Antioxidant and antihypertensive effects of garlic protein and its hydrolysates and the related mechanism

Comments on "health-promoting properties of bioactive proteins and peptides of garlic (Allium sativum)", food chemistry 435 (2024) 137632-137,643, DOI: 10.1016/j.foodchem.2023.137632

The article "Health-promoting properties of bioactive proteins and peptides of garlic (Allium sativum)" by Ezeorba et al. (Food Chemistry 435 (2024) 137632-137,643, DOI: https://doi.org/10.1016/j.foodchem.2023.137632), offers a comprehensive review of the literature on the bioactive proteins and peptides found in garlic. This study serves as a valuable resource for professionals in the fields of research, nutrition, and healthcare who are interested in the medicinal and nutritional aspects of garlic. This Letter to the Editor aims to address some inaccuracies and omissions found in the above-mentioned article. It corrects the reported lack of biological activity data for certain peptides, clarifies the immunomodulatory effects attributed to garlic's components, and adjusts the reported protein content range for garlic varieties. These refinements aim to enhance the accuracy and utility of the information presented in this article for future research.

Chitosan based ethanolicAllium Sativumextract hydrogel film: a novel skin tissue regeneration platform for 2nd degree burn wound healing

This study investigated the potential of ethanolic garlic extract-loaded chitosan hydrogel film for burn wound healing in an animal model. The ethanolic garlic extract was prepared by macerating fresh ground garlic cloves in ethanol for 24 h, followed by filtration and concentration using a rotary evaporator. Hydrogels were then prepared by casting a chitosan solution with garlic extract added at varying concentrations for optimization and, following drying, subjected to various characterization tests, including moisture adsorption (MA), water vapor transmission rate (WVTR), and water vapor permeability rate (WVPR), erosion, swelling, tensile strength, vibrational, and thermal analysis, and surface morphology. The optimized hydrogel (G2) was then analyzedin vivofor its potential for healing 2nd degree burn wounds in rats, and histological examination of skin samples on day 14 of the healing period. Results showed optimized hydrogel (G2; chitosan: 2 g, garlic extract: 1 g) had MA of 56.8% ± 2.7%, WVTR and WVPR of 0.00074 ± 0.0002, and 0.000 498 946 ± 0.0001, eroded up to 11.3% ± 0.05%, 80.7% ± 0.04% of swelling index, and tensile strength of 16.6 ± 0.9 MPa, which could be attributed to the formation of additional linkages between formulation ingredients and garlic extract constituents at OH/NH and C=O, translating into an increase in transition melting temperature and enthalpy (ΔT= 238.83 °C ± 1.2 °C, ΔH= 4.95 ± 0.8 J g-1) of the chitosan moieties compared with blank. Animal testing revealed G2 formulation significantly reduced the wound size within 14 d of the experiment (37.3 ± 6.8-187.5 ± 21.5 mm2) and had significantly higher reepithelization (86.3 ± 6.8-26.8 ± 21.5 and 38.2% ± 15.3%) compared to untreated and blank groups by hastening uniform and compact deposition of collagen fibers at the wound site, cementing developed formulation a promising platform for skin regeneration.

Cardiovascular Effects of Herbal Products and Their Interaction with Antihypertensive Drugs-Comprehensive Review

Hypertension is a highly prevalent population-level disease that represents an important risk factor for several cardiovascular complications and occupies a leading position in mortality statistics. Antihypertensive therapy includes a wide variety of drugs. Additionally, the potential antihypertensive and cardioprotective effects of several phytotherapy products have been evaluated, as these could also be a valuable therapeutic option for the prevention, improvement or treatment of hypertension and its complications. The present review includes an evaluation of the cardioprotective and antihypertensive effects of garlic, Aloe vera, green tea, Ginkgo biloba, berberine, ginseng, Nigella sativa, Apium graveolens, thyme, cinnamon and ginger, and their possible interactions with antihypertensive drugs. A literature search was undertaken via the PubMed, Google Scholar, Embase and Cochrane databases. Research articles, systematic reviews and meta-analyses published between 2010 and 2023, in the English, Hungarian, and Romanian languages were selected.

Changes in Garlic Quality during Fermentation under Different Conditions

One of the garlic processing methods is fermentation, which produces black garlic with completely different chemical, physical, sensory, culinary, and health-enhancing properties. Our study aimed to compare the influence of various processing conditions on the quality indicators of black garlic (BG). Samples of white garlic (WG) were placed in laboratory climatic chambers. BG1 samples were packed in plastic bags and vacuumed, BG2 and BG3 samples were packed in textile mesh bags. BG1 samples were fermented in 70% humidity at 50 °C for 28 days, BG2 samples in 85% humidity at 60 °C for 99 days, and BG3 samples in 80% humidity at 80 °C for 14 days. The dependence of changes in chemical composition, color, and texture of garlic on fermentation conditions was analyzed. Proximate composition analyses and antioxidant activity of WG and BG were performed using standard methods. It was established that regardless of the fermentation conditions, BG's chemical composition became richer than WG's. They significantly increased vitamin C content (1.5-5.8 fold), titratable acidity (14.7-21.0 fold), protein (1.4-3.2 fold), fiber (4.6-7.0 fold), and ash (1.2-3.9 fold) content, amount of total phenolic compounds (6.6-9.6 fold) and antioxidant activity (5.3-9.9 fold). Fermented garlic turned dark in color and soft and sticky in texture. The higher fermentation temperature (80 °C) but the shorter time (14 days) had the greatest positive effect on the quality of black garlic.

Health-promoting properties of bioactive proteins and peptides of garlic (Allium sativum)

Garlic is a popular food spice with diverse and well-established medicinal properties. Many research interests have been directed toward the biological activities of the phytochemical constituents of garlic. However, prospects of its bioactive proteins and peptides have been understudied to date. With the advances in food proteomics/peptide research, a review of studies on garlic bioactive proteins and peptides, especially on their nature, extraction, and biological activities, is timely. Garlic has been reported to express several proteins, endogenous and protein-derived peptides with interesting bioactivities, including antioxidant, anti-inflammatory, antibacterial, antifungal, anti-proliferative, antiviral, anti-hypertensive and immunomodulatory activities, suggesting their therapeutic and pharmacological potentials. Compared to legumes, the low protein contents of garlic bulbs and their low stability are possible limitations that would hinder future applications. We suggest adopting heterologous expression systems for peptide overproduction and stability enhancement. Therefore, we recommend increased scientific interest in the bioactive peptides of garlic and other spice plants.

Two novel angiotensin I-converting enzyme inhibitory peptides from garlic protein: In silico screening, stability, antihypertensive effects in vivo and underlying mechanisms

This study aimed to screen novel angiotensin I-converting enzyme (ACE) inhibitory peptides from garlic proteins and to explore their underlying antihypertensive mechanisms in vivo. After simulated hydrolysis and in silico screening, two novel peptides (MGR and HDCF) were obtained with the highest ACE inhibitory activity (IC50 of 4.50 μM and 26.38 μM) and acted as competitive inhibitors. They interacted with key residues in the ACE receptor mainly through hydrogen bonding and exhibited excellent stability against high temperature, extreme pH, and gastrointestinal digestion. In spontaneously hypertensive rats, MGR and HDCF effectively lowered blood pressure after single or continuous treatments. This was mainly achieved by balancing the renin-angiotensin system, improving renal and cardiac impairment, and regulating endothelial dysfunction. These findings suggested that garlic proteins were potentially suitable materials to prepare ACE inhibitory peptides and provided two promising candidates for ACE inhibition as functional food ingredients.

Screening potential hypertensive peptides using two consecutive bioassay-guided SPE fractionations and identification of an ACE inhibitory peptide, DHSTAVW (DW7), derived from pearl garlic protein hydrolysate

The pearl garlic (Allium sativum L.) protein (PGP) was digested using pepsin, trypsin, α-chymotrypsin, thermolysin, and simulated gastrointestinal digestion. The α-chymotrypsin hydrolysate showed the highest angiotensin-I-converting enzyme inhibitory (ACEI) activity, with an IC₅₀ value of 190.9 ± 11µg/mL. A reversed-phase C₁₈ solid-phase extraction (RP-SPE) cartridge was used for the first fractionation, and the S4 fraction from RP-SPE showed the most potent ACEI activity (IC₅₀ = 124.1 ± 11 3µg/mL). The S4 fraction was further fractionated using a hydrophilic interaction liquid chromatography SPE (HILIC-SPE). The H4 fraction from HILIC-SPE showed the highest ACEI activity (IC₅₀ = 57.7 ± 3µg/mL). Four ACEI peptides (DHSTAVW, KLAKVF, KLSTAASF, and KETPEAHVF) were identified from the H4 fraction using liquid chromatography-tandem mass spectrometry (LC-MS/MS), and their biological activities were appraised in silico. Among the identified α-chymotryptic peptides, DHSTAVW (DW7), derived from I lectin partial protein, exhibited the most potent ACEI activity (IC₅₀ value of 2.8 ± 0.1µM). DW7 was resistant to simulated gastrointestinal digestion, and it was classified as a prodrug-type inhibitor according to the preincubation experiment. The inhibition kinetics indicated that DW7 was a competitive inhibitor, which was rationalized by the molecular docking simulation. The quantities of DW7 in 1mg of hydrolysate, S4 fraction, and H4 fraction were quantified using LC-MS/MS to give 3.1 ± 0.1, 4.2 ± 0.1, and 13.2 ± 0.1µg, respectively. The amount of DW7 was significantly increased by 4.2-fold compared with the hydrolysate, which suggested that this method is efficient for active peptide screening.

Comparative Analysis of the Antioxidant, Antidiabetic, Antibacterial, Cytoprotective Potential and Metabolite Profile of Two Endophytic Penicillium spp

The current study assessed the metabolite abundance, alpha (α)-amylase and α-glucosidase inhibitory, antioxidant, and antibacterial activity of the ethyl acetate extract (EAE) of endophytic Penicillium lanosum (PL) and Penicillium radiatolobatum (PR). A higher extract yield was found in EAE-PR with a total phenolic content of 119.87 ± 3.74 mg of GAE/g DW and a total flavonoid content of 16.26 ± 1.95 mg of QE/g DW. The EAE-PR inhibited α-amylase and scavenged ABTS+ radicals with a half-maximal inhibitory concentration (IC₅₀) of 362.5 and 37.5 µg/mL, respectively. Compared with EAE-PL, EAE-PR exhibited higher antibacterial activity against Gram-positive and Gram-negative pathogens. Treatment with EAE-PR (1000 µg/mL) did not cause significant toxicity in the HEK-293 cell line compared to the control cells (p < 0.05). EAE-PR treatments (250-1000 µg/mL) showed higher cytoprotective effects toward H₂O₂-stressed HEK-293 cells compared with ascorbic acid (AA). The UHPLC-Q-TOF-MS/MS analysis revealed the presence of thiophene A (C₁₃H₈S), limonene (C₁₀H₁₆), and phenylacetic acid (C₈H₈O₂) in EAE-PR. Furthermore, these compounds demonstrated substantial interactions with diabetes (α-amylase and α-glucosidase), oxidative stress (NADPH-oxidase), and bacteria (D-alanine D-alanine ligase)-related enzymes/proteins evidenced in silico molecular docking analysis.

Therapeutic Potential of Allicin and Aged Garlic Extract in Alzheimer’s Disease

Garlic, Allium sativum, has long been utilized for a number of medicinal purposes around the world, and its medical benefits have been well documented. The health benefits of garlic likely arise from a wide variety of components, possibly working synergistically. Garlic and garlic extracts, especially aged garlic extracts (AGEs), are rich in bioactive compounds, with potent anti-inflammatory, antioxidant and neuroprotective activities. In light of these effects, garlic and its components have been examined in experimental models of Alzheimer’s disease (AD), the most common form of dementia without therapy, and a growing health concern in aging societies. With the aim of offering an updated overview, this paper reviews the chemical composition, metabolism and bioavailability of garlic bioactive compounds. In addition, it provides an overview of signaling mechanisms triggered by garlic derivatives, with a focus on allicin and AGE, to improve learning and memory.

Chrysophyllum cainito. L alleviates diabetic and complications by playing antioxidant, antiglycation, hypoglycemic roles and the chemical profile analysis

ETHNOPHARMACOLOGICAL RELEVANCE

Chrysophyllum cainito L. (C. cainito) is a traditional folk medicine in tropical area which can be an alternative agent for diabetes mellitus. Although the antioxidant and antidiabetic activity of the extracts are reported, little is known on the antiglycation activity and effects on diabetic complications.

AIM OF THE STUDY

This work was aimed to investigate the chemical profile, antidiabetic, antioxidant activities of C. cainito. Especially, the antiglycation potential as well as the relationships between components and activities were evaluated.

MATERIALS AND METHODS

The content of the primary components (polyphenols, flavonoids, steroids, and triterpenes), antioxidant, and hypoglycemic effects of ethanolic extracts from C. cainito leaves (CCE-1, 2, 3, 4) and stems (CSE-1, 2, 3, 4) were analyzed and detected. The chemical profiles of CCE-2 were characterized by HPLC-Q-TOF-MS/MS. The antiglycation and protection against oxidative stress effects were determined by in vitro assays. Relationship between bioactivities and components was analyzed by principal component analysis (PCA), heatmap analysis, and Pearson correlation analysis.

RESULTS

The composition was diverse between leaves and stem extracts with different activities. CCE-2 possessed the highest DPPH scavenging activity. CSE-2 displayed the highest ABTS scavenging activity and ferric reducing power. While CCE-3 showed the most effective inhibition on α-amylase and α-glucosidase activity (IC₅₀ 4.103 ± 0.332 μg/mL and 0.180 ± 0.006 mg/mL, respectively). PCA analysis showed that the most important variables in PC1 (60.7%) were total polyphenol and antioxidant activities. The hypoglycemic activity and contents of steroids showed important correlation. Advanced glycation end products formation was effectively inhibited by CCE-2 with myricetin 3-O-rhamnoside as the main constituent. CCE-3 displayed the highest protection effect against L02 cell line oxidation damage.

CONCLUSIONS

C. cainito leaves might be a promising candidate for antioxidant, hypoglycemic and antiglycation dietary supplement or potential agent against diabetes associated chronic diseases.

Engineering Concanavalin B to Release Bioactive Peptides against Metabolic Syndrome

Metabolic syndrome is a severe public health issue characterized by multiple metabolic disturbances. Current treatments prescribe a particular drug for each of them, producing multiple side effects. As a first step towards a more integral approach, we applied our recently described methodology to design single proteins, based in the Concanavalin B scaffold (1CNV), that contain several bioactive peptides (BPs), including antioxidant and lipid-lowering activities as well as inhibitors of dipeptidyl peptidase IV (DPPIV) and the angiotensin converting enzyme. Modified Concanavalin (CNV44), the designed protein that showed the best in silico properties, was expressed in high yields in E. coli and purified to homogeneity. After in vitro digestion with gastrointestinal enzymes, all the biological activities tested where higher in CNV44 when compared to the non-modified protein 1CNV, or to other previous reports. The results presented here represent the first in vitro evidence of a modified protein with the potential to treat metabolic syndrome and open the venue for the design of proteins to treat other non-communicable diseases.

Enzyme-Assisted Extraction to Obtain Phenolic-Enriched Wine Lees with Enhanced Bioactivity in Hypertensive Rats

The antihypertensive effect of the soluble fraction of wine lees (WL) from Cabernet variety grapes was recently reported by our group. This blood pressure (BP)-lowering effect was attributed to the presence of flavanols and anthocyanins. In this context, phenolic-enriched wine lees (PWL) could potentially exhibit a stronger bioactivity. Therefore, the aim of this study was to obtain a soluble fraction of WL with increased phenolic content and evaluate its functionality. The PWL were obtained using an enzyme-assisted extraction based on the hydrolysis of WL proteins with Flavourzyme^®. They contained 57.20% more total phenolic compounds than WL, with anthocyanins and flavanols being the largest families present. In addition, PWL also showed greater angiotensin-converting enzyme inhibitory and antioxidant activities. Finally, the antihypertensive activity of the PWL was evaluated in spontaneously hypertensive rats. A single dose of 5 mL/kg body weight of PWL showed a greater BP-lowering effect than the one shown by WL. Moreover, this antihypertensive effect was more prolonged than the one produced by the antihypertensive drug Captopril. These results demonstrate that enzymatic protein hydrolysis is a useful method to maximize the extraction of phenolic compounds from WL and to obtain extracts with enhanced functionalities.

Phytotherapy for Cardiovascular Disease: A Bench-to-Bedside Approach

At present, cardiovascular disease (CVD) remains the leading cause of morbidity and mortality worldwide, and global trends suggest that this panorama will persist or worsen in the near future. Thus, optimization of treatment strategies and the introduction of novel therapeutic alternatives for CVD represent key objectives in contemporary biomedical research. In recent years, phytotherapy-defined as the therapeutic use of whole or minimally modified plant components-has ignited large scientific interest, with a resurgence of abundant investigation on a wide array of medicinal herbs (MH) for CVD and other conditions. Numerous MH have been observed to intervene in the pathophysiology of CVD via a myriad of molecular mechanisms, including antiinflammatory, anti-oxidant, and other beneficial properties, which translate into the amelioration of three essential aspects of the pathogenesis of CVD: Dyslipidemia, atherosclerosis, and hypertension. Although the preclinical data in this scenario is very rich, the true clinical impact of MH and their purported mechanisms of action is less clear, as large-scale robust research in this regard is in relatively early stages and faces important methodological challenges. This review offers a comprehensive look at the most prominent preclinical and clinical evidence currently available concerning the use of MH in the treatment of CVD from a bench-to-bedside approach.

Antioxidant and enzymes inhibitory properties of Amaranth leaf protein hydrolyzates and ultrafiltration peptide fractions

Amaranth leaf protein isolate (ALI) was hydrolyzed using four different proteases (alcalase, trypsin, pepsin, and chymotrypsin) followed by fractionation of the pepsin hydrolyzate (PH) into different sizes using ultrafiltration membrane. Gel permeation chromatography showed that all the hydrolyzates had smaller size peptides (<7 kDa) than the protein isolate (>32 kDa). The chymotrypsin hydrolyzate had higher contents of hydrophobic amino acid (44.95%) compared to alcalase (42.72%), pepsin (43.93%), and trypsin (40.95%) hydrolyzates. The PH had stronger DPPH, hydroxyl radical, and superoxide radical scavenging activities than the other protein hydrolyzates but weaker Ferric reducing antioxidant power and metal chelating activities when compared to the peptide fractions. The <1 kDa peptide fraction exhibited stronger DPPH, hydroxyl, and superoxide radicals scavenging activities than the higher molecular weight (>1 kDa) fractions. Fractionation of PH also resulted in enhanced inhibition of α-amylase and ACE activities but weaker α-glucosidase inhibition. PRACTICAL APPLICATIONS: ALI was hydrolyzed using four proteases to produce protein hydrolyzates. The most active of the hydrolyzate was then fractionated to produce fractions of different molecular sizes. The results of the analyses showed that the hydrolyzates and the fractions showed good antioxidant and enzyme inhibitory activities such as the inhibition of ACE, α-amylase, and glucosidase enzymes. The results suggest that the enzymatic hydrolyzates and peptide fractions could be used as ingredients in the nutraceutical and functional food industries to scavenge free radicals and inhibit angiotensin-converting enzyme activity.