Abstract: The antimicrobial spectrum of the extracts from different parts of Loropetalum chinense was determined to lay a foundation for their protection, comprehensive development and utilization. The results showed that the ethyl acetate extracts (EtOAc) from the branches and leaves of L. chinense had significant inhibitory effects on 9 plant pathogenic fungi and 9 animal pathogenic bacteria, except that the inhibition rate against Pestalotiopsis theae and Alternaria citri were respectively 25.58% and 48.30% at 5 g/L of the EtOAc extract of branches, the inhibition rate against the other seven plant pathogenic fungi exceeds 50%, with an EC₅₀ value of 0.297 8-3.768 8 g/L. Among them, the extract of branches had much higher virulence against Alternaria oleracea, Colletotrichum capsici, and Cochliobolus miyabeanus, respectively with EC₅₀ values of 0.756 4, 0.297 8,and 1.361 2 g/L, less than 2 g/L, and especially had higher virulence against Colletotrichum capsici, with an EC₅₀ value less than 0.5 g/L. The EtOAc extract of leaves had an inhibition rate of over 50% against the other 8 tested pathogens except for the Pestalotiopsis theae at 26.77%. The EC₅₀ values of 8 tested pathogens range from 1.036 0 to 3.807 6 g/L. Similarly, the EtOAc extract of leaves also had high toxicity against C. miyabeanus, A. oleracea, and C. capsici, respectively with EC₅₀ values of 1.812 6, 1.376 7, and 1.036 0 g/L, less than 2 g/L. The EtOAc extracts of the branches and leaves had significant inhibitory effects on 9 animal pathogenic bacteria with MICs of 0.156 25-2.500 00 g/L and 0.156 25-1.250 00 g/L, respectively. There was relatively higher inhibitory activity of the branches extract against 5 animal pathogens, including Bacillus anthraci, Staphyloccocus aureus, Bacillus subtilis, Bacillus cereus, and Micrococcus luteus, with MIC values less than 1 g/L. For the leaves extract, except for the MIC of 1.25 g/L for Escherichia coli, the MIC was less than 1 g/L for the other 8 tested animal pathogenic bacteria. In addition, its inhibitory activity of leaves extract against five pathogenic bacteria, i.e., Bacillus cereus, Micrococcus luteus, Bacterium paratyphosum B, Micrococcus lysodeikticus, and Bacillus megaterium, was higher than that of branches extract. The research results indicated that L. chinense has broad-spectrum antimicrobial activity, and laid a foundation for its application in agricultural and medical antimicrobial activities.

Key words: Loropetalum chinense, ethyl acetate extract, plant pathogenic fungi, animal pathogenic bacteria, inhibitory activity