Phytochemical analysis of Humulus lupulus seed

Abstract

Introduction: Humulus lupulus (Hop) female inflorescence possess medicinal properties and the key compounds of it are identified, however, few research have elaborated the chemical composition of hop seeds thoroughly. Objective: Phytochemical and biological analysis of Humulus lupulus seeds.Methods and materials: Extraction was done with Soxhlet apparatus using solvents petroleum ether (PE), chloroform (CHL) and methanol (MeOH). A part of hops seed lipid content was saponified and the rest was fractionated using VLC method. Major compounds were isolated and analyzed with GC-MS. CHL extract was fractionated using chromatography methods. MeOH extract was fractionated with ethyl acetate (EtOAc) and further fractionated via reverse phase HPLC. The main compounds of the EtOAc fraction and CHL extract were analyzed with NMR method. Antioxidant activity, antibacterial and antimalarial effects were evaluated for the extracts.Results: GC-MS analysis of hop seed lipid content revealed linoleic acid, palmitic acid, γ-linolenic acid, stearic acid. Identified compounds by NMR analysis in the chloroform extract and EtOAc fraction were ortho-phthalic acid and catechin, respectively. The antioxidant activity RC50 value of EtOAc fraction was 201.57 µg/mL. The IC50 value of the MeOH extract against E. coli, S. aureus were 250 and 167 µg/mL and 3.57 mg/mL in the antimalaria test.Discussion and conclusion: The results suggest the potential hop seeds application as an eminent source of oil and long chained ω6 and ω9 fatty acids, antioxidative and preservative agent in the food industries. The complex o-phthalic acid derivatives present in CHL extract can be attributed to plasticizer pollution. The strong antioxidant effect of EtOAc and its activity against MRSA biofilm is considered to be caused by high content of catechins.