Jee Hyung Jung

Psammaplin A, a natural bromotyrosine derivative from a sponge, possesses the antibacterial activity against methicillin-resistantStaphylococcus aureus and the DNA gyrase-inhibitory activity

Psammaplin A, a natural bromotyrosine derivative from an associated form of two sponges (Poecillastra sp. andJaspis sp.) was found to possess the antimicrobial effect on the Grampositive bacteria, especially on methicillin-resistantStaphylococcus aureus (MRSA). The minimal inhibitory concentration of psammaplin A against twenty one MRSAs ranged from 0.781 to 6.25 μg/ml, while that of ciprofloxacin was 0.391∼3.125 μg/ml. Psammaplin A could not bind to penicillin binding protein, but inhibited the DNA synthesis and the DNA gyrase activity with the respective 50% (DNA synthesis) and 100% (DNA gyrase) inhibitory concentration 2.83 and 100 μ/ml. These results indicate that psammaplin A has a considerable antibacterial activity, although restricted to a somewhat narrow range of bacteria, probably by inhibiting DNA gyrase.

Antioxidant effect ofSalvia miltiorrhiza.

A strong antioxidant activity, which was measured by the radical scavenging effect on 1,1-diphenyl-2-picrylhydrazyl(DPPH) radical, was detected in the methanol extract ofSalvia miltiorrhiza Bunge (Labiatae). By activity-directed fractionation, compounds 1 and 2 were isolated as antioxidant principles ofS. miltiorrhiza. Compounds 1 and 2 were identified as dimethyl lithospermate and 3-(3,4-dihydroxyphenyl)lactamide, respectively, on the basis of spectral data. The radical scavenging effect of compounds 1 and 2 on DPPH radical exceeded that of L-ascorbic acid which is a well known antioxidant. These two compounds also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method and cytoprotective effect againstt-BHP in cultured liver cell.

A naphthalene glycoside from Cassia tora

Abstract From the seeds of Cassia tora , a new naphthalene glycoside was isolated and characterized as 2- acetyl -3-O-β- d -apiofuranosyloxy -8-O-β- d -glucopyranosyloxy-1,6-dimethoxynaphthalene (cassitoroside).

Alaternin glucoside isomer from cassia tora

Abstract From the seeds of Cassia tora, an anthraquinone glucoside was isolated and characterized as alaternin 2-O-β- d -glucopyranoside.

The NMR assignments of anthraquinones fromCassia tora

The1H- and13C-NMR spectra of alaternin, aurantio-obtusin, chryso-obtusin, obtusin and 2-glucosyl obtusifolin isolated from the seeds ofCassia tora have been assigned based on HMBC, long-range HETCOR, fully1H-coupled13C-NMR, deuterium isotope experiment, and by comparison with the model compounds.

NMR assignments of two furofuran lignans from sesame seeds

Two furofuran lignans, sesamolin and sesangolin were isolated from the seeds ofSesamum indicum andS. angolense, respectively. Detailed analysis of the1H- and13C-NMR spectra of these lignans was carried out by the application of two-dimensional1H-1H COSY and1H-13C multiple-bond, multiple-quantum spectroscopic correlation techniques.

Cytotoxic constituents ofSaussurea lappa

The crude extract ofSaussurea lappa displayed significant lethality to brine shrimp larvae. Investigation of the causative components by bioactivity-directed fractionation resulted in the isolation of three C17-polyene alcohols. Based on various nmr spectral data, these compounds were idenfitied as shikokiols which had been previously isolated fromCirsium nipponicum and/orCentaurea aegyptica. These C17-polyene alcohols exhibited moderate cytotoxicities against the human tumor cell lines, A549, SK-OV-3, SK-MEL-2, XF498, and HCT15.

The NMR assignments of torilin fromTorilis japonica

A guaian type sesquiterpene, torilin, was isolated from the hexane extract of the fruits ofTorilis japonica. The1H- and13C-signals of this compound have been fully assigned utilizing1H-1H COSY, HMQC, and HMBC experiments.

Cytotoxic constituents ofSorbaria sorbifolia var.stellipila.

The acivity-guided fractionation upon the MeOH extract of the aerial parts ofSorbaria sorbifolia var.stellipila led to the isolation of two cucurbitacin-compounds, cucurbitacin D and cucurbitacin F, as active principles. Two compounds were shown to exhibit significant cytotoxicity against cultured human tumor cell lines, A-549, SK-OV-3, SK-MEL-2, XF-498, and HCT 15.

A rubrofusarin gentiobioside isomer from roastedCassia tora.

From the roasted seeds ofCassia tora L., a new naphthopyrone glycoside was isolated and characterized as 10-[(β-D-glucopyranosyl-(1→6)-O-β-D-glucopyranosyl)oxyl-5-hydroxy-8-methoxy-2-methyl-4H-naphtho [1,2-b]pyran-4-one(isorubrofusarin gentiobioside). Along with isorubrofusarin gentiobioside, alaternin and adenosine were isolated and identified.