Jong Seong Kang

Antioxidant and memory enhancing effects of purple sweet potato anthocyanin and cordyceps mushroom extract

The effects of purple sweet potato anthocyanin (SPA) and Cordyceps mushroom extract (CME) on lipid peroxidation, 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals and cognitive deficits were examined. Both SPA and CME exhibited DPPH radical scavenging activities with similar potency. In contrast, only SPA was shown to effectively inhibit lipid peroxidation initiated by Fe2+ and ascorbic acid in rat brain homogenates. Furthermore, SPA markedly enhanced cognitive performance, assessed by passive avoidance test in ethanol-treated mice. Combined treatments with SPA and CME did not significantly influence the effects of SPA alone. These results demonstrate that anthocyanin prepared from purple sweet potato exhibits memory enhancing effects, which may be associated with its antioxidant properties.

Quantitative determination of salidroside and tyrosol from the underground part ofRhodiola rosea by high performance liquid chromatography

A reversed-phase high performance liquid chromatographic method was developed to determine salidroside and tyrosol simultaneously in theRhodiola rosea. The optimum condition was Nova-Pak C18 as stationary phase, 6.5% methanol in water as mobile phase and detection at UV 225 nm. The identification was carried out by comparing the retention, time and LC/MS spectrum of the relevant peaks with those of isolated standards. The contents of salidroside and tyrosol in the samples gathered from various area in China were ranged over 1.3–11.1 mg/g and 0.3–2.2 mg/g, respectively.

Quantitative determination of eleutheroside B and E fromAcanthopanax species by high performance liquid chromatography

Reversed-phase high performance liquid chromatographic method was applied for the determination of eleutheroside B and E in the variousAcanthopanax species collected in Korea. The stationary phase used was Zorbax 300 SB C18 and a mobile phase program was used, which started at 6% acetonitrile for 2 min, and then a linear gradient was operated for the next 18 min to 17% acetonitrile at a flow rate of 1.0 ml/min. The column effluent was monitored at UV 210 nm. Identification was carried out by comparing the retention time and the LC/MS spectrum of each peak corresponding to eleutheroside B and E from sample with those of standards. In general, the contents of eleutheroside B and E in stems were higher than those in roots.Acanthopanax species could be classified into two groups based upon the contents of eleutheroside B and E: one group contains no or very little eleutheroside B and another contains both eleutheroside B and E.

Inhibitory activity of diacylglycerol acyltransferase by tanshinones from the root of Salvia miltiorrhiza.

The inhibitory activity of tanshinones fromSalvia miltiorrhiza was tested on rat liver diacylglycerol acyltransferase (DGAT). Cryptotanshinone (1) and 15, 16-dihydrotanshinone I (3) exhibited potent DGAT inhibitory activities dose-dependently with IC50 values of 10.5 μg/ml and 11.1 μg/ml. However, tanshinone HA (2) and tanshinone I (4) showed very weak inhibition (IC50 value: > 250 μg/ml). A dihydrofuran moiety was seemed to be responsible for the stronger inhibitory activity

A novel δ-lactam-based histone deacetylase inhibitor, KBH-A42, induces cell cycle arrest and apoptosis in colon cancer cells

In this study, we investigated the anti-tumor activity of KBH-A42 [N-hydroxy-3-(2-oxo-1-(3-phenylpropyl)-1,2,5,6-tetrahydropyridin-3-yl)propanamide], a novel synthetic histone deacetylase (HDAC) inhibitor. KBH-A42 inhibited a variety of HDAC isoforms in enzyme assays and suppressed growth of various cancer cell lines. Among the cell lines examined, colon cancer cells, including SW620, SW480 and HCT-15, were the cell types most sensitive to KBH-A42. KBH-A42 inhibition of cancer cell growth was comparable to or stronger than that of suberoylanilide hydroxamic acid (SAHA), a well-known HDAC inhibitor approved by the FDA to treat cutaneous T cell lymphomas. In SW620 cells, KBH-A42 increased the acetylation of histones, mediated cell cycle arrest (G1 arrest at low doses and G2 arrest at high doses), and induced apoptosis. The cell cycle arrest and apoptosis induced by KBH-A42 might be mediated through up-regulation of p21(Waf1) and activation of caspases, respectively. In addition, KBH-A42 inhibited SW620 tumor growth in a human tumor xenograft model. Taken together, our results indicate that KBH-A42 exerts an anti-tumor activity in vitro and in vivo and is a promising therapeutic candidate to treat human cancers.

Quantitative determination of psoralen and angelicin from some medicinal herbs by high performance liquid chromatography

A reversed-phase high performance liquid chromatographic method was developed to determine the contents of psoralen and angelicin from some medicinal herbs. The optimum eluent for chromatography was 20 v/v% acetonitrile in water on a Zorbax 300SB C18 column. The identification was carried out by comparing the retention time and mass spectra of the relevant peaks with their standards. The variation of the concentration of psoralen and angelicin was wide between different species. The seeds ofPsoralea corylifolia showed the highest contents of psoralen (7.8 mg/g) and angelicin (2.3 mg/g) among the tested herbs.

Ameliorating effect of balloon flower saponin on the ethanol-induced memory impairment in mice

The ameliorating effect of the root extract of Platycodon grandiflorum (Campanulaceae) on ethanol‐induced cognitive dysfunction in mice was investigated. The mice with repeated administration of the root extract of P. grandiflorum, crude saponin fraction and platycoside E, a main ingredient of crude saponin fraction, showed a markedly prolonged step‐through latency period (STL) on the passive avoidance task performed after acute ethanol intoxication, respectively. The present results suggest that the memory enhancing effect of the extract was ascribed mainly to the saponin fraction and that saponin of P. grandiflorum, particularly platycoside E could exert a beneficial effect on memory impairment in mice. Copyright

Determination of stability constants of the inclusion complexes of β-blockers in heptakis (2,3-dimethyl-6-sulfato)-β-cyclodextrin

The β-blockers possess at least one chiral center and the S(-)-enantiomer shows higher affinity for binding to the β-adrenergic receptors than antipode. The stability constants of acebutolol, celiprolol, propranolol and terbutaline in the inclusion complexes with single-isomer heptakis (2,3-dimethyl-6-sulfato)-β-cyclodextrin (HDMS-β-CD) were determined by capillary electrophoresis. The approximation and linear double reciprocal methods were adapted with comparable results. Among the β-blockers studied, propranolol had the lowest stability constant but the highest enantioselectivity, indicating that the magnitudes of the stability constants carried little information about enantioseparation. The magnitudes of enantioselectivities between the enantiomer pair were in the order of propranolol > celiprolol > terbutaline > acebutolol.

Enantiomeric Ratio of Shikonin Derivatives as a Possible Key for the Determination of the Origin of Lithospermi Radix

An HPLC method was developed to resolve the enantiomers of shikonin derivatives of the Lithospermi Radix. The optimum mobile phase on a Chiracel AD column was 5% isopropanol inn-hexane with flow rate of 1 ml/min. Establishment of this method made possible to determine the ratios of shikonin/acetylshikonin or alkanin/acetylalkanin in the same root. The correlation of the ratios of these substance pairs appeared characteristic for the country where they were originated from. All of the Korean species showed significantly higher ratios of shikonin/acetylshikonin and alkanin/acetylalkanin than the Chinese ones. This method would be useful to determine the origin of Lithospermi Radix.

Glutathione conjugates of 2- or 6-substituted 5,8-dimethoxy-1,4-naphthoquinone derivatives: Formation and structure

Thirty-four glutathione conjugates of 5,8-dimethoxy-1,4-naphthoquinones (DMNQ) were synthesized and their structure was determined. The yield of GSH conjugate was dependent on size of alkyl group; the longer the size of alkyl group was, the lower was the yield. It was also found that the length of alkyl side chain influenced the chemical shift of quinonoid protons; the quinonoid protons of 2-glutathionyl DMNQ derivatives with R=H to propyl, 6.51–6.59 ppm vs. other ones with R=butyl to heptyl, 6.64–6.68 ppm. This was explained to be due to a folding effect of longer alkyl group. Glutathione (GSH) reacted with DMNQ derivative first to form a 1,4-adduct (2- or 3-glutathionyl-1,4-dihydroxy-5,8-dimethoxynaphthalenes) and then, the adduct was autooxidized to 2- or 3-glutathionyl-DMNQ derivatives. Moreover, GSH reduced DMNQ derivatives to their hydrogenated products. It was suggested that such an organic reaction might play an important role for a study of metabolism or toxicity of DMNQ derivatives in the living cells.