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Summary Black rice bran was fermented with Bacillus subtilis KU3 isolated from Korean traditional food, Kimchi. Antioxidant and cytotoxic activities of the fermented black rice bran were investigated. Total phenolic and anthocyanin contents decreased from 171.54 mg GAE g−1 and 2.31 mg g−1 to 139.13 mg GAE g−1 and 2.12 mg g−1, respectively, after fermentation. Antioxidant activities determined by 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging, β-carotene bleaching and ferric thiocyanate assay were correlated with total phenolic and anthocyanin contents. Non-fermented black rice bran extract (NFBE) showed greater antioxidant activities than fermented black rice bran extract (FBE). Cytotoxic activities measured by MTT assay showed that both NFBE and FBE had over 50% activities. The cytotoxic activities of FBE against MCF-7 and HeLa cells were 71.65% and 68.07%, respectively, at 8.0 mg mL−1, but those of NFBE were lower than 50%. These results suggested that the cytotoxic activity of black rice bran improved through fermentation, while antioxidant activity reduced.

Antioxidant and in vitro anti-inflammatory activities of citrus (Citrus unshiu) peel extracts and their acid hydrolysates were evaluated. Citrus peel extracts were extracted by subcritical water, hot water, and ethanol. Subcritical water extraction led to extract more phenolic compounds than hot water or ethanol extraction. Acid hydrolysis more than doubled the extracts’ total phenolics and flavonoids. Acid hydrolysates showed greater DPPH-radical scavenging activities and antioxidant activities, as assayed by β-carotene bleaching and ferric thiocyanate, than the initial extracts. Anti-inflammatory activities of citrus peel extracts and hydrolysates, determined by the inhibition of hyaluronidase activity, showed that the inhibition activities of hot water and ethanol extracts increased from 2.1 and 1.8% to 37.0 and 18.5%, respectively, upon acid hydrolysis; however, the anti-inflammatory activity of the subcritical water extract was not improved. These results indicated that acid hydrolysis of citrus peel extracts regardless of their extraction methods improved the antioxidative and anti-inflammatory activities.

Onion (Allium cepa L.) peels were extracted by ethanol, hot water and subcritical water (SW) extraction and their antioxidant activities were evaluated. Extraction yields of SW extraction were 4-fold higher than ethanol extraction. However, the ethanol extraction increased the total phenolics contents (327.5 mg GAE/g extract) and flavonoids contents (183.95 mg QE/g extract) in the onion peel extract. The onion peel extracts by ethanol extraction showed greater DPPH radical scavenging activities and greater antioxidant activities determined by ferric thiocyanate assay than those by hot water extraction and SW extraction at 165°C. Antioxidant activity of onion peel extract by SW extraction at 110°C was similar to that of ethanol extraction. HPLC profiles revealed that SW extraction at lower temperature (110°C) increased the concentration of quercetin. These results demonstrated that the onion peel extracts produced by SW extraction technique have great potential as a source for useful antioxidant.

The objective of this study was to evaluate the antibacterial activity of a novel flavonoid, 7-O-butyl naringenin, as well as natural flavonoids (quercetin, naringenin) against methicillin-resistant Staphylococcus aureus (MRSA). 7-O-butyl naringenin showed great anti-MRSA, with a MIC (minimum inhibitory concentration) value of 0.625 mM. The number of cells treated with 25 μM 7-O-butyl naringenin was reduced by 5.2 log CFU/mL compared with the control (DMSO). The result indicated that 7-O-butyl naringenin was more effective than the two natural flavonoids against MRSA, and may have potential as a novel therapeutic agent for MRSA infections.

In this study, the antimicrobial effects of an onion peel extract prepared using subcritical water extraction (SWE) were assessed for possible development into new bio-functional materials. The extraction temperatures were controlled to 110 and 160°C. At 0.15, 0.3, 0.6, and 1.2 mg extract/mL of broth, the growth inhibition and bactericidal activity of SWE extracts against Bacillus cereus KCCM 40935 and KCCM 11341 were compared with those of ethanol and hot-water extracts. In the case of B. cereus KCCM 40935, it appeared that over 0.6 mg/mL of SWE (110°C) extract exerted a bactericidal effect, and 1.2 mg/mL of SWE (160°C) extract exerted a bacteriostatic effect during culturing, and also that B. cereus KCCM 11341 was more resistant than B. cereus KCCM 40935. Furthermore, our results demonstrated that the death time of 107 CFU/mL of B. cereus KCCM 40935 treated with SWE (110°C) extract at 1.2 mg/mL was 60 min at maximum in 0.8% NaCl. Additionally, the cells damaged by SWE extract were observed with a SEM. It was suggested that an extract of onion peels prepared via SWE (110°C) could be used as a functional biomaterial for the food or pharmaceutical industries.

The antimicrobial effects of the natural flavonoids kaempferol, quercetin, apigenin, and naringenin as well as a novel fla-vonoid 7-O-butyl naringenin against the growth of four meat-born Staphylococcus aureus strains were evaluated. First, theflavonoids were screened for inhibitory effects against the growth of each strain using the paper disc diffusion method. Sec-ond, the growth inhibitory effects of flavonoids that showed antimicrobial activity were measured using the microplatemethod. Third, the bactericidal effects of flavonoids were evaluated in a 0.8% (w/v) NaCl solution. All flavonoids showedbacteriostatic effects at >20 mM. Among the flavonoids studied, quercetin was more effective than the others tested. How-ever, the inhibitory effect of 7-O-butyl naringenin on growth of S. aureus KCCM 32395 was greater than that of quercetinat the same concentration. Additionally, 7-O-butyl naringenin exhibited significant bactericidal effects at >25 µM. Whenbacterial cells were examined using scanning electron microscopy, it appeared that the S. aureus membranes were damagedor morphologically changed when treated with quercetin and 7-O-butyl naringenin at 200 µM.Key words: flavonoid, 7-O-butyl naringenin, Staphylococcus aureus, antimicrobial effect

The objective of this study was to evaluate the antimicrobial effects of various natural flavonoids against growth of psy-chotropic Bacillus cereus strains, which cause dairy food outbreaks. Flavonoids were first screened for their ability to inhibitgrowth of B. cereus strains using the paper-disc diffusion test. Second, the growth inhibitory effect of selected flavonoidswas evaluated in tryptic soy broth supplemented with 0.6% yeast extract, and the bactericidal effect of the flavonoids wasmeasured in 0.8% (w/v) NaCl solution. Based on the paper-disc diffusion test, kaempferol was effectively active against B.cereus P14 and B. cereus KCCM 40935. Kaempferol had an antimicrobial effect at concentrations greater than 100 µM, andthe numbers of B. cereus P14 and B. cereus KCCM 40935 decreased by 3.55 and 1.5 log cycles, respectively. The cell num-bers of B. cereus P14 and B. cereus KCCM 40935 treated with 50 µM kaempferol were reduced by 4.18 and 2.84 log cyclesduring a 24 h incubation to test the bactericidal effect of kaempferol ( p

The objective of this study was to evaluate the antimicrobial and antioxidative effects of the onion peels extract prepared via the subcritical water extraction (SWE) method. First, the number of cells treated with the extract was reduced by 0.7–1.1 log CFU/mL compared with the control. The SWE extract showed 76.08% scavenging activity and it was more effective than butylated hydroxytoluene (BHT) at 61.3 ppm in lipid peroxidation inhibitory effects. In addition, the antioxidative effect of SWE extract measured via the ferric thiocyanate (FTC) method was 2-fold that of BHT. The results of this study suggest that the onion peels extract prepared via the SWE method may have potential alternative antimicrobial and antioxidative effects as functional substances.

We have studied iron porphyrin complex-catalyzed oxygenations of hydrocarbons by several oxidants (i.e., hydrogen peroxide, tert-butyl hydroperoxide, and m-chloroperoxybenzoic acid (MCPBA)) in the presence of H218O. In the olefin epoxidation and alkane hydroxylation reactions catalyzed by (meso-tetrakis(pentafluorophenyl)porphinato)iron(III) chloride [Fe(F20TPP)Cl], the percentages of 18O incorporated into the oxygenated products were found to be the same in all of the reactions of hydrogen peroxide, tert-butyl hydroperoxide, and MCPBA, leading us to conclude that a common high-valent iron oxo complex was the reactive intermediate responsible for oxygen atom transfer. When the epoxidation of cyclooctene by MCPBA and H2O2 was performed at low temperature in the presence of H218O, it was found that there was no 18O-incorporation from labeled water into cyclooctene oxide. We interpreted the lack of 18O-incorporation in these reactions with that an electronegatively-substituted iron porphyrin complex forms a ...

Ginseng leaf/stem extract produced by subcritical water extraction at high temperature (190°C) possess higher cytotoxic activity against human cancer cell lines than ethanol extract. Subcritical water extraction can be a great candidate for extraction of functional substance from ginseng leaves/stems.

Nickel(II) cyclam and several other NiII complexes of tetraazamacrocyclic ligands were found to inhibit autoxidation of aldehydes. The NiII complexes that were effective had relatively low NiIII/NiII reduction potentials. Nickel(III) cyclam was found not to be an inhibitor. We propose that these NiII complexes terminate the free-radical chain reaction by trapping the intermediate acylperoxy radical.