Title : Native Greek hop plants: Study of antimicrobial and antiproliferative activity of extracts
Abstract:
Hop is one of the main ingredients in beer that imparts many aromas, flavors, and colors, and is currently extensively investigated for its medicinal potential. In the present study, we investigated aqueous and ethanolic extracts isolated from Greek indigenous plants which were collected from different regions of Central Greece (Livadia, Ypati, and Mavrilo). As controls, supercritical fluid extracts (SFE, CO2-based) from commercially available varieties were used. The profiles of all extracts concerning volatile and non-volatile compounds were analyzed using GC/MS, and the content of chalcones, flavones, and bitter acids were analyzed using LC/MS. Antimicrobial activity tests (minimum inhibitory concentration, MIC, and minimum lethal concentration, MLC) on beer spoilage bacteria (Lactobacilli, Saccharomyces, Aspergillus) were performed with extracts form three regions for the years 2022 and 2023. In all cases we observed that in all cases ethanolic extracts were significantly more potent than the aqueous, and that MIC and MLC was highly dependent on the region of origin and on the year of the harvest. Ethanolic, aqueous and SFE extracts were also tested for their antiproliferative activity on the Hela cancer cell line and IC50 values for 48 and 72 hours of treatment were calculated (we report mean and standard deviation). The IC50 values were 548 (202) and 346 (157) μg/ml for the aqueous extracts of Livadia and Ypati (year 2022), respectively. Ethanolic extracts showed increased antiproliferative activities with IC50 of 90 (62) and 58 (10) μg/ml, respectively. Conclusively, our results corroborate the notion that indigenous hop plants exert differences in a spectrum of biocompounds and antimicrobial and antiproliferative activities, suggesting that the phytogenetic capital of indigenous Greek hop warrants extensive further investigation to uncoverpotential important health-beneficial properties.
