Kyeong-Soo Chung

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.

Studies on the antibiotic constituents of Korean basidiomycetes(IV). Preliminary examination of the mycelial cultures of the 17 basidiomycetous strains

To investigate the antibiotic constituents of Korean basidiomycetes the carpophores of the wood-rotting basidiomycetes were collected from several locations of Korea, and from them 17 mycelial strains were isolated on potato-dextrose-agar plates supplemented with tetracycline (20 μg/ml). The isolated strains were shake-cultured in glucose-peptone-yeast extract medium and then the antibacterial activities of the culture filtrates were assessed by disc-plate method. Among them, 12 strains (70.6%) were active, and basidiomycete strain LMCB-109 (Daedalea quercina) and LMCB-116 showed potent activities against all the six bacterial target organisms includingSerratia marcescens.

Studies on the adsorption properties of Korean kaolin IV the adsorption of bacteria by activated halloysiste

Studies on the adsorption of four kinds of bacteria,Staphylococcus aureus, Sarcina lutea, Escherichia coli andSerratia marcescens by activated Korean kaolins have been carried out to innovate utilization as adsorbent preparations. In connection with particle size and size fraction, the adsorption was examined by colony counting and spectroscopy. Korean kaolin was purified from Hadong white species of preminum grade and three size fractions were derived from passage through BS# 100, #200 and #325 mesh sieves, respectively. These were activated at 105° or 280° for three hours and at 550 °C for one hours. The results indicated that the adsorbing power of Korean kaolin was superior forS. aureus andS. lutea, butE. coli andS. marcescens were not adsorbed by clays. The smaller the particle size, the greater was adsorbing power for Gram-positive bacteria. There appears to be justification for its further investigations as an ingredient in intestinal adsorbent preparations.

Studies on the Hemolytic Activities of Korean Wild Mushrooms (III) - Hemolytic Characteristics and in vivo Toxicity of Hemolysin of Hebelma crustuliniforme -

In the previous studies, we surveyed 68 Korean wild mushrooms for their hemolytic activity and found that cold-water extract of Hebeloma crustuliniforme contained heat-resistant hemolysin. In this study, partially purified hemolysin of the mushroom was obtained by cold-water extraction followed by precipitation with ammonium sulfate, solubility fractionation and then dialysis. The hemolysin was found to be > 12,000 in molecular weight and its optimal hemolytic temperature was and it`s hemolytic activity, on washed erythrocytes and unwashed erythrocytes, respectively, was in the order of sheep > rat > human mouse > chicken and sheep > mouse > human rat > chicken. When ip injected into ICR mice at 1.38 mg/kg, it incurred prompt hemolysis as well as severe renal toxicity and hepatotoxicity. These results strongly suggest that the toxicity of Hebeloma crustuliniforme, which had been well-known as a toxic wild mushroom, may be at least partly due to its hemolysin.

Antitumor effect of212bismuth-conjugated anti-IL-2R monoclonal antibody(2E4) on a IL-2 receptor positive tumor EL4J3.4

The antitumor effects of the 2E4 and anti-Tac, monoclonal antibodies directed to IL-2 receptor (IL-2R), conjugated with α-particle emitting radionuclide bismuth-212, were compared. The212Bi-2E4 demonstrated specific cytotoxicity to EL4J3.4, a IL-2R+ cell line, than to EL4J, a IL-2R− cell line in thymidine incorporation assay.212Bi-2E4 exerted the maximal antitumor effect in that % T/C in C57BL/6 mice implanted with EL4J3.4 ascitic tumor was 331% at the concentration of 50 μCi, while that of212Bi-anti-Tac was 258% at 100 μCi.