Chemical Composition and In Vitro Biological Activity of Angelica Root and Hop Strobile Essential Oils and Hydrolates

Abstract

The purpose of this study was to obtain additional value of hydrolates (HYs), by-products during essential oil distillation. Chemical compositions of angelica and hop hydrolates were determined and compared with the corresponding essential oils, and their biological potential tested. Steam distilled essential oils and hydrolates were analyzed by GC-MS, and their biological potential was tested for antioxidant (DPPH, ABTS and reduction power) and antimicrobial activities (against nine bacteria and fungi). Hydrolates were additionally tested for allelopathic activity (on corn and redroot pigweed). The investigated essential oils have totally different volatile profiles and aromas in comparison to hydrolates. The most dominant constituents in the angelica essential oil were limonene, β-phellandrene, α-pinene, α-phellandrene and δ-3-carene, while in the hydrolate it was trans-verbenol. In the hop essential oil the most dominant constituents were myrcene and α-humulene, while in the hydrolate isovaleric acid and linalool were dominant. Angelica essential oil showed higher antioxidant activity in comparison with hop, while hydrolates displayed significantly lower antioxidant activity. Low antimicrobial potential of both essential oils was observed in the case of Enterococcus faecalis, Escherichia coli, Saccharomyces cerevisiae and Candida albicans. Antimicrobial activity was not detected in neither of the two hydrolates. In terms of allelopathic activity, hydrolates showed a dose-dependent decreasing activity on germination and seedling growth of corn and redroot pigweed. Angelica and hop essential oils are mainly used in food, cosmetic and pharmaceutical industries because of their aroma. Hydrolates, as by-products, possess potential for application in agriculture as natural herbicides.