The hop cones (Humulus lupulus L.): Chemical composition, antioxidant properties and molecular docking simulations

Hop cones are valuable raw materials in the brewing industry, as well as in medicine. The aim of the study was to determine the content of selected groups of phytochemical constituents in the pharmaceutical grade herbs of hop cones Humulus lupulus L. and to examine the antioxidant activity of the essential oil (EOHl). In addition, molecular docking was performed to elucidated interactions of different hops cones components with the main enzymes involved in diabetes type II and hypertension. Total flavonoids and phenolic contents are spectrophotometrically determined. The content EOHl was determined by hydrodistillation. Volatile compounds were identified by GC-FID and GC-MS. Antioxidant effectiveness of EOHl is examined by DPPH radical scavenging method. Docking study was performed using Molecular Operating Environment software (MOE). The tested hop cones contained up to about 4.20% of total phenolic compounds and up to about 0.37% flavonoids. The content of EOHl reached up to 0.495% v/w with τ-cadinol and α–humulene as the main ingredients. In addition, EOHl contained up to 4.87 mg/ml polyphenolic compounds. The radical-scavenging activity of EOHl ranged from 25.31 mM to 66.99 mM expressed as Trolox equivalents. Docking simulations showed that the most probable potent inhibitors of dipeptidyl peptidase-4, alpha-amylase, alpha-glucosidase, and angiotensin converting enzyme (ACE) were rutin and astragalin with high energy score compared to the reference ligand. From the results obtained it could be predicted that anti-diabetic and antihypertensive potential of hopes cones could be attributed to the presence of rutin and astragalin.