Screening of antimicrobial activity for medicinal herb extracts

Abstract

Twenty kinds of medicinal herbs were extracted by water and 95% ethanol and then antimicrobial activity of the extracts was investigated against various kinds of microorganisms. Water extracts of Gardeniae fructus (Gardenia jasminoides), Lycii fructus (Lycium chinense) and Schizandrae fructus (Schizandra chinensis) showed inhibitory effects on the growth of most of the bacteria. In the case of ethanol extracts, the 3 kinds of the samples such as Gardeniae fructus, Schizandrae fructus and Lithospermi radix (Lithospermum erythrorhizon) showed inhibitory effects on the growth of almost all bacteria. In particular, ethanol extract from Phellodendri cortex (Phellodendron amurense) showed the best inhibitory effect on the growth of S. aureus in the concentration of 0.01%. By the way, inhibitory effects of water extracts from these medicinal herbs were not so good on the growth of fungi but those of ethanol extracts were better and ethanol extracts of Phellodendri cortex showed best. Antimicrobial activity was variable according to the used extracting solvent. For example, inhibitory effets of ethanol ext-racts were times better than those of water extracts. Ethanol extract of Lithospermi radix was the most effective not only bactericidal effects but also sensory evaluation tests for tastes.