• Microbiology and Biotechnology Letters
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• v.38 no.1
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• pp.105-111
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• 2010

Caesalpinia sappan L. has long been commonly used in oriental folk medicines to treat diseases. To investigate the antibacterial effects from C. sappan L. heart wood, the MeOH soluble extract was successively fractionated by using hexane, $CHC1_3$, EtOAc, BuOH, MeOH, and $H_2O$. Among of these extracts, the EtOAc fraction which partitioned to 3.94% of the highest yields was to be the most active against all human pathogenic bacteria in this experiment. In addition, the antibacterial activities of the EtOAc fraction were more effective against Gram (+) bacteria compared to those against Gram (-) bacteria, which showed difference of the antibacterial activities against Gram (-) bacteria. To confirm the identity of the active substances, the EtOAc fraction was further separated by silica gel adsorption column, high performance liquid chromatography, and 98.48% purity of brazilin (1.67 mg)/EtOAc (10 mg) fraction was obtained from 300 g of C. sappan L. heart wood. The isolated active substance was a single compound of yellow crystalline, and was identified as brazilin ($C_{16}H_{14}O_5$) by MS, and $^lH$-NMR and $^{13}C$-NMR. These results suggest that the brazilin in the EtOAc fraction from MeOH extract of C. sappan L. has a potential as a natural therapeutic agent against human pathogenic Gram (+) bacteria such as Staphylococcus aureus.

• Korean Journal of Microbiology
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• v.46 no.2
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• pp.200-206
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• 2010

In this study, we investigated the antibacterial effect of 69 oriental medicinal herbs (OMHs) on Actinomyces viscocus, Streptococcus sobrinus, and two strains of Streptococcus mutans as oral bacteria. Methanol extracts of OMHs were used in the first antibacterial test, and then boiled water, ethanol, methanol, and ethyl acetate extracts of C. japonica, C. sappan, P. mume, and S. chinensis were used in the second test. Boiled water extract of C. japonica was shown to have the most superior effect on oral bacteria. The extract yield of boiled water extract of C. japonica was 22%, and the growth of oral bacteria was almost inhibited at over a 180 mg/ml concentration. Antibacterial effect compound analyzed by UPLC method was identified as berberine, and the content was 25.54%. In addition, the extract appeared to be stable at $121^{\circ}C$ for 15 min.

• Journal of Microbiology and Biotechnology
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• v.10 no.3
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• pp.394-398
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• 2000

A methanol extract of the root of Peucedanum japonicum, used as a medicinal herb, showed an inhibitory effect on mammalian topoisomerase I activity. The methanol extract was suspended in ethyl acetate, and a topoisomerase I inhibitor in the organic soluble fraction was then isolated by silica gel and thin layer chromatography. The topoisomerase I inhibitory compound was indentified as falcarindiol based on the analysis of EI-MS, $^1$H and \ulcornerC NMR spectroscopy. This inhibitory showed cytotoxicity against human leukemia Jurkat T and HL60 cells with an IC\ulcorner value of 7 $\mu\textrm{g}$/ml. These results suggest the possibility of falcarindiol as a new anticancer agent which can be expected to have a synergistic effect on other anticancer drugs. In addition, the present data show that falcarindiol has antifungal, yet not antibacterial, activity.

• Natural Product Sciences
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• v.15 no.3
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• pp.130-133
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• 2009

The crude extract of the mycelium of Cladosporium was found to exhibit antimicrobial activity against the Staphylococcus aureus, methicillin-resistant S. aureus, and multidrug-resistant S. aureus. Bioassayguided fractionation of an organic extract led to the isolation of an acetophenone derivative, clavatol (2',4'-dihydroxy-3',5'-dimethylacetophenone) (1), and a benzodiazepine alkaloid, circumdatin A (2). Compound 1 showed moderate antibacterial activity against S. aureus, methicillin-resistant S. aureus, and multidrug-resistant S. aureus with minimum inhibitory concentration (MIC) values of 62.5, 62.5, 31.0 $\mu$g/mL, respectively, but compound 2 was inactive. Compounds 1 and 2 exhibited UV-A protection activity with ED$_{50}$ values of 227.0 and 82.0 $\mu$M, respectively, indicating that they were more potent than the positive control, oxybenzone (ED$_{50}$ 350 $\mu$M), a common sunscreen agent.

• Fisheries and Aquatic Sciences
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• v.14 no.4
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• pp.251-256
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• 2011

We screened for antibacterial substances against methicillin-resistant Staphylococcus aureus (MRSA). Methanolic extract of Eisenia bicyclis exhibited anti-MRSA activity according to a disk diffusion assay. To identify the active compound(s), the methanolic extract was further fractionated using hexane, dichloromethane, ethyl acetate, and n-butanol. The ethyl acetate-soluble fraction showed both the greatest anti-MRSA activity and the highest polyphenol content. The minimum inhibitory concentrations of the ethyl acetate fraction ranged from 32 to 64 ${\mu}g$ per mL against methicillin-susceptible S. aureus and MRSA strains. High-performance liquid chromatography analysis revealed that both the methanolic extract and the ethyl acetate soluble fraction contained sizeable quantities of dieckol, which is a known anti-MRSA compound. Thus, these data strongly suggest that the anti-MRSA activity of E. bicyclis may be mediated by phlorotannins such as dieckol.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.81-86
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• 2019

A yellow resin (gamboge) from Garcinia hanburyi has been widely used as folk medicine due to its antibacterial and antitumor activities. We isolated four ${\alpha}$-glucosidase inhibitory compounds from the methanol extract of gamboge. The compounds (1-4) were identified as gambogoic acid (1), moreollic acid (2), gambogic acid (3), and 10-methoxygambogenic acid (4), respectively through spectroscopic data including 2D-NMR and HREIMS. All compounds were examined in the enzyme inhibition assay against ${\alpha}$-glucosidase to identify their inhibitory potencies and kinetic behavior. All compounds (1-4) showed enzyme inhibition against ${\alpha}$-glucosidase, but the activity was significantly affected by the methoxy group on C-10 of ring A and pentenyl pyran moiety of ring D. For example, compound 1 ($IC_{50}=41.4{\mu}M$) bearing pyran ring eight times effective that 4 ($IC_{50}=350.6{\mu}M$) having geranyl group itself. Most active compound was found out to be gambogoic acid (1) which was analyzed most abundant metabolite in gamboge by LC-ESI-MS/MS. In kinetic study, compounds 1 and 2 were proved as noncompetitive inhibitors.

• Korean Journal of Chemical Engineering
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• v.35 no.11
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• pp.2313-2320
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• 2018

Tetramethylene-1,4-bis(N,N-dodecylammonium bromide), cationic gemini surfactant, (12-4-12) was first synthesized with an one-step and shortened procedure and its interfacial and antimicrobial properties were compared with a conventional single-chain cationic surfactant, cetyltrimethylammonium bromide (CTAB). The interfacial and thermodynamic properties of both surfactants reveal that critical micelle concentration (CMC) of this novel synthetic cationic dimeric surfactant is lower than that of cationic monomeric surfactant at almost 15 times of its magnitude, which is due to the increase in hydrophobicity of the surfactant molecules by having dual hydrocarbon chains. In comparison with CTAB, the produced compound 12-4-12 yields much better interfacial and thermodynamic properties. The antimicrobial activities of the synthesized gemini surfactant were tested against eight strains of bacteria, as well as two strains of fungi. The results showed that both 12-4-12 compound and CTAB exhibited higher inhibitory effects on the growth of Gram-positive bacteria and fungi than that of Gram-negative bacteria. The minimum inhibitory concentrations in molar of 12-4-12 against all tested Gram-negative bacteria were lower than those of CTAB, which is hypothetically due to the lower HLB together with smaller CMC values of our gemini surfactant.

• Journal of the Korean Chemical Society
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• v.45 no.4
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• pp.325-333
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• 2001

The 4-substituted tetrazolo[1,5-a]quinoxalines were synthesized from 4-chlorotetrazolo-[1,5-a]quinoxaline(8) or 4-hydrazinotetrazolo[1,5-a]quinoxaline(9). Refluxing of the tetrazolo[1,5-a]quinoxaline(12) in N,N-dimethylformamide gave the 1,2,4-triazolo[3,4-c]tetrazolo[1,5-a]quinoxaline(13), which was also obtained by the reaction of compound 9 with ethyl chloroformate in N,N-dimethylformamide. The reaction of compound 9 with isothiocyanates in ethanol provided the tetrazolo[1,5-a]quinoxalines(14), whose reaction with dimethyl acetylenedicarboxylate afforded the tetrazolo[1,5-a]quinoxalines(15). The tetrazolo [1,5-a]quinoxalines(18) were obtained by the reaction of compound 9 with alkyl (ethoxymethylene)cyanoacetates. Some of the compounds showed antibacterial, antifungal or algicidal activities against some strains.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.2
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• pp.214-221
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• 1997

The volatile essential oil isolated from Houttuynia cordata were separated to 11 fractions by Prep-HPLC, of these, a fraction(Fr. 6) which carried the characteristic Houttuynia cordata flavor(fishy) contained 2-undecanone, ${\beta}-myrcene$, ${\beta}-ocimene$, 1-decanol and decanoyl acetaldehyde, as identified by GC-MS. From this observation, it may be inferred that 2-undecanone and decanoyl acetaldehyde could be the compounds which play a crucial role in flavoring of Houttuynia cordata. In test of antibacterial activity of eleven fractions of volatile essential oil from H.C., the growths of nine Gram negative bacteria were inhibited obviously when treated with and Fr. 6 including 2-undecanone, ${\beta}-myrcene$, ${\beta}-ocimene$, 1-decanol and decanoyl acetaldehyde, and Fr. 5 including decanal, endobornylacetate, fenchene and decanoic acid, respectively.

• Food Science and Preservation
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• v.18 no.1
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• pp.87-90
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• 2011

The methanol extracts of 19 commercial herb medicines was analyzed to antibacterial activities against Edwardsiella tarda, causing several fish diseases. Rhus javanica showed most strong antibacterial activity against E. tarda and Escherichia coli. Methanol extract of R. javanica was further extracted using several organic solvents having different polarity. Extract from ethyl acetate fraction showed strong activity against E. tarda as well as E. coli. Minimal inhibitory concentration, MIC of R. javanica extract was measured and resulted showing $64\;{\mu}g/m{\ell}$ for E. tarda and $256\;{\mu}g/m{\ell}$ for E. coli. It is needed that, from these results, further purification and isolation of reposible compound of these activities and further study on the synergy effect using combination with antibiotics against pathogenic bacteria.