Mee-Sook Lee

Kidney bean husk extracts exert antitumor effect by inducing apoptosis involving AMP-activated protein kinase signaling pathway.

In this study, we investigated the molecular basis of Korean kidney bean husk extract, with emphasis on its ability to control intracellular signaling cascades of AMP‐activated protein kinase (AMPK) responsible for inducing antitumor activities in colon cancer cells. Recently, the evolutionarily conserved serine/threonine kinase, AMPK, has emerged as a possible target molecule of tumor control. We investigated the effects of Korean kidney bean husk extract on apoptosis regulation and the activation of AMPK. Korean kidney bean husk extract exhibited a series of antitumor effects such as cell death and apoptotic body appearance. These antitumor potentials were accompanied by the increase in p‐AMPK and p‐Acc as well as antitumor proteins p53 and p21. The stimulation of AMPK by this extract was blocked with the synthetic AMPK inhibitor Compound C at 10 μmol/L, and the combined treatment of Compound C and the AMPK activator AICAR (5‐aminoimiazole‐4‐carboxamide‐1‐β‐d‐ribofuranoside) showed that Compound C could inhibit the activation of AMPK at the concentration of 20 μmol/L. In conclusion, the ability of carcinogenesis control by Korean kidney bean husk extract with high potency suggests its value as an antitumor agent in colon cancer therapy.

Effects of Cotreatment of 12‐O‐tetradecanoylphorbol‐13‐acetate and H2O2 on Apoptotic Regulation via AMP‐Activated Protein Kinase–Cyclooxygenase‐2 Signals

Colorectal cancer displays elevated cyclooxygenase‐2 (COX‐2) expression, and several studies have suggested that COX‐2 expression is associated with parameters of aggressive colon cancer. AMP‐activated protein kinase (AMPK) is a sensor of cellular energy status, and recent studies indicate that AMPK activation strongly suppresses cell proliferation in nonmalignant cells as well as in tumor cells. As a metabolic sensing signal, AMPK is involved in cancer cell apoptosis. In HT‐29 colon cancer cells, the regulation of COX‐2 expression by treating with TPA (12‐O‐tetradecanoylphorbol‐13‐acetate), low‐level H2O2, high‐level H2O2, and finally the combinations of TPA and low H2O2 or high H2O2 was investigated. We found that COX‐2 expression levels with treatment reacted as follows: with TPA alone > TPA and low H2O2 > low H2O2 > high H2O2 > TPA and high H2O2. COX‐2 regulation by these agents was accompanied by the alteration of AMPK control. The apoptotic bodies were detected as follows: high level of H2O2 > TPA > low level of H2O2. The present findings suggest that both COX‐2 stimulators (TPA and H2O2) might have differential effects on COX‐2 and AMPK regulation and further apoptotic regulation.

Analysis of Traditional Korean Food Patterns According to the Healthy Longevity Diet Based on the Database of Favorite Korean Foods

The traditional Korean diet is reevaluated as the healthy longevity diet, because it is nutritionally balanced and contains less fat and more complex carbohydrates and fiber than the Western diet. In the traditional Korean diet, energy from cereals is 55– 60% of total energy, while that from fat energy is 15–20%, and the ratio of the weight of vegetables/meat and fish is over 2. The traditional Korean diet is largely composed of two parts: Joo-sik (staple foods), and Boo-sik (dishes), which in turn is composed of Joo-chan (main dishes) and Boo-chan (side dishes). Joo-sik is boiled rice, the main source of carbohydrates, with some barley, beans, peas, millet, and red beans. Joo-chan consists of meat, fish, eggs, beans, and their products as the sources of protein. Boo-chan contains vegetables, mushrooms, or seaweed as the sources of minerals and vitamins. Besides, soup and Kimchi are always served basically. Soup is made with various vegetables, seaweeds, meat, shellfish, or bone. Especially soybean paste and tofu, which contain saponin, isoflavone, and other active substances, are widely used for soup. The favorite fish are mackeral, soury, and herring, which supply w-3 fatty acids and conjugated linoleic acid. Especially, Kimchi, standing for a group of fermented vegetables enriched with fiber, vitamins, minerals, antioxidants, lactobacillus, and some unknown substances, is reported to have hypolipidemic, anticancer, antimutagenic, microbial, growth inhibitory, and plateletaggregation inhibitory effects. Garlic, green pepper, ginger, sesame seeds and oil, and the perilla seeds and oil are usually used as seasonings. Based on these data, it is suggested that the traditional Korean diet helps to prevent obesity, cardiovascular disease, cancer, and degenerative diseases, which are the major causes of mortality and morbidity in the elderly.

Effects of long-term supplementation of policosanol on blood cholesterol/glucose levels and 3-hydroxy-3-methylglutaryl coenzyme a reductase activity in a rat model fed high cholesterol diets

Policosanol is a well-defined nutraceutical for the management of blood cholesterol levels. The present study examined (i) the effect of policosanol supplementation on blood cholesterol and glucose levels and (ii) changes in hepatic cholesterol biosynthesis using 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMG-CoA reductase) activity in Wistar rats fed high cholesterol diets. The Wistar rats were assigned randomly to high-cholesterol diets (1.25% cholesterol) with or without policosanol (8.0 mg/kg body weight) for 6 weeks. Compared with the control group, dietary treatment with policosanol resulted in a significant decrease of blood cholesterol (p<0.01), blood glucose (p<0.01), triglyceride (p<0.001), and low density lipoprotein-cholesterol levels (p<0.01) and HMG-CoA reductase activity (p<0.001) in the liver. These results indicate that policosanol decreases blood cholesterol levels by suppressing cholesterol biosynthesis via decrease of HMG-CoA activity. Policosanol has the potential to be developed into an effective dietary strategy for both postprandial hyperglycemia and hypercholesterolemia.

Effect of supplementation of low-molecular-weight chitosan oligosaccharide, GO2KA1, on postprandial blood glucose levels in healthy individuals following bread consumption

The effect of chitosan oligosaccharide (GO2KA1) administration on postprandial blood glucose levels of subjects with normal blood glucose levels was evaluated following bread consumption. Postprandial blood glucose levels were determined for 2 h after bread ingestion with or without 500 mg of GO2KA1. GO2KA1 significantly lowered the mean, maximum, and minimum levels of postprandial blood glucose at 30 min after the meal. Postprandial blood glucose levels were decreased by about 25% (from 155.11±13.06 to 138.50±13.59, p<0.01) at 30 min when compared to control. Furthermore, we observed that the area under the concentration-time curve (AUCt) was decreased by about 6% (from 255.46±15.43 to 240.15±14.22, p<0.05) and the peak concentration of blood glucose (Cmax) was decreased by about 11% (from 157.94±10.90 to 140.61±12.52, p<0.01) when compared to control. However, postprandial the time to reach Cmax (Tmax) levels were the same as those found in control. Our findings suggest that GO2KA1 limits the increase in postprandial blood glucose levels following bread consumption.

Comparison of the Antimicrobial and Antioxidant Activities of Selected Wheat Varieties

Antibacterial and antioxidant activities of wheat seed ethyl acetate extracts for Jokyoung (JK), Dark northern spring (DNS), Keumkang (KK), Woori (WR), and Winter wheat (WW) were investigated. Antibacterial activities were evaluated in vitro against the common food and cosmetic industry contaminants Escherichia coli, Salmonella typhimurium, and Staphylococcus aureus using well diffusion assays. WW had the highest inhibitory activity against all tested strains, with S. aureus being the most sensitive strain. The minimum inhibitory concentration (MIC) values of WW and WR against S. aureus were 0.50 and 1.25 mg/mL, respectively. The 2,6-dimethoxy-1,4- benzoquinone (DMBQ) content was measured using HPLC. The antibacterial activities of wheat seed extracts were correlated with the total phenolic contents (Pearson’s correlation coefficient=0.994), with the ABTS radical scavenging activity (0.978), and with the DMBQ content (0.968). WW and WR have potential for use as natural antimicrobials for prevention of food and cosmetics spoilage.