Jeong-Yong Cho

Isolation and identification of antioxidative compounds and their activities from Suaeda japonica

The ethyl acetate (EtOAc) and chloroform (CHCl3) layers obtained after solvent fractionation of a H2O suspension of powdered Suaeda japonica juice showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicalscavenging activity than other layers. Eighteen compounds were purified and isolated from the EtOAc and CHCl3 layers using chromatography following DPPH radicalscavenging assay. These compounds were identified as dihydroferulic acid methyl ester (1), pyrocatechol (2), syringic acid (3), apigenin (4), isorhamnetin (5), kaempferol (6), dihydroferulic acid (7), vanillic acid (8), 4-hydroxybenzoic acid (9), acetophlorglucine (10), homoeriodictyol (11), naringenin (12), quercetin (13), luteolin (14), 9-epiblumenol C (15), scopoletin (16), dihydroisorhamnetin (17), and chrysoeriol (18). The structures of these compounds were determined by mass spectrometry and nuclear magnetic resonance analyses. The isolated compounds were newly identified from this plant. Compounds 13 and 14 exhibited higher DPPH radical-scavenging activity and an inhibition effect against ferric ion-induced lipid oxidation of rat liver when compared to α-tocopherol and other compounds.

Mineral-rich Solar Sea Salt Generates Less Oxidative Stress in Rats than Mineral-deficient Salt

Certain solar sea salts have a high content of essential minerals other than NaCl. The effects of minerals in sea salts on oxidative stress in rats were investigated. Mineral-rich salt (MRS) and mineral-deficient salt (MDS) did not scavenge DPPH radicals. When MRS and MDS (equivalent to 1.8 g NaCl/kg/day) and a saline control were orally administered to rats for 7 weeks, MRS group rats showed lower levels of plasma lipid oxidation than MDS group rats. MRS group rats exhibited significantly lower levels of protein carbonyls and 8-hydroxy-2′-deoxyguanosine in the liver than MDS group rats. MRS group rats showed lower protein expression of NF-κB p65 in adipose tissue than MDS group rats. Intake of MRS may generate less oxidative stress than intake of MDS.

Sesquiterpene lactones and scopoletins from Artemisia scoparia Waldst. & Kit. and their angiotensin I-converting enzyme inhibitory activities

Ten compounds, including a new guaiane-type sesquiterpene lactone, were isolated from the aerial parts of Artemisia scoparia. The structure of the new compound was determined to be 5-hydroxyguaia-3(4),11(13),10(14)-trien-6α,12-olide, named scoparanolide. Six known sesquiterpene lactones [estafiatone, 3β,4α-dihydroxyguaia-11(13),10(14)-dien-6α,12-olide, estafiatin, preeupatundin, 3β-hydroxycostunolide, and ludovicin B] and three known coumarin derivatives (scopoletin, scoparone, and isofraxidin) were identified by nuclear magnetic resonance and electrospray ionization mass spectroscopy. Six known sesquiterpene lactones were found for the first time in this plant. The angiotensin I-converting enzyme inhibitory activities of coumarin derivatives and scopoletins were significantly higher compared to those of sesquiterpene lactones and quercetin.

Isolation and identification of N-butyl-tetrahydro-5-oxofuran-2-carboxamide produced by Bacillus sp. L60 and its antifungal activity

Rhizoctonia solani is the cause of substantial economic loss in many crops. The aim of this study is to investigate biocontrol potential of Bacillus sp. L60 against R. solani and to purify an antifungal compound. In this study, Bacillus sp. L60 demonstrated significant antagonism toward R. solani with the dual culture assay. The antifungal compound was extracted from Bacillus sp. L60 culture supernatant with n‐butanol, and identified as N‐butyl‐tetrahydro‐5‐oxofuran‐2‐carboxamide (BT‐5O‐2C) having molecular weights of 185.1052 Da with the formula C9H15NO3 using NMR and HR‐ESI‐MS analysis. The minimum inhibitory concentration (MIC) value of the antifungal compound was 256 µg ml−1 against R. solani. Therefore, our results clearly demonstrated BT‐5O‐2C as well as Bacillus sp. L60 as potential biological control agents for the management of R. solani.

Isolation and identification of α-glucosidase inhibitors from the stem bark of the nutgall tree (Rhus javanica Linné)

Ethyl acetate (EtOAc) layer obtained after the solvent fractionation of hot water extracts from nutgall tree (Rhus javanica) stem bark showed higher α-glucosidase inhibition activity than other layers. A novel acetophenone glucoside (4) and six known phenolic compounds were isolated from the EtOAc layer. The structure of 4 was determined to be 3,4,5-trihydroxyacetophenone 4-O-β-d-glucopyranoside. The six known compounds were identified as gallic acid (1), 5-methylresorcinol (2), methylgallate (3), 3-hydroxy-5-methylphenol 1-O-β-d-(6′-galloyl)glucopyranoside (5), scopoletin (6), and phlorizin (7). Their chemical structures were determined by electrospray ionization mass spectrometry and nuclear magnetic resonance analyses. Compound 5 was newly identified from this plant. Compounds 6 and 7 showed significantly higher α-glucosidase inhibition activity than other compounds.