Rak-Hun Jeong

A New flavonolignan from the aerial Parts of Oryza sativa L. inhibits nitric oxide production in RAW 264.7 macrophage cells

Fresh and chopped aerial parts of Oryza sativa were extracted in 80% aqueous mehthanol, and the concentrated extract was successively partitioned using n-hexane, ethyl acetate (EtOAc), nbutanol, and H2O. From the EtOAc fraction, a new flavonolignan (2) and a known flavonolignan, salcolin B (1), were isolated through repeated SiO2 and octadecyl silica gel column chromatography. Based on NMR, mass spectrometer, and IR spectroscopic data, the chemical structure of compound (2) was determined to be tricin-4’-O-[erythro-β-guaiacyl-(7’’-O-methyl)-glyceryl] ether, which has thus far never been reported and was named salcolin C (2). Salcolin B (1) and salcolin C (2) dose-dependently inhibited nitric oxide production in RAW 264.7 cells with IC50 values of 29.8±0.6 and 10.8±1.0 μM, respectively, without visible toxic effect.

Anti-inflammatory lignans from the fruits of Acanthopanax sessiliflorus.

A new lignan, named acanthosessilin A (1), as well as eight known lignan and lignan glycosides 2−9 were isolated from an ethanolic extract of Acanthopanax sessiliflorus fruits. The chemical structures were determined by spectroscopic methods, including HR-EIMS, 1D NMR (1H, 13C, DEPT), 2D NMR (gCOSY, gHSQC, gHMBC, NOESY), and IR spectroscopy. All isolated compounds were tested for the ability to inhibit LPS-induced nitric oxide production in RAW264.7 macrophages.

New flavonolignan glucoside from the aerial parts of Oryza sativa

A new flavonolignan glucoside, tricin-4′-O-(erythro-β-guaiacylglyceryl)ether 9′′-O-β-D-glucopyranoside (9′′-O-glucopyranosyl salcolin B), was isolated from the aerial parts of Oryza sativa L. The structure of the compound was established on the basis of NMR, FAB-MS, and IR spectroscopic data.

Neolignans from the Fruits of Magnolia obovata and Their Inhibition Effect on NO Production in LPS-Induced RAW 264.7 Cells

Three new neolignans, named 9-methoxyobovatol (6), magnobovatol (7), and 2-hydroxyobovaaldehyde (9), along with six known ones, magnolol (1), honokiol (2), isomagnolol (3), obovatol (4), obovatal (5), and obovaaldehyde (8), were isolated from the fruits of Magnolia obovata using silica gel and ODS column chromatography. From the results of spectroscopic data including EIMS, IR, 1H- and 13C-NMR, DEPT, and 2D-NMR (gCOSY, gHSQC, gHMBC), the chemical structures were determined. All isolated compounds were evaluated for inhibition activity on nitric oxide production in LPS-induced RAW 264.7 cells, and compounds 1-4, 6, 7, and 9 showed significant activity with IC50 values of 15.8 ± 0.3, 3.3 ± 1.2, 14.1 ± 0.9, 6.2 ± 1.2, 14.8 ± 2.3, 14.2 ± 1.2, and 14.8 ± 3.2 µM, respectively, without any visible toxic effect.

Inhibition effect of phenyl compounds from the Oryza sativa roots on melanin production in murine B16-F10 melanoma cells

Five phenyl compounds, vanillin (1), methyl trans-ferulate (2), trans-p-coumaric acid methyl ester (3), N-benzoyltryptamine (4), and N-(trans-cinnamoyl)tryptamine (5), were isolated from the roots of Oryza sativa L. and identified on the basis of spectroscopic data. Compounds 3 and 5 showed strong inhibition effect on melanin production in murine B16-F10 melanoma cells and tyrosinase activity. Also, the quantitative analysis of the compounds was carried out using LC/MS/MS experiment. Compounds 3 and 5 could be used as skin-whitening agents.

New indoles from the roots of Brassica rapa ssp. campestris

Two new indoles, 2-C-β-D-glucopyranosyl-1-methoxyindole-3-acetonitrile (1) and 6-hydroxy-1-methylindole3-acetonitrile (2), along with two known indoles [caulilexin C (3) and arvelexin (4)], were isolated from turnip roots (Brassica rapa ssp. campestris L.). The structures of the compounds were established on the basis of NMR, FAB-MS, and IR spectroscopic data.

Comparative analysis of physicochemicals and antioxidative properties in new red rice (Oryza sativa L. cv. Gunganghongmi)

The main objectives of this study were to investigate physicochemicals and antioxidant activities of new red rice (Oryza sativa cv. Gunganghongmi (GH)) by comparing normal brown (Nampyeongbyeo, NB) and reported red rice (Jukjinjubyeo, JB) in Korea. The nutritional constituents, including protein, oil, sugar, fatty acid, GABA, and γ-oryzanol were not significantly different between normal brown and colored rice. However, the ethanol extract of GH showed the highest phenolic content (24.7 ± 1.3 mg g−1). The ethanol extracts of GH showed higher scavenging activities against DPPH (0.2 mg mL−1 = 62.1 ± 2.5%) and ABTS (0.2 mg mL−1 = 63.2 ± 3.5%) radicals. Moreover, GH more inhibited LPS-induced nitric oxide (NO) production (13.2 ± 1.4 μM) than JB (18.3 ± 2.3 μM) and NB (22.1 ± 1.4 μM) at the same concentration (0.2 mg mL−1) without cytotoxicity. These results suggest that new red rice (GH) would be considered to be new functional rice due to its anti-oxidative effect and high nutrition.

Diterpenes from the roots of Oryza sativa L. and their inhibition activity on NO production in LPS-stimulated RAW264.7 macrophages.

Two new pimarane diterpenoids, momilactone D (3) and momilactone E (5), along with three known diterpenoids, momilactone A (1), sandaracopimaradien‐3‐one (2), and oryzalexin A (4) were isolated from Oryza sativa roots. The chemical structures of the compounds were determined by spectroscopic data analysis. The isolated diterpenoids were evaluated for their ability to inhibit NO production and iNOS mRNA and protein expression in LPS‐stimulated RAW264.7 macrophages. Compound 4 showed strong inhibition activity on NO production, and compounds 1 and 4 decreased the expression of iNOS mRNA and protein levels.

Feruloyl Sucrose Esters from Oryza sativa Roots and Their Tyrosinase Inhibition Activity

One new feruloyl sucrose ester, 3-feruloyl-4′,6′-diacetyl sucrose (1), along with five known feruloyl sucrose esters, 3,6-diferuloyl-3′,6′-diacetyl sucrose (2), smilaside A (3), 3,6-diferuloyl-6′-acetyl sucrose (4), 3-feruloyl-6′-acetyl sucrose (5), and 3,6-diferuloyl sucrose (6), was isolated from Oryza sativa roots. The chemical structures of the compounds were determined by spectroscopic data analysis. The six isolated feruloyl sucrose esters were evaluated for their inhibitory effect on mushroom tyrosinase in vitro.

Phytochemical constituents from the florets of tiger grass Thysanolaena latifolia from Nepal

Phytochemical investigation on the florets of Thysanolaena latifolia leads to the isolation of a new compound 6″-O-acetylorientin-2″-O-α-L-rhamnopyranoside (1), named amrisoside and other 34 known compounds. The chemical structures of the compounds were determined from the interpretation of spectroscopic data including NMR, MS, and IR. This is the first report of phytochemical constituents from the monotypic genus Thysanolaena.