Pilju Choi

Efficient thermal deglycosylation of ginsenoside Rd and its contribution to the improved anticancer activity of ginseng.

The root of ginseng is a famous functional food and a herbal medicine. Research into the development of a method for increasing the pharmaceutical effect of ginseng by conversion of ginsenosides, the major active components of ginseng, by high-temperature and high-pressure thermal processing has been conducted. However, changes in the structures of each ginsenoside by heat processing and their contributions to anticancer activity have not yet been fully elucidated. Here, we investigated whether anticancer activity of ginsenosides, such as Rb1, Rb2, Rc, Rd, and Re, was associated with changes in the structures of each ginsenoside by heat processing in human stomach cancer AGS cells. Upon heat processing at 120 °C, most peaks of ginsenosides Rb1, Rb2, Rc, and Rd disappeared and the contents of less-polar ginsenosides 20(S,R)-Rg3, Rk1, and Rg5 were newly detected. From the quantitative analysis of ginsenosides, the generated amounts of less-polar ginsenosides were the highest after heat processing of ginsenoside Rd. After heat processing, the diol-type ginsenosides Rb1, Rb2, Rc, and Rd gained significant antiproliferative activity. In particular, ginsenoside Rd induced the strongest cell death among the diol-type ginsenosides, whereas the triol-type gisenoside Re showed weak antiproliferative activity. Ginsenoside Rd-induced cell death was associated with caspase-dependent apoptosis. Taken together, these results demonstrate that deglycosylation of Rd contributes to improved anticancer activity of ginseng and provide new insight on the mechanism of increased anticancer effects of ginsenosides upon heat processing.

Protective Effects of Processed Ginseng and Its Active Ginsenosides on Cisplatin-Induced Nephrotoxicity: In Vitro and in Vivo Studies.

Although cisplatin can dramatically improve the survival rate in cancer patients, its use is limited by its nephrotoxicity. Previous investigations showed that Panax ginseng contains components that exhibit protective activity against cisplatin-induced nephropathy. The aim of the present study is to investigate the effect of microwave-assisted processing on the protective effect of ginseng and identify ginsenosides that are active against cisplatin-induced kidney damage to evaluate the potential of using ginseng in the management of nephrotoxicity. The LLC-PK1 cell damage by cisplatin was significantly decreased by treatment with microwave-processed ginseng (MG) and ginsenosides Rg3, Rg5, and Rk1. Reduced expression of p53 and c-Jun N-terminal kinase proteins by cisplatin in LLC-PK1 cells was markedly ameliorated after Rg3 and Rg5/Rk1 treatment. Additionally, elevated expression of cleaved caspase-3 was significantly reduced by ginsenosides Rg5, Rk1, and with even greater potency, Rg3. Moreover, MG and its fraction containing active ginsenosides showed protective effects against cisplatin-induced nephropathy in mice. We found that ginsenosides Rg3, Rg5, and Rk1 generated during the heat treatment of ginseng ameliorate renal damage by regulating inflammation and apoptosis. Results of current experiments provide evidence of the renoprotective effects and therapeutic potential of MG and its active ginsenosides, both in vitro and in vivo.

Increase in apoptotic effect of Panax ginseng by microwave processing in human prostate cancer cells: in vitro and in vivo studies

Background Ginseng, which is widely used in functional foods and as an herbal medicine, has been reported to reduce the proliferation of prostate cancer cells by mechanisms that are not yet fully understood. Methods This study was designed to investigate the changes in ginsenoside content in ginseng after treatment with a microwave-irradiation thermal process and to verify the anticancer effects of the extracts. To confirm the anticancer effect of microwave-irradiated processed ginseng (MG), it was tested in three human prostate cancer cell lines (DU145, LNCaP, and PC-3 cells). Involvements of apoptosis and autophagy were assessed using Western blotting. Results After microwave treatment, the content of ginsenosides Rg1, Re, Rb1, Rc, Rb2, and Rd in the extracts decreased, whereas the content of ginsenosides 20(S)-Rg3, 20(R)-Rg3, Rk1, and Rg5 increased. Antiproliferation results for the human cancer cell lines treated with ginseng extracts indicate that PC-3 cells treated with MG showed the highest activity with an half maximal inhibitory concentration of 48 μg/mL. We also showed that MG suppresses the growth of human prostate cancer cell xenografts in athymic nude mice as an in vivo model. This growth suppression by MG is associated with the inductions of cell death and autophagy. Conclusion Therefore, heat processing by microwave irradiation is a useful method to enhance the anticancer effect of ginseng by increasing the content of ginsenosides Rg3, Rg5, and Rk1.

Total synthesis and dual PPARα/γ agonist effects of amorphastilbol and its synthetic derivatives.

Amorphastilbol (APH-1), isolated from a Robinia pseudoacacia var. umbraculifer [corrected] seed extract, is a biologically interesting natural trans-stilbene compound with dual peroxisome proliferator-activated receptor (PPAR) α/γ agonist activity. After total synthesis of APH-1 and its derivatives by Pd-catalyzed Suzuki-Miyaura cross-coupling of a common (E)-styryl bromide intermediate and various aromatic trifluoroborate compounds, we biologically evaluated APH-2-APH-12 for PPAR agonist activity. APH-4 and APH-11 were effective PPARα/γ transcriptional activators, compared with APH-1. Therefore, we suggest that APH-4 and APH-11 are novel dual PPARα/γ agonists and are potentially useful for treating type 2 diabetes by enhancing glucose and lipid metabolism.

Anti-Human Rhinoviral Activity of Polybromocatechol Compounds Isolated from the Rhodophyta, Neorhodomela aculeata

An extract of the red alga, Neorhodomela aculeata, exhibited antiviral activity against human rhinoviruses. Bioassay-guided purification was performed to yield six compounds, which were subsequently identified as lanosol (1) and five polybromocatechols (2–6) by spectroscopic methods, including 1D and 2D NMR and mass spectrometric analyses. Structurally, all of these compounds, except compound 5, contain one or two 2,3-dibromo-4,5-dihydroxyphenyl moieties. In a biological activity assay, compound 1 was found to possess antiviral activity with a 50% inhibitory concentration (IC50) of 2.50 μg/mL against HRV2. Compound 3 showed anti-HRV2 activity, with an IC50 of 7.11 μg/mL, and anti-HRV3 activity, with an IC50 of 4.69 μg/mL, without demonstrable cytotoxicity at a concentration of 20 μg/mL. Collectively, the results suggest that compounds 1 and 3 are candidates for novel therapeutics against two different groups of human rhinovirus.

Effect of Amino Acids on the Generation of Ginsenoside Rg3 Epimers by Heat Processing and the Anticancer Activities of Epimers in A2780 Human Ovarian Cancer Cells

Ginsenosides are the active components of Panax ginseng. Many research studies indicate that these deglycosylated, less-polar ginsenosides have better bioactivity than the major ginsenosides. In the present study, we sought to verify the enhanced anticancer effect of P. ginseng extract after undergoing the Maillard reaction as well as elucidate the underlying mechanism of action. The effects of 9 amino acids were tested; among them, the content of 20(S)-Rg3 in the ginseng extract increased to more than 30, 20, and 20% when processed with valine, arginine, and alanine, respectively, compared with that after normal heat processing. The ginseng extract that was heat-processed with arginine exhibited the most potent inhibitory effect on A2780 ovarian cancer cell proliferation. Therefore, the generation of 20(S)-Rg3 was suggested to be involved in this effect. Moreover, the inhibitory effect of 20(S)-Rg3 on A2780 cell proliferation was significantly stronger than that of 20(R)-Rg3. Protein expression levels of cleaved caspase-3, caspase-8, caspase-9, and PARP in the A2780 ovarian cancer cells markedly increased, whereas the expression of BID decreased after 20(S)-Rg3 treatment. Therefore, we confirmed that the anticancer effects of the products of ginseng that was heat-processed with arginine are mediated mainly via the generation of the less-polar ginsenoside 20(S)-Rg3.

Important role of Maillard reaction in the protective effect of heat-processed ginsenoside Re-serine mixture against cisplatin-induced nephrotoxicity in LLC-PK1 cells

The aim of the present study was to verify the important role of Maillard reaction in the protective effect of heat-processed ginsenoside Re-serine mixture against oxidative stress-induced nephrotoxicity. The free radical-scavenging activity of ginsenoside Re-serine mixture was increased by heat-processing. Ginsenoside Re was transformed into less-polar ginsenosides such as Rg(2), Rg(6) and F(4) by heat-processing, and the glucose molecule at carbon-20 was separated. The improved-free radical-scavenging activity by heat-processing was mediated by the generation of antioxidant Maillard reaction products (MRPs) from the reaction of glucose with serine. Moreover, MRPs from ginsenoside Re-serine mixture showed protective effect against cisplatin-induced renal epithelial cell damage.

Renoprotective effects of Maillard reaction products generated during heat treatment of ginsenoside Re with leucine

The structural change of ginsenoside and the generation of Maillard reaction products (MRPs) are important to the increase in the biological activities of Panax ginseng. This study was carried out to identify the renoprotective active component of P. ginseng using the Maillard reaction model experiment with ginsenoside Re and leucine. Ginsenoside Re was gradually converted into less-polar ginsenosides Rg2, Rg6 and F4 by heat-processing, followed by separation of the glucosyl moiety at carbon-20. The free radical-scavenging activity of the ginsenoside Re-leucine mixture was increased by heat-processing. The improved free radical-scavenging activity by heat-processing was mediated by the generation of MRPs from the reaction of glucose and leucine. The cisplatin-induced LLC-PK1 renal cell damage was also significantly reduced by treatment with MRPs. Moreover, the heat-processed glucose-leucine mixture (major MRPs from the ginsenoside Re-leucine mixture) showed protective effects against cisplatin-induced oxidative renal damage in rats through the inhibition of caspase-3 activation.

Stimulation of Innate Immune Function by Panax ginseng after Heat Processing

Panax ginseng Meyer has been used for the treatment of immune diseases and for strengthening the immune function. In this study, we evaluated the innate immune-stimulating functions and action mechanisms of white ginseng (WG) and heat-processed ginseng (HPG) in RAW264.7 cells. According to LC-MS analysis results, WG contained typical ginsenosides, such as Rb1, Rc, Rb2, Rd, and Rg1, whereas HPG contained Rg3, Rk1, and Rg5 as well as typical ginsenosides. HPG, not WG, enhanced NF-κB transcriptional activity, cytokine production (IL-6 and TNF-α), and MHC class I and II expression in RAW264.7 cells. In addition, HPG phosphorylated MAPKs and NF-kB pathways. In experiments with inhibitors, the ERK inhibitor completely suppressed the effect of HPG on IL-6 and TNF-α production. HPG-induced c-Jun activation was suppressed by an ERK inhibitor and partially suppressed by JNK, p38, and IκBα inhibitors. Collectively, these results suggested that HPG containing Rg3, Rg5, and Rk1 increased macrophage activation which was regulated by the ERK/c-Jun pathway in RAW264.7 cells.

Renoprotective Effects of Hypoxylonol C and F Isolated from Hypoxylon truncatum against Cisplatin-Induced Cytotoxicity in LLC-PK1 Cells

Although cisplatin is the standard platinum-based anticancer drug used to treat various solid tumors, it can cause damage in normal kidney cells. Protective strategies against cisplatin-induced nephrotoxicity are, therefore, clinically important and urgently required. To address this challenge, we investigated the renoprotective effects of Hypoxylon truncatum, a ball-shaped wood-rotting fungus. Chemical investigation of the active fraction from the methanol extract of H. truncatum resulted in the isolation and identification of the renoprotective compounds, hypoxylonol C and F, which ameliorated cisplatin-induced nephrotoxicity to approximately 80% of the control value at 5 μM. The mechanism of this effect was further investigated using hypoxylonol F, which showed a protective effect at the lowest concentration. Upregulated phosphorylation of p38, extracellular signal-regulated kinases, and c-Jun N-terminal kinases following cisplatin treatment were markedly decreased after pre-treatment with hypoxylonol F. In addition, the protein expression level of cleaved caspase-3 was significantly reduced after co-treatment with hypoxylonol F. These results show that blocking the mitogen-activated protein kinase signaling cascade plays a critical role in mediating the renoprotective effect of hypoxylonol F isolated from H. truncatum fruiting bodies.