(1) RESEARCH PROGRESS OF CHLOROGENIC ACID
1. Anti-inflammatory and antioxidant
Heat stress has a significant effect on the performance of poultry. Chlorogenic acid (CGA) has antibacterial, anti-inflammatory and antioxidant effects. Chen Fang et al. (2021) studied the effects of dietary CGA supplementation on intestinal health and cecal microflora composition of chicks under acute heat stress, and randomly divided 100-day-old Hy-line brown chickens into 4 groups. Hens in control group (C) and heat stress group (HS) were fed a basal diet, and hens in HS + CGA300 and HS + CGA600 groups were fed the basal diet supplemented with 300 and 600mg/kg CGA for 2 weeks, respectively. Broilers in HS group, HS + CGA 300 group and HS + CGA 600 group were exposed to 38℃ for 4h, while the control group was maintained at 25℃. The results showed that dietary CGA can alleviate the decrease of T-AOC and T-SOD activities and increase of IL-1β and TNF-α induced by acute heat stress. Dietary supplementation of 600mg/kg CGA can improve the abundance of beneficial bacteria, such as: The relative abundance of beneficial bacteria genera such as Rikenellaceae RC9_gut_group, Ruminococcaceae UCG-005 and Christensenellaceae R-7_Group can reduce the abundance of inflammatory related bacteria, such as Suttelia. Therefore, CGA can ameliorate acute heat stress injury by inhibiting inflammation, enhancing antioxidant capacity and regulating cecal microflora composition.
2. Inhibit bacteria and regulate intestinal barrier function
-- Zhang Xinheng et al. (2020) Investigated the effects of chlorogenic acid (CA) on intestinal health, growth performance, oxidative stress, inflammatory response and blood biochemical indices of SPF chickens infected with Clostridium perfringens (CP). The results showed that chlorogenic acid could effectively improve the growth performance, inhibit the damage of small intestine structure, enhance antioxidant capacity, inhibit the damage of ileum mucosa construction and tight connection, inhibit inflammatory cytokines and improve blood biochemical indexes. Zhuo Chunliu et al. (2020) studied that after abdominal air sac infection with EScherichia coli O78, the mortality rate of laying chicks increased significantly, the intestinal tight junction function was impaired, cecal microflora changed, and immunity decreased. However, chlorogenic acid supplementation tended to increase the contents of IgA and IgM in serum of chickens infected with EScherichia coli O78, decreased the expression of il-1 β, IL-2 and IFN- α in serum, promoted the expression of jejunum tight junction protein gene, and increased the relative abundance of Firmicide in cecum of chickens in chlorogenic acid group. The relative abundance of Bacteroidetes and Proteobacteria decreased. Results show that stevia chlorogenic acid by inhibiting intestinal proinflammatory cytokines gene expression, activation of the host cell immunity and humoral immunity, and by increasing the intestinal tight junction protein gene expression and optimization of the intestinal microbial flora, thus inhibiting the intestinal tissue inflammation, improve the intestinal barrier function, enhance egg chicks immunity, to resist e. coli infection.
-- Yao Shanshan et al. (2020) discussed the elimination of drug resistance of chicken escherichia coli by chlorogenic acid by transcriptomic sequencing technology, and 1.25mg/mL chlorogenic acid can reduce the MIC of levofloxacin to drug-resistant reverse strains from 16μg/mL to 4-8 μg/mL. It can reduce the stress resistance of bacteria, inhibit the activity of drug resistance genes and inhibit the recombination of bacterial DNA, which can eliminate levofloxacin resistance of drug resistant EScherichia coli to a certain extent, and thus play the role of inhibition and elimination of drug resistance.
- king Jesus Qiang (2020), the results showed that chlorogenic acid can relieve LPS induced intestinal injury, and chlorogenic acid of intestinal stem cell number and function of adjustment may be implement intestinal injury protection function of chlorogenic acid, the basis of through intestinal organs for in vitro research model, based on constructing the intestinal type of organ damage model induced by LPS, Combined with JAK signaling pathway inhibitors, the mechanism of chlorogenic acid regulating intestinal stem cell function was explored. The results showed that the concentration of 1mM chlorogenic acid decreased from 0.5mM to 0.1 mM in duodenum after digestion by stomach, and caffeic acid and quinic acid were produced during this process. Chlorogenic acid promoted the expression of JAK signaling pathway in lPS-induced intestinal injury apoptosis stage. Chlorogenic acid plays a protective role in intestinal epithelial injury by activating the number of intestinal stem cells through the regulation of JAK signaling pathway in the proliferation stage of intestinal injury mice.
- Chlorogenic acid has obvious bacteriostatic effect on Clostridium perfringens and Escherichia coli, can eliminate drug resistance of EScherichia coli, alleviate lPS-induced intestinal injury of EScherichia coli, and regulate intestinal barrier function.
3. Regulate immunity and antiviral
-- Muhammad Abaidullah et al. (2021) studied the antiviral properties of CGA against infectious bronchitis virus (IBV) in vivo and in vitro for the first time. In vitro experiments confirmed that CGA significantly reduced the relative mRNA expression of IBV-N in CEK cells. 400mg/kg CGA-H can reduce the expression level of IBV-N mRNA and reduce the injury of trachea and lung. The expression levels of IL-6, IL-1β, IL-12 and NF-κB mRNA in trachea were significantly decreased, while the expression levels of IL-22 and IL-10 were increased. Cga-h treatment significantly increased the expression levels of MDA5, MAVS, TLR7, MyD88, IRF7, IFN-β and IFN- α in trachea and lung. Cga-h significantly induced proliferation of CD3+, CD4+ and CD4+/ CD8+, and significantly increased serum IgA, IgG and IgM levels. In conclusion, high concentration of CGA is a strong anti-IBV compound, which can effectively regulate innate immunity through MDA5, TLR7 and NF-κB signaling pathways, and induce cellular and humoral immune responses in CHICKENS infected with IBV.
-- Li Yinju et al. (2021) To investigate the protective effects of baicalin and chlorogenic acid on the inflammatory response caused by IBDV infection in chicken embryos. Chicken embryos at 9 days of age were randomly divided into 3 groups and treated with different concentrations of baicalin and chlorogenic acid and no treatment as control. 48 h after hatching, each group was inoculated with one virulence. The survival rate of the embryos was monitored daily, and the viral load in the liver and the content of inflammatory mediators in the liver were detected by QRT-PCR. When baicalin and chlorogenic acid concentrations were 108 and 215mg/ egg, respectively, they showed significant antiviral potential, significantly reducing histamine production, significantly inhibiting the activation of nf-kb, and thus inhibiting the production of pro-inflammatory cytokines TNF-α and il-1 β. The results showed that baicalin and chlorogenic acid have anti-IBDV properties and help prevent inflammation-related diseases.
- Chlorogenic acid has a good antiviral effect on infectious bronchitis virus (IBV) and Bursa of Fabricius virus (IBDV), mainly by inhibiting the expression of inflammatory factors, activating the body's immune system, to achieve the effect of disease prevention.
(2) APPLICATION PROSPECTS
Existing research data show that chlorogenic acid has anti-inflammatory, antioxidant, bacteriostatic, intestinal health improvement, antiviral and immune regulation effects, and can reduce the risk of many infectious diseases at the intestinal level. Chlorogenic acid is a natural, green and safe food additive and feed additive, which can replace synthetic chemical growth promoters (antibiotics) and immune enhancers, and has broad application prospects.
