Jong-Pyung Kim

Sesquiterpene O-naphthoquinones from the root bark of Ulmus davidiana

Three new sesquiterpene ortho-naphthoquinones, davidianones A, B and C, together with four known compounds, mansonones E, F, H and I, were isolated from the root bark of Ulmus davidiana. On the basis of spectral data including pulse field gradient two-dimensional NMR spectroscopy, the structures of new compounds were established as 3-hydroxymethyl-6,9-dimethylnaphtho(1,8-b,c)pyran-7,8-dione, 6-methoxycarbonyl-3,9-dimethylnaphtho(1,8-b,c)pyran-7,8-dione, 6-dimethoxymethyl-3,9-dimethylnaphtho(1.8-b,c)pyran-7,8-d ion e, respectively. Their antioxidative activities were evaluated by a thiobarbituric acid method using rat liver microsomes, with mansonone F showing the greatest activity.

Lipid peroxidation inhibitory activity of some constituents isolated from the stem bark ofEucalyptus globulus

Twelve compounds with lipid peroxidation inhibitory activity were isolated from the stem bark ofE. globulus. Their structures were assigned as a new aromatic monoterpene (1) and eleven known compounds, pinoresinol (2), vomifoliol (3), 3,4,5-trimethoxyphenol 1-O-β-D-(6′-O-galloyl)glucopyranoside (4), methyl gallate (5), rhamnazin (6), rhamnetin (7), eriodictyol (8), quercetin (9), taxifolin (10), engelitin (11), and catechin (12) on the basis of UV, mass, and NMR spectroscopic analyses. These compounds except vomifoliol significantly inhibited lipid peroxidation in rat liver microsome.

Hirsutenols D, E and F, New Sesquiterpenes from the Culture Broth of Stereum hirsutum

New sesquiterpenes, hirsutenols D~F, were isolated from the fermentation broth of Stereum hirsutum, and their structures were determined on the basis of various spectroscopic analyses. Hirsutenols E and F showed significant scavenging activity against superoxide anion radicals with EC50 values of 1.62 and 0.39 mM, respectively.

Prevention of UV Radiation-Induced Premature Skin Aging in Hairless Mice by the Novel Compound Melanocin A

Abstract Repetitive exposure of the skin to UV radiation induces various harmful changes, such as thickening, wrinkle formation, inflammation and carcinogenesis. A variety of natural compounds and synthetic compounds have been studied to determine whether they can prevent UV-induced harmful effects. In this study, we investigated the effect of a novel compound, Melanocin A, which was isolated from Eupenicillium shearii F80695, on UV-induced premature skin aging. First, we studied the effect of Melanocin A on UV-induced matrix metalloproteinase (MMP)–9 expression in an immortalized human keratinocyte cell line, HaCaT, in vitro. Acute UV irradiation induced MMP-9 expression at both the mRNA and protein levels and Melanocin A suppressed this expression in a dose-dependent manner. We then investigated the effect of Melanocin A on UV-induced skin changes in hairless mice in vivo. Chronic exposure of hairless mouse dorsal skin to UV increased skin thickness and induced wrinkle formation and the gelatinase activities of MMP-2 and MMP-9. Moreover, Melanocin A significantly suppressed UV-induced morphologic skin changes and MMP-2 and MMP-9 expression. Taken together, these results show that Melanocin A can prevent the harmful effects of UV that lead to skin aging. Therefore, we suggest that Melanocin A should be viewed as a potential therapeutic agent for preventing and/or treating premature skin aging.

Benzastatins E, F, and G: New indoline alkaloids with neuronal cell protecting activity from Streptomyces nitrosporeus

Abstract Three new indoline alkaloids, benzastatins E (5), F (6), and G (7), were isolated from the culture broth of Streptomyces nitrosporeus 30643 as neuronal cell protecting substances. Their structures were elucidated on the basis of spectral data. 5, 6 and 7 suppressed glutamate toxicity in N18-RE-105 cells with EC50 values of 1.7, 3.6, and 12.2 μM, respectively.

Inoscavin A, a new free radical scavenger from the mushroom Inonotus xeranticus

Abstract A new free radical scavenger named inoscavin A was isolated from the methanolic extract of the mushroom Inonotus xeranticus . The structure of inoscavin A was elucidated by NMR spectroscopic method.

Deoxyverrucosidin, a novel GRP78/BiP down-regulator, produced by Penicillium sp

Glucose-regulated protein 78 (GRP78) resides in endoplasmic reticulum (ER) and plays a role in protecting tumor cells against the toxic effects of anticancer agents. During the search for down-regulators of GRP78 using a reporter gene (luciferase) assay system, we isolated a novel compound designated as deoxyverrucosidin (1), a congener of verrucosidin (2), from Penicillium sp. and identified it as a down-regulator of the grp78 gene. The structure of 1 was determined by mainly ESI-mass and two-dimensional NMR spectra. 1 dose-dependently inhibited the expression of GRP78 promoter with an IC50 of 30 nM.

Agrocybenine, novel class alkaloid from the Korean mushroom Agrocybe cylindracea

Abstract A new type alkaloid agrocybenine was isolated from mushroom Agrocybe cylindracea . The structure of agrocybenine was elucidated by spectroscopic methods, especially 15 N-NMR studies using pulsed field gradient(PFG)-HMBC and HMQC techniques.

Antioxidant Activities of Vaccinium uliginosum L. Extract and Its Active Components

Vaccinium uliginosum L. (also known as bog bilberry) is a low-growing deciduous shrub classified in the Ericaceae family of plants, which includes numerous Vaccinium berries, blueberries, and cranberries. Berries of the Ericaceae family are known to contain organic acids, vitamins, glycosides, and anthocyanins and have been reported to have antioxidant activity. In order to identify the antioxidative principles of V. uliginosum, we separated water extracts into polyphenol, anthocyanin-rich (pigment), and sugar/acid fractions by using ethyl acetate, acidic methanol (MeOH), and 0.01 N HCl. Antioxidant activities were assessed by 2,2-diphenyl-1-picrylhydrazyl (DPPH), superoxide radical, and hydroxyl radical assays. The crude extract and fractions containing polyphenol and pigment exhibited the greatest antioxidant activities with 50% inhibitory concentration (IC(50)) values of 85.8 microg/mL, 33.2 microg/mL, and 16.7 microg/mL, respectively, for the DPPH assay and 48.1 microg/mL, 83.8 microg/mL, and 51.9 microg/mL for the nonenzymatic superoxide radical assay. The fractions containing polyphenol, pigment, and sugar/acid significantly inhibited xanthine oxidase. To investigate the functional compounds from the active fractions, we purified the polyphenol fraction and separated the compounds by using chromatographic techniques. The crude extract was dissolved in MeOH and further purified by reversed-phase high-performance liquid chromatography (HPLC) using MeOH-water (35:65 vol/vol) (with 0.04% trifluoroacetic acid) to obtain VU-EA-1 (16.6 mg), VU-EA-2 (8.5 mg), VU-EA-3 (19.8 mg), VU-EA-4 (12.8 mg), VU-EA-5 (6.5 mg), and VU-EA-6 (23.5 mg). The MeOH-washed fraction from the HPLC was concentrated and purified by reversed-phase HPLC using MeOH-water (50:50 vol/vol) to give VU-EA-10 (12.4 mg). Antioxidant activity was assessed by DPPH, superoxide radical, and hydroxyl radical assays. The isolated compounds exhibited dose-dependent antioxidant activity with IC(50) values of 7.6 microg/mL (VU-EA-10) for the DPPH assay, 67.8 microg/mL (VU-EA-4) for the nonenzymatic superoxide radical assay, and 3.7 microg/mL (VU-EA-10) and 7.6 microg/ml (VU-EA-6) for the enzymatic superoxide radical assay and 30% inhibitory concentration values of 0.58 microg/mL (VU-EA-1), 0.57 microg/mL (VU-EA-5), and 0.70 microg/mL (VU-EA-6) for the hydroxyl radical assay. In conclusion, V. uliginosum had potent antioxidative activity, and flavonoids were isolated as the main active principles.

Methoxylaricinolic acid, a new sesquiterpene from the fruiting bodies of Stereum ostrea.

Methoxylaricinolic acid (1), a new sesquiterpene with drimane skeleton was isolated from the fruiting bodies of Stereum ostrea, together with the known compound laricinolic acid (2). The structure of 1 was determined as 12-methoxy-7-oxo-11-drimanoic acid on the basis of spectroscopic analysis.