Potential Role of Protocatechuic Acid as Natural Feed Additives in Farm Animal Production

Protocatechuic acid attenuates isoproterenol-induced heart failure by modulating cardiac oxidative stress, LDL-R/SREBP-2/PPAR-α, and Bax/Bcl-2 /Bcl-xL/Cyt.c/ Caspase - 9 and Caspase - 3 pathways

Worldwide, heart failure (HF) is among the top causes of morbidity and mortality. Curative interventions using natural products for cardiovascular diseases have gained substantial attention worldwide. At present, there is little research on the protective mechanisms of protocatechuic acid in HF. Hence, we evaluated the protective mechanisms of protocatechuic acid on cardiac oxidative stress, low-density lipoprotein-receptor (LDL-R)/sterol regulatory element-binding protein-2 (SREBP-2)/peroxisome proliferator-activated receptor-α(PPAR-α) and B-cell lymphoma-2 associated-x (Bax)/B-cell lymphoma gene-2(Bcl-2)/B-cell lymphoma-extra large(Bcl-xL)/Cytochrome c (Cyt.c)/Caspase-3/Caspase -9 pathways in isoproterenol-induced HF rats. Rats were induced HF by isoproterenol (5 mg/kg body weight) daily for 7 days. Then, rats were treated with protocatechuic acid (16 mg/kg body weight) for four weeks. The serum HF diagnostic marker and heart lipid hydroperoxides were increased and systolic and diastolic pressure and heart antioxidants were reduced in the isoproterenol-induced HF rats. Moreover, serum and heart total cholesterol, triglycerides, and serum low-density lipoprotein-cholesterol and liver 3-hydroxy-3 -methylglutaryl coenzyme A reductase were elevated and serum high density lipoprotein-cholesterol was reduced in the HF rats. Furthermore, lipid peroxidation products in the heart lysosomal fraction and lysosomal enzymes in the serum and heart were increased.A reverse transcription-polymerase chain reaction study revealed altered expression of hepatic LDL-R, SREBP-2, and PPAR- α and myocardial expression of Bax, Bcl-2, Bcl-xL, Cyt.c, Caspases-3, and -9 genes. Nevertheless, HF rats treated with protocatechuic acid considerably attenuated all the hemodynamic, biochemical, molecular, transmission electron microscopic, and histological parameters investigated and protected HF rats, by its potent antioxidant, anti-hyperlipidemic and anti-apoptotic mechanisms.

Cell-free system for one-pot production of protocatechuate via a two-enzyme cascade with coenzyme regeneration

Protocatechuate, an aromatic compound with significant industrial application, has garnered increasing interest in its production through various metabolic engineering methods. However, these methods still face limitations that hinder their feasibility for large-scale industrial application. Therefore cell-free systems could serve as a better alternative in this field. Here, we describe a two-enzyme cascade system utilizing benzaldehyde dehydrogenase (AspBADH) and p-hydroxybenzoate hydroxylase (AspPHBH) for protocatechuate production from 4-hydroxybenzaldehyde (4-HBAL), with coenzyme regeneration enabled within the system. We first characterized the enzymatic activity of AspBADH and then integrated AspPHBH into an in-vitro system for protocatechuate production. Optimal conditions were identified as pH 7.4 and a temperature range of 20-40 °C, achieving approximately 50 % substrate conversion with a 1:1 enzyme ratio at a concentration of 15 mg/ml. Notably, increasing the ratio of AspBADH to AspPHBH further enhanced conversion efficiency. To improve industrial applicability, we immobilized the enzymes in glutaraldehyde-crosslinked chitosan beads, which enhanced reusability and stability. The immobilized enzyme cascade exhibited over 90 % substrate conversion in a single cycle and a 60 % total yield after purification. Although the specific activity decreased compared to the free enzymes, the immobilized system demonstrated reusability, maintaining activity through 8 cycles.

Transcriptomic and proteomic analysis of the jejunum revealed the effects and mechanism of protocatechuic acid on alleviating Salmonella typhimurium infection in chickens

Salmonella typhimurium is a common cause of gastroenteritis, which infects animals and human. Protocatechuic acid has anti-inflammatory, immunoregulatory and anti-pathogenic effects, and is expected to be an effective choice for alleviating Salmonella infection and intestinal injury. A total of 180 1-d female, yellow-feathered chickens were randomly allocated into 3 treatment groups, the controls (Ctr), the Salmonella-challenged treatment (Sal) and the protocatechuic acid treatment (PA). Birds were fed a basal diet for 18 d, with birds in PA supplemented with 600 mg/kg protocatechuic acid. On 14 and 16 d, birds in Sal and PA were orally challenged with 109 CFU S. typhimurium, while birds in Ctr received an equal amount of PBS. The results showed that protocatechuic acid improved growth performance and jejunal structure in Salmonella-infected chickens (P < 0.05). In addition, protocatechuic acid suppressed (P < 0.05) the secretion of plasmal IgG, IL-1β, and IFN-β, and jejunal mucosal IL-6, IFN-β, complement protein 3 and 4. Mechanistically, the transcriptomic results showed that dietary protocatechuic acid inhibited acute inflammatory response and activated the signaling pathways of cytokine-cytokine receptor interaction, complement and coagulation cascades. Results of proteomic showed that protocatechuic acid inhibited the positive regulation of dendritic cell cytokine production and I-κB kinase/NF-κB signaling, as well as cytokine-cytokine receptor interaction and MAPK signaling pathways, and activated the mTOR signaling pathways. These results were critical to both suppressing the secretion of inflammatory cytokines and restoring the intestinal function. Dietary protocatechuic acid (600 mg/kg) was effective to alleviate Salmonella infection, as it suppressed the levels of cytokines and complement protein by inhibiting MAPK, I-κB kinase/NF-κB and enhancing the mTOR signaling pathway, thus offset the decline in weight loss and intestinal injury caused by infection.

Effects of Flavonoids in Fructus Aurantii Immaturus on Carcass Traits, Meat Quality and Antioxidant Capacity in Finishing Pigs

This experiment aimed to explore the effects of flavonoids in Fructus Aurantii Immaturus (FFAI) on carcass traits, meat quality, and the antioxidant capacity of finishing pigs. The results indicated that the addition of an appropriate amount of FFAI into their diet could significantly reduce the backfat thickness and perirenal fat percentage of finishing pigs, as well as the drip loss, water-holding capacity, shear force, and the levels of lactate, glucose-6-phosphate, glucose, ATP, phosphofructokinase, and pyruvate in the longissimus dorsi (LD) muscle. It also elevated the levels of flavor amino acids such as glutamate, serine, and threonine, and enriched the composition of flavor substances, including benzene and octanal, which significantly contributed to the enhancement of pork flavor. Furthermore, it enhanced the expression levels of MyHC I and MyHC IIa. In summary, the appropriate addition of FFAI to the diet could improve the carcass traits, meat quality, and antioxidant capacity of finishing pigs. The optimal level of FFAI supplementation is 0.12%.

Achyrocline satureioides infusion, popularly prepared and consumed, has an in vitro protective effect on human neural cells exposed to rotenone

ETHNOPHARMACOLOGICAL RELEVANCE

Traditional harvest of Achyrocline satureioides (AS) occurs at dawn on Good Friday in some South American countries. Inflorescences are traditionally used as infusions for several disorders, including neuropsychiatric disorders. Pillows and cushions are popularly filled with AS to attenuate the symptoms of depression, anxiety, and sleep disturbances. However, evidence for the potential beneficial effects of AS on human neural cells remains unclear.

AIM OF THE STUDY

An in vitro model of SH-SY5Y human neural cells was applied to evaluate the effect of AS infusion, prepared as commonly used, on cells exposed to rotenone and to investigate its potential for neuropsychiatric disorders.

MATERIALS AND METHODS

A hot aqueous extract was obtained from a traditionally prepared AS inflorescence infusion and chemically characterized by high-resolution mass spectrometry and spectrophotometric quantification of total polyphenols, tannins, and flavonoids. The SH-SY5Y cell cultures were treated with AS extract at concentrations of 1, 3, 5, 10, 50, 100, and 300 μL/mL to determine the potential cyto- and genotoxic effects of AS on neural cells using MTT, Neutral Red, and GEMO assays. Apoptosis modulation was assessed using flow cytometry and apoptosis-modulating genes were evaluated by qRT-PCR. The protective effect of AS on the neurotoxicity triggered by rotenone exposure (30 nM) was determined by analyzing cellular viability and oxidative markers such as lipid peroxidation and protein carbonylation, and DNA damage was assessed by micronucleus assay.

RESULTS

The AS extract, as traditionally prepared, had estimated concentrations of 409.973 ± 31.107 μg/mL, 0.1041 ± 0.0246 mg GAE/mL, and 63.309 ± 3.178 mg QE/mL of total tannins, total polyphenols, and flavonoids, respectively. At concentrations of 30 and 100 μl/mL, AS decreased apoptotic events, whereas the highest concentration (300 μl/mL) increased apoptosis compared to that in the control (p < 0.05). In cells exposed to rotenone, AS treatment induced cell proliferation, reduced DNA damage (as evaluated by micronuclei), and reduced lipid and protein oxidation.

CONCLUSIONS

The data indicate the non-cytotoxic and beneficial effects of AS extract on human neural cells by reducing cellular mortality and oxidative stress in neural cells triggered by rotenone exposure.

Protocatechuic acid alleviates polycystic ovary syndrome symptoms in mice by PI3K signaling in granulosa cells to relieve ROS pressure and apoptosis

BACKGROUND

Polycystic ovary syndrome (PCOS) is a complicated gynecological endocrine disease that occurs in women of childbearing age. Protocatechuic acid is a phenol-rich compound derived from herbs and owns vital functions in numerous diseases. Howbeit, protocatechuic acid's impact on PCOS is unknown.

METHODS

A combination of in vivo and in vitro models was examined in this study. C57BL/6 mice were injected subcutaneously daily with dehydroepiandrosterone to establish a PCOS mouse model, and protocatechuic acid was intraperitoneally injected into PCOS mice. Granulosa cells of PCOS ovaries were also isolated. The function of protocatechuic acid was appraised using enzyme-linked immunosorbent assay, hematoxylin-eosin staining, reactive oxygen species (ROS) and LC3 levels analysis, flow cytometry, quantitative real-time PCR, and western blot. Meanwhile, the mechanism of protocatechuic acid was assessed with a series of molecular experiments.

RESULTS

Protocatechuic acid owned no apparent toxic effect on mice. Functionally, protocatechuic acid owned a function of mitigating PCOS in vivo. Meanwhile, protocatechuic acid repressed ROS, autophagy, and apoptosis of PCOS ovarian granulosa cells in vitro. Mechanistically, rescue assays elucidated that the protective function of protocatechuic acid against PCOS was interrelated to the activation of the PI3K/AKT/mTOR axis.

CONCLUSION

Protocatechuic acid alleviated PCOS symptoms in mice through PI3K signaling in granulosa cells to reduce ROS levels and apoptosis.

Flavonols and Flavones as Potential anti-Inflammatory, Antioxidant, and Antibacterial Compounds

Plant preparations have been used to treat various diseases and discussed for centuries. Research has advanced to discover and identify the plant components with beneficial effects and reveal their underlying mechanisms. Flavonoids are phytoconstituents with anti-inflammatory, antimutagenic, anticarcinogenic, and antimicrobial properties. Herein, we listed and contextualized various aspects of the protective effects of the flavonols quercetin, isoquercetin, kaempferol, and myricetin and the flavones luteolin, apigenin, 3 $\prime$ ,4 $\prime$ -dihydroxyflavone, baicalein, scutellarein, lucenin-2, vicenin-2, diosmetin, nobiletin, tangeretin, and 5-O-methyl-scutellarein. We presented their structural characteristics and subclasses, importance, occurrence, and food sources. The bioactive compounds present in our diet, such as fruits and vegetables, may affect the health and disease state. Therefore, we discussed the role of these compounds in inflammation, oxidative mechanisms, and bacterial metabolism; moreover, we discussed their synergism with antibiotics for better disease outcomes. Indiscriminate use of antibiotics allows the emergence of multidrug-resistant bacterial strains; thus, bioactive compounds may be used for adjuvant treatment of infectious diseases caused by resistant and opportunistic bacteria via direct and indirect mechanisms. We also focused on the reported mechanisms and intracellular targets of flavonols and flavones, which support their therapeutic role in inflammatory and infectious diseases.