• Bulletin of the Korean Chemical Society
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• v.32 no.10
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• pp.3707-3711
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• 2011

Silver nanoparticles coated with silica can be obtained by the reduction of $AgNO_3$ with hydrazine in the presence of NaOH-stabilized, active silicic acid (polysilicic acid). The size of the silver nanoparticles and the silica shell thicknesses were affected by varying the hydrazine content, the active silicic acid content and the experimental method (e.g. hydrothermal method). Typically, silver nanoparticles sized around 40 nm were aggregated, connected by silica. The presence of peaks centered around 400 nm in UV-vis spectra corresponds to the surface plasmon resonance of silver nanoparticles. The size of the aggregated silver nanoparticles increased with increasing hydrazine concentration. Under hydrothermal conditions at $150^{\circ}C$ the formation of individual silica particles was observed and the sizes of the silver nanoparticles were reduced. The hydrothermal treatment of silver nanoparticles at $180^{\circ}C$ gives a well-defined Ag@$SiO_2$ core-shell in aggregated silica sol particles. The absorption band observed at around 412 nm were red-shifted with respect to the uncoated silver nanoparticles (${\lambda}_{max}$ = 399 nm) due to the larger refractive index of silica compared to that of water. The formation of silver nanoparticles coated with silica is confirmed by UV-visible absorption spectra, transmission electron microscopy (TEM) and energy-dispersive spectroscopy (EDS) data.

• Natural Product Sciences
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• v.5 no.1
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• pp.1-6
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• 1999

This study was devised to observe the antitumor activity of mugwort (Artemisia princeps Pampan.) against ICR mice inoculated with sarcoma-180 cells. The antitumor compounds were partially purified from petroleum ether extract of mugwort by silicic acid column chromatography. The active fraction used in in vivo test was obtained under the elution with acetone in silicic acid column chromatography. When the acetone fraction was intraperitoneally injected to the mice which had been subcutaneously inoculated on the left groin with sarcoma-180, the growth rate of tumor (sarcoma-180 mass) was inhibited by 30%. In case the acetone fraction was injected to the mice which had been inoculated intraperitoneally with sarcoma-180, the average life span was prolonged by 20%. After the injection of the active fraction, the spleen index and ${\gamma}-globulin$ ratio (%) were increased significantly (p<0.05). The administration of acetone fraction did not cause any abnormality in the body and the homeostasis of mice. Those observations suggest that the acetone fraction of mugwort extract has an antitumor effect in vivo.

• Proceedings of the Ginseng society Conference
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• 1978.09a
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• pp.43-49
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• 1978

This study was devised to observe the cytotoxic activity of extracts of Panax ginseng root against some cancer cells and to purify the crude extract. Three kinds of cancer cells(leukemic cells L5178Y, HeLa cells and Sarcoma 180 cells) and mouse embryo cells (as normal cells) were used for this study. The ginseng roots were extracted with petroleum ether in soxhlet apparatus, and the crude extracts were purified by the silicic acid column chromatography and thin-layer chromatography methods. The results obtained are summarized as follows; 1. Eight to ten mg of the petroleum ether extract (crude extract) were obtained from 1 g of Panax ginseng root, and its activities per mg were about 1,000 units. 2. Doubling time of the L5178Y cells was increased to two fold by 24 hours incubation in culture medium containing about one ${\mu}g$ of extract per ml, and eight and ten folds higher concentration of ginseng extract were required for the Sarcoma 180 cells and HeLa cells, respectively, than for the leukemic cells(L5178Y) to inhibit the cellular growth to the same degree. 3. When the L5178Y cells were exposed to medium containing various concentration of the extract for 24 hours before initiation of the soft agar cloning procedure, about $99\%$ of the L5178Y cells were killed at concentration of 8 units per ml. 4. The growth rate of mouse embryo cell (as normal cell) was not affected by the culture with media containing various amounts (1.45 to 30.0 ${\mu}g/ml$) of the extract. 5. The crude extract could be purified about four times by silicic acid column chromatography using several solvent systems, and one spot of active compound could be obtained on the thin-layer chromatogram. 6. In the Swiss mice inoculated with Sarcoma 180 cells, a survival time of the experimental group (injection group of active compound) was extended more. 1.5 to 2.0 times than the control group's(no injection group).

• Journal of the Korean Society of Food Science and Nutrition
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• v.36 no.2
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• pp.149-154
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• 2007

An antibacterial substance to the Streptococcus mutans, a causative bacterium for decayed teeth, was isolated from the dried sea mustard, Undaria pinnatifida, and identified by GC and GC/MS. Acetone extract from the sea mustard (10.4 kg), was evaporated and partitioned to 4 fractions such as hexane, chloroform, butanol and water. The most active chloroform fraction were further purified through basic alumina, silicic acid and ODS column, successively, and finally, 3 antibacterial substances were isolated on the HPLC attached ODS column by using 95% MeOH and guided with UV detector (254 nm). Antibacterial substances (total 160mg, yield $1.5\times10^{-3}$%) had the same Rf value (0.42) on the TLC developed hexane diethyl ether acetic acid (80:30:1) and those methyl esters moved to 0.95. They were identified as the same unsaturated fatty acid, $C_{18:4,\;n-3}$ (3,6,9,12-octadecatetraenoic acid, stearidonic acid) compared relative retention times (15.5 min) with authentic fatty acid on the GC chromatogram. It was further confirmed unambiguously on the GC/MS giving molecular ion peak at m/z 290 which coincided with its methyl ester.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.62 no.1
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• pp.1-8
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• 2017

We investigated the effect of silicate coating of rice seeds on bakanae disease incidence and the quality of seedlings raised in seedling boxes and transplanted into pots. The silicate-coated rice seed (SCS) was prepared as follows. Naturally infested rice seeds not previously subjected to any fungicidal treatment were dressed with a mixture of 25% silicic acid at pH 11 and 300-mesh zeolite powder at a ratio of 50 g dry seed - 9 mL silicic acid - 25 g zeolite powder. The following nursery conditions were provided : Early sowing, dense seeding in a glass house with mulching overnight and no artificial heating, which were the ideal conditions for determining the effect on the seed. The nursery plants were evaluated for Gibberella. fujikuroi infection or to determine the recovery to normal growth of infected nursery plants in the Wagner pot. Seedlings emerged 2-3 days earlier for the SCS than they did for the non-SCS control, while damping-off and bakanae disease incidence were remarkably reduced. Specifically, bakanae disease incidence in the SCS was limited to only 7.8% for 80 days after sowing, as compared to 91.6% of the non-SCS control. For the 45-days-old SCS nursery seedlings, the fresh weight was increased by 11% and was two times heavier, with only mild damage compared to that observed for non-SCS. Even after transplanting, SCS treatment contributed to a lower incidence of further infections and possibly to recovery of the seedlings to normal growth as compared to that observed in symptomatic plants in the pot. The active pathogenic macro-conidia and micro-conidia were considerably lower in the soil, root, and seedling sheath base of the SCS. In particular, the underdeveloped macro-conidia with straight oblong shape without intact septum were isolated in the SCS ; this phenotype is likely to be at a comparative etiological disadvantage when compared to that of typical active macro-conidia, which are slightly sickle-shaped with 3-7 intact septa. A active intact conidia with high inoculum potential were rarely observed in the tissue of the seedlings treated only in the SCS. We propose that promising result was likely achieved via inhibition of the development of intact pathogenic conidia, in concert with the aerobic, acidic conditions induced by the physiochemical characteristics associated with the air porosity of zeolite, alkalinity of silicate and the seed husk as a carbon source. In addition, the resistance of the healthy plants to pathogenic conidia was also important factor.

• Journal of Ginseng Research
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• v.17 no.1
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• pp.52-60
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• 1993

Panax ginseng has been extensively used in the traditional oriental medicine as a restorative, tonic and Prophylactic agent. Recently, several reports regarding to anticancer effects of Panax ginseng has accumulated. These studies emphasized the fact that the anticancer activities might be due to a glycoside group called ginsenoside or pan.u saponin which has a water soluble characteristic. However, the authors and collaborates demonstrated that a highly lipid soluble component in extract of Panax ginseng roots contains a considerable cytotoxic activities against marine leukemic cells (L1210, P388) and human censer cells (HRT-18, HT-29, HCT48). This study was devised to observe the cytotoxic activities of Petroleum-ether extract of Panax giuseng roots (crude GBD and its Partially Purified fraction from silicic acid column chromatography (7 : 3 GX) against sarcoma-180 (5-180) and Walker carcinosar- coma 256 (Walker 256) in vivo, and murine leukemic Lymphocytes (L1210) and human rectal cancer cells (HRT-18) and human colon cancer cells (HT-29 and HCT48) in vitro. Each cell-line was cultured in medium containing serial concentration of the crude GX or 7 : 3 GX in vitro. A highly lipid soluble compound in the extract of Panax ginseng root was cytocidal to murine leukemic cells and human colon and rectal cancer cells in vitro. In the meantime, ginseng saponin derivatives did not have cytotoxic effects at its corresponding concentration. The growth rates of the cancer cells in medium containing ginseng extracts were inhibited gradually to a significant degree roughly in proportion to the increase of the extract concentration. The cytotoxic activity of 7 : 3 GX was about 3 times more potent than that of crude GX, one unit of cytotoxic activity against L1210 cells being equivalent to 2.54 Ug and 058 Ug for the crude GX and 7 : 3 GX, respectively. The Ri value of the active compound on silica- gel thin layer chromatography with petroleum-ether/ethyl ether/acetic acid mixture (90 : 10 : 1, v/v/v) as a developing so lvent was 053. While, the Panaxydol and Panaxynol as active compounds were purified from Petroleum-ether extract of Panax ginseng root by Drs. Ahn and Kim, and author found out that the one unit of cytotoxic activity of the Panaxydol and Panaxynol against L1210 cells being equivalent to 056 Ug and 0.3918 respectively. The survival times of mice inoculated with S-180 cells were extended about 1.5 to 2 times by the 7 : 3 GX treatment compared with their control group. The significantly decreased hemoglobin values of rats after inoculation with Walker 256 were recovered to normal range by oral administration of the crude Gt The synthetic levels of protein, DNA and RNA in human colon and rectal cancer cells were significantly diminished by treatment with the crude GX, which can explain a part of the origin of its anticancer activity.

• Journal of the Korean Society of Food Science and Nutrition
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• v.21 no.4
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• pp.353-366
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• 1992

This study was devised to purify the compound from tuna that have cytotoxic activities against various cancer cell lines and to observe its immunopotentiating activities. The cytotoxic compound was partially purified 277 fold, from petroleum ehter extract (crude extract) of tuna by silicic acid column chromatography (fraction D) and thin layer chromatography (Spot I). Cytotoxic activity was monitored using human colon cancer cell, HCT-48. The active compound (Spot I) was composed of seven materials which are fatty acids of four kinds ($C_{14:0},\;C_{16:0},\;C_{17:1},\;and\;C_{18:0}$) and unknown three fat materials. The active compound has cytotoxic activities against various cancer cell lines, that is, murine leukemic lymphocytes (L1210, P388) and human rectal (HRT-18) and colon cancer cells (HCT-48, HT-29). The patterns of size distribution of HCT-48 cells in the medium containing tuna extract were shifted to direction of the small size region. Also, the microscopic shape of HCT-48 cells were shrinked and distracted. The number of plaque forming cell and immunoglobin fraction of serum protein obtained from tuna-treated mice were increased, but natural killer cell activity was not affected.