HPLC-DAD phenolics analysis, α-glucosidase, α-amylase inhibitory, molecular docking and nutritional profiles of Persicaria hydropiper L

Background: Natural phenolic compounds and Phenolics-rich medicinal plants are also of great interest in the management of diabetes. The current study was aimed to analyze phenolics in P. hydropiepr L extracts via HPLC-DAD analysis and assess their anti-diabetic potentials using in-vitro and in-silico approaches.

Methods: Plant crude methanolic extract (Ph.Cme) was evaluated for the presence of phenolic compounds using HPLC-DAD analysis. Subsequently, samples including crude (Ph.Cr), hexane (Ph.Hex), chloroform (Ph.Chf), ethyl acetate (Ph.EtAc), butanol (Ph.Bt), aqueous (Ph.Aq) and saponins (Ph.Sp) were tested for α-glucsidase and α-amylase inhibitory potentials and identified compounds were docked against these target enzymes using Molecular Operating Environment (MOE) software. Fractions were also analyzed for the nutritional contents and acute toxicity was performed in animals.

Results: In HPLC-DAD analysis of Ph.Cme, 24 compounds were indentfied and quantified. Among these, Kaemferol-3-(p-coumaroyl-diglucoside)-7-glucoside (275.4 mg g^{- 1}), p-Coumaroylhexose-4-hexoside (96.5 mg g^{- 1}), Quercetin-3-glucoronide (76.0 mg g^{- 1}), 4-Caffeoylquinic acid (58.1 mg g^{- 1}), Quercetin (57.9 mg g^{- 1}), 5,7,3'-Trihydroxy-3,6,4',5'-tetramethoxyflavone (55.5 mg g^{- 1}), 5-Feruloylquinic acid (45.8 mg g^{- 1}), Cyanidin-3-glucoside (26.8 mg g^{- 1}), Delphinidin-3-glucoside (24 mg g^{- 1}), Quercetin-3-hexoside (20.7 mg g^{- 1}) were highly abundant compounds. In α-glucosidase inhibition assay, Ph.Sp were most effective with IC₅₀ value of 100 μg mL-1. Likewise in α-amylase inhibition assay, Ph.Chf, Ph.Sp and Ph.Cme were most potent fractions displayed IC₅₀ values of 90, 100 and 200 μg mL-1 respectively. Docking with the α-glucosidase enzyme revealed top ranked conformations for majority of the compounds with Kaemferol-3-(p-coumaroyl-diglucoside)-7-glucoside as the most active compound with docking score of - 19.80899, forming 14 hydrogen bonds, two pi-H and two pi-pi linkages with the Tyr 71, Phe 158, Phe 177, Gln 181, Arg 212, Asp 214, Glu 276, Phe 300, Val 303, Tyr 344, Asp 349, Gln 350, Arg 439, and Asp 408 residues of the enzyme. Likewise, docking with α-amylase revealed that most of the compounds are well accommodated in the active site residues (Trp 59, Tyr 62, Thr 163, Leu 165, Arg 195, Asp 197, Glu 240, Asp 300, His 305, Asp 356) of the enzyme and Cyanidin-3-rutinoside displayed most active compound with docking score of - 15.03757.

Conclusions: Phytochemical studies revealed the presence of highly valuable phenolic compounds, which might be responsible for the anti-diabetic potentials of the plant samples.