## 3 Results and Discussion
### Molecular Docking of Abundant Phenolic Compounds  
The functions of various phenolic compounds in \(\alpha\)-glucosidase inhibitory activities were predicted by employing in silico molecular docking. Using computational methods, such as molecular docking, it is possible to accurately forecast the affinities as well as modes of binding of a target molecule (or ligand) to a specific protein (or receptor). Figure 4A,B shows the predicted 2D and 3D binding geometries of chlorogenic acid (A) and puncafolin (B) in the \(\alpha\)-glucosidase protein (5 NN8), respectively. The calculated binding energies are given in Table S3. Punicafolin was docked to the protein structure of 5 NN8. During the molecular docking process, puncafolin was placed in the binding site of 5 NN8 and allowed to interact with the surrounding amino acid residues. PHE 649 is considered to be a hydrophobic amino acid. Punicafolin also established hydrophobic bonds with the amino acid residues, such as PHE 525, ALA 284, and TRP 481. Chlorogenic acid (Figure 4A) created a single hydrogen bond with each of the ASP 404 as well as ASP 518, another one with a molecule of water, two hydrogen bonds with ASP 282, and one with the hydrophobic PHE 649, which refers to as \(\pi\)-\(\pi\) stating with this same compound. Quercetin 3-(2-galloylglucoside) formed hydrogen bonds with water molecules, the positively charged ARG 600, the negatively charged ASP 518, the negatively charged ASP 282, ASP 616 (negatively charged), the negatively charged ASP 404, and two hydrophobic bonds with PHE 525 and ALA 284; and PHE 525, TRP 481, as well as PHE 649 connecting with Pi-Pi bonding. Myricitrin, in addition to quercetin, formed one hydrogen bond association with hydrophobic ALA 284, negatively charged ASP 616, and EDO 1024, while two bonds of hydrogen with the negatively charged ASP 282. They possessed a single Pi-Pi binding with TRP 481 and a kind of double Pi-Pi stacking hydrophobically associated with PHE 525. Specifically, rutin formed four collective hydrogen bonds: one with ASP 404, two with ASP 616, and a final one with ASP 518. Additionally, it interacted with one amino acid residue, i.e., TRP 481, via Pi-Pi stacking. Twelve hydrogen bonds were formed by acrobse: two with ASP 404, ASP 518, SER 523, and ASP 282; it also forms three OH groups taken from molecules of water that additionally formed hydrogen bonds with ASP 281 as well as ASP 645. Naringin formed hydrogen bonding associations with EDO 1024, PHE 525, ASP 282, LEU 678, as well as ARG 281, along with one Pi-Pi stacking contact with TRP 481. Additionally, diosmin formed four hydrogen connections with ASP 282, which is negatively charged, and one with the similarly negatively charged ASP 616. The binding energies of puncafolin, rutin, acarbose, procyanidin B2, puncalagin, myricitrin, 3-feruloylquinic acid, taxifolin, diosmin, chlorogenic acid, quercetin-3-O-arabinoside, naringin, 3-p-coumaoylquinic acid, myricetin, apigenin 8-C-glucose, quercetin, kaempfer, ellagic acid, carnscic acid, isorhamnetin, luteolin, hesperetin, (-)-epicatechin, gallic acid, protocatechuic acid, 3-O-sinapoylquinic acid, Isorhamnetin, caffe acid, pyrogallol, \(p\)-hydroxybenzoic acid, \(p\)-coumaric acid and cinnamic acid in 5 NN8 were calculated as \(-\)12.16, \(-\)11.14, \(-\)10.56, \(-\)10.05, \(-\)9.95, \(-\)9.59, \(-\)9.32, \(-\)9.13, \(-\)8.77, \(-\)8.17, \(-\)7.59, \(-\)7.58, \(-\)7.38, \(-\)6.92, \(-\)6.44, \(-\)6.01, \(-\)5.94, \(-\)5.91, \(-\)5.68, \(-\)5.67, \(-\)5.47, \(-\)5.36, \(-\)5.10, \(-\)4.96, \(-\)4.91, \(-\)4.89, \(-\)4.87, \(-\)4.80, \(-\)4.30, \(-\)3.80, and \(-\)3.04, respectively. Punicafolin is expected to have a higher binding affinity than the other chosen phenolic compounds. Rutin and procyanidin B2 have a stronger ability of \(\alpha\)-glucosidase-inhibition than other non-anthocyanin flavonoids. It is interesting to note that 3-feruloylquinic acid has a greater affinity for binding than diosmin, taxifolin, quercetin, naringin, chlorogenic acid, myricetin, isorhamnetin, as well as luteolin.