Dieckol is a natural positive allosteric modulator of GABAA-benzodiazepine receptors and enhances inhibitory synaptic activity in cultured neurons.

Phlorotannin supplement (PS) is a natural hypnotic substrate that modulates γ-aminobutyric acid type A (GABAA)-benzodiazepine (BZD) receptors. However, there is a lack of functional data assessing the role of individual components of PS, such as Dieckol, as allosteric activators of GABAA receptors (GABAAR). Using the whole cell patch clamp technique, we demonstrated that PS functionally enhanced the activity of GABAA-BZD receptors in a heterologous system and in primary cultured neurons. Application of diazepam (DZP) or Dieckol (1) increased GABAAR-mediated inward current in HEK293T cells containing the α1 subunit in a dose-dependent manner, (2) which was blocked by co-treatment with the selective benzodiazepine site antagonist, flumazenil (FLZ); it also (3) increased the amplitude of GABAA-BZD receptors in primary cultured neurons, which was blocked by FLZ and (4) attenuated spontaneous activity in cultured neurons. These results indicate that PS and Dieckol act as positive allosteric activators of GABAA-BZD receptors, which might be the underlying mechanism of the sedative-hypnotic effect of PS. To our knowledge, this is the first study to directly link Dieckol-induced GABAAR activation via the BZD site binding and suppression of spontaneous neuronal activity in vitro.

Anti-Fatigue Effect of Prunus Mume Vinegar in High-Intensity Exercised Rats.

Nowadays, new types of vinegar have been developed using various raw materials and biotechnological processes. The fruit of Prunus mume has been extensively distributed in East Asia and used as a folk medication for fatigue. In this study, the Prunus mume vinegar (PV) was produced by a two-step fermentation and was evaluated for its anti-fatigue activity by C2C12 myoblasts and high-intensity exercised rats. The administration of PV significantly improved running endurance and glycogen accumulation in the liver and muscle of PV supplemented rats compared to sedentary and exercised control groups. In addition, PV supplementation elicited lower fatigue-related serum biomarkers, for instance, ammonia, inorganic phosphate, and lactate. PV administered rats exhibited higher lactate dehydrogenase activity and glutathione peroxidase activity, and lower creatine kinase activity and malondialdehyde levels. Furthermore, phenolic compounds in PV were identified using HPLC analysis. The phenolic acids analyzed in PV were protocatechuic acid, syringic acid, chlorogenic acid, and its derivates. These results indicate that the administration of PV with antioxidative property contributes to the improvement of fatigue recovery in exhausted rats. The findings of this study suggest that the PV containing various bioactive constituents can be used as a functional material against fatigue caused by high-intensity exercise.

Protective Effect of Prunus mume Fermented with Mixed Lactic Acid Bacteria in Dextran Sodium Sulfate-Induced Colitis.

The fruit of Prunus mume (PM) is widely cultivated in East Asia, and it has been used as a folk medication for gastrointestinal disorders, e.g., diarrhea, stomach ache and ulceration. In this study, the pectinase-treated PM juice (PJ) was fermented with Lactobacillus strains containing fundamental organic acids and free amino acids. The PJ fermented with Lactobacillus plantarum and L. casei (FP) was investigated for its protective effect in dextran sodium sulfate (DSS)-induced colitis mice model. The administration of FP reduced lipid peroxidation and histopathological colitis symptoms, e.g., shortening of the colon length, depletion of mucin, epithelial injury and ulceration, in colonic tissues. The FP-supplemented group showed the alleviation of pro-inflammatory cytokines. Compared with the DSS control group, the supplementation of FP significantly reduced the levels of serum interferon-γ (IFN-γ), interleukin (IL)-1ß, IL-6, IL-12 and IL-17 as well as colonic tumor necrosis factor-α, IFN-γ, IL-12 and IL-17. Furthermore, the DSS-induced TUNEL-positive area was significantly reduced by the FP supplementation. These results show that the supplementation of FP fermented with mixed lactic acid bacteria, L. plantarum and L. casei, elucidated the protective effect in DSS-induced colitis mice. Hence, this study suggests that FP can be utilized as a natural therapeutic agent for colitis and intestinal inflammation.

A Standardized Phlorotannin Supplement Attenuates Caffeine-Induced Sleep Disruption in Mice.

In our previous studies, a standardized phlorotannin (brown seaweed polyphenol) supplement (PS) exhibited sleep-promoting effects via type A γ-aminobutyric acid-benzodiazepine receptors in mice. In addition, in human clinical trials, it decreased wake after sleep onset in adults with sleep disturbance. In this follow-up study, we investigated whether PS attenuates caffeine-induced sleep disruption in mice. The effects of PS were evaluated in a caffeine model by analyzing sleep architecture based on electroencephalogram and electromyogram findings, and were compared with the effects of a well-known sedative-hypnotic drug zolpidem (ZPD). As expected, oral administration of caffeine (25 mg/kg) significantly increased sleep latency and decreased the amount of non-rapid eye movement sleep (NREMS). In the caffeine + PS and caffeine + ZPD groups, PS (500 mg/kg) attenuated caffeine-induced sleep disruption, and its effects were comparable with those of ZPD (10 mg/kg). In particular, PS inhibited the arousal effects of caffeine without change in delta activity during NREMS, whereas ZPD produced a decrease in the delta activity. Considering global trends in coffee and energy drink consumption, our finding suggest that PS may be useful to relieve transitory insomnia symptoms caused by caffeine consumption, unlike the prescription drug ZPD.

Auriculasin-induced ROS causes prostate cancer cell death via induction of apoptosis.

Recent studies have demonstrated that natural agents targeting the accumulation of reactive oxygen species (ROS) that selectively kill, leaving normal cells undamaged, can suppress prostate cancer. Here, we show that auriculasin, derived from Flemingia philippinensis, induces significant cell death and apoptosis via ROS generation in prostate cancer cells. Auriculasin treatment resulted in selective apoptotic cell death in LNCaP prostate cancer cells, characterized by DNA fragmentation, accumulation of sub-G1 cell population, cleavage of poly (ADP-ribose) polymerase (PARP), regulation of Bax/Bcl-2 ratio, increase of cytosolic apoptosis-inducing factor (AIF) and endonuclease G (EndoG), in addition to inhibiting tumor growth in a xenograft mouse model. Interestingly, auriculasin-induced apoptosis did not result in caspase-3, -8, and -9 activations. We found that auriculasin treatment decreased phosphorylation of AKT/mTOR/p70s6k in a dose- and time-dependent manner. Further, cellular ROS levels increased in LNCaP cells treated with auriculasin and blocking ROS accumulation with ROS scavengers resulted in inhibition of auriculasin-induced PARP cleavage, AIF increase, upregulation of Bax/Bcl-2 ratio, and decrease in AKT/mTOR phosphorylation. Taken together, these data suggest that auriculasin targets ROS-mediated caspase-independent pathways and suppresses PI3K/AKT/mTOR signaling, which leads to apoptosis and decreased tumor growth.

Browning control of fresh-cut lettuce by phytoncide treatment.

Phytoncide essential oil derived from pine leaves was applied for the control of enzymatic browning of fresh-cut lettuce. Changes in the browning characteristics of cut lettuce treated with phytoncide in an water or ethanol solution (1%, v/v) at 10°C were investigated for 12days at 4°C. Other samples dipped in distilled water or 95% ethanol were used as the controls. The samples treated with phytoncide in an ethanol solution showed significantly higher L* values and lower a* values, ΔE values, browning index, phenolic compounds, and enzyme activities (PPO, POD, PAL) related to browning. The samples dipped in distilled water showed the opposite tendency. On the basis of changes in the browning characteristics, anti-browning effects of each treatment, phytoncide in an ethanol solution was the most effective treatment applied. These results suggest that phytoncide treatment could be used as an effective method for controlling enzymatic browning in fresh-cut lettuce.

Seed viability and functional properties of broccoli sprouts during germination and postharvest storage as affected by irradiation of seeds.

The viability of broccoli seeds and functional properties, such as ascorbic acid, carotenoid, chlorophyll, and total phenol contents, of broccoli sprouts grown from irradiated seeds were evaluated. The seeds were irradiated using electron beam and gamma ray at doses up to 8 kGy. High germination percentages (>90%) were observed in seeds irradiated at < or =4 kGy, but the yield ratio and sprout length decreased with increased irradiation dose. Irradiation at > or =6 kGy resulted in curling of the sprout roots. Germinated seeds contained higher amounts of nutrients than raw seeds but the nutritional quality of sprouts decreased during postharvest storage. Radiation treatment hampered the growth of irradiated seeds resulting in underdeveloped sprouts with decreased ascorbic acid, carotenoid, and chlorophyll contents. In addition, the decrease in functional content of sprouts was more substantial in samples grown from high-dose (5 kGy) irradiated seeds than that of the low-dose (1 kGy) treated ones. Seed irradiation did not negatively affect the total phenol content of sprouts. In general, electron beam and gamma irradiation of broccoli seeds showed similar effects on the viability and functional properties of sprouts.

Supplementation of SK1 from Platycodi radix ameliorates obesity and glucose intolerance in mice fed a high-fat diet.

This study investigated the beneficial effects of SK1 on obesity and insulin resistance in C57BL/6 mice, which were fed a high-fat diet (37% calories from fat). SK1 is an edible saponin-rich compound from Platycodi radix. The mice were supplemented with two doses of SK1 (0.5% and 1.0%, wt/wt) for 9 weeks. The body weight, visceral fat mass, and adipocyte area were significantly decreased in the SK1 supplemented-groups in a dose-dependent manner compared to the high-fat group. The SK1 supplement significantly lowered plasma triglycerides, total cholesterol, and free fatty acid levels, whereas it significantly elevated the fecal excretion of lipids in the diet-induced obese mice. Supplementation of SK1 decreased the triglyceride and cholesterol levels and the accumulation of lipid droplets in the liver compared to the high-fat control group. High-fat diet induced glucose intolerance and insulin resistance with the elevation of blood glucose levels compared to the normal group; however, the SK1 supplement significantly improved postprandial glucose levels and insulin resistance index. After 9 weeks of being fed a high-fat diet, the mice presented with significantly increased activities of hepatic fatty acid synthase, fatty acid beta-oxidation, and glucokinase; however, both 0.5% and 1.0% SK1 supplementation normalized these activities. Notably, SK1 supplementation effectively diminished the ratio of fatty acid biosynthesis to fatty acid oxidation compared to the high-fat group. These results indicate that SK1 exhibits a potential anti-obesity effect and may prevent glucose intolerance by reducing body weight and fat accumulation, increasing fecal lipid excretions, and regulating hepatic lipid and glucose metabolism in high-fat fed mice.

Beneficial effect of chungkukjang on regulating blood glucose and pancreatic beta-cell functions in C75BL/KsJ-db/db mice.

The current study investigated the antidiabetic effect of chungkukjang, a widely used traditional Korean soybean fermentation food, in a type 2 diabetic animal model, C57BL/KsJ-db/db mice. After a 2-week acclimation period, the db/db mice (male, 5 weeks old) were divided into three groups: diabetic control (AIN-76 diet), chungkukjang (5 g/100 g of diet), and rosiglitazone (0.005 g/100 g of diet). The supplementation of chungkukjang induced a significant reduction of blood glucose and glycosylated hemoglobin level, and it improved insulin tolerance compared to the diabetic control group. Plasma and pancreatic insulin levels of the chungkukjang-supplemented group were significantly higher than those of the diabetic control mice, and the plasma glucagon level was also significantly different. The supplementation of chungkukjang and rosiglitazone significantly elevated hepatic glucokinase activity with a simultaneous reduction of glucose-6-phosphatase and phosphoenolpyruvate carboxykinase activity in the db/db mice compared to the diabetic control mice. In addition, the chungkukjang-supplemented group had an increased hepatic glycogen content compared to the diabetic control and rosiglitazone-supplemented groups. Consequently, these results suggest that chungkukjang may be beneficial in improving insulin resistance and hyperglycemia in type 2 diabetic animals that are partly medicated by the regulation of hepatic glucose enzymes and insulin sensitivity in peripheral tissues.

Ether fraction of methanol extracts of Gastrodia elata, medicinal herb protects against neuronal cell damage after transient global ischemia in gerbils.

Gastrodia elata (GE), a medicinal herb, has been used traditionally for the treatment of convulsive diseases such as epilepsy in oriental countries including South Korea and still occupies an important place in traditional medicine in Asia. We designed this study to examine whether the ether fraction of methanol extracts (EFME) of GE protects the hippocampal neuronal damage induced by transient global ischemia in a gerbil model. Gerbils were treated with the EFME of GE (200 or 500 mg/kg per day, p.o.) for 14 days before brain ischemia. The lower dose of EFME of GE failed to attenuate the hippocampal neuronal damage in the CA1 region. However, the higher dose of EFME of GE attenuated the hippocampal neuronal damage in the CA1 region. The present results show that the EFME of GE has a protective effect against neuronal damage following global ischemia in gerbils.

Ethyl ether fraction of Gastrodia elata Blume protects amyloid beta peptide-induced cell death.

Alzheimer's disease is the most common cause of dementia in the elderly. Recently, it has been reported that Alzheimer's disease is associated with cell death in neuronal cells including the hippocampus. Amyloid beta-peptide stimulates neuronal cell death, but the underlying signaling pathways are poorly understood. In order to develop anti-dementia agents with potential therapeutic value, we examined the effect of the herbal compound Gastrodia elata Blume (GEB) on neuronal cell death induced by amyloid beta-peptide in IMR-32 neuroblastoma cells. The fractionation of GEB was carried out in various solvents. The hydroxyl radical scavenging effect of the ethyl ether fraction was more potent than any other fractions. In cells treated with amyloid beta-peptide, the neuroprotective effect of the ethyl ether, chloroform, and butanol fractions was 92, 44, and 39%, respectively, compared with control. Taken together, these results suggest that the ethyl ether fraction of GEB contains one or more compounds that dramatically reduce amyloid beta-peptide induced neuronal cell death in vitro.