Jong Hee Park

Hepatoprotective activity of scopoletin, a constituent ofSolanum lyratum

Scopoletin (7-hydroxy-6-methoxycoumarin), a coumarin, was isolated from the aerial part ofSolanum lyratum Thunb. by the activity-guided fractionation employing carbon tetrachloride-intoxicated primary cultured rat hepatocytes as a screening system. Its hepatoprotective activity was first evaluated by measuring the release of glutamic pyruvic transaminase and sorbitol dehydrogenase from carbon tetrachloride-intoxicated rat hepatocytes into the culture medium. Scopoletin significantly reduced the releases of glutamic pyruvic transaminase and sorbitol dehydrogenase from the carbon tetrachloride-intoxicated primary cultured rat hepatocytes by 53% and 58%, respectively, from the toxicity in a dose-dependent manner over concentration ranges of 1 μM to 50 μM. Further studies revealed that at the concentration of 10 μM, scopoletin significantly preserved glutathione content by 50% and the activity of superoxide dismutase by 36% and also inhibited the production of malondialdehyde to the degree as seen in the control.

Flavonoids from Spatholobus suberectus

Two pterocarpans [(6aR,11aR)-maackiain, (6aR,11aR)-medicarpin], one flavanone [(2S)-7-hydroxy-6-methoxy-flavanone], one isoflavan (sativan) and two isoflavones (pseudobaptige-nin, genistein) were isolated from theSpatholobus suberectus (Leguminosae). Their chemical structures were determined by comparison of their spectroscopic parameters of CD, EIMS, 1D-NMR and 2D-NMR with those reported in the literatures. All of these compounds are reported for the first time from this plant through the present study.

Rhododendrin, an analgesic/anti-inflammatory arylbutanoid glycoside, from the leaves of Rhododendron aureum

To identify an analgesic/anti-inflammatory component from the leaves of Rhododendron aureum (Ericaceae), phytochemical isolation and pharmacological assays (writhing assays and vascular permeability assay for analgesic action in mice; carrageenan-induced paw edemaand TPA-induced ear edema assays of anti-inflammatory action in rats) were performed. Four compounds were isolated from the active fraction (BuOH fraction) by silica gel column chromatography and identified as (−)-rhododendrol, (−)-rhododendrin, avicularin and hyperoside by spectroscopic methods. Rhododendrin, the main compound of the BuOH fraction, exhibited significant analgesic actions in mice and anti-inflammatory actions in rats. This compound accounted for 3.1% of the MeOH extract and 0.48% of dried leaves, respectively, on HPLC analysis. These results suggest that rhododendrin is the major biologically active substance in the leaves of R. aureum with analgesic/anti-inflammatory activity.

Catechin glycoside fromUlmus davidiana

Catechin and catechin glycoside named uldavioside A were isolated from the Korean folk medicineUlmus davidiana. Based on chemical and physicochemical evidences, their structure have been determined as (+)-catechin (1) and (+)-catechin-5-O-β-D-apiofuranoside (2).

Phytochemical study onPrunus davidiana

From the stem ofPrunus davidiana, naringenin and its glucoside, kaempferol and its glucoside, dihydrokaempferol, kaempferide glucoside, hesperetin glucoside, quercetin glucoside, d-catechin and β-sitosterol glucoside were isolated.

Chemical study on the stem ofCudrania tricuspidata

From the stem ofCudrania tricuspidata, β-sitosterol, β-sitosterol glucoside, arthocarpesin, norarthocarpetin, and 5-O-methyl genistein were isolated and characterized by spectral data.