Anticancer effects of kimchi fermented for different times and with added ingredients in human HT-29 colon cancer cells

Fermented Vegetables: Health Benefits, Defects, and Current Technological Solutions

This review summarizes current studies on fermented vegetables, analyzing the changes in nutritional components during pickling, the health benefits of fermented vegetables, and their safety concerns. Additionally, the review provides an overview of the applications of emergent non-thermal technologies for addressing these safety concerns during the production and processing of fermented vegetables. It was found that vitamin C would commonly be lost, the soluble protein would degrade into free amino acids, new nutrient compositions would be produced, and the flavor correlated with the chemical changes. These changes would be influenced by the variety/location of raw materials, the original bacterial population, starter cultures, fermentation conditions, seasoning additions, and post-fermentation processing. Consuming fermented vegetables benefits human health, including antibacterial effects, regulating intestinal bacterial populations, and promoting health (anti-cancer effects, anti-diabetes effects, and immune regulation). However, fermented vegetables have chemical and biological safety concerns, such as biogenic amines and the formation of nitrites, as well as the existence of pathogenic microorganisms. To reduce hazardous components and control the quality of fermented vegetables, unique starter cultures, high pressure, ultrasound, cold plasma, photodynamic, and other technologies can be used to solve these problems.

Molecular Mechanism of L-Pyroglutamic Acid Interaction with the Human Sour Receptor

Taste is classified into five types, each of which has evolved to play its respective role in mammalian survival. Sour taste is one of the important ways to judge whether food has gone bad, and the sour taste receptor (PKD2L1) is the gene behind it. Here, we investigated whether L-pyroglutamic acid interacts with sour taste receptors through electrophysiology and mutation experiments using Xenopus oocytes. R299 of hPKD2L1 was revealed to be involved in L-pyroglutamic acid binding in a concentration-dependent manner. As a result, it is possible to objectify the change in signal intensity according to the concentration of L-pyroglutamic acid, an active ingredient involved in the taste of kimchi, at the molecular level. Since the taste of other ingredients can also be measured with the method used in this experiment, it is expected that an objective database of taste can be created.

Rapid Quantitative Analysis of Metabolites in Kimchi Using LC-Q-Orbitrap MS

Kimchi is a traditional Korean salted spontaneous lactic acid bacteria (LAB)-fermented food made using various vegetables. Organic acids, free sugars, and amino acids are key metabolites produced during LAB fermentation that determine the taste and quality of kimchi. However, each metabolite is typically analyzed using an independent analytical method, which is time-consuming and expensive. Therefore, in this study, we developed a method based on LC-Q-Orbitrap MS using which 20 types of representative fermented kimchi metabolites were selected and simultaneously analyzed within 10 min. The established method was validated, and its detection and quantification limits, linearity, precision, and accuracy were found to satisfy the Association of Official Agricultural Chemists (AOAC) validation guidelines. The 20 metabolites were simultaneously extracted from kimchi with different degrees of fermentation and quantitatively analyzed using LC-Q-Orbitrap MS. These results were analyzed using linear discriminant analysis and heat mapping, and the metabolites were grouped into early, middle, and late stages of fermentation. Malic acid (6.518-7.701 mMol) was only present in the initial stage of fermentation, and l-phenylalanine rapidly increased from the middle stage (2.180 mMol) to late stage (4.770 mMol). Lactic acid, which is representative of the sour taste of kimchi, was detected in the middle stage and increased rapidly up to 74.452 mMol in the late stage. In summary, in this study, 20 major kimchi metabolites were accurately analyzed within 10 min and grouped based on the degree of fermentation. Therefore, the method established in this study accurately and rapidly provides information on kimchi consumption and fermentation that could be highly valuable to the kimchi industry and kimchi consumers.

Kimchi markedly induces apoptosis in HT-29 human colon carcinoma cells

This study investigated kimchi-induced apoptosis in HT-29 human colon carcinoma cells. Three types of kimchi samples were prepared: standardized kimchi brined with general commercial Baechu cabbage by a standardized recipe (SK), Amtak Baechu kimchi brined with Amtak Baechu cabbage by a standardized recipe (AmK), and anticancer kimchi brined with organically cultivated Baechu cabbage by a functional recipe (AK). MTT assay, qRT-PCR, and Western blotting analysis were performed. The results indicate that AmK and AK, especially AK significantly upregulated mRNA expression of apoptosis-related genes Bim, Bax, Bak, caspase-8, -9, -3, and p53 but suppressed Bcl-xL and Bcl-2 expression. In addition, AK treatment significantly upregulated protein expression levels of caspase-3 but strikingly reduced the protein expression level of Bcl-2 (p < .05), followed by AmK treatment. Our data suggest that AK and AmK can markedly suppress the proliferation of HT-29 cells via activation of apoptosis. PRACTICAL APPLICATIONS: Colon cancer is the fourth cancer with the highest incidence in the world. Cell apoptosis is a type of programmed cell death and plays an important role in the cancer cells study. Kimchi is a traditional fermented food in Korea, with a relatively high daily consumption. Our present study used three kinds of kimchi which prepared with different main ingredients and recipes. The results suggest that organically cultivated Baechu cabbage and functional recipe in kimchi preparation play an important role in the anticancer efficacy of kimchi, which has been shown to promote induction of apoptosis in HT-29 cells.

Probiotic Properties and Neuroprotective Effects of Lactobacillus buchneri KU200793 Isolated from Korean Fermented Foods

The purpose of this study was to evaluate the probiotic characteristics and neuroprotective effects of bacteria isolated from Korean fermented foods. Three bacterial strains (Lactobacillus fermentum KU200060, Lactobacillus delbrueckii KU200171, and Lactobacillus buchneri KU200793) showed potential probiotic properties, such as high tolerance against artificial gastric juice and bile salts, sensitivity to antibiotics, nonproduction of carcinogenic enzymes, and high adhesion to intestinal cells. Heat-killed L. fermentum KU200060 and L. buchneri KU200793 showed higher antioxidant activity than heat-killed L. delbrueckii KU200171. The conditioned medium (CM) was used to evaluate the reaction between HT-29 cells and each heat-killed strain. All CMs protected SH-SY5Y cells from 1-methyl-4-phenylpyridinium (MPP⁺)-induced toxicity. The expression of brain-derived neurotropic factor (BDNF) mRNA in HT-29 cells treated with CM containing heat-killed L. buchneri KU200793 was the highest. The CM significantly reduced the Bax/Bcl-2 ratio and increased BDNF mRNA expression in SH-SY5Y cells treated with MPP⁺. These results indicate that L. buchneri KU200793 can be used as a prophylactic functional food, having probiotic potential and neuroprotective effects.

Lower Mg and S contents in solar salt used in kimchi enhances the taste and anticancer effects on HT-29 colon carcinoma cells

The anticancer effects of kimchi prepared with different kinds of solar salts were evaluated in an in vitro cellular system using HT-29 human colon carcinoma cells. Four kinds of kimchi samples were prepared, using different solar salts: conventionally manufactured solar salt (CS), filtered sea water solar salt (FS), dehydrated solar salt by centrifuging (DS), and washed-dehydrated solar salt (WDS). Prepared kimchi samples were presented as CSK, FSK, DSK, and WDSK, respectively. The pH values, acidity, and sensory evaluation were determined after 3 week fermentation at 5 °C (pH 4.3), and WDSK exhibited the best fermented characteristics and taste among the 4 samples examined. In the HT-29 cell growth inhibitory activity assay, all 4 kimchi samples exert dose-dependent cell growth inhibition, with WDSK showing significant growth inhibition of HT-29 cells. mRNA and protein expression levels of apoptosis and cell cycle arrest related factors reveals that WDSK significantly increases the mRNA expression levels of Bax, Bim, caspases-3, caspases-9, and p21 as compared to other kimchi samples, at a concentration of 4.0 mg mL⁻¹. In addition, WDSK treatment strongly decreases the Bcl-2 protein expression (on western blot) in HT-29 cells, as compared to the control group (no kimchi treatment) and significantly increases the protein expression levels of Bax, caspases-3, caspases-9, and p53. Inductively coupled plasma atomic emission spectrometry (ICP-OES) reveals that WDS possesses a different mineral composition when compared to the other three solar salts; notably, the lower Mg (9.3 g kg⁻¹) and S (4.7 g kg⁻¹) content of WDS may cause better taste, fermented characteristcs, and functionality of WDSK. These results indicate WDS to be the ideal solar salt for kimchi preparation, which enhances the taste due to its lower Mg and S contents, and increases the anticancer effects by exerting better pro-apoptosis and cell cycle arrest abilities in HT-29 cells.

The anticancer effects of kimchi prepared with different kinds of solar salts were evaluated in an in vitro cellular system using HT-29 human colon carcinoma cells.

Bioactive Compounds in Kimchi Improve the Cognitive and Memory Functions Impaired by Amyloid Beta

This study investigated the abilities of kimchi and its bioactive compounds to ameliorate amyloid beta (Aβ)-induced memory and cognitive impairments. Mice were given a single intracerebroventricular injection of Aβ_25-35, followed by a daily oral administration of capsaicin (10 mg·kg-bw^–1), 3-(4′-hydroxyl-3′,5′-dimethoxyphenyl)propionic acid (50 mg/kg bw), quercetin (50 mg/kg bw), ascorbic acid (50 mg/kg bw), or kimchi methanol extract (KME; 200 mg/kg bw) for 2 weeks (n = 7 per group). Carboxymethylcellulose was used as a vehicle for the normal and control groups. Behavioral task tests showed that the learning and memory abilities were significantly waned by the injected Aβ_25-35, but these cognitive deficits were recovered by the administrated KME and kimchi bioactive compounds (p < 0.05). The reactive oxygen species, peroxynitrite, and thiobarbituric acid reactive substances levels were lower, and the glutathione level was higher, in the KME and bioactive compound groups than in the control group (p < 0.05). In the KME and bioactive compound groups, the protein expression levels of antioxidant enzymes (nuclear factor (erythroid-derived 2)-like 2-regulated superoxide dismutase-1 and glutathione peroxidase) were increased, whereas those of inflammation-related enzymes (nuclear factor-kappaB -regulated inducible nitric oxide synthase and cyclooxygenase-2) were decreased (p < 0.05). Thus, the antioxidative and anti-inflammatory properties of bioactive compounds-rich kimchi might help to attenuate the symptoms of Alzheimer’s disease.

Bioactive Compounds of Kimchi Inhibit Apoptosis by Attenuating Endoplasmic Reticulum Stress in the Brain of Amyloid β-Injected Mice

This study investigated the inhibitory effects of kimchi bioactive compounds against endoplasmic reticulum (ER) stress-induced apoptosis in amyloid beta (Aβ)-injected mice. Mice received a single intracerebroventricular injection of Aβ_25-35, except for the normal group. Mice were subjected to oral administration of 10 mg of capsaicin, 50 mg of 3-(4'-hydroxyl-3',5'-dimethoxyphenyl)propionic acid (HDMPPA), 50 mg of quercetin, 50 mg of ascorbic acid, or 200 mg of kimchi methanol extract (KME) per kilogram of body weight for 2 weeks ( n = 7 per group). In the in vitro blood-brain barrier (BBB) permeability test, all bioactive compounds penetrated the BBB except ascorbic acid. The protein expression level of APP, BACE, and p-Tau elevated by Aβ injection was decreased by kimchi bioactive compounds ( P < 0.05). Quercetin, HDMPPA, and KME decreased oxidative stress, as indicated by ROS and TBARS levels ( P < 0.05). The protein expression level of ER stress markers GRP78, p-PERK, p-eIF2α, XBP1, and CHOP and the proapoptotic molecules Bax, p-JNK, and cleaved caspases-3 and -9 decreased ( P < 0.05). In contrast, the protein expression level of antiapoptotic molecules Bcl2 and cIAP increased ( P < 0.05). These results were supported by histological analysis.

Probiotic characterization of Bacillus subtilis P223 isolated from kimchi

Probiotic characteristics of Bacillus subtilis P223 isolated from kimchi were investigated in this study. Spore cells of B. subtilis P223 showed high tolerance to artificial gastric juice (pH 2.5, 0.3% pepsin, 3 h) and bile salts (0.3% oxgall, 24 h). Spore cells of B. subtilis P223 showed more adherence to intestinal cells (HT-29 cells) than vegetative cells. In addition, B. subtilis P223 showed high autoaggregation ability, similar to a commercial strain (Bacillus clausii ATCC 700160). Moreover, its coaggregation abilities with pathogens were strong. The adherence of three pathogens (Salmonella enteritidis ATCC 13076, Listeria monocytogenes ATCC 15313, and Escherichia coli ATCC 25922) to HT-29 cells was inhibited by B. subtilis P223. It was found that B. subtilis P223 could not produce β-glucuronidase, a carcinogenic enzyme. However, it had amylase and protease activities. Antibiotic susceptibility was measured using disk diffusion assay. It was revealed that B. subtilis P223 was only resistant to streptomycin among eight kinds of antibiotics. In addition, B. subtilis P223 showed no hemolysis activity. It did not have enterotoxin genes. Results of this study suggest that B. subtilis P223 isolated from kimchi has potential as a probiotic strain.