• Archives of Pharmacal Research
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• v.28 no.12
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• pp.1376-1380
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• 2005

In this study, ethanolic extracts from 18 seaweed variants were assessed for hepatoprotective activity against tacrine-induced cytotoxicity in Hep G2 cells. Only one of these, Ecklonia stolonifera Okamura (Laminariaceae), a member of the brown algae, exhibited promising hepatoprotective activity. Bioassay-guided fractionation of the active ethyl acetate (EtOAc) soluble fraction obtained from the ethanolic extract of E. stolonifera, resulted in the isolation of several phlorotannins [phloroglucinol (1), eckstolonol (2), eckol (3), phlorofucofuroeckol A (4), and dieckol (5)]. Compounds 2 and 4 were determined to protect Hep G2 cells against the cytotoxic effects of tacrine, with $EC_{50}$ values of 62.0 and 79.2 $\mu$g/mL, respectively. Silybin, a well characterized hepatoprotective agent, was used as a positive control, and exhibited an $EC_{50}$ value of 50.0 $\mu$g/mL. It has been suggested that the phlorotannins derived from marine brown algae might prove useful sources in the development of novel hepatoprotective agents.

• Natural Product Sciences
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• v.25 no.1
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• pp.76-80
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• 2019

Bioactivity-guided fractionation of MeOH extract of the dried fruits of Amomum tsao-ko led to isolation of nine compounds (1 - 9). Their structures were elucidated by spectroscopic methods including extensive 1D and 2D-NMR, as alpinetin (1), naringenin-5-O-methyl ether (2), naringenin (3), hesperetin (4), 2',4',6'-trihydroxy-4-methoxy chalcone (5), tsaokoin (6), boesenbergin B (7), 4-hydroxyboesenbergin B (8), and tsaokoarylone (9). Of these, compound 8 was isolated from a natural source for the first time, which was previously reported as a synthetic product. The isolated compounds (1 - 9) were tested for their inhibitory effects on LPS-induced nitric oxide production in RAW 264.7 macrophages. Among them, three chalcone derivatives (compounds 5, 7, and 8) and a diarylheptanoid (compound 9) exhibited significant inhibitory activity on the NO production with $IC_{50}$ values ranging from 10.9 to $22.5{\mu}M$.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.383.1-383.1
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• 2002

In connection with our studies on the isolation of hepatoprotective constituents from natural products. we have recently reported hepatoprotective compounds including phenolic bakuchiol. diarylheptanoids. furocoumarins. In the course of continuing efforts. the aqueous extract of the roots of Agrimonia pilosa Ledeb. (Rosaceae) was found to exhibit promising hepatoprotective activity. A. pilosa is a perennial herb distributed throughout South Korea. and its roots have been used as the hemostatic. antimalarial. and antidysenteric agent in oriental medicine. Chemical investigation of the aqueous extract of the roots of this plant. as guided by hepatoprotective active catechin (2). Compound 1 showed hepatoprotective effects on both tacrine-induced cytotoxicity in human level derived Hep G2 cells and tert-hydroperoxide-induced cytotoxicity in rat primary hepatocyles with $EC_{50}$ values of 66.2 $\pm$ 2.8 and 22.9 $\pm$ 2.6 $\mu\textrm{M}$ respectively.

• Korean Journal of Pharmacognosy
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• v.30 no.4
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• pp.397-403
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• 1999

Tyrosinase plays an important role in the process of melanin polymer biosynthesis. Therefore, the enzyme inhibitors have been of great concern as cosmetics to have skin-whitening effects on the local hyperpigmentation. During the search for new inhibitory compounds on melanin polymer biosynthesis from natural sources, MeOH extracts of 589 higher plants were tested for the inhibitory effect on tyrosinase activity by the muschroom tyrosinase assay in vitro. Among plants tested, the leaves of Cercis chinensis exhibited potent inhibitory effect on mushroom tyrosinase activity. Subsequently seven active compounds were isolated from the ethyl acetate soluble part of acetone extract of the leaves of C. chinensis by the activity guided fractionation monitoring the inhibitory effect on tyrosinase activity. Their chemical structures were identified as $kaempferol-3-0-{\alpha}-L-rhamnoside$, quercitrin, $myricetin-3-0-{\alpha}-L-rhamnoside$, myricetin-3-0-(2'-O-galloyl)- ${\alpha}$ -L-rhamopyranoside (desmanthin), (-)-epicatechin-3-0-gallate, (-)-epigallocatechin-3-0-gallate, and methyl gallate on the basis of the speculation of spectral data and chemical reaction. Among the flavonol rhamnosides, myricetin-3-0-(2'-O-galloyl)- -L-rhamnoside(desmanthin) showed most potent inhibitory effect on tyrosinase activity and the structure of B-ring in flavonol moiety was related to the activity. (-)-Epigallocatechin-3-O-gallate having pyrogallol group in flavan-3-ol moiety exhibited more potent inhibitory effect than (-)-epicatechin-3-0-gallate having catechol group in flavan-3-ol moiety on mushroom tyrosinase activity.

• YAKHAK HOEJI
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• v.50 no.2
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• pp.136-143
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• 2006

Roots of Scutellaria baicalensis have been used for fever remedy; diuresis, antiphlogistic. For the investigation of the active component from aerial parts of Scutellaria baicalensis, MeOH extracts from aerial parts of Scutellaria baicalensis were suspended with $H_2O$, and partitioned by $CHCl_3$. In order to investigate the efficacy of antioxidative activity the activity guided fraction and isolation of physiologically active substance were peformed. Its $H_2O,\;30\%,\;60\%$ MeOH and MeOH fractions were examined on antioxidative activity using DPPH method and TBARS assay; It was revealed that $30\%\;and\;60\%$ MeOH fractions have significant anti-oxidative activity. its fractions testing type I allergy, compound 48/80 induced systemic anaphylaxis was applied. As a result, compared with reference (cromolygate), these fraction significantly inhibited systemic anaphylaxis by $71\%\;and\;57\%$, respectively. From $30\%,\;60\%$ MeOH fraction, five compounds were isolated and elucidated apigenin 6-C-${\alpha}$-L-arabinopyranosyl-8-C-${\beta}$-D-glucopyranoside (isoschaftside, I), scutellarein 7-O-${\beta}$-D-glucuronopyranoside (scutellarin, II), apigenin 7-O- ${\beta}$-D-glucuronopyranoside (III), isoscutellarein 8-O-${\beta}$-D-glucuronopyranoside (IV), kaempferol 3-O-${\beta}$-D-glucopyranoside (V) through their physicochemical data and spectroscopic methods. We measured radical scavenging activity with DPPH method and anti-lipid peroxidative efficacy on human LDL with TBARS assay. [$I] showed antioxidant activities in order. Type I allergy compound 48/80 induced systemic anaphylaxis was applied. $[V inhibited systemic anaphylaxis in order.

• Natural Product Sciences
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• v.22 no.3
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• pp.220-224
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• 2016

Anti-Helicobacter pylori activity guided fractionation led to the isolation of five anthraquinones, two stilbenes and one naphthoquinone from the EtOAc fraction of Polygonum cuspidatum, using silica gel column chromatography, Sephadex-LH20, MPLC and recrystallization. The chemical structures were identified to be physcion (1), emodin (2), anthraglycoside B (3), trans-resveratrol (4), anthraglycoside A (5), polydatin (6), 2-methoxy-6-acetyl-7-methyljuglone (7) and citreorosein (8) by UV, $^1H$-NMR, $^{13}C$-NMR and mass spectrometry. Anti-Helicobacter pylori activity including MIC values of each compound was evaluated. All of the isolates exhibited anti-H. pylori activity of which MIC values were lower than that of a positive control, quercetin. Compounds 2 and 7 showed potent growth inhibitory activity. Especially, a naphthoquinone, compound 7 displayed most potent antibacterial activity with $MIC_{50}$ value of $0.30{\mu}M$ and $MIC_{90}$ value of $0.39{\mu}M$. Although anti-H. pylori activity of this plant was previously reported, this is the first report on that of compounds isolated from this species. From these findings, P. cuspidatum roots or its isolates may be useful for H. pylori infection and further study is needed to elucidate mechanism of action.

• YAKHAK HOEJI
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• v.50 no.6
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• pp.351-357
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• 2006

Polygoni Radix (Polygonaceae) has been used as renal disoder hematopoietic, menstrual irregularity and antiaging in Korean folk medicine. Specially aerial parts has been used for insomnia and sedative agent. In order to investigate the efficacy of antioxidant activity on these aerial parts, the bio-activity guided fraction and isolation of physiologically active substance were performed. H$_2$O, 30%, 60%, 100% MeOH were examined antioxidant activity by DPPH method. It was revealed that 30%, 60% MeOH fractions have significantly antioxidant activity. From 60% MeOH fraction, six known flavonoid glycosides (quercetin, quercetin 3-O-${\beta}$-D-galactopyranosyl-4'-O-glucopyrano side-3'-methyl ether, quercetin 3-O-${\alpha}$-L-rhannopyranoside, quercetin 3-O- ${\alpha}$-L-rhamnopyranoside-4'-methylethor, quorcetin 3-O-${\beta}$-D-galactopyranoside, quercetin 3-O-${\beta}$-D-galactopyranoside) and 3,4-Oihydrocinnarnic acid were isolated. To investigate the antioxidant activities of each com-pounds, we measured radical scavening activity with DPPH method and anti-lipid peroxidative efficacy on low density lipo-protein (LDL) with TBARS assay and anti-acetylcholinestrase activity with Ellman's Test. Four compounds (ll, IV Vl, Vll) of quercetin glycosides showed significant activity.

• Microbiology and Biotechnology Letters
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• v.32 no.1
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• pp.47-51
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• 2004

Drug resistance is one of the most significant impediments to successful chemotherapy of cancer. Multidrug-resistance Is characterized by decreased cellular sensitivity to anticancer agents due to the overexpression of P-glycoprotein. By using adriamycin-resistance CL02 cancer cells, we undertook the screening fur agents which were effective to multidrug-resistant cancer cells from strains of the species Sorangium cellulosum isolated in our laboratory. Sorangium cellulose, cellulose-degrading myxobacteria have recently proved to be a rich source of novel anticancer agents. One of the significant examples is the promising anticancer agent epothilone. JW 1006 is the first strain of Sorangium cellulosum which was selected by us for the isolation of a metabolite by a biological screening because of a high cytotoxic activity against the CL02 cancer cells. Cytotoxicity-guided chromatographic fractionation of the culture broth led to the Isolation of two active principles, disorazole $A_1$ and $A_2$. They showed potent cytotoxicity against CL02 cancer cells with $IC_{50}$ values in the picomolar range, and were as active against drug-resistant cancer cells CL02 and CP70 as against the corresponding sensitive cells.

• Korean Journal of Medicinal Crop Science
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• v.13 no.4
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• pp.182-185
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• 2005

Bioassay-guided isolation of the dried roots of Aralia continentalis led to the isolation of (-)-pimara-8(14), 15dien-19-oic acid (continentalic acid) and $(24E)-Stigmasta-5,22-dien-3{\beta}-ol$ (stagmasterol). Their structures were elucidated using $^1H-NMR$, $^{13}C-NMR$, UV and mass spectra analyses. The gram-positive bacterial, including methicilline-resistant (MRSA), were more sensitive to the continentalic acid and stagmasterol than gram-negative bacterial.

• Korean Journal of Pharmacognosy
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• v.34 no.2 s.133
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• pp.138-141
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• 2003

In order to screen new tyrosinase inhibiting principle which is expected to be a new biofunctional skin whitening cosmetics, we have isolated 600 strains of the marine- derived fungi and investigated tyrosinase inhibiting activity for their acetone extracts. The significant activities (>70% Inhibition) were observed in the extract of 10 strains of fungi (MFA7, MFA27, MFA58, MFA317, MFA318, MFA345, MFA412, MFA552, MFA562, MFA581). These active strains were cultured in SWS medium with 1 L scale and the resulting broth and mycelium were extracted to afford mycelium extract (000M) and broth extract (000B), respectively. Tyrosinase inhibiting activity for all extracts has been tested. As the results, the broth extracts of 4 strains (27B, 58B, 552B and 581B) exhibited relatively high levels of activity of $IC_{50}$ values of $3.0-19.0\;{\mu}g/mL$. The active component of 581B was purified by assay-guided isolation to yield the known kojic acid (1), and its structure was determined by physicochemical evidence. Kojic acid showed the significant tyrosinase inhibitory activity with $IC_{50}$ values of $12.0\;{\mu}M$.