Antihypertensive activity of the ACE-renin inhibitory peptide derived from Moringa oleifera protein

Two novel angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibiting peptides from tilapia (Oreochromis mossambicus) skin and their molecular docking mechanism

In the study, papain was used to hydrolyze tilapia (Oreochromis mossambicus) skin to obtain a tilapia skin hydrolysate (TSH) with dual angiotensin-converting enzyme (ACE) and dipeptidyl peptidase IV (DPP-IV) inhibitory activities. The resulting TSH was sequentially fractionated by ultrafiltration, size exclusion separation chromatography, and reverse-phase high-performance liquid chromatography. Its inhibitory effects on ACE and DPP-IV were determined by commercial reagent kits. Two peptides purified from TSH were identified as Gly-Pro-Leu-Gly-Ala-Leu (GPLGAL) and Lys-Pro-Ala-Gly-Asn (KPAGN) by the ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Inhibitory concentration (IC50) of GPLGAL on ACE and DPP-IV were 117.20 ± 1.69 and 187.10 ± 2.75 µM, respectively. IC50 of KPAGN on ACE and DPP-IV were 137.40 ± 2.33 and 259.20 ± 2.85 µM, respectively. The molecular simulation demonstrated that the binding affinities of GPLGAL to ACE and DPP-IV proteins were -8.5 and -7.4 kcal/mol, respectively, whereas those of KPAGN to ACE and DPP-IV proteins were -7.9 and -6.7 kcal/mol, respectively. GPLGAL interacted with 21 amino acid residues of the ACE active site, whereas KPAGN engaged with 19 amino acid residues. Additionally, GPLGAL interacted with 10 amino acid residues of the DPP-IV active site, whereas KPAGN engaged with 13 amino acid residues. The two peptides predominantly occupied the active sites of ACE (His513, Tyr523, and Ala354) and DPP-IV (Tyr662 and Arg125) through hydrogen bonding. This leads to the deactivation of ACE and DPP-IV. PRACTICAL APPLICATION: Accelerate tilapia skin development and high-value utilization; provide foundation for preparing the peptides with dual ACE and DPP-IV inhibiting activity.

Isolation and identification of angiotensin-converting enzyme inhibitory peptides from Tartary buckwheat albumin

BACKGROUND

Tartary buckwheat protein peptides have been shown to be able to inhibit angiotensin-converting enzyme (ACE), but the exact protein type has been less studied for ACE activity inhibition, and only a few types of ACE inhibitory peptides have been reported. In this study, we purified and identified ACE inhibitory peptides from albumin hydrolysate (AH).

RESULTS

Albumin, globulin, prolamin and glutelin were extracted from Tartary buckwheat, and their ACE active peptides were obtained by a pepsin-trypsin sequential hydrolysis process. All four hydrolysates exhibited ACE inhibitory activity, and AH displayed the strongest ACE inhibition activity and the highest peptide yield (82.28%). At 0.2 mg mL^-1 , the inhibition rate of AH was 79.89%, followed by globulin hydrolysate at 71.84%, while prolamin hydrolysate and glutelin hydrolysate showed lower inhibition rates. The peptides with the highest inhibition rate were then isolated from AH using gel filtration chromatography and reversed-phase high-performance liquid chromatography, and identified using nanoscale high-performance liquid chromatography-tandem mass spectrometry. After isolation and purification, 42 ACE inhibitory peptides were identified in the fraction with the highest inhibition rate, 14 of which were completely novel discoveries in this study. These 14 peptides showed potent ACE inhibitory effects through computer analysis.

CONCLUSION

Tartary buckwheat albumin can be used as a good source of ACE inhibitory peptides and can be further developed and utilized as edible supplements or drugs. © 2023 Society of Chemical Industry.

Moringa oleifera Lam.: a comprehensive review on active components, health benefits and application

Moringa oleifera Lam. is an edible therapeutic plant that is native to India and widely cultivated in tropical countries. In this paper, the current application of M. oleifera was discussed by summarizing its medicinal parts, active components and potential mechanism. The emerging products of various formats such as drug preparation and product application reported in the last years were also clarified. Based on literature reports, the unique components and biological activities of M. oleifera need to be further studied. In the future, a variety of new technologies should be applied to the development of M. oleifera products, to enrich the varieties of dosage forms, improve the bitter taste masking technology, and make it better for use in the fields of food and medicine.

Alternative Protein Sources and Novel Foods: Benefits, Food Applications and Safety Issues

The increasing size of the human population and the shortage of highly valuable proteinaceous ingredients has prompted the international community to scout for new, sustainable, and natural protein resources from invertebrates (e.g., insects) and underutilized legume crops, unexploited terrestrial and aquatic weeds, and fungi. Insect proteins are known for their nutritional value, being rich in proteins with a good balance of essential amino acids and being a valuable source of essential fatty acids and trace elements. Unconventional legume crops were found rich in nutritional, phytochemical, and therapeutic properties, showing excellent abilities to survive extreme environmental conditions. This review evaluates the recent state of underutilized legume crops, aquatic weeds, fungi, and insects intended as alternative protein sources, from ingredient production to their incorporation in food products, including their food formulations and the functional characteristics of alternative plant-based proteins and edible insect proteins as novel foods. Emphasis is also placed on safety issues due to the presence of anti-nutritional factors and allergenic proteins in insects and/or underutilized legumes. The functional and biological activities of protein hydrolysates from different protein sources are reviewed, along with bioactive peptides displaying antihypertensive, antioxidant, antidiabetic, and/or antimicrobial activity. Due to the healthy properties of these foods for the high abundance of bioactive peptides and phytochemicals, more consumers are expected to turn to vegetarianism or veganism in the future, and the increasing demand for such products will be a challenge for the future.

Preparation and activity evaluation of angiotensin-I converting enzyme inhibitory peptides from protein hydrolysate of mulberry leaf

Angiotensin-I converting enzyme (ACE) inhibitory peptides drew wide attention in the food industry because of their natural reliability, non-toxicity, and safety. However, the characteristics of ACE inhibitory peptides obtained from protein hydrolysate of mulberry leaf prepared by Flavourzyme were still unclear. Based on the single-factor test, the Plackett-Burman test and response surface test were used to determine the key factors affecting the ACE inhibition rate in mulberry leaf protein hydrolysate and the optimum conditions of enzymatic hydrolysis. The results showed that the optimum technical parameters were as follows: the ratio of material to liquid is 1: 25 (w / v, g/mL), the Flavourzyme to substrate ratio was 3,000 U/g, the temperature of enzymatic hydrolysis was 50°C, pH was 6.3, and the time of enzymatic hydrolysis was 2.9 h. The ACE inhibitory peptides in the mulberry leaf protein hydrolysates were purified by ultrafiltration and gel filtration, aiming to obtain the highest active component. The 12 peptide sequences were identified by reverse liquid chromatography-mass spectrometry, and then, they were docked to the crystal structure of human angiotensin-I converting enzyme (1O8A), and the interaction mechanisms of 12 peptide sequences and 1O8A were analyzed. The docking results showed that among the 12 peptide sequences, ERFNVE (792.37 Da), TELVLK (351.72 Da), MELVLK (366.72 Da), and FDDKLD (376.67 Da), all had the lowest docking energy, and inhibition constant. The chemosynthetic ERFNVE (IC₅₀: 2.65 mg/mL), TELVLK (IC₅₀: 0.98 mg/mL), MELVLK (IC₅₀:1.90 mg/mL) and FDDKLD (IC₅₀:0.70 mg/mL) demonstrated high ACE-inhibitory activity with competitive inhibition mode. These results indicated that the ACE-inhibiting peptides from mulberry leaf protein hydrolyzed (FHMP) had the potential activities to inhibit ACE and could be used as functional food or drugs to inhibit ACE. This work provides positive support for mining the biological activity of mulberry leaves in the treatment of hypertension.

Is now the time for a Rubiscuit or Ruburger? Increased interest in Rubisco as a food protein

Much of the research on Rubisco aims at increasing crop yields, with the ultimate aim of increasing plant production to feed an increasing global population. However, since the identification of Rubisco as the most abundant protein in leaf material, it has also been touted as a direct source of dietary protein. The nutritional and functional properties of Rubisco are on a par with those of many animal proteins, and are superior to those of many other plant proteins. Purified Rubisco isolates are easily digestible, nutritionally complete, and have excellent foaming, gelling, and emulsifying properties. Despite this potential, challenges in efficiently extracting and separating Rubisco have limited its use as a global foodstuff. Leaves are lower in protein than seeds, requiring large amounts of biomass to be processed. This material normally needs to be processed quickly to avoid degradation of the final product. Extraction of Rubisco from the plant material requires breaking down the cell walls and rupturing the chloroplast. In order to obtain high-quality protein, Rubisco needs to be separated from chlorophyll, and then concentrated for final use. However, with increased consumer demand for plant protein, there is increased interest in the potential of leaf protein, and many commercial plants are now being established aimed at producing Rubisco as a food protein, with over US$60 million of funding invested in the past 5 years. Is now the time for increased use of Rubisco in food production as a nitrogen source, rather than just providing a carbon source?

Effects of Moringa oleifera Lam. Supplementation on Inflammatory and Cardiometabolic Markers in Subjects with Prediabetes

Different parts of the Moringa oleifera Lam. (MO) tree are consumed as food or food supplements for their nutritional and medicinal value; however, very few human studies have been published on the topic. The current work was aimed to provide ancillary analysis to the antidiabetic effects previously reported in a double-blind, randomized, placebo-controlled, parallel group intervention conducted in patients with prediabetes. Thus, the effect of MO leaves on blood and fecal inflammatory markers, serum lipid profile, plasma antioxidant capacity and blood pressure was studied in participants who consumed 6 × 400 mg capsule/day of MO dry leaf powder (MO, n = 31) or placebo (PLC, n = 34) over 12 weeks. Differences between groups were assessed using each biomarker’s change score with, adjustment for fat status and the baseline value. In addition, a decision tree analysis was performed to find individual characteristics influencing the glycemic response to MO supplementation. No differences in the biomarker’s change scores were found between the groups; however, the decision tree analysis revealed that plasma TNF-α was a significant predictor of the subject’s HbA1c response (improvement YES/NO; 77% correct classification) in the MO group. In conclusion, TNF-α seems to be a key factor to identify potential respondents to MO leaf powder.

Bioactive Properties of Peptides and Polysaccharides Derived from Peanut Worms: A Review

Peanut worms (Sipunculids) are unsegmented marine worms that usually inhabit shallow waters. Peanut worms are good source of bioactive compounds including peptides and polysaccharides. Many recent studies have investigated the bioactive properties of peptides and polysaccharides derived from peanut worms in order to enhance their applications in food and pharmaceutical industries. The peptides and polysaccharides isolated from peanut worms have been reported to possess anti-hypertensive, anti-oxidant, immunomodulatory, anti-inflammatory, anti-cancer, anti-hypoxia and wound healing activities through the modulation of various molecular mechanisms. Most researchers used in vitro, cell culture and animal models for the determination of bioactivities of peanut worm derived compounds. However, studies in humans have not been performed considerably. Therefore, it is important to conduct more human studies for better utilization of marine bioactive compounds (peptides and polysaccharides) derived from peanut worms. This review mainly focuses on the bioactive properties of peptides and polysaccharides of peanut worms and their molecular mechanisms.

Health benefits and phenolic compounds of Moringa oleifera leaves: A comprehensive review

BACKGROUND

Moringa oleifera Lam (MO) is native to India and is a cash crop widely cultivated in tropical and sub-tropical areas. The health improving properties of MO has been studied from a long time ago for the numerous phenolic compounds, including vitamins, flavonoids, phenolic acids, isothiocyanates, tannins and saponins, which are present in considerable amounts in the plant. A growing spectrum of therapeutic characteristics of MO leaves has been found and used in the remission or treatment of oxidative stress, liver disease, neurological disease, hyperglycemia and cancer.

HYPOTHESIS

This review focused on researches applying MO or MO leaf extract as a functional food or cure against various disease and cellular injuries. We believed it would help the discovery of therapeutic application of MO and understanding of MO phytochemistry.

METHODS

The data collected in this review were extracted from researches indexed in Web of Science, google scholar, PubMed, Science Direct and Scopus to find out health benefits and biological activities of MO leaves polyphenols. The studies reporting mechanistic route of phenolic compounds of MO leaves were also considered in the present study.

RESULTS

It has been reported that polyphenols of MO leaf have protective characteristics against neurodegenerative disorders through reducing DNA damage, activation of AchE activity and inhibition of caspase-3 activity. It has been reported that, they protected the kidney from damage caused by melamine through suppressed the pro-inflammatory cytokine, metallopeptidase inhibitor 1 (TIMP-1), and kidney injury molecule 1 (KIM-1). Similarly, methanol extract of MO leaves has low hypoglycemic attributes and attenuate the risk of diabetes caused by alloxan by enhancing lipid metabolism and stimulating insulin release, glucose uptake, and glycogen synthesis. In addition, MO leaves are becoming the best phytomedicine to reduce hypertension, which are naturally known as angiotensin-1converting enzyme (ACE), acetylcholinesterase, arginase and phosphodiesterase 5 (PDE5) inhibitors.

CONCLUSION

MO leaves extract as a health promoting food additives for human and animals due to its great protective effect against many diseases and the widely persistent environmental toxins which disrupted cellular metabolic function. More studies are required to use the phenolic compounds of MO leaves to develop and produce drugs for controlling and treatment of various diseases.