Antioxidant, Anti-obesity or Anti-diabetic composition

Abstract

The present invention relates to an antioxidant, anti-obesity, or anti-diabetic composition comprising GABA tea leaves or an extract thereof.

Description

Compositions for antioxidant, anti-obesity or anti-diabetic purposes

[0001] The present invention relates to an antioxidant, anti-obesity or anti-diabetic composition.

[0002]

[0003] Obesity, defined as excessive fat accumulation, is associated with numerous chronic diseases, including hyperlipidemia, hyperglycemia, diabetes, and metabolic syndrome, and remains a significant global health problem. The prevalence of obesity has rapidly increased worldwide due to energy imbalances and changes in the gut microbiome caused by genetic and environmental factors. Since 1980, the number of people with obesity has doubled, affecting approximately one-third of the global population. Obesity is associated with various chronic diseases, including hyperlipidemia, hyperglycemia, diabetes, and metabolic syndrome. Despite the numerous medications available for the treatment of obesity, they often have various side effects.

[0004] Tea is renowned for its health benefits beyond its basic nutritional value. A widely consumed beverage worldwide, it plays a crucial role in promoting healthy aging and preventing chronic diseases. Scientifically known as Camellia sinensis Thecae, green tea is rich in polyphenols, such as epigallocatechin-3-gallate (EGCG). It is prepared in its unfermented form, which involves drying and steaming fresh leaves to preserve the polyphenol content. Post-fermented tea, derived through microbial fermentation, is increasingly recognized for its role in reducing the risk of hyperlipidemia and atherosclerosis. The naturally occurring amino acid γ-aminobutyric acid (GABA), found in tea, increases polyphenol concentration and antioxidant capacity, particularly under heat stress. This tea, rich in various bioactive compounds, is often referred to as a "functional tea" due to its wide range of health benefits.

[0005] Tea polyphenols, known as catechins, are flavonoids with a unique α-phenyl-benzopyran structure. These polyphenols, including EGCG, epicatechin-3-gallate (ECG), epigallocatechin (EGC), and epicatechin (EC), are classified as ester and non-ester catechins. The antioxidant properties of catechins depend on their molecular structure, particularly the arrangement of their hydroxyl groups. The unique 4-oxo, 3-hydroxy C ring structure enhances their resistance to oxidation.

[0006]

[0007] The present invention aims to provide an antioxidant, anti-obesity or anti-diabetic composition with few side effects.

[0008] The purpose of the present invention is to provide a composition having excellent antioxidant, anti-obesity or anti-diabetic effects.

[0009]

[0010] 1. An antioxidant, anti-obesity or anti-diabetic composition comprising GABA tea leaves or an extract thereof.

[0011] 2. In the above 1, the GABA tea leaves are an antioxidant, anti-obesity or anti-diabetic composition obtained by anaerobic treatment, killing and rinsing green tea leaves.

[0012] 3. In the above 1, the extract is an antioxidant, anti-obesity or anti-diabetic composition which is a water-immersed extract of GABA tea leaves.

[0013] 4. In the above 1, the composition is an antioxidant, anti-obesity or anti-diabetic composition that is a pharmaceutical composition or a health functional food composition.

[0014]

[0015] The composition of the present invention is derived from natural products and has few side effects.

[0016] The composition of the present invention exhibits excellent antioxidant, anti-obesity, and anti-diabetic effects. Specifically, it exhibits improved effects on weight loss, inhibition of liver fat accumulation, and regulation of glucose metabolism.

[0017]

[0018] Figure 1. Antioxidant activity and phenolic content of functional tea extracts. (a) Total phenol and (b) total flavonoid contents of functional tea extracts. Antioxidant activity measured by (c) total phenolic compound radical scavenging activity, (d) DPPH radical scavenging activity, and (e) ABTS radical scavenging activity in functional tea extracts at various concentrations. GABA, γ-aminobutyric acid; EGC, epigallocatechin; C, vitamin C; EC, epicatechin; EGCG, epigallocatechin-3-gallate; ECG, epicatechin-3-gallate.

[0019] Figure 2. Effects of green tea, fermented tea, and GABA extracts on a high-fat diet mouse model. (a) Average body weight change over 13 weeks; (b) Comparison of final body weight gain between groups; (c) Food intake monitored weekly; (d) Food efficiency ratios of obese mice treated with green tea, fermented tea, and GABA extracts. Green tea, fermented tea extract, and GABA extract were found to reduce obesity indices in mice fed a high-fat diet, with GABA being particularly effective. ND, normal diet with water; HFD, high-fat diet with water; GT, high-fat diet supplemented with green tea; FT, high-fat diet supplemented with fermented tea; GBT, high-fat diet supplemented with GABA; GABA, γ-aminobutyric acid.

[0020] Figure 3. Anti-obesity effects of functional tea extracts in a high-fat diet mouse model. (a) Photographs of body size, liver, epididymal fat, and peri-renal fat across five groups: ND, HFD, GT, FT, and GBT. (b) Bar graphs showing mouse body weight, (c) liver weight, (d) epididymal fat weight, and (e) peri-renal fat weight, show the effects of each dietary treatment. ND, normal diet with water; HFD, high-fat diet with water; GT, high-fat diet supplemented with green tea; FT, high-fat diet supplemented with fermented tea; GBT, high-fat diet supplemented with GABA tea; GABA, γ-aminobutyric acid.

[0021] Figure 4. Functional tea extracts effectively reduce hepatic fat accumulation induced by a high-fat diet. (a) Images show H&E and ORO-stained liver sections from the ND, HFD, GT, FT, and GBT groups. H&E staining reveals cellular structure, whereas ORO specifically highlights lipid droplets characteristic of fatty liver or steatosis. (b) The accompanying bar graph quantifies lipid droplet size in these groups based on ORO staining intensity, showing the varying degrees of lipid accumulation, with statistical differences indicated by letters. These results suggest that green tea, fermented tea extract, and GABA tea extract are effective in reducing hepatic fat accumulation induced by a high-fat diet. H&E, hematoxylin and eosin; ORO, oil red O staining; ND, normal diet with water; HFD, high-fat diet with water; GT, high-fat diet supplemented with green tea; FT, high-fat diet supplemented with fermented tea; GBT, high-fat diet supplemented with GABA tea; GABA, γ-aminobutyric acid.

[0022] Figure 5. Effects of functional tea extracts on biochemical markers related to obesity. The graph details the effects of green tea, fermented tea, and GABA tea extracts on (a) TG levels, (b) TC levels, (c) free fatty acid concentrations, (d) AST activity as a liver function marker, (e) serum leptin levels related to body fat mass, and (f) serum insulin levels related to glucose metabolism. Functional tea extracts appear to alleviate obesity-related biochemical markers in mice fed a high-fat diet. TG, serum triglycerides; TC, serum total cholesterol; AST, aspartate aminotransferase; ND, normal diet with water; HFD, high-fat diet with water; GT, high-fat diet supplemented with green tea; FT, high-fat diet supplemented with fermented tea; GBT, high-fat diet supplemented with GABA tea; GABA, γ-aminobutyric acid.

[0023] Figure 6. Functional tea extracts regulate glucose metabolism in mice. (a) Trends in fasting blood glucose levels over 13 weeks for ND, HFD, and tea extract-treated (GT, FT, GBT) diets. (b) Bar graph of fasting glucose levels after 13 weeks, showing a significant decrease in the tea treatment group. ND, normal diet with water; HFD, high-fat diet with water; GT, high-fat diet supplemented with green tea; FT, high-fat diet supplemented with fermented tea; GBT, high-fat diet supplemented with GABA tea; GABA, γ-aminobutyric acid.

[0024] Figure 7. The effects of these teas on various obesity-related parameters were investigated using a high-fat diet-induced obese mouse model (C57BL / 6). Mice were divided into five groups: a regular diet with water, a high-fat diet with water, and a high-fat diet supplemented with green tea, fermented tea, or GABA tea. Key metabolic indicators, including body weight, perirenal and hepatic fat, adipocyte lipid accumulation, serum cholesterol, leptin, insulin, and fasting blood glucose, were monitored for 13 weeks.

[0025]

[0026] The present invention is described in detail below.

[0027]

[0028] The present invention relates to an antioxidant, anti-obesity or anti-diabetic composition.

[0029] The composition of the present invention comprises GABA tea leaves or an extract thereof.

[0030] GABA tea is a type of tea that has increased GABA (γ-aminobutyric acid) content due to the addition of anaerobic treatment to the green tea manufacturing process.

[0031] Green tea is typically obtained through a process of plucking, fixation (inactivation of tea leaf oxidative enzymes), and rolling (rubbing). Afterwards, it may undergo further processes such as drying and flavoring (final drying).

[0032] GABA tea may be further treated anaerobicly before slaughter. This may involve, for example, removing air and sealing it or filling it with nitrogen.

[0033] GABA tea leaf extract may be a GABA tea leaf water-soaked extract. For example, it may be obtained by adding a specified amount of water to GABA tea leaves, steeping them for a specified period of time, and then removing the tea leaves.

[0034] Water can be added in amounts ranging from 10 to 1000 times the weight of the tea leaves, for example.

[0035] Extraction can be performed at room temperature or under heating.

[0036] The time can be, for example, 5 minutes to 2 hours.

[0037] GABA leaves or their extracts have excellent antioxidant, anti-obesity, and anti-diabetic effects. Therefore, they can be used as compositions for these purposes.

[0038] The composition of the present invention may be a pharmaceutical composition or a health functional food composition.

[0039] The pharmaceutical composition of the present invention can be formulated and used in the form of oral formulations such as powders, granules, tablets, capsules, suspensions, emulsions, syrups, aerosols, external preparations, suppositories, and sterile injection solutions, according to conventional methods, but is not limited thereto.

[0040] Carriers, excipients, and diluents that may be contained in the pharmaceutical composition of the present invention include, but are not limited to, lactose, dextrose, sucrose, dextrin, maltodextrin, sorbitol, mannitol, xylitol, erythritol, maltitol, starch, acacia gum, alginate, gelatin, calcium phosphate, calcium silicate, cellulose, methyl cellulose, microcrystalline cellulose, polyvinyl pyrrolidone, water, methylhydroxybenzoate, propylhydroxybenzoate, talc, magnesium stearate, and mineral oil. When formulating, diluents or excipients such as commonly used fillers, extenders, binders, wetting agents, disintegrants, and surfactants are used, but are not limited thereto.

[0041] Solid preparations for oral administration include, but are not limited to, tablets, pills, powders, granules, and capsules. However, these solid preparations are prepared by mixing at least one excipient, such as starch, calcium carbonate, sucrose or lactose, or gelatin. In addition to simple excipients, lubricants such as magnesium stearate and talc may also be used.

[0042] Liquid preparations for oral administration include suspensions, solutions, emulsions, and syrups. In addition to commonly used simple diluents such as water and liquid paraffin, they may contain various excipients such as wetting agents, sweeteners, flavoring agents, and preservatives. Preparations for parenteral administration include sterile aqueous solutions, non-aqueous solvents, suspensions, emulsions, lyophilized preparations, and suppositories. Non-aqueous solvents and suspensions can include propylene glycol, polyethylene glycol, vegetable oils such as olive oil, and injectable esters such as ethyl oleate. Suppository bases can include witepsol, macrogol, Tween 61, cacao butter, laurin butter, and glycerogelatin.

[0043] The pharmaceutical composition of the present invention is administered in a pharmaceutically effective amount. In the present invention, "pharmaceutically effective amount" means an amount sufficient to treat a disease with a reasonable benefit / risk ratio applicable to medical treatment. The effective dosage level may be determined based on the type and severity of the patient's disease, the activity and sensitivity of the drug to the drug, the time of administration, the route of administration and excretion rate, the duration of treatment, concomitant drugs, and other factors well known in the medical field. The pharmaceutical composition of the present invention may be administered as an individual therapeutic agent or in combination with other therapeutic agents, may be administered sequentially or simultaneously with conventional therapeutic agents, and may be administered singly or in multiple doses. It is important to consider all of the above factors and administer an amount that achieves the maximum effect with the minimum amount without causing side effects, and this can be easily determined by those skilled in the art.

[0044] In the pharmaceutical composition of the present invention, the effective dose may vary depending on the patient's age, sex, and weight, and is generally 1 to 6000 mg per kg of body weight, preferably 60 to 600 mg, administered once or in three divided doses. However, since the dosage may increase or decrease depending on the route of administration, severity of the disease, sex, body weight, age, etc., the above dosage does not limit the scope of the present invention in any way.

[0045] The above health functional food composition refers to a food manufactured and processed using raw materials or ingredients with functionality useful to the human body according to the Health Functional Food Act, and the functionality may mean consuming it for the purpose of obtaining a useful effect for health purposes such as regulating nutrients for the structure and function of the human body or physiological action.

[0046] The above health functional food may contain conventional food additives, and unless otherwise provided, the suitability of the food additives may be determined by the specifications and standards for the relevant item in accordance with the general provisions and general test methods of the Food Additive Code approved by the Ministry of Food and Drug Safety.

[0047] The items listed in the above food additive code include, for example, chemical compounds such as ketones, glycine, potassium citrate, nicotinic acid, and cinnamic acid; natural additives such as persimmon pigment, licorice extract, crystalline cellulose, high-molecular-weight pigment, and guar gum; and mixed preparations such as sodium L-glutamate preparations, alkaline agents for noodles, preservative preparations, and tar color preparations.

[0048] The above health functional food can be used in a variety of ways in foods and beverages, and can be used in, for example, various foods, beverages, gum, tea, vitamin complexes, health functional food supplements, food additives, etc.

[0049] The above health functional food can be manufactured and processed into any one formulation selected from the group consisting of tablets, granules, powder, capsules, liquid solutions, and pills.

[0050] Specifically, the above-mentioned health functional food in tablet form can be manufactured by conventionally granulating a mixture of excipients, binders, disintegrants, and other additives, then adding a lubricant and compression molding, or by directly compression molding the mixture. In addition, the above-mentioned health functional food in tablet form can contain a maturing agent and the like, if necessary, and can also be coated with an appropriate coating agent, if necessary.

[0051] Among the health functional foods in capsule form, hard capsules can be manufactured by filling a mixture of additives such as excipients or their granular or coated granular materials into a regular hard capsule, and soft capsules can be manufactured by filling a mixture of additives such as excipients into a capsule base such as gelatin. The soft capsules can contain a plasticizer such as glycerin or sorbitol, a coloring agent, a preservative, etc., as needed.

[0052] The above-mentioned ring-shaped health functional food can be prepared by forming a mixture of excipients, binders, disintegrants, etc. in an appropriate manner, and, if necessary, can be coated with white sugar or another appropriate coating agent, or can be coated with starch, talc, or an appropriate substance.

[0053] The above granular health functional food can be manufactured into a granular form by an appropriate method using a mixture of excipients, binders, disintegrants, etc., and may contain flavoring agents, flavoring agents, etc., as needed.

[0054] In addition, the definitions of terms for the above excipients, binders, disintegrants, lubricants, maturing agents, flavoring agents, etc. are those described in documents known in the art and may include those having the same or similar functions.

[0055] Anyone skilled in the art of the present invention will be able to apply the present invention by changing the type and introduction ratio of each component based on the description of the present invention, and if the same technical effect is achieved despite the above modification, it will be considered to be included in the technical idea of ​​the present invention.

[0056] The present invention will be described in more detail with reference to the following examples.

[0057]

[0058] Example

[0059] Materials and Methods

[0060] Experimental materials

[0061] Extracts of green tea, fermented tea, and GABA tea were obtained from the Hadong Green Tea Research Institute in Korea.

[0062] Green tea is made through the process of plucking - fixation (to inactivate tea leaf oxidase) - rolling (to knead) - drying - final drying. The tea leaves are roasted at high temperatures (over 250℃) to inactivate the polyphenol oxidase in the tea leaves and maintain their green color. Fermented tea refers to black tea and goes through the stages of plucking - withering - oxidation (or fermentation) - drying. During this process, polyphenol oxidase is activated (oxidation for 3-4 hours at room temperature), turning the green tea leaves into reddish brown. GABA tea is made using a method that increases the content of GABA, a free amino acid, and goes through the process of leaf collection - anaerobic treatment (sealing with air removed or nitrogen filling, etc.) for 24 hours - killing - keeping in mind - drying. Except for the anaerobic treatment, the method is the same as making green tea.

[0063] The extraction process was as follows: For each tea variety, 20 g of raw material was mixed with 2 liters of distilled water (100 times the amount of tea). The mixture was then incubated in a shaking incubator (IS-971R, JS Research Inc., Gongju-si, Korea) at 100 rpm and 25°C for 30 minutes. After incubation, the extract was filtered using a Whatman No. 2 filter and stored at 4°C until needed for the experiment.

[0064]

[0065] Antioxidant action of tea extract

[0066] The antioxidant activity of green tea, fermented tea, and GABA tea extracts was evaluated by measuring the radical scavenging ability using DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2'-casino-bis[3-ethylbenzothiazoline-6-sulfonic acid]) assays.

[0067]

[0068] laboratory animals

[0069] Thirty-five 3-week-old male C57BL / 6 mice were procured from KOATECH (Pyeongtaek-si). The mice were housed in groups of seven in cages measuring 500 x 300 x 200 mm and covered with sawdust. The breeding facility at Gyeongsang National University in Jinju, South Korea, maintained a controlled environment with a temperature of 20.7–21.2°C, a relative humidity of 49.9%–54.2%, ventilation rates of 10–15 times per hour, and a 12-h light cycle (8:00 AM to 8:00 PM) at an illumination intensity of 200–300 LUX. The mice had free access to food and water during the acclimation and experimental periods. Environmental conditions, including temperature and humidity, were monitored every 30 minutes using an automated device, and the illumination intensity was regularly checked to ensure consistency.

[0070] Before the experiment began, all mice were acclimated to a standard chow diet (Harlan Laboratories Inc., Catalog No. 2018S, 12% fat, 63% carbohydrate, 25% protein) for one week. To induce obesity, mice were fed a high-fat diet (Research Diets Inc., D12492; 60% fat, 20% carbohydrate, 20% protein). The experimental groups were as follows: normal diet + water (ND); high-fat diet + water (HFD); high-fat diet + green tea (GT); high-fat diet + fermented tea (FT); and high-fat diet + GABA (GBT). Mice fed the high-fat diet for 13 weeks were administered tea extract dissolved in saline twice daily at a dose of 7.5 mL / kg. All animal welfare and experimental procedures complied with the National Institutes of Health (NIH) Publication No. 8023 (revised 1978) Guide for the Care and Use of Laboratory Animals. The research protocol was approved by the Animal Research Laboratory of Gyeongsang National University (GNU-190924-M0044).

[0071]

[0072] Monitoring body weight and nutritional intake in mice

[0073] Rats' body weights were measured before and every two weeks thereafter, after administration of the tea extract. Food intake was recorded weekly during the 13-week study period.

[0074]

[0075] Quantification of adipose tissue mass

[0076] After extraction, adipose tissue from various sites, including the left and right epididymis, viscera, perirenal (left and right), and brown fat, was washed with saline. The tissues were then dried using filter paper and weighed to determine adipose tissue mass.

[0077]

[0078] Histological evaluation of liver and adipose tissue

[0079] To examine hepatic lipid accumulation, liver tissue was excised, immediately frozen in liquid nitrogen, and stored at -70°C. For histological analysis, the tissue was prepared as pre-frozen slide samples. Lipid distribution within the liver was observed under a light microscope using Oil Red O (ORO) staining. The size and distribution of lipid droplets were analyzed to assess the extent of lipid deposition.

[0080]

[0081] Histological analysis of hepatic lipid accumulation

[0082] For liver lipid analysis, we used ORO staining, a standard method for detecting neutral lipids and triglycerides in frozen liver sections. This technique helped identify fat accumulated in liver tissue. Tissue slides were covered with glycerol gel and observed at 200X magnification. At least five images per section were randomly captured. The percentage of ORO-stained area was quantified using the COLUMBUS image data storage and analysis system (PerkinElmer, USA), using an algorithm suitable for quantitative analysis of ORO-stained sections based on an intensity segmentation method. This analysis included intensity thresholding for image segmentation, first separating the tissue from the background, and then identifying ORO-stained lipid droplets within the tissue.

[0083]

[0084] Comprehensive blood biochemistry analysis

[0085] Blood samples were collected from the hearts of euthanized rats. Plasma was separated by centrifugation for subsequent analysis. Plasma triglyceride levels were measured using an enzymatic kit based on the Muller method. Total cholesterol was measured by absorbance readings at 550 and 500 nm using an enzymatic kit according to the Richmond method. Aspartate aminotransferase (AST) levels were measured using an automated serum analyzer to provide insight into potential hepatic and renal adverse effects of tea extract administration. Serum concentrations of leptin, adiponectin, and insulin were quantified using mouse-specific immunoassay kits (R&D Systems, Minneapolis, MN, USA).

[0086]

[0087] Statistical analysis

[0088] Statistical analyses were performed using GraphPad Prism 7 software (GraphPad Software, La Jolla, CA, USA). Data are presented as the mean ± standard error of the mean. One-way ANOVA, least significant difference test, and Student's t-test were used for statistical evaluation.

[0089]

[0090] result

[0091] Antioxidant capacity and phenol content of tea extracts

[0092] The contents of GABA, theanine, caffeine, vitamin C, EGCG, EGC, ECG, EC, and total catechins in green tea, fermented tea, and GABA tea were analyzed (Figures 1A and 1B). The results showed that green tea contained the highest amounts of theanine, caffeine, vitamin C, EGCG, ECG, and total catechins, whereas GABA tea was richest in GABA, EGC, and EC. Fermented tea had a relatively low polyphenol content.

[0093] To determine the antioxidant activity of the functional tea extracts, in vitro assays were performed, including measurements of total phenolic radical scavenging activity (Fig. 1C), DPPH radical scavenging activity (Fig. 1D), and ABTS radical cation scavenging activity (Fig. 1E). In the comprehensive analysis, the green tea treatment group exhibited the highest antioxidant capacity. The fermented tea treatment group exhibited the next highest antioxidant capacity in terms of total phenolic radical scavenging activity, while the GABA tea treatment group exhibited the second highest DPPH radical scavenging activity.

[0094]

[0095] Effects of Functional Tea Extracts on Body Weight and Food Efficiency

[0096] An obese mouse model was established by feeding mice with a high-fat diet (HFD) for 13 weeks. The average body weight of the HFD group was 45.16 g, which was significantly higher than that of the ND group (27.14 g). Over the 13-week period, the ND group gained 10.16 g, while the HFD group gained significantly more (26.73 g) (Fig. 2A). In contrast, the GT, FT, and GBT groups showed smaller weight gains (22.89 g, 20.1 g, and 21.46 g, respectively) (Fig. 2B), reaching 75.2% to 85.6% of the weight gain observed in the HFD group. GT2 was particularly effective in suppressing weight gain.

[0097] Despite having lower food intake than the ND group, the HFD group showed higher feed efficiency (Fig. 2C; Table 1). Daily food intake was slightly lower in the GT group (2.02 g) and the FT group (1.19 g), compared to 2.11 g in the HFD group. Feed efficiency decreased by 12.46% in the GT group, 11.09% in the FT group, and 10.73% in the GBT group, whereas it decreased by 13.94% in the HFD group (Fig. 2D). In particular, the GBT group showed a significantly suppressive effect on body weight gain and lower feed efficiency compared to the FT group, despite a 10.6% increase in food intake. These results indicate that all three tea extracts have the potential to promote weight loss and improve metabolic efficiency in a high-fat diet-induced obesity model.

[0098]

[0099]

[0100]

[0101] Anti-obesity effects of functional tea extracts

[0102] We confirmed that mice fed a HFD developed obesity, as evidenced by increased body size compared to the ND group. In contrast, groups treated with GT, FT, and GBT showed a significant decrease in body size compared to the HFD group (Figure 3A). Specifically, the body weight of the HFD group more than doubled compared to the ND group (Figure 3B), and liver weight increased from 0.96 g to 1.44 g. In contrast, GT, FT, and GBT treatments reduced liver weight to 1.14 g, 1.08 g, and 1.12 g, respectively, demonstrating a protective effect against HFD-induced liver weight gain.

[0103] In addition, epididymal fat in the HFD group increased by 266%, from 1.01 g in the ND group to 2.69 g. This increase was effectively alleviated in the tea-administered group, with GT and GBT showing a 23.9% decrease in epididymal fat (Fig. 3D). Perirenal fat also increased rapidly, reaching 1.46 g, a 372.9% increase compared to 0.39 g in the ND group. Administration of functional tea extracts resulted in a significant decrease in perirenal fat in the GT, FT, and GBT-administered groups (Fig. 3E), with a particularly notable effect in reducing fat accumulation in the abdominal area.

[0104]

[0105] Reduction of lipid accumulation by functional tea extracts

[0106] Histological examination of liver tissue after 13 weeks of dietary treatment revealed significant differences between the groups. The ND group maintained typical liver morphology. In contrast, the HFD group exhibited significant fat accumulation, characterized by foam cell formation, large lipid droplets, and cell necrosis. This group also showed signs of inflammatory cell infiltration. In contrast, the GT, FT, and GBT groups exhibited reduced droplet-like fat accumulation. However, some inflammatory and Kupffer cell activation were observed (Figure 4A). These results indicate that functional tea extracts effectively alleviate liver damage commonly associated with a high-fat diet.

[0107] The extent of lipid deposition was further quantified using ORO staining, highlighting the size and distribution of lipid granules in the liver tissue (Fig. 4B). The livers of the HFD group showed typical indicators of fatty liver disease, as evidenced by a significant number of lipid droplets. In contrast, the livers of the GT, FT, and GBT groups showed a marked reduction in lipid storage, highlighting the efficacy of these tea extracts in reducing histological markers of fatty liver disease.

[0108]

[0109] Effects of Functional Tea Extracts on Obesity-Related Biochemical Markers

[0110] The effects of functional tea extracts on serum lipid profiles and other biochemical markers associated with obesity in mice were evaluated. In the ND group, serum triglyceride (TG) levels were measured at 69.7 mg / dL, whereas in the HFD group, they decreased to 55.0 mg / dL. The GT, FT, and GBT groups showed TG levels of 60.1 mg / dL, 58.9 mg / dL, and 55.8 mg / dL, respectively, with no statistically significant differences from the HFD group (Fig. 5A).

[0111] Serum total cholesterol (TC) levels were significantly higher in the HFD group than in the ND group (173 mg / dL). However, the groups treated with tea extract showed lower total cholesterol levels (151.1 mg / dL in GT, 141.3 mg / dL in FT, and 127.3 mg / dL in GBT) (Fig. 5B). Free fatty acid concentrations were lower in all groups than in the ND group, but these differences were not statistically significant (Fig. 5C).

[0112] Liver function assessed by AST activity increased in the HFD group, but the difference was not statistically significant. The FT and GBT groups showed a decreasing trend compared to the HFD group, indicating that the tea extract did not adversely affect liver function (Fig. 5D). Serum leptin levels were significantly increased in the HFD group to 38.9 ng / mL compared to 5.74 ng / mL in the ND group, and decreased in the tea extract group to 31.8 ng / mL in GT, 27.98 ng / mL in FT, and 27.36 ng / mL in GBT, reflecting a significant decrease in leptin concentration (Fig. 5F). Similarly, insulin levels increased from 0.19 ng / mL in the ND group to 0.41 ng / mL in the HFD group, whereas they were significantly lower in the tea extract group to 0.28 ng / mL in GT, 0.25 ng / mL in FT, and 0.30 ng / mL in GBT. This suggests that tea extract exerts an effect of suppressing the increase in serum insulin induced by a high-fat diet (Fig. 5E).

[0113]

[0114] Effects of functional tea extracts on fasting blood sugar control

[0115] In both the ND and HFD groups, fasting blood glucose levels gradually increased over the experimental period. However, the groups administered functional tea extracts (GT, FT, GBT) showed a decrease in fasting blood glucose levels over several weeks (Fig. 6A).

[0116] After 13 weeks, the fasting blood glucose levels in the HFD group were significantly higher than those in the ND group. Notably, the GT, FT, and GBT groups showed significant reductions in fasting blood glucose levels (Figure 6B). These results highlight the dual role of tea extract in managing body weight and blood glucose levels, suggesting its potential as a comprehensive dietary supplement for improving metabolic health.

Claims

1. An antioxidant, anti-obesity or anti-diabetic composition comprising GABA tea leaves or an extract thereof.

2. In claim 1, the GABA tea leaves are an antioxidant, anti-obesity or anti-diabetic composition obtained by anaerobic treatment, killing and rinsing green tea leaves.

3. In claim 1, the extract is an antioxidant, anti-obesity or anti-diabetic composition which is a water-soaked extract of GABA tea leaves.

4. In claim 1, the composition is an antioxidant, anti-obesity or anti-diabetic composition that is a pharmaceutical composition or a health functional food composition.

Images