Antihypertensive effect of novel angiotensin I converting enzyme inhibitory peptide from chum salmon (Oncorhynchus keta) skin in spontaneously hypertensive rats

Bioactive Peptide of Marine Origin for the Prevention and Treatment of Non-Communicable Diseases

Non-communicable diseases (NCD) are the leading cause of death and disability worldwide. The four main leading causes of NCD are cardiovascular diseases, cancers, respiratory diseases and diabetes. Recognizing the devastating impact of NCD, novel prevention and treatment strategies are extensively sought. Marine organisms are considered as an important source of bioactive peptides that can exert biological functions to prevent and treatment of NCD. Recent pharmacological investigations reported cardio protective, anticancer, antioxidative, anti-diabetic, and anti-obesity effects of marine-derived bioactive peptides. Moreover, there is available evidence supporting the utilization of marine organisms and its bioactive peptides to alleviate NCD. Marine-derived bioactive peptides are alternative sources for synthetic ingredients that can contribute to a consumer's well-being, as a part of nutraceuticals and functional foods. This contribution focus on the bioactive peptides derived from marine organisms and elaborates its possible prevention and therapeutic roles in NCD.

Two novel peptides with angiotensin I converting enzyme inhibitory and antioxidative activities from Scorpaena notata muscle protein hydrolysate

Fish protein hydrolysate was prepared from muscle of small red scorpionfish (Scorpaena notata) by treatment with a protease from the fungus Penicillium digitatum. Protein hydrolysate was found to strongly inhibit the angiotensin I converting enzyme and exhibited high antioxidative activity through 1,1-diphenyl-2-picrylhydrazyl free radical scavenging assay. After ultrafiltration, peptides were isolated by a two-step procedure: size exclusion chromatography on a Toyopearl HW-40 followed by reversed-phase high-performance liquid chromatography with a high purification yield of 2.5 mg of peptide per gram of initial protein. Two major peptides were then identified by nanoscale liquid chromatography coupled to tandem mass spectrometry (nano-LC-MS/MS), corresponding to the following sequences: Leu-Val-Thr-Gly-Asp-Asp-Lys-Thr-Asn-Leu-Lys (1,204.665 Da) and Asp-Thr-Gly-Ser-Asp-Lys-Lys-Gln-Leu (992.511 Da). These peptides, mainly composed of hydrophilic amino acids, showed high antioxidative and angiotensin I converting enzyme inhibitory activities. These data suggest that the two novel peptides isolated from the muscle hydrolysate of small red scorpionfish can be a beneficial ingredient for functional foods or pharmaceuticals against hypertension and oxidative stress.

A Review of the Latest Advances in Encrypted Bioactive Peptides from Protein-Rich Waste

Bioactive peptides are considered the new generation of biologically active regulators that not only prevent the mechanism of oxidation and microbial degradation in foods but also enhanced the treatment of various diseases and disorders, thus increasing quality of life. This review article emphasizes recent advances in bioactive peptide technology, such as: (i) new strategies for transforming bioactive peptides from residual waste into added-value products; (ii) nanotechnology for the encapsulation, protection and release of controlled peptides; and (iii) use of techniques of large-scale recovery and purification of peptides aiming at future applications to pharmaceutical and food industries.

In vitro angiotensin I converting enzyme inhibition by a peptide isolated from Chiropsalmus quadrigatus Haeckel (box jellyfish) venom hydrolysate

The anti-angiotensin I converting enzyme activity of box jellyfish, Chiropsalmus quadrigatus Haeckel venom hydrolysate was studied. The venom extract was obtained by centrifugation and ultrasonication. Protein concentration of 12.99 μg/mL was determined using Bradford assay. The pepsin and papain hydrolysate was tested for its toxicity by Limit test following the OECD Guideline 425 using 5 female Sprague-Dawley rats. Results showed that the hydrolysate is nontoxic with an LD50 above 2000 mg/kg. In vitro angiotensin I converting enzyme (ACE) inhibitory activity was determined using ACE kit-WST. Isolation of ACE inhibitory peptides using column chromatography with SP-Sephadex G-25 yielded 8 pooled fractions with fraction 3 (86.5%) exhibiting the highest activity. This was followed by reverse phase - high performance liquid chromatography (RP-HPLC) with an octadecyl silica column (Inertsil ODS-3) using methanol:water 15:85 at a flow rate of 1.0 mL/min. Among the 13 fractions separated with the RP-HPLC, fraction 3.5 exhibited the highest ACE inhibitory activity (84.1%). The peptide sequence ACPGPNPGRP (IC50 2.03 μM) from fraction 3.5 was identified using Matrix-assisted laser desorption/ionization with time-of-flight tandem mass spectroscopy analysis (MALDI-TOF/MS).

Valorization of tomato waste proteins through production of antioxidant and antibacterial hydrolysates by proteolytic Bacillus subtilis: optimization of fermentation conditions

In this study, protein-rich waste of tomato processing industries was fermented by Bacillus subtilis A14h to produce hydrolysates with antioxidant and antibacterial activities. The effects of different levels of initial pH, incubation temperature, fermentation time, protein concentration and inoculum size on proteolytic activity, release of amino acids and peptides, antioxidant and antibacterial activities of hydrolysates were evaluated and optimized by using response surface methodology (RSM). Results showed that all the evaluated variables significantly influenced the hydrolysis and bioactivities of hydrolysates in polynomial models. Hydrolysates showed remarkable 2, 2'-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity (up to 70 %), ferric ion reducing power, and inhibitory activity against B. cereus (up to 69.8 %) and E. coli (up to 29.8 %). Overall, good correlation between the concentration of amino acids and peptides, and antioxidant as well as antibacterial activities (in particular for B. cereus inhibition activity) was observed. Finally, optimum conditions for fermentative conversion of tomato waste proteins to antioxidant and antibacterial hydrolysates were established. Results of this study showed that tomato waste protein can be valorized to produce antioxidant and antibacterial hydrolysates in a fermentative system using B. subtilis A14h.

Purification, identification and structural modelling of DPP-IV inhibiting peptides from barbel protein hydrolysate

Inhibition of DPP-IV may improve glycemic control in diabetics by preventing the rapid breakdown and there by prolonging the physiological action of incretin hormones. Barbel muscle protein hydrolysate (BMPH) was noted to exhibit DPP-IV inhibitory activity, with an IC50 value of 1.94mg/mL. It was fractionated into five major fractions (FI-FV) by size exclusion chromatography using a Superdex peptide. The FIII fraction was noted to display the highest inhibitory activity, with an IC50 value of 1.23mg/mL, and was, therefore, further fractionated by RP-HPLC. Four major peptide sub-fractions were selected. The results revealed that the SF4 sub-fraction showed the highest DPP-IV inhibitory activity, with an IC50 value of 0.21mg/mL. This sub-fraction was submitted to RP-HPLC, ESI-MS, and ESI-MS/MS analyses. The findings indicated that SF4 consisted of two peptides (IC50=96μg/mL), namely PP1 and PP2, whose structures were identified as Trp-Ser-Gly (330Da) and Phe-Ser-Asp (349Da), respectively. This is the first report of these sequences from barbel proteins. The structural modelling through docking simulations results with DPP-IV showed that the Trp-Ser-Gly peptide bound to DPP-IV with high affinity. Overall, the results suggested that BMPH can be considered as a promising natural source of DPP-IV inhibitory peptides.