• Korean Journal of Pharmacognosy
• /
• v.27 no.2
• /
• pp.136-141
• /
• 1996

We have previously reported the isolation of nine hydrolisable tannins and five flavonoids from the aerial parts of Euphorbia ebracteolata. Further investigation about the same plant has led to the isolation of 5-O-caffeoyl quinic acid, kaempferol $3-O-(2'-O-galloyl-{\beta}-_D-glucoside)$ and euphorbin A.

• YAKHAK HOEJI
• /
• v.40 no.2
• /
• pp.170-176
• /
• 1996

A chemical examination of the aerial parts of Euphorbia pekinensis $R_{UPRECHT}$. (Euphorbiaceae) has led to the isolation of seven hydrolyzable tannins and ten fl avonoid glycosides. The former ones have been identified as gallic acid, methylgallate, 3-O-galloyl shikimic acid, 1,3,4,6-tetra-O-galloyl-${\beta}-_D$-glucose, 1,2,3,4,6-penta-O-galloyl-${\beta}-_D$-glucose, corilagin, geraniin and the latter ones as isoquercitrin, quercitrin, astragalin, afzelin, prunin, rutin, kaempferol-3-O-rutinoside, quercetin-3-O-(2"-O-galloyl)-${\beta}-_D$-glucoside and quercetin-3-O-(2"-O-galloyl)-${\alpha}-_L$-rhamnoside on the basis of chemical and spectroscopic evidence.

• Korean Journal of Pharmacognosy
• /
• v.27 no.2
• /
• pp.142-145
• /
• 1996

We have previously reported the isolation of seven hydrolyzable tannins and nine flavonoids from Euphorbia pekinensis Ruprecht. Further investigation about the same plant has led to the isolation of kaempferol, quercetin, kaempferol $3-O-(2'-O-galloyl-{\beta}-_D-glucoside)$, quercetin 3-O-(2'-O-galloylrutinoside), ellagic acid and acetonyl geraniin. These compounds were isolated from this plant for the first time.

• Korean Journal of Pharmacognosy
• /
• v.27 no.3
• /
• pp.238-245
• /
• 1996

The activity guided fractionation of $CH_2Cl_2$ soluble part of Platycarya strobilacea leaves(Juglandaceae) has led to the isolation of eight active principles, identified as 5-hydroxy-2-methoxy-1,4-naphthoquinone(1), ursolic acid(2), gallic acid(3), 4,8-dihydroxynaphthalene $1-O-{\beta}-_D-glucoside(4)$, eriodictyol(5), quercetin $3-O-(2'-O-galloyl)-{\beta}-_D-glucoside(6)$. quercetin $3-O-(2'-O-galloyl)-{\beta}-_D-galactoside(7)$ and quercetin $3-O-{\alpha}-_L-rhamnoside(8)$ by the means of chemical and spectral evidence, respectively.

• Korean Journal of Pharmacognosy
• /
• v.30 no.3
• /
• pp.295-300
• /
• 1999

Seven compounds were isolated from the n-BuOH extract of the dried stem barks of Rhus javanica L. On the basis of physico-chemical, spectroscopic evidences and comparison with authentic samples, the compounds $1{\sim}7$ were identified as gallic acid (1), methyl gallate (2), scopoletin (3), scopolin (4), $1,\;2,\;3,\;4,\;6-penta-O-galloyl-{\beta}-D-glucose$ (5), orcinol (6) and $orcinol-{\beta}-D-glucoside$ (7). Among these compounds, scopolin, $orcinol-{\beta}-D-glucoside$ were isolated from this plant for the first time.

• Korean Journal of Pharmacognosy
• /
• v.23 no.3
• /
• pp.126-131
• /
• 1992

Four flavonoids were isolated from the aerial parts of Euphorbia ebracteolata. On the basis of chemical and spectroscopic evidence, the structures of these compounds were established as $quercetin-3-O-{\beta}-D-glucoside$(isoquercitrin)(I), quercetin-3-O-rutinoside(rutin)(II), kaempferol-3-O-rutinoside(III) and $quercetin-3-O-(2'-O-galloyl)-{\beta}-D-glucoside$(IV) which was the main flavonoidal component in this plant. The isolation of flavonoids from E. ebracteolata is the first example.

• Korean Journal of Pharmacognosy
• /
• v.24 no.4
• /
• pp.319-321
• /
• 1993

A tannin compound has been isolated from the underground part of Rosa rugosa Thunb. and its structure has been established to be methyl gallate $3-O-{\beta}-D-(6'-O-galloyl)-glucopyranoside(1)$ on the basis of chemical and spectroscopic evidences. This compound was the first example in this plant.

• Korean Journal of Food Science and Technology
• /
• v.45 no.6
• /
• pp.777-784
• /
• 2013

The ethyl acetate (EtOAc) layer of Canavalia gladiata (sword bean) methanol extracts showed higher 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging activity than other layers. Four phenolic compounds were isolated from the EtOAc layer by silica gel column chromatography and prep-HPLC using a guided DPPH radical-scavenging assay. The isolated compounds were identified as methyl gallate (1), gallic acid (2), 1,6-di-O-galloyl ${\beta}$-$\small{D}$-glucopyranoside (3), and 1,4,6-tri-O-galloyl ${\beta}$-$\small{D}$-glucopyranoside (4) based on MS and NMR analyses. Among the four compounds, no. 4 was isolated from this plant for the first time. Their DPPH radical-scavenging activities based on $SC_{50}$ decreased in the following order: 4 (6.9 ${\mu}M$)>3 (8.3 ${\mu}M$)>2 (10.0 ${\mu}M$)>1 (10.3 ${\mu}M$).

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