• The Plant Pathology Journal
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• v.17 no.2
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• pp.83-87
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• 2001

Disease resistance in plants is often controlled by gene-for-gene mechanism in which avirulence (avr) gene products encoding by pathogens are specifically recognized, either directly or indirectly by plant disease resistance (R) gene products. Recent studies arising from molecular cloning of a number of R genes from various plant species that confer resistance to different pathogens and corresponding avr genes from various pathogens resulted in the accumulation of a wealth of knowledge on mode of action of gene-for-gene interaction. Specially, members of the NBS-LRR class of R genes encoding proteins containing a nucleotide binding site (NBS) and carboxyl-terminal leucine-rich repeats (LRRs) confer resistance to very different types of phytopathogens, such as bacteria, fungi, oomycetes, viruses, nematodes and aphids. This article reviewed the molecular events that occur up-stream of defense response pathway, specially, bacterial avr gene protein recognition mediated by NBS-LRR type R gene product in plant based on current research results of well studied model plants.

• Natural Product Sciences
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• v.15 no.4
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• pp.234-240
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• 2009

Phytochemical investigation of the MeOH extract of the aerial parts of Bistorta manshuriensis resulted in the isolation of two cerebrosides, two lactams, six phenolic compounds and seven flavonoids. Their chemical structures were characterized by spectroscopic methods to be pinelloside (1), soyacerebroside I (2), pterolactam (3), 5-hydroxypyrrolidine-2-one (4), vanillic acid (5), caffeic acid methyl ester (6), protocatechuic acid (7), caffeic acid (8), 3,5-di-O-caffeoyl quinic acid methyl ester (9), chlorogenic acid methyl ester (10), avicularin (11), afzelin (12), quercetin (13), isoorientin (14), quercetin 3-O-${\beta}$-D-glucoside (15), quercitrin (16), and luteolin (17). The isolated compounds (1 - 4, 7, 12, 14) were isolated for the first time from this plant source and the compounds 1 - 4, 9 and 10 were first reported from the genus Bistorta. Compound 17 exhibited moderate cytotoxicity and compound 6 exhibited weak cytotoxicity against four human cancer cell lines in vitro using an SRB bioassay.

• Natural Product Sciences
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• v.15 no.1
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• pp.44-49
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• 2009

Seven monoterpenes, three sesquiterpenes, three phenolics and one flavonoid were isolated from the MeOH extract of Amomum xanthioides. Their structures were determined by spectroscopic methods to be caryophyllene oxide (1), bornyl acetate (2), nerolidol (3), spathulenol (4), (-)-borneol (5), (+)-5-endohydroxycamphor (6), vanillic acid (7), protocatechuic acid methyl ester (8), betulabuside A (9), (1R,4S,6R)-6-hydroxyfenchan-2-one-6-O-$\beta$-D-glucopyranoside (10), (1S,4R,6S)-6-hydroxybornan-2-one-6-O-$\beta$-D-glucopyranoside (11), (1R,2S,4S,5R)-angelicoidenol 2-O-$\beta$-D-glucopyranoside (12), 1-O-vanilloyl-$\beta$-D-glucopyranoside (13), and quercetin-3-rhamnopyranoside (14). Compounds 6-14 were isolated for the first time from this plant source. Compounds 3 and 4 exhibited moderate cytotoxicity against four human cancer cell lines in vitro using a SRB bioassay.

• Natural Product Sciences
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• v.14 no.1
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• pp.37-46
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• 2008

From the 70% EtOH extract of the roots of Astragalus membranaceus (Leguminosae), fifteen saponins were isolated and identified as astragaloside I (1), isoastragaloside II (2), astragaloside II (3), agroastragaloside I (4), cyclogaleginoside B (5), cycloaraloside A (6), brachyoside B (7), agroastragaloside II (8), astragaloside III (9), astragaloside IV (10), astramembranoside A (11), astramembranoside B (12), cylocanthoside E (13), cyclounifolioside B (14) and azukisaponin V methyl ester (15) by spectroscopic methods. Ten compounds 1 - 3, 5 - 7, 9 - 11 and 14 have cycloastragenol as an aglycon, and four compounds 4, 8 , 12, and 13 have cyclocanthogenin as an aglycon. The hairy roots of A. membranaceus were shown to produce previously unreported cycloartane-type saponins such as agroastragalosides I (4) and II (8) and cycloastragenol $3-O-{\beta}-D-xyloside$ (5), together with the known saponins. This is the first report of these saponins (4, 5, and 8) from the intact plant. Although the occurrence of the oleanane-type triterpene saponin, azukisaponin V methyl ester (15), in Astragalus plants has been demonstrated by others, this is the first report of the azukisaponin V methyl ester (15) from the Astragalus plants.

• Natural Product Sciences
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• v.14 no.4
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• pp.281-288
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• 2008

From the MeOH extract of the whole plants of Lathyrus davidii (Fabaceae), thirteen constituents were isolated and identified as the flavonoids astragalin, isoquercitrin, nicotiflorin, and rutin, as the saponins soyasapogenol B 3-O-${\beta}$-D-glucuronopyranoside, azukisaponins II and V, soyasaponins II and V and as 4-O-${\beta}$-Dglucopyranosyl syringic acid, uracil and n-hexacosanol. Five saponins and 4-O-${\beta}$-D-glucopyranosyl syringic acid were isolated from the BuOH fraction as their methyl esters. Ombuoside (rutin 7,4'-di-O-methyl ether) was also isolated from the methylated BuOH-soluble fraction. However, no ombuoside was detected in the HPLC analysis of the nonmethylated BuOH fraction. Therefore, ombuoside is an artifact derived from methylation of rutin. All of these compounds were isolated for the first time from this plant.

• Proceedings of the Korean Society of Plant Biotechnology Conference
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• 2005.11a
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• pp.415-415
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• 2005

• Proceedings of the PSK Conference
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• 2001.04a
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• pp.203.1-203.1
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• 2001

• Natural Product Sciences
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• v.9 no.2
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• pp.112-116
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• 2003

The antitumor and immunostimulating activities of Acanthopanax sessiliflorus fruits were investigated. Polysaccharide isolated from this plant, when administered consecutively for 9 days at 50 and 100 mg/kg i.p. in mice, caused a significant increase in the life span and a significant decrease in the tumor weight and volume in mice inoculated with Sarcoma-180 tumor cells. Polysaccharide was also demonstrated to exhibit phagocytosis-enhancing activity as measured by the carbon clearance in mice. Polysaccharide, when administered i.p. at 50 and 100 mg/kg/day for 3 consecutive days, exhibited a significant RCtr/RCc [the rate of regression coefficient of the animals teated (RCtr) to that of the control (RCc)], being 1.44 (PI = 1), 1.52 (PI = 2) which was approximately the same with that of enhancement of phagocytosis, its potency as expressed by the regression coefficient ratio of zymosan (RCtr/RCc = 1.55, PI = 2), a typical phagocytosis enhancer. Polysaccharide also caused a significant increase in the acid phosphatase activity representing lysosomal enzymes in macrophages at 1-100 ig/ml in vitro in compliance with in vivo results. These results suggest that the antitumor activity of polysaccharide might be related to the immunostimulating function.

• Archives of Pharmacal Research
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• v.28 no.1
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• pp.34-38
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• 2005

A new neolignan, named simplidin was isolated from the n-butanol extract of stem of Firmiana simplex, together with six known compounds, scopoletin (1), syrigaresinol (2), aquillochin (3), nitidanin (4), tamarixetin 3-rhamnoside (6), and quercitrin (7). On the basis of spectral and chemical evidence, simplidin (5) was determined to be rel-(7R, 8R)-4, 5, 9, 9'-tetrahydroxy-3,3'­dimethoxy-7-O-5', 8-O-4'-neolignan. All the six compounds were also isolated for the first time from this plant.

• Korean Journal of Pharmacognosy
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• v.11 no.2
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• pp.61-65
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• 1980

As a folkloric medicine, Siegesbeckia pubescens has been used for treatment of brain stroke and hypertension. Diterpene compound, 16,17-dihydroxy 16-${\beta}-(-)$ kaurane-19-oic acid, was isolated from the plant. Its potential antihypertensive activity was evaluated againstan animal model of hypertension, Okamoto-SHR. When diterpene compound with dose of 50mg/kg/day was orally administered, it exhibited mild antihypertensive activity comparable with propranolol administration dose of 75mg/kg/day.