Hyun Young Kim

Roasting enhances antioxidant effect of bitter melon (Momordica charantia L.) increasing in flavan-3-ol and phenolic acid contents

Bitter melon (BM, Momordica charantia L) has various biological functions including antidiabetic, anticancer, anti-inflammatory, antiviral, and antioxidant activities. In this study, the antioxidant effects of BM fruits, leaves, stems, and roots after roasting using DPPH, ABTS, reducing power, and ferric reducing/antioxidant power (FRAP) assays were compared. The roasted BM exhibited significantly higher antioxidant activity than unroasted BM in the test methods used. Particularly, the roasted BM roots showed the highest antioxidant activity compared to any other extracts. Antioxidant compounds including flavan-3-ols and phenolic acids increased, whereas flavanols decreased in the BM following roast processing. Moreover, the total phenolic contents and flavan-3-ol and phenolic acid contents were markedly increased, leading to a general increase in antioxidant activities after roasting. These results suggest that the roasting BM extracts could be used as a potential source of natural antioxidants in certain food and medicinal applications.

Increase in antioxidant and anticancer effects of ginsenoside Re–lysine mixture by Maillard reaction

Ginsenosides are the main active components of Panax ginseng. Structural changes in diol type ginsenosides along with generation of Maillard reaction products (MRPs) are strongly associated with increased free radical-scavenging activities. Ginsenoside Re, one of the major triol type ginsenosides of P. ginseng, possesses a hydrophobic four-ring steroid-like structure with hydrophilic sugar moieties at carbons-3 and -20. The aim of the present study was to identify changes in the structure, antioxidant and anticancer effects of ginsenoside Re upon Maillard reaction. Ginsenoside Re was transformed into less-polar ginsenosides, namely Rg(2), Rg(6) and F(4) by heat-processing. Free radical-scavenging activity of the ginsenoside Re-lysine mixture increased upon heat processing. This improved free radical-scavenging activity mediated by antioxidant MRPs, which were generated through Maillard reaction of a glucosyl moiety separated from carbon-20 of ginsenoside Re and lysine. The increased anticancer effect of ginsenoside Re-lysine mixture upon heat processing was mainly derived from the generation of less-polar ginsenosides through the regulation of Bcl-2 and Bax, as well as caspase-dependent apoptotic pathway. These results reported here have shed significant new lights on the mechanism of increased antioxidant and anticancer effects of P. ginseng upon heat processing.

Protective Effect of Tetrahydrocurcumin against Cisplatin-Induced Renal Damage: In Vitro and In Vivo Studies

The adverse effects of anticancer drugs can prompt patients to end their treatment despite the efficacy. Cisplatin is a platinum-based molecule widely used to treat various forms of cancer, but frequent and long-term use of cisplatin is limited due to severe nephrotoxicity. In the present study, we investigated the protective effect and mechanism of tetrahydrocurcumin on cisplatin-induced kidney damage, oxidative stress, and inflammation to evaluate its possible use in renal damage. Cisplatin-induced LLC-PK1 renal cell damage was significantly reduced by tetrahydrocurcumin treatment. Additionally, the protective effect of tetrahydrocurcumin on cisplatin-induced oxidative renal damage was investigated in rats. Tetrahydrocurcumin was orally administered every day at a dose of 80 mg/kg body weight for ten days, and a single dose of cisplatin was administered intraperitoneally (7.5 mg/kg body weight) in 0.9 % saline on day four. The creatinine clearance levels, which were markers of renal dysfunction, in cisplatin-treated rats were recovered nearly back to normal levels after administration of tetrahydrocurcumin. Moreover, tetrahydrocurcumin exhibited protective effects against cisplatin-induced oxidative renal damage in rats by inhibiting cyclooxygenase-2 and caspase-3 activation. These results collectively provide therapeutic evidence that tetrahydrocurcumin ameliorates renal damage by regulating inflammation and apoptosis.

Polysaccharides from Korean Citrus hallabong peels inhibit angiogenesis and breast cancer cell migration

Although the peel of the hallabong (Citrus sphaerocarpa) fruit is rich in polysaccharides, which are valuable dietary ingredients for human health, it is normally wasted. The present study aimed to utilize the peel waste and identify properties it may have against breast cancer metastasis. Hallabong peel extract containing crude polysaccharides was fractionated by gel permeation chromatography to produce four different polysaccharide fractions (HBE-I, -II, -III, and -IV). The HBE polysaccharides significantly blocked tube formation of human umbilical vein vascular endothelial cells (HUVECs), at a concentration of 12.5 or 25 μg/mL. Tube formation appeared to be more sensitive to HBE-II than to other HBE polysaccharides. HBE-II also inhibited breast cancer cell migration, through downregulation of matrix metalloproteinase-9 (MMP-9) in MDA-MB-231 triple-negative breast cancer cells. Therefore, inhibition of tube formation and MMP-9-mediated migration observed in HUVEC and MDA-MB-231 cells, respectively, are likely to be important therapeutic targets in triple-negative breast cancer metastasis.

Oligonol improves memory and cognition under an amyloid β25-35-induced Alzheimer's mouse model

Alzheimers disease is an age-dependent progressive neurodegenerative disorder that results in impairments of memory and cognitive function. It is hypothesized that oligonol has ameliorative effects on memory impairment and reduced cognitive functions in mice with Alzheimers disease induced by amyloid β(25-35) (Aβ(25-35)) injection. The protective effect of an oligonol against Aβ(25-35)-induced memory impairment was investigated in an in vivo Alzheimers mouse model. The aggregation of Aβ25-35 was induced by incubation at 37°C for 3 days before injection into mice brains (5 nmol/mouse), and then oligonol was orally administered at 100 and 200 mg/kg of body weight for 2 weeks. Memory and cognition were observed in T-maze, object recognition, and Morris water maze tests. The group injected with Aβ(25-35) showed impairments in both recognition and memory. However, novel object recognition and new route awareness abilities were dose dependently improved by the oral administration of oligonol. In addition, the results of the Morris water maze test indicated that oligonol exerted protective activity against cognitive impairment induced by Aβ(25-35). Furthermore, nitric oxide formation and lipid peroxidation were significantly elevated by Aβ(25-35), whereas oligonol treatment significantly decreased nitric oxide formation and lipid peroxidation in the brain, liver, and kidneys. The present results suggest that oligonol improves Aβ(25-35)-induced memory deficit and cognition impairment.

Identification of anti-cancer active components of Taraxacum coreanum on human gastric cancer AGS cells

Anti-cancer effects were compared amongst Taraxacum coreanum extract, its fractions, and 7 ingredients (β-sitosterol, daucosterol, taraxasteryl acetate, chrysoeriol, diosmetin, luteolin, and luteoloside). Exposure to the ethyl acetate fraction (50 and 100 μg/mL) of T. coreanum extract and luteolin (10 and 50 μM) for 24 h induced the cleavage of poly (ADP-ribose) polymerase (PARP), caspase-3, and caspase-8, in a dose-dependent manner. These findings demonstrate that luteolin is the main active component of T. coreanum extract activating caspases-3 and -8 which contribute to apoptotic cell death.

The Butanol Fraction of Bitter Melon (Momordica charantia) Scavenges Free Radicals and Attenuates Oxidative Stress

To investigate radical scavenging effects and protective activities of bitter melon (Momordica charantia) against oxidative stress, in vitro and a cellular system using LLC-PK1 renal epithelial cells were used in this study. The butanol (BuOH) fraction of bitter melon scavenged 63.4% and 87.1% of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals at concentrations of 250 and 500 μg/mL, respectively. In addition, the BuOH fraction of bitter melon effectively scavenged hydroxyl radicals (·OH). At all concentrations tested, the scavenging activity of the BuOH fraction was more potent than that of the positive control, ascorbic acid. Furthermore, under the LLC-PK1 cellular model, the cells showed a decline in viability and an increase in lipid peroxidation through oxidative stress induced by pyrogallol, a generator of superoxide anion (O2−). However, the BuOH fraction of bitter melon significantly and dose-dependently inhibited cytotoxicity. In addition, 3-morpholinosydnonimine (SIN-1), a generator of peroxynitrite (ONOO−) formed by simultaneous releases of nitric oxide and O2−, caused cytotoxicity in the LLC-PK1 cells while the BuOH fraction of bitter melon ameliorated oxidative damage induced by ONOO−. These results indicate that BuOH fraction of bitter melon has protective activities against oxidative damage induced by free radicals.

Protective effects of 3,4-seco-lupane type triterpenes from Acanthopanax senticosus against advanced glycation endproducts

Advanced glycation end products (AGEs) are thought to be directly involved in diabetes mellitus and aging. In this study, the protective activities of 3,4-seco-lupane type triterpenes (chiisanogenin and chiisanoside) from Acanthopanaxsenticosus against the formation of AGEs were examined using in vitro glycation reactions. Of the two isolated compounds, chiisanogenin exhibited strong inhibitory activity against the formation of AGEs. The inhibitory activity of chiisanogenin was similar level in 50 μM treatment with the AGE inhibitor aminoguanidine, which was used as a positive control. These results suggest that chiisanogenin from A. senticosus is a bioactive component that contributes to glycation-associated diseases.

The protective activity of linear furanocoumarins from Angelica dahurica against glucose-mediated protein damage

Advanced glycation end products (AGEs) are known to be directly involved in diabetes mellitus and aging. Therefore, protective activities of isoimperatorin, imperatorin, byakangelicin, and oxypeucedanin hydrate from Angelica dahurica on the formation of AGEs were examined using an in vitro glycation reaction. Isoimperatorin showed strong inhibitory activity against the formation of AGEs. The inhibitory activity of isoimperatorin was more potent than that of the positive control, aminoguanidine. These results suggest that isoimperatorin from A. dahurica may be a promising agent for the treatment of glycation-associated diseases.

Beneficial effects of a medicinal herb, Cirsium japonicum var. maackii, extract and its major component, cirsimaritin on breast cancer metastasis in MDA-MB-231 breast cancer cells

The biological activities of the ethanol extract from Cirsium japonicum var. maackii (ICF-1) and its major component, polyphenol cirsimaritin, were investigated as part of the search for possible alternative drugs for breast cancer. Three in vitro cell-based assays were used: the cell proliferation assay, tube-formation assay, and Western blot analysis. Both the ICF-1 extract and cirsimaritin inhibited the viability of HUVECs in a dose-dependent manner. The inhibition achieved was 36.89% at a level of 200μg/ml by the ICF-1 extract and 62.04% at a level of 100μM by cirsimaritin. The ICF-1 extract and cirsimaritin reduced tube formation by 12.69% at level of 25μg/ml and 32.18% at the levels of 6.25μM, respectively. Cirsimaritin inhibited angiogenesis by downregulation of VEGF, p-Akt and p-ERK in MDA-MB-231 cells, suggesting that cirsimaritin is potentially useful as an anti-metastatic agent. The present study demonstrated that Cirsium japonicum extract and its active component cirsimaritin is an excellent candidate as an alternative anti-breast cancer drug.