Fungal endophytes have been found to exist in many plant species and appear to be important to their plant hosts. However, the diversity and biological activities of these fungi remain largely unknown. Zanthoxylum simulans Hance, a popular natural spice and medicinal plant, commonly known as Szechuan pepper or Chinese-pepper, grows on Kinmen Island, Taiwan. In this study, leaf and stem samples of Z. simulans, collected in summer and winter, were screened for antimicrobial and anti-inflammatory metabolite-producing endophytic fungi. A total of 113 endophytic strains were isolated and cultured from Z. simulans, among which 23 were found to possess antimicrobial activity, belonging to six fungal genera: Penicillium (26.09%, 6), Colletotrichum (21.74%, 5), Diaporthe (21.74%, 5), Daldinia (17.39%, 4), Alternaria (8.70%, 2), and Didymella (4.34%, 1). We also found that the number of species with antimicrobial activity and their compositions differed between summer and winter. Our study demonstrated that Z. simulans might contain large and diverse communities of endophytic fungi, and its community composition varies seasonally. In addition, fungal endophytes produce antimicrobial agents, which may protect their hosts against pathogens and could be a potential source of natural antibiotics.
Conventional chemical antiseptics used for treatment of oral infections often produce side-effects, which restrict their long-term use. Plants are considered as perspective sources of novel natural antiseptics. However, little is still known about their inhibitory properties against oral pathogens. The objective of this study was to test in vitro antimicrobial activities of generally recognized as safe (GRAS) species against planktonic cultures of cariogenic, periodontal and candidal microorganisms and identify active compounds of the most active extracts. Growth-inhibitory effects of ethanol extracts from 109 GRAS plant species, six Humulus lupulus cultivars and two hop supercritical CO2 extracts were evaluated using broth microdilution method. The chemical analysis was done through high-performance liquid chromatography. Best results were obtained for supercritical CO2 and ethanol extracts of H. lupulus with minimum inhibitory concentrations (MIC) ≥8 μg/mL and ≥16 μg/mL, respectively. The chemical analysis of supercritical CO2H. lupulus extracts revealed that α- and β-acids were their main constituents. Capsicum annuum and Capsicum frutescens showed antibacterial effect against Streptococcus sobrinus and Streptococcus salivarius (MIC=64-128 μg/mL). These strains were further inhibited by Zanthoxylum clava-herculis (MIC=64-128 μg/mL) and Myristica fragrans (both MIC≥128 μg/mL). The latter also exhibited antimicrobial activity against Fusobacterium nucleatum (MIC=64 μg/mL). Punica granatum possessed inhibitory effects against Candida albicans (MIC=128 μg/mL) and F. nucleatum (MIC=64 μg/mL). The results indicate that supercritical CO2H. lupulus extracts together with ethanol extracts of C. annuum, C. frutescens, M. fragrans, P. granatum and Z. clava-herculis are promising materials for further investigation on new antiseptic agents of oral care products.
- MeSH
- Anti-Bacterial Agents chemistry MeSH
- Candida albicans drug effects MeSH
- Capsicum chemistry MeSH
- Ethanol MeSH
- Fusobacterium nucleatum drug effects MeSH
- Humulus chemistry MeSH
- Microbial Sensitivity Tests MeSH
- Myristica chemistry MeSH
- Plant Extracts chemistry MeSH
- Streptococcus sobrinus drug effects MeSH
- Zanthoxylum chemistry MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
