Application of indole-3-lactic acid in preparation of product for promoting appetite

Abstract

The invention discloses application of indole-3-lactic acid in preparation of a product for promoting appetite, and belongs to the technical field of functional food. The invention provides an application of indole-3-lactic acid in preparation of a product for promoting appetite. The ILA is taken as a core active component and is used for preparing a functional product for promoting appetite, an appetite regulation network is remodeled by targeting an intestinal microorganism-intestinal-brain axis, and an innovative strategy is provided for intervention of inappetence.

Description

Technical Field

[0001] The present invention relates to the application of indole-3-lactic acid in the preparation of products for promoting appetite, and belongs to the technical field of functional foods. Background Art

[0002] In recent years, with the change of people's lifestyle in modern society, anorexia caused by various physiological, psychological or environmental factors has gradually become an important health problem. Anorexia is a common physiological or pathological state, which widely exists in chronic wasting diseases (such as cancer, chronic kidney disease, liver disease), neuropsychiatric diseases (such as anorexia nervosa, depression, anxiety disorder), infectious diseases and senile degenerative diseases. Long-term loss of appetite will lead to poor nutritional intake, decreased immunity and metabolic disorders, seriously affecting the quality of life and clinical prognosis of patients. At present, the main intervention methods for anorexia include drug therapy (such as mirtazapine, megestrol acetate, etc.) and nutritional support treatment. However, the existing drugs are often accompanied by side effects such as drowsiness, endocrine disorders and dependence, while nutritional supplements can only relieve symptoms in the short term and cannot fundamentally regulate the neural or metabolic pathways of appetite. Therefore, it is of great clinical significance to develop a safe, efficient and highly targeted appetite promoter.

[0003] Appetite is a key factor controlling the feeding behavior of humans and animals, which is mainly controlled by the coordinated action of peripheral tissues and the central nervous system and is regulated by a variety of hormones, neurotransmitters and metabolites of intestinal flora. The latest research found that by using microbiota sequencing and metabolomics to comprehensively characterize the gut microbiome and metabolome maps of humans and mice, it was revealed that there were profound and complex microbiota disruptions in the gut microbiota of patients with anorexia nervosa (AN) and functional serum metabolite changes. Small molecule metabolites may act through blood circulation or through the gut-microbiota-brain neuron signaling pathway, thus affecting the regulation of appetite, mood and behavior by the brain. As the main metabolite of intestinal flora, tryptophan metabolites are important substances for intestinal-brain communication. They directly or indirectly affect the functions of the host in metabolism, immunity, nerves and appetite through signal transduction between peripheral hormones and the central nervous system, the gut-brain axis and other pathways, and have become a current research hotspot. For example, serotonin can not only stimulate the secretion of peripheral appetite hormones, but also act as a neurotransmitter to transmit signals from the intestine to the brain and mediate appetite control.

[0004] Indole-3-lactic acid (ILA) is a substance produced by the metabolism of tryptophan by intestinal flora. There is currently no research clearly revealing the appetite-promoting effect of ILA and its mechanism, and its application in food or drugs is still blank. Summary of the Invention

[0005] Aiming at the defects existing in the prior art, the object of the present invention is to propose using indole-3-lactic acid (ILA) as a core active ingredient for preparing a functional product for promoting appetite, remodeling the appetite regulation network by targeting the gut microbiota-gut-brain axis, and providing an innovative strategy for the intervention of anorexia.

[0006] In order to achieve the above object, the following technical solutions are provided:

[0007] The present invention provides the application of indole-3-lactic acid in the preparation of a product for promoting appetite.

[0008] In one embodiment, the promotion of appetite is mainly achieved by indole-3-lactic acid increasing the proportion of c-fos positive neurons in the nucleus of the solitary tract (NTS).

[0009] In one embodiment, the promotion of appetite is mainly achieved by indole-3-lactic acid down-regulating the expression of neuropeptide Y (Npy) gene and agouti-related protein (Agrp) gene and up-regulating the expression of proopiomelanocortin (Pomc) gene.

[0010] In one embodiment, the promotion of appetite is mainly achieved by indole-3-lactic acid alleviating the compensatory increase in the level of ghrelin in serum.

[0011] In one embodiment, the product includes any one of food, medicine, functional food, nutritional supplement, food additive or health care product.

[0012] In one embodiment, the gavage dose of the indole-3-lactic acid active ingredient in the product is 50-70 mg / kg BW; preferably 50 mg / kg BW.

[0013] In one embodiment, the indole-3-lactic acid (ILA) is an indole-3-lactic acid suspension or an indole-3-lactic acid microcapsule sustained-release preparation.

[0014] In one embodiment, the food is dairy products, soy products or fruit and vegetable products produced by using ILA, or using ILA microcapsule sustained-release preparation and microbial preparation capable of metabolizing to produce ILA.

[0015] In one embodiment, the dairy products include one or more of fermented milk, flavored fermented milk, fermented milk beverage, cream, cheese, milk-containing beverage or milk powder; the soy products include any one of soy milk and soy milk powder; the fruit and vegetable products include fruit and vegetable products prepared from at least one of Chinese cabbage, white radish, cucumber, beet, yellow peach or waxberry products.

[0016] In one embodiment, the food is a fermented food, including solid food, liquid food or semi-solid food.

[0017] In one embodiment, the food is a beverage or snack containing ILA, or a food produced using an ILA microcapsule sustained-release preparation, and a microbial preparation capable of metabolizing to produce ILA.

[0018] In one embodiment, the drug contains ILA, a drug carrier, and / or a pharmaceutical excipient.

[0019] In one embodiment, the drug carrier includes one or more of commonly used medical polymer microcapsules, nanoparticles, solid lipid nanoparticles, mesoporous silica nanoparticles, and metal-organic frameworks.

[0020] In one embodiment, the pharmaceutical excipient includes one or more of excipients (such as starch, microcrystalline cellulose), stabilizers (such as ascorbic acid, sodium benzoate, and citric acid), novel carriers (such as liposomes or nanoparticles), taste improvers (such as sweeteners, flavors, spices), stabilizers or packaging materials (such as aluminum foil, plastic film).

[0021] In one embodiment, the dosage form of the drug is a granule, capsule, tablet, pill, or oral liquid.

[0022] The present invention also provides the use of indole-3-lactic acid in the preparation of a product for relieving anorexia and loss of appetite.

[0023] In one embodiment, the product includes any one of food, drugs, functional foods, nutritional supplements, food additives, or health products.

[0024] In one embodiment, the relieving of anorexia and loss of appetite is mainly achieved by indole-3-lactic acid by increasing the proportion of c-fos positive neurons in the nucleus of the solitary tract (NTS) to relieve anorexia and loss of appetite.

[0025] In one embodiment, the relieving of anorexia and loss of appetite is mainly achieved by indole-3-lactic acid by downregulating the expression of neuropeptide Y (Npy) gene and agouti-related protein (Agrp) gene and upregulating the expression of proopiomelanocortin (Pomc) gene to relieve anorexia and loss of appetite.

[0026] In one embodiment, the relieving of anorexia and loss of appetite is mainly achieved by indole-3-lactic acid by relieving the compensatory increase in the level of ghrelin in the serum to relieve anorexia and loss of appetite.

[0027] The present invention also provides a drug for relieving the disorder of hypothalamic appetite neuropeptide levels, and the active ingredient of the drug is indole-3-lactic acid.

[0028] In one embodiment, alleviating the disorder of hypothalamic anorexigenic neuropeptide levels includes reducing the expression levels of Agrp and Npy genes or / and increasing the expression level of the Pomc gene.

[0029] Beneficial effects:

[0030] The application of ILA provided by the present invention in the preparation of products for promoting appetite:

[0031] (1) By intervening in anorexia model mice with ILA solution or ILA microcapsule sustained-release preparation, it was found that ILA can effectively promote appetite and relieve the decrease in food intake of anorexia mice; it can enhance the adaptability of mice to the anorexia model and relieve the weight loss caused by anorexia;

[0032] (2) By intervening in anorexia model mice with ILA solution or ILA microcapsule sustained-release preparation, the energy state of anorexia model mice is improved, the compensatory demand for ghrelin secretion by the body is reduced, and the compensatory increase in serum ghrelin level is relieved;

[0033] (3) By intervening in anorexia model mice with ILA solution or ILA microcapsule sustained-release preparation, the disorder of hypothalamic anorexigenic neuropeptide levels is alleviated, the abnormal expression of Agrp and Npy gene levels is reduced, the expression level of the Pomc gene is increased, and the negative energy state of anorexia model mice is significantly relieved, and the appetite of anorexia mice is improved;

[0034] (4) By intervening in anorexia model mice with ILA solution or ILA microcapsule sustained-release preparation, the proportion of c-fos + cells is significantly increased compared with that of anorexia model mice. c-fos is widely expressed in the solitary tract nucleus, stimulating the activation of the solitary tract nucleus vagus nerve and relieving mouse anorexia. Description of the drawings

[0035] Figure 1 It is the effect diagram of the influence of ILA on the appetite and weight of anorexia model mice; (A) Daily food intake of mice; (B) Daily weight of mice; where *P<0.05, **P<0.01, ***P<0.001, ****P<0.0001; #P<0.05, ##P<0.01, P<0.001;

[0036] Figure 2 It is the effect diagram of the influence of ILA on the level of ghrelin in the serum of anorexia model mice; where *P<0.05, **P<0.01;

[0037] Figure 3Effect diagram of the regulation of the central nervous system by ILA in anorexia model mice; (A) Relative mRNA expression of AgRP in the hypothalamus of mice; (B) Relative mRNA expression of Npy in the hypothalamus of mice; (C) Relative mRNA expression of Pomc in the hypothalamus of mice; where **P<0.01, ***P<0.001, ****P<0.0001;

[0038] Figure 4 Effect diagram of the activation of c-fos positive neurons by ILA in the nucleus of the solitary tract (NTS) of anorexia model mice; where *P<0.05, ***P<0.001. Specific implementation mode

[0039] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the scope of protection of the present invention. The following specific implementation modes further describe the present invention.

[0040] Raw material sources involved in the present invention:

[0041] ILA was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.

[0042] Preparation of ILA solution: Weigh a certain mass of ILA and dissolve it in sterilized physiological saline, and then ultrasonically form a uniform suspension.

[0043] Preparation of embedded ILA microcapsule preparation: Weigh a certain weight of sodium alginate (SA) and dissolve it in ultrapure water to prepare a 2% SA solution. Stir it at 1200 rad on a magnetic stirrer at room temperature for 30 min until the solution becomes a transparent and homogeneous colloidal liquid; at the same time, weigh a certain weight of CaCl2 and dissolve it in ultrapure water to prepare a 1.5% CaCl2 solution, and mix it evenly at room temperature until the solution is clear and transparent; then weigh ILA and suspend it in the prepared SA solution. Under the propulsion of a micro-infusion pump, the suspension is slowly and uniformly sprayed into a 1.5% CaCl2 solution under the action of a high-voltage DC power supply with a magnetic field of 20 V through a microcapsule generator for 15 min to form a sodium alginate-ILA-calcium chloride microcapsule embedding system; after encapsulation, wash it 3 times with Hanks solution and add physiological saline for preservation for later use.

[0044] Establishment of anorexia model and animal experiment treatment: The 1st - 3rd days were the adaptation period, and the experimental mice were housed individually. The model mice were placed in cages with running wheels (the running wheels were self - moving rotors). From the 1st day to the 3rd day, free drinking water and standard diet were provided to each group. On the 4th day, the dark cycle began. Food was available at a fixed time period each day (6 h), and water could still be obtained unrestrictedly. 200 μL of normal saline was used for gavage. On each subsequent day, the food - available time was reduced by 1 h successively and then stabilized at 3 h / day. Data such as body weight and food intake were measured before food supply. The cages were checked every day to ensure that the mice did not hide food. Mice were removed from the model when their body weight was less than 25% of the original weight.

[0045] Example 1

[0046] Application of ILA in improving the symptoms of anorexia - model mice, the specific steps are as follows:

[0047] Fifty 6 - week - old healthy female C57BL / 6J mice were taken, adapted to the environment for 3 days, and randomly divided into 5 groups: healthy control group, food - restricted control group, anorexia model group (positive control), ILA intervention group, and embedded ILA intervention group; each group contained 10 mice. Among them, the gavage dose of the ILA intervention group and the embedded ILA intervention group was 50 mg / kg BW; the healthy control group, food - restricted control group, and anorexia model group (positive control) were gavaged with 0.9% normal saline after sterilization treatment. Gavage started at 18:00 every evening, 0.2 mL each time; the specific treatment process is shown in Table 1:

[0048] Table 1 Grouping and treatment methods of animal experiments

[0049]

[0050] Result analysis

[0051] (1) Promoting effect of ILA on food intake of anorexia - model mice

[0052] The experimental results of the food intake of mice are as Figure 1 (A) shown. From Figure 1As can be seen from (A), since the feeding time of the mice in the food restriction control group and the anorexia model group was restricted from the 4th day, the food intake was generally lower than that of the healthy control group. Compared with the food restriction control group, the food intake of the anorexia model group decreased significantly by 0.2685 g on the 7th day (P < 0.01), by 0.7876 g on the 8th day (P < 0.0001), and by 0.5681 g on the 9th day (P < 0.001), which proved the successful establishment of the anorexia model. Compared with the anorexia model group, the food intake of the ILA intervention group increased significantly by 0.3508 g on the 7th day (P < 0.001), by 0.6196 g on the 8th day (P < 0.0001), and by 0.5336 g on the 9th day (P < 0.001), making the food intake of the mice equivalent to that of the food restriction control group (P > 0.05). Compared with the anorexia model group, the food intake of the embedded ILA intervention group increased significantly by 0.469 g on the 8th day (P < 0.01) and by 0.47 g on the 9th day (P < 0.05). Compared with the embedded ILA intervention group, the food intake of the mice in the ILA intervention group was higher on the 9th day (P < 0.05). Generally speaking, ILA has a good effect on promoting appetite and can relieve the anorexia symptoms of ABA mice.

[0053] (2) Effect of ILA on the weight gain of anorexia model mice

[0054] The body weight of the mice was weighed daily, and it was calculated as the percentage of the body weight on the day to the body weight in the baseline period, where the body weight in the baseline period was the average body weight from the 1st day to the 3rd day.

[0055] The results are as Figure 1As shown in (B), since the feeding time of mice was restricted from the 4th day, the body weights of the mice in the calorie restriction control group and the anorexia model group were generally lower than those in the healthy control group. Compared with the calorie restriction control group, the body weight of the anorexia model group began to decrease significantly from the 7th day, being 94.46% of the calorie restriction control group (P < 0.05), further decreasing to 92.24% of the calorie restriction control group on the 8th day (P < 0.01), and dropping to 89.97% of the calorie restriction control group on the 9th day (P < 0.001), indicating that the anorexia model was successfully established. From the 8th day, ILA drug intervention had a significant improvement effect on the body weight of anorexia model mice. Compared with the anorexia model group, the body weight increased by 6.80% on the 8th day (P < 0.01) and by 7.83% on the 9th day (P < 0.001) after ILA drug intervention, and its body weight was comparable to that of the calorie restriction food group (P > 0.05). From the 8th day, compared with the anorexia model group, the body weight of the embedded ILA intervention group increased by 5.62% on the 8th day (P < 0.05) and by 7.71% on the 9th day (P < 0.001), and its body weight was comparable to that of the calorie restriction food group (P > 0.05). There was no significant difference in body weight changes between the ILA intervention group and the embedded ILA intervention group. Generally speaking, ILA had a good effect in alleviating the weight loss caused by exercise anorexia.

[0056] (3) ILA alleviates the compensatory increase in the level of ghrelin in the serum of anorectic mice

[0057] The mice in Example 1 were euthanized by eyeball blood collection at 9:00 in the morning on the 10th day. The taken serum was left standing at room temperature for 30 min, and then centrifuged at 1500 g for 10 min. The supernatant was transferred to a new centrifuge tube. The content of ghrelin in the mouse serum was detected using a mouse Ghrelin ELISA kit; the specific operation steps refer to the kit instruction manual.

[0058] Ghrelin is a peptide hormone mainly synthesized in the gastrointestinal tract. It is the only known orexigenic hormone secreted by the gastrointestinal tract at present. Its main function is to promote appetite and energy intake. It enhances appetite by activating the growth hormone secretagogue receptor (GHS-R1a receptor) in the hypothalamus, and at the same time can also stimulate the secretion of growth hormone (GH) to regulate energy metabolism and fat storage.

[0059] The results are as Figure 2 shown. By Figure 2It can be seen that there was no significant change in the serum Ghrelin content between the healthy control group and the food-restricted control group (P>0.05). Compared with the food-restricted control group, the serum ghrelin level of the anorexia model group of mice increased by 1.35 times (P<0.01), indicating that this model can effectively induce an increase in Ghrelin secretion and the anorexia model was successfully constructed. Compared with the anorexia model group, the serum Ghrelin level of the mice in the ILA intervention group decreased significantly by 75.45% (P<0.05), and there was also a downward trend in the embedded ILA intervention group, and the serum ghrelin level of its mice decreased to 75.43% of the anorexia model group. In addition, there was no significant difference in the serum Ghrelin level between the ILA intervention group and the embedded ILA intervention group (P>0.05). Generally speaking, ILA intervention can relieve the compensatory increase in the serum Ghrelin level of anorexia model mice, which may be due to the fact that ILA relieves exercise-induced anorexia by regulating the Ghrelin signaling pathway. However, the effect of the ILA embedding preparation is weaker than that of free ILA, which may be related to its release characteristics or bioavailability.

[0060] (4) ILA can significantly improve the abnormal expression of hypothalamic appetite regulatory genes in anorectic mice

[0061] After the mice in Example 1 were euthanized at 9:00 am on the 10th day, the mouse brain tissues were taken, and the hypothalamus was separated on ice. Real-time fluorescence quantitative polymerase chain reaction (qRT-PCR) was used to measure the mRNA expression levels of Agrp, Npy, Pomc, and β-actin (internal reference) genes. The primer sequences used are shown in Table 2.

[0062] Table 2 qPCR primer sequences

[0063]

[0064] 1. ILA downregulates the mRNA expression of the agouti-related protein (Agrp) gene in anorectic mice

[0065] AgRP (Agouti-related peptide, AgRP neuropeptide) is a neuropeptide secreted by NPY / AgRP neurons in the arcuate nucleus (ARC) of the hypothalamus and plays a key role in appetite regulation and energy balance. AgRP is co-expressed with NPY and acts to increase appetite, reduce metabolism, and reduce energy consumption.

[0066] The results are as Figure 3As shown in (A), there was no significant difference in the expression level of hypothalamic Agrp gene between the healthy control group and the food-restricted control group. Compared with the food-restricted control group, the expression level of Agrp gene in the anorexia model group was significantly increased by 8.77-fold (P < 0.0001), indicating that there was a more severe negative energy balance in the anorexia model group. The ILA drug intervention reduced the expression level of Agrp to 21.81% of that in the anorexia model group (P < 0.001), alleviating the negative energy balance. After the ILA drug intervention, compared with the food-restricted control group and the healthy control group, the expression level of Agrp gene in the ILA intervention group was only increased by 1.83-fold (P < 0.05). At the same time, compared with the anorexia model group, the Agrp gene level in the embedded ILA intervention group was reduced to 23.43% (P < 0.001), indicating that the ILA embedding preparation also had the effect of alleviating the negative energy balance caused by anorexia. There was no significant difference in the expression level of hypothalamic Agrp gene between the ILA drug intervention group and the embedded ILA intervention group. In summary, the results suggest that ILA may improve energy balance and feeding behavior by regulating appetite signals in the hypothalamus and inhibiting the abnormally upregulated Agrp.

[0067] 2. ILA downregulates the expression of neuropeptide Y (Npy) gene in anorectic mice

[0068] Neuropeptide Y (NPY) is a neuropeptide widely present in the central nervous system and peripheral tissues of mammals. In terms of feeding regulation, NPY is one of the strongest orexigenic signals in the center, mainly promoting food intake by activating NPY Y1 and Y5 receptors in the hypothalamus. When the body is in an energy-deficient state, NPY / AgRP neurons are activated and release NPY, while inhibiting the orexigenic antagonist - proopiomelanocortin (POMC) neurons, reducing the release of its downstream α-melanocyte-stimulating hormone (α-MSH), thereby weakening the appetite inhibitory signal.

[0069] The results are as Figure 3(As shown in (B)), there was no significant difference between the healthy control group and the food-restricted control group. Compared with the food-restricted control group, the Npy gene expression level in the anorexia model group was significantly increased by 5.77-fold (P < 0.0001), indicating that there was a more severe negative energy balance in the anorexia model group. ILA intervention reduced the Npy expression level to 25.25% of that in the anorexia model group (P < 0.001), alleviating the negative energy balance. After ILA drug intervention, compared with the healthy control group, the Npy gene expression level in the ILA intervention group was only increased by 1.60-fold (P < 0.01), and compared with the food-restricted control group, the Npy gene expression level in the ILA intervention group was only increased by 1.45-fold (P < 0.05). After the intervention with the ILA microcapsule embedding preparation, compared with the anorexia model group, the Npy gene expression level in the embedded ILA intervention group was decreased by 3.72-fold (P < 0.001), and compared with the food-restricted control group, there was no significant difference in the Npy gene expression level in the embedded ILA intervention group (P > 0.05). Moreover, there was no significant difference in the hypothalamic Npy gene expression level between the ILA drug intervention group and the embedded ILA intervention group. The results indicate that ILA may improve energy balance and feeding behavior by regulating appetite signals in the hypothalamus and inhibiting abnormally upregulated Npy.

[0070] 3. ILA upregulates the expression of pro-opiomelanocortin (Pomc) gene in anorectic mice

[0071] Pro-opiomelanocortin (POMC) is a multifunctional precursor protein that plays a key role in metabolic regulation and energy balance. POMC neurons are mainly located in the arcuate nucleus (ARC) of the hypothalamus, and it produces multiple bioactive peptides through processing, such as adrenocorticotropic hormone (ACTH), α-melanocyte-stimulating hormone (α-MSH), and β-endorphin. Among them, α-MSH is one of the main neuropeptides regulating feeding behavior, and it inhibits appetite and promotes energy consumption by acting on the melanocortin-4 receptor (MC4R). Chronic activation of POMC neurons inhibits food intake and increases metabolic rate, preventing the occurrence of obesity. In a state of energy deprivation, such as fasting or activity-based anorexia model (ABA model), the activity of POMC neurons is inhibited, resulting in a decrease in the release of α-MSH, thereby reducing the activation of MC4R and ultimately promoting feeding behavior. In addition, the inhibition of POMC neurons is usually accompanied by an increase in ghrelin levels, and ghrelin can antagonize the action of α-MSH on MC4R by activating AgRP (Agouti-related peptide) neurons in the hypothalamus, further enhancing appetite.

[0072] The results are as Figure 3(C) As shown, there was no significant difference between the healthy control group and the food-restricted control group. Compared with the food-restricted control group, the Pomc gene expression level in the anorexia model group was significantly reduced by 47.38% (P < 0.001), indicating that the anorexia model group had a more severe negative energy state. ILA intervention significantly increased the Pomc gene expression level, which was 1.86 times that of the anorexia model group (P < 0.01), alleviating the negative energy balance caused by anorexia. After ILA drug intervention, there was no significant difference in the Pomc gene expression level compared with the healthy control group and the food-restricted control group, indicating that the normal expression of the Pomc gene level was restored after ILA administration. In addition, after ILA microcapsule embedding preparation intervention, compared with the anorexia model group, the Pomc gene expression level in the embedded ILA intervention group was up-regulated by 1.62 times (P < 0.001), and there was no significant difference in the Pomc gene expression level in the embedded ILA intervention group compared with the food-restricted control group (P > 0.05). There was no significant difference in the hypothalamic Pomc gene expression level between the ILA drug intervention group and the embedded ILA intervention group. This indicates that the ILA embedding form did not significantly affect its effect on regulating Pomc. This result is consistent with the aforementioned experimental data on ILA promoting food intake, further supporting the potential role of ILA in alleviating the negative energy state of the ABA model. In summary, the results indicate that ILA may relieve the abnormal down-regulation of Pomc by regulating the appetite signal in the hypothalamus, thereby improving energy balance and feeding behavior.

[0073] (5) ILA significantly increased the proportion of c-fos positive neurons in the nucleus of the solitary tract (NTS) of anorexic mice

[0074] The mice in Example 1 were euthanized at 9:00 in the morning. Three mice in each group received intragastric administration of placebo (0.9% normal saline), ILA solution, and embedded ILA preparation 30 minutes before euthanasia. The intragastric administration dose for each mouse was 200 μl. The whole brains of the mice were immersed in paraformaldehyde solution and sent to Wuhan Sevier Biotechnology Co., Ltd. for paraffin section and immunofluorescence detection.

[0075] High levels of c-fos activation are considered one of the markers of neuronal activation. ILA may affect hypothalamic feeding regulatory neurons (such as AgRP / NPY or POMC neurons) through the vagus nerve-nucleus of the solitary tract (NTS) pathway, thereby regulating feeding behavior. Detecting NTS c-fos can explore the effect of ILA on the signal of this pathway.

[0076] The results are as Figure 4As shown, there was no significant difference in the proportion of c-fos positive cells between the healthy control group and the food-restricted control group. Compared with the food-restricted control group, the NTS c-fos signal in the anorexia model group was significantly weakened by 0.24-fold (P < 0.05), while ILA alleviated the attenuation of the NTS c-fos signal caused by the anorexia model. In the ILA drug intervention group, the expression of c-fos increased significantly, showing a highly significant difference compared with the anorexia model group (P < 0.001), and the expression level was 2.61 times that of the food-restricted control group. At the same time, in the embedded ILA intervention group, the expression of c-fos increased significantly, showing a significant difference compared with the anorexia model group (P < 0.001), and its c-fos expression level was 2.49 times that of the food-restricted control group. There was no obvious difference in the expression level of c-fos in the positive cells between the ILA drug intervention group and the embedded ILA intervention group. In summary, the results indicate that ILA treatment can strongly activate the neurons in the NTS region.

[0077] The embodiments provided above are not intended to limit the scope covered by the present invention, nor are the described steps intended to limit the order of their execution. Obvious improvements made by those skilled in the art to the present invention in combination with the existing common general knowledge also fall within the protection scope defined by the claims of the present invention.

Claims

1. Use of indole-3-lactic acid in the preparation of a product for promoting appetite.

2. The application according to claim 1, wherein The promotion of appetite is mainly achieved by indole-3-lactic acid through alleviating the compensatory increase in ghrelin levels in serum and increasing the proportion of c-fos positive neurons in the solitary tract nucleus.

3. The application according to claim 1, characterized in that, The promotion of appetite is mainly achieved by indole-3-lactic acid through down-regulating the expression of neuropeptide Y Npy gene and agouti-related protein Agrp gene and up-regulating the expression of proopiomelanocortin Pomc gene.

4. The application according to claim 1, wherein The product includes any one of food, medicine, functional food, nutritional supplement, food additive or health care product.

5. The application according to claim 1, wherein The indole-3-lactic acid is indole-3-lactic acid suspension or indole-3-lactic acid microcapsule sustained-release preparation.

6. The application according to claim 4, wherein the medicine comprises ILA, a drug carrier and / or a pharmaceutical excipient.

7. The application according to claim 6, wherein The drug carrier includes one or more of polymer microcapsules, nanoparticles, solid lipid nanoparticles, mesoporous silica nanoparticles, metal-organic frameworks commonly used in medicine.

8. Use of indole-3-lactic acid in the preparation of a product for relieving anorexia and loss of appetite.

9. A drug for alleviating the disorder of hypothalamic orexigenic neuropeptide levels, characterized in that, The active ingredient of the medicine is indole-3-lactic acid.

10. The medicament according to claim 9, wherein The alleviation of the disorder of hypothalamic appetite neuropeptides includes reducing the expression levels of Agrp and Npy genes and / or increasing the expression level of Pomc gene.

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