Evaluation on antioxidant properties of sixteen plant species from Jeju Island in Korea

In this study, the antioxidant properties of 80 % ethanol extracts of 16 species of plants from Jeju Island in Korea were evaluated using various antioxidant assays, including the DPPH (1,1-Diphenyl-2-pricrylhydrazyl) radical scavenging, superoxide scavenging, xanthine oxidase inhibition and hydrogen peroxide scavenging activities. Among the 16 plant extracts tested, CN-13 showed strong antioxidant properties in the DPPH radical scavenging and hydrogen peroxide scavenging tests. The CN-13 ethanol extract was thus selected to be used for further experiments, and was separated into various fractions using four different organic solvents (n-hexane, methylene chloride, ethyl acetate and butanol). The ethyl acetate fraction of CN-13 extract evidenced strong DPPH radical scavenging properties as compared to the other fractions. The ethyl acetate fraction also strongly inhibited DNA-damage induced by hydrogen peroxide-oxidative damage in a mouse lymphoma (L5178Y-R) cell line. Moreover, a correlation between the total phenolic content of the extract, and its antioxidant property was reported

Trans-1,3-diphenyl-2,3-epoxypropan-1-one, a chalcone derivative, induces apoptosis via ROS-mediated down-regulation of Bcl-xL in human leukemia HL-60 cells

The anticancer effects of trans-1,3-diphenyl-2,3-epoxypropan-1-one (DPEP), a chalcone derivative, were investigated in human leukemia HL-60 cells. Treatment of HL-60 cells with various concentration of DPEP resulted in a sequence of events characteristic of apoptosis, including loss of cell viability, morphological changes, and increased sub-G1 DNA content. We demonstrated that DPEP elevates reactive oxygen species (ROS) levels in HL-60 cells, and that the ROS scavenger N-acetylcysteine (NAC) could block DPEP-induced ROS generation and apoptosis. Western blot analysis revealed that DPEP inhibits Bcl-xL expression, leading to caspase-3 activation and poly-ADP-ribose polymerase (PARP) cleavage, thereby inducing apoptosis. However, NAC pretreatment significantly inhibited the activation of caspase-3 and PARP cleavage and reduced Bcl-xL levels. These findings provide the first evidence that DPEP may inhibit the growth of HL-60 cells and induce apoptosis through a ROS-mediated Bcl-xL pathway

6,7-Dimethoxy-4-methylcoumarin suppresses pro-inflammatory mediator expression through inactivation of the NF-kappaB and MAPK pathways in LPS-induced RAW 264.7 cells

In this study, we investigated the ability of 6,7-dimethoxy-4-methylcoumarin (DMC) to inhibit lipopolysaccharide (LPS)-induced expression of pro-inflammatory mediators in mouse macrophage (RAW 264.7) cells, and the molecular mechanism through which this inhibition occurred. Our results indicated that DMC down regulated LPS-induced nitric oxide (NO) synthase (iNOS) and cyclooxygenase-2 (COX-2) expression, thereby reducing the production of NO and prostaglandin E2 (PGE2) in LPS-activated RAW 264.7 cells. Furthermore, DMC suppressed LPS-induced production of pro-inflammatory cytokines such as interleukin (IL)-1β, IL-6, and tumor necrosis factor (TNF)-α. To elucidate the mechanism underlying the anti- inflammatory activity of DMC, we assessed its effects on the mitogen-activated protein kinase (MAPK) pathway and the activity and expression of nuclear transcription factor kappa-B (NF-κB). The experiments demonstrated that DMC inhibited LPS-induced phosphorylation of extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinase (JNK), and p38. In addition, it attenuated LPS-induced NF-κB activation via the inhibition of IκB-α phosphorylation. Taken together, these data suggest that DMC exerts its anti-inflammatory effects in RAW 264.7 cells through the inhibition of LPS-stimulated NF-κB and MAPK signaling, thereby downregulating the expression of pro-inflammatory mediators

Gillisia marina sp. nov., from seashore sand, and emended description of the genus Gillisia

A Gram-staining-negative, strictly aerobic, rod-shaped bacterium, designated CBA3202 T , was isolated from seashore sand on Jeju Island, Republic of Korea. Based on the 16S rRNA gene sequence analysis, strain CBA3202 T was allocated to the genus Gillisia (family Flavobacteriaceae) and was most closely related to the type strain of Gillisia mitskevichiae (99.0 % 16S rRNA gene sequence similarity). Optimal growth occurred at 25 6C and with 3 % NaCl. The only isoprenoid quinone was menaquinone-6 (MK-6), the predominant fatty acids were C 16 : 0 , iso-C 15 : 1 G, iso-C 16 : 0 and summed feature 3 (comprising C 16 : 1 v6c and/or C 16 : 1 v7c), and the DNA G+C content was 34.9 mol%. The polar lipids were phosphatidylethanolamine, two unidentified aminolipids and several unidentified polar lipids. Based on phylogenetic inference and phenotypic data, we conclude that strain CBA3202 T represents a novel species of the genus Gillisia, for which the name Gillisia marina sp. nov. is proposed. The type strain is CBA3202