Abstract

The feasibility and the effect of acid or alkali hydrolysis in microwave-assisted extraction as well as the antibacterial activity of the resulting extracts were studied to select appropriate phenols extraction method. The results demonstrated that acid hydrolysis was suitable for the extraction of phenols from Geranium sibiricum and hydrochloric acid (HCl) hydrolysis do not only performed the highest effectiveness, but also enhanced its antibacterial capacity. After the process was optimized, the total phenols content, yields of corilagin and geraniin were increased by 28.60, 53.80 and 35.65%, respectively, as compared to only 20% in microwave-assisted extraction (MAE). Scanning electron microscopy (SEM) was employed to verify the destructive effects of the methods, the results represented that HCl hydrolysis in MAE method had dramatic destructiveness on cell wall. Thus, HCl hydrolysis in MAE provides an efficient and rapid approach for the natural products extraction and the research also provides a valuable nature resource for healthy food industry.

Key words: Phenols, Hydrolysis method, Microwave-assisted extraction, Geranium sibiricum Linne, Antibacterial activity.