discovery and identification of new potent α-glucosidase inhibitors from Morus alba L. and the interaction mechanism

Structurally Diverse Stilbenoids as Potent α-Glucosidase Inhibitors with Antidiabetic Effect from Morus alba

“…The M. alba root bark extract was prepared as we described formerly and further processed to acquire 30, 50, 80, and 95% EtOH-H 2 O eluates on macroporous resin CC. 13 The 80% eluate (600 g) was separated by silica gel CC (petroleum ether−EtOAc, 20:1 to 1:2) to give 14 fractions A−N. Fraction L (13 g) was processed by MCI gel CC (50−100% MeOH-H 2 O) to obtain seven further subfractions (L1−L7).…”

“…Subfraction B-F7 was first fractionated by a Sephadex LH-20 column (in MeOH) and then purified by HPLC (50% MeCN-H 2 O) to yield 5 (1.7 mg, t R = 6.5 min) and 4 (2.1 mg, t R = 7.5 min), while B-F8 was processed with the same procedure to give 3 (1.0 mg, t R = 6.5 min, HPLC condition: 65% MeCN-H 2 O). Fraction B-G (2.3 g) was processed by RP-C 18 CC (30−100% MeOH-H 2 O) to afford six subfractions (B-G1 to B-G6), and B-G5 was first fractionated by Sephadex LH-20 CC (in MeOH) and then purified by HPLC to afford 12 (7.0 mg, t R = 13.5 min) and 9 (3.0 mg, t R = 13 min) with 50 and 52% MeCN 13 C NMR data (in CD 3 OD) see Tables 1 and 2 13 C NMR data (in CD 3 OD) see Tables 1 and 2…”

“…The inhibition kinetics of compound 6 toward α-glucosidase was explored as recently reported. 13 Briefly, the doses of 6 were chosen from around the IC 50 value, with pNPG at 2, 4, 8, and 16 mM as substrates. The absorbance at 405 nm was tested every 5 min in a 96-well plate.…”

“…Molecular docking experiments were carried out as we described formerly. 13 In brief, homology modeling from the existing crystal structure (PDB code: 3AXH) for the currently used α-glucosidase was first performed using SWISS-MODEL program (https://swissmodel.expasy.org/). Then, the protein and target molecules were prepared with the Protein Preparation Wizard panel in Schrodinger software and Chem3D 14.0 software, respectively.…”

Anti‐inflammatory Polyketides from an Endophytic Fungus Chaetomium sp. UJN‐EF006 of Vaccinium bracteatum

“…[5] In addition, the Chaetomium fungi are also famous in the scientific community for their ability to metabolize a variety of bioactive natural products especially cytochalasans and azaphilones, [6] and these two important groups of compounds have been considered to be suitable chemotaxonomic markers for genus Chaetomium. [7] As part of our recent years' efforts to search for bioactive ingredients from medicinal herbs with dietary values, [8][9][10][11] we have lately isolated iridoids and lignans with diverse bioactivities as the major chemical constituents in the leaves of Vaccinium bracteatum. [12] Since plant-derived endophytic fungi have emerged as an important source of bioactive natural products in the last two decades, [13][14] the chemical diversity of V. bracteatum metabolites has thus inspired us to start a project aiming to explore the bioactive metabolites produced by the endophytic fungi of this plant.…”