• Biomedical Science Letters
• /
• v.13 no.3
• /
• pp.189-195
• /
• 2007

This study was carried out to examine antimicrobial substances from medicinal plants, the ethanol extracts of 38 medicinal plants were tested for the antimicrobial activity against Staphylococcus aureus ATCC 25923 and methicillin-resistant Staphylococcus aureus ATCC 43300. The extracts of Glycyrrhiza uralensis, Sophora flavescens, Dryopteris crassirhizoma, and Pinas densiflora showed significant antimicrobial activities against both S. aureus ATCC 25923 and methicillin-resistant S. aureus ATCC 43300. The extract of Dryopteris crassirhizoma among these medical plants showed the highest antimicrobial activity. These results suggested that the extracts from Dryopteris crassirhizoma, Sophora flavescens, Pinas densiflora, and Glycyrrhiza uralensis could be the potential source of antimicrobial agents against methicillin-resistant S. aureus and S. aureus.

• Natural Product Sciences
• /
• v.5 no.4
• /
• pp.172-176
• /
• 1999

A total of 43 extracts from 21 species of Malaysian flowering plants were screened for antimicrobial and cytotoxic activities. Antimicrobial activity was tested against fungi, including yeast and candida, as well as Gram-positive and Gram-negative bacteria, and cytotoxicity was assayed using the CEM-SS and HT-29 cell lines. The methanol extracts of the roots and stems of Plumeria acutifolia showed the highest antimicrobial activity, i.e. against Saccharomyces cerevisiae and Candida lipolytica, and mostly moderate activity against the other microbes such as Aspergillus ochraceous and Saccharomyces lipolytica. Phyllanthus emblica also showed moderate activity especially that of the methanol extracts. The methanol extract of the roots of Plumeria acutifolia showed the strongest cytotoxic activity $(CD_{50}=\;3\;{\mu}g/ml)$. Most of Zingiberaceae species gave negative results for antimicrobial activity and showed low cytotoxic activity.

• Korean Journal of Plant Resources
• /
• v.17 no.3
• /
• pp.278-282
• /
• 2004

We investigated antimicrobial activity of methanol extract from Angelica gigas and A. acutiloba against three gram-positive bacteria(Bacilius cereus, B. subtilis, and Staphylococcus aureus), two gram-negative bacteria (Escherichia coli and Pseudomonas fluorescens), and one yeast (Saccharomyces cerevisiae). The antimicrobial activity was shown in only ethyl acetate fraction of shoot and root extracts from A. gigas. The activity of the fraction of shoot extract was remarkably potent against S. aureus. The ethyl acetate fraction of root extract showed great antimicrobial activity against B. subtilis and E. coli. The n-hexane fraction of shoot extract and the water fraction of root extract from A. acutiloba were not showed antimicrobial activity, in contrast, the ether fraction of shoot and root extracts showed great antimicrobial activity. S. cerevisiae was not inhibited by any fractions and species.

• Preventive Nutrition and Food Science
• /
• v.3 no.4
• /
• pp.324-328
• /
• 1998

We screened the methanol extracts from 133 plant species growing in Korea for antimicrobial activity against enterohemorrhagic Escherichia coli 0157 : H7. Those are selected from three plant grouping ; traditional medicinal herbs, edible plants, and flowers. They were tested by disk diffusion assay. From evaluation of the inhibition zone diameter of microbial growth, we found that the flower extract of Rhododendron Schilpenbachii Max had the most significant antimicrobial activity against this bacteria. Extracts from most of the vegetables and plants did not show antimicrobial activity except for the leaves of Ginkgo biloba L. and seeds of Prunus Dallicina L. did not show antimicrobial activity except for the leaves of Ginkgo biloba L. and the seeds of Prunus sallicina L.

• The Plant Pathology Journal
• /
• v.25 no.4
• /
• pp.352-360
• /
• 2009

The potential of three plants extracts, to protect potato plants against bacterial wilt caused by Ralstonia solanacearum was determined under greenhouse and field conditions. All soil drenching treatments of aqueous plant extracts of Hibsicus sabdariffa, Punica granatum and Eucalyptus globulus significantly reduced the disease severity compared with inoculated control. Although the applications of all three plant extracts resulted in similar reductions of disease severity in field up 63.23 to 68.39%, treatment of E. globulus leaf extract was found greater in restricting the symptom development than other the two plant extracts in the greenhouse. More than 94% reduction in the bacterial wilt symptom was observed in potato plants. All tested plant extracts were effective in inhibiting the growth of bacterial pathogen, not only in vitro, but also in stem of potato plants as compared with the inoculated control Potato plants treated with extract of H. sabdariffa reduced bacterial growth more effectively than treatment with P. granatum and E. globulus. Activity of defence-related enzymes, including peroxidase, polyphenoloxidase and phenylalanine ammonia lyase, were significantly increased in plants treated with the plant extracts compared to the control during the experimental period. In general, the higher enzymes activities were determined in both inoculated and non-inoculated treated potato plants after 8 days from plant extracts treatment. These results suggested that these plant extracts may be play an important role in controlling the potato bacterial wilt disease, through they have antimicrobial activity and induction of systemic resistance in potato plants.

• Journal of Plant Biotechnology
• /
• v.47 no.1
• /
• pp.90-99
• /
• 2020

This study aimed to screen for plants with antimicrobial potential among the evergreen woody species of South Korea that are used for horticulture and landscaping and to provide basic information about plants with proven antimicrobial activity to underpin future research. The plant materials were extracted under various conditions, and the antimicrobial activities of the extracts were evaluated by agar diffusion assay. The screening tests demonstrated that the crude extracts of 43 species had inhibitory effects against S. aureus. The inhibitory activities of four species (Elaeocarpus sylvestris, Camellia japonica, Cleyera japonica, and Quercus salicina) were relatively higher than that of the synthetic antimicrobial agents methylparaben and phenoxyethanol. The highest inhibitory activity was observed with the leaf extracts (extracted with methanol for 30 minutes) of E. sylvestris, based on induction of the largest inhibition zone of 23.3 mm in size. In addition, solvent fractions of E. sylvestris were evaluated. The largest inhibitory zone of 23.1 mm was observed for the n-butanol fraction, which is likely to contain effective compounds that exhibit inhibitory activity against S. aureus. In contrast, n-hexane and residual aqueous fractions showed no antimicrobial activity. Overall, our findings confirm that evergreen woody plants native to South Korea have potential antimicrobial activity.

• Advances in Traditional Medicine
• /
• v.5 no.1
• /
• pp.57-61
• /
• 2005

Ethanol and aqueous extracts of Cassia auriculata were tested in vitro against fungi (Candida albicans and Microsporum canis) and bacteria (Escherichia coli, Salmonella enteriditis, Staphylococcus aureus and Bacillus subtilis). M. canis showed dose-dependent susceptibility only towards ethanol leaf and bark extracts. C. albicans, were resistant to all types of plant extracts. Results were statistically smaller to antifungal drug ketoconazole and miconazole at equivalent concentration. Both ethanol and aqueous extracts of Cassia auriculata leaves and barks exhibit antibacterial activity against S. aureus and only the ethanol extracts of leaf and bark were detected against Bacillus subtilis. The results were compared to antibacterial drugs chloramphenicol, ampicillin, penicillin G, and enrofloxacin. The antibacterial activity was statistically similar to penicillin G. Based on the current findings, it can be concluded that this plant has antimicrobial activity, which is as potent as standard antimicrobial drugs.

• The Plant Pathology Journal
• /
• v.16 no.5
• /
• pp.286-289
• /
• 2000

Mechanol extracts of three cold-tolerant eucalyptus trees-Eucalyptus darlympleana, E. gunnii and E. unigera were screened for antimicrobial activity against twenty two phyto-pathogenic fungi and six food-borne bacterial pathogens. E. unigera showed the antagonistic activity against all the tested pathogens. Among the tested fungal pathogens, Pythium species were highly sensitive to the leaf extracts. Especially, P. vanterpoolii, a causal agent of leaf blight in creeping bentgrass (Agrostis palustris), was completely inhibited by the extracts. The eucalyptus extracts were also effective in inhibiting the fungal growth of Botrytis cinerea and Phomopsis sp. isolated from the lesions of kiwifruit soft rot during post-harvest storage. Escherichia coli O-157 was less sensitive to the inhibition than the other bacterial pathogens tested. It was likely that Gram positive bacteria-Bacillus subtilis and Streptococcus mutans were more sensitive to the eucalyptus extracts than Gram negative bacteria-Escherichia coli, Salmonella enteritidis and Pseudomonas aeruginosa. Our findings suggest that the cold-tolerant eucalyptus species have antimicrobial properties that can serve the development of novel fungitoxic agents or food preservatives.

• Microbiology and Biotechnology Letters
• /
• v.32 no.4
• /
• pp.352-355
• /
• 2004

The extracts from 70 different plant natural products were used to investigate the antimicrobial activities against Brachyspira hyodrsenteriae, the causative agent of swine dysentery. Among them, the extracts from Terminalia chehula exhibited the highest antimicrobial activities against B. hyodysenteriae. It showed the antimicrobial activity against B. hyodysensteriae mostly in parts of its shell. Minimum inhibitory concentration (MIC) of the water extracts of T chehula was 12.5 mg/ml. After organic solvent extractions, the ethylacetate extracts exhibited higher antimicrobial activities against B. hyodysenteriae, and their antimicroactivities were similar to that of the tannin. In conclusion, these findings suggest that the extracts from T chebula may be used as animal feed additives for their antimicrobial activities against B. hyodysenteriae.

• CELLMED
• /
• v.2 no.2
• /
• pp.20.1-20.5
• /
• 2012

$Gynura$ $segetum$ (Lour.) Merr. ($Compositae$) is a well recognized medicinal plant in Indonesia and Malaysia. It is believed to have an anticoagulant effect and is used in treating snake-bites, inflammations and other skin afflictions. This study was carried out to evaluate the antimicrobial effects of $Gynura$ $segetum$ leaves extracts and its fractions. The chemical compositions of the active extracts were also determined. The antimicrobial activities of different solvent extracts of leaves of $Gynura$ $segetum$ were evaluated using the agar well-diffusion method. The Minimum Inhibitory Concentration (MIC) of the active subfractions was determined by the tube dilution method. Gas Chromatography-mass spectrometry (GC-MS) analysis was carried out to identify the chemical compositions of the active extracts. The ethyl acetate fraction and its subfraction E4 performed potent antimicrobial activities and fifteen known chemical constituents were identified by GCMS analysis as 4-vinylphenol, 1-tetradecene, phenol, 2,4-bis(1,1-dimethylethyl), 1-hexadecene, E-15-heptadecenal, hexadecanoic acid, 1,2-benzenedicarboxylic acid, dibutyl ester, 1-docosene, octadecanoic acid, 1-eicosene, cyclotetracosane, 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl)ester, butanedioic acid, monomethyl ester, niacin and 4-hydroxy-benzoic acid. The results of this study suggested a connection between the antimicrobial activities and the chemical structures. The plant may be used as a potential source for antimicrobial agents.