Analysis of novel angiotensin-I-converting enzyme inhibitory peptides from protease-hydrolyzed marine shrimp Acetes chinensis

Free radical scavenging and angiotensin-I converting enzyme inhibitory peptides from Pacific cod (Gadus macrocephalus) skin gelatin

Potent antioxidative peptides were purified from Pacific cod (Gadus macrocephalus) skin gelatin using alcalase, neutrase, papain, trypsin, pepsin, and α-chymotrypsin. Among them, the papain hydrolysate exhibited the highest antioxidant activity. Therefore, it was further purified and obtained two peptides with amino acid sequences of Thr-Cys-Ser-Pro (388 Da) and Thr-Gly-Gly-Gly-Asn-Val (485.5 Da). The antioxidant activity of the purified peptides was performed by electron spin resonance technique. Moreover, their intracellular free radical scavenging activity using 2',7'-dichlorofluorescin diacetate and the protective effect against oxidation-induced DNA damage were evaluated in mouse macrophages (RAW 264.7 cells). Furthermore, both peptides have shown potential angiotensin-I converting enzyme inhibitory effect. The present study demonstrated that the peptides derived from Pacific cod (G. macrocephalus) skin gelatin could be used in the food industry as functional ingredients with potent antioxidative and antihypertensive benefits.

Bioactive peptides from muscle sources: meat and fish

Bioactive peptides have been identified in a range of foods, including plant, milk and muscle, e.g., beef, chicken, pork and fish muscle proteins. Bioactive peptides from food proteins offer major potential for incorporation into functional foods and nutraceuticals. The aim of this paper is to present an outline of the bioactive peptides identified in the muscle protein of meat to date, with a focus on muscle protein from domestic animals and fish. The majority of research on bioactives from meat sources has focused on angiotensin-1-converting enzyme (ACE) inhibitory and antioxidant peptides.

Shrimp shell peptide hydrolysates inhibit human cancer cell proliferation

BACKGROUND

Shrimp wastes contain high-quality protein that is underutilized, and particularly peptides derived from shrimp wastes (normally used as animal feed) have not been utilized for bioactive properties. Hence the objective was to utilize shrimp waste proteins in generating peptides and to investigate these for cancer antiproliferative activities. The objectives involved hydrolyzing shrimp proteins (intact in shell) using a food-grade Cryotin enzyme, obtaining gastrointestinal resistant peptides, fractionation to generate < 10, 10-30 and > 30 kDa fractions, and evaluating for colon and liver cancer cell growth inhibitory effects. Three shrimp shells--whole langostino lobster shells from El Salvador (South America), shrimp shells from St Petersburg, FL (USA), and shrimp shell whites from the Gulf of Mexico, LA (USA)--were evaluated for the study.

RESULTS

Peptide fractions (<10 and 10-30 kDa) obtained from shrimp shell whites (Gulf of Mexico) as well as from langostino shells (El Salvador) significantly inhibited the growth of both colon and liver cancer cells by 60%, while < 10 kDa fraction from shrimp shells (FL) inhibited growth of liver cancer cells alone by 55%, compared to controls.

CONCLUSION

The promising anticancer peptide fractions from shrimp waste proteins has the potential for novel nutraceutical ingredient applications.

Angiotensin-I-converting enzyme (ACE) inhibitors from marine resources: prospects in the pharmaceutical industry

Hypertension or high blood pressure is one of the major independent risk factors for cardiovascular diseases. Angiotensin-I-converting enzyme (EC 3.4.15.1; ACE) plays an important physiological role in regulation of blood pressure by converting angiotensin I to angiotensin II, a potent vasoconstrictor. Therefore, the inhibition of ACE activity is a major target in the prevention of hypertension. Recently, the search for natural ACE inhibitors as alternatives to synthetic drugs is of great interest to prevent several side effects and a number of novel compounds such as bioactive peptides, chitooligosaccharide derivatives (COS) and phlorotannins have been derived from marine organisms as potential ACE inhibitors. These inhibitory derivatives can be developed as nutraceuticals and pharmaceuticals with potential to prevent hypertension. Hence, the aim of this review is to discuss the marine-derived ACE inhibitors and their future prospects as novel therapeutic drug candidates for treat hypertension.

Pilot and plant scaled production of ACE inhibitory hydrolysates from Acetes chinensis and its in vivo antihypertensive effect

The angiotensin-I-converting enzyme (ACE) inhibitory oligopeptide-enriched hydrolysates from Acetes chinensis by treatment with the protease from Bacillus sp. SM98011 were produced at pilot scale (100 L) and plant scale (1000 L). The pilot and plant scaled hydrolysate products almost had the same properties as that at laboratory scale. Spray-drying had little effect on the peptide composition and bioactivity of the hydrolysates. The plant scaled hydrolysates were used to study its blood pressure-depressing effect in vivo. It caused reduce of 18.3-38.6 mmHg of the blood pressure of spontaneously hypertensive rats in dose-dependent manner in the range of 100-1,200 mg/kg/day. Histopathologic study showed that the pathologic changes of heart and brain in SHRs got obvious alleviation after treatment of the hydrolysates.

Production of novel angiotensin I-converting enzyme inhibitory peptides by fermentation of marine shrimp Acetes chinensis with Lactobacillus fermentum SM 605

Acetes chinensis is an underutilized shrimp species thriving in Bo Hai Gulf of China. Its hydrolysate digested with protease SM98011 has been previously shown to have high angiotensin I-converting enzyme (ACE) inhibitory activity (He et al., J Pept Sci 12:726-733, 2006). In this article, A. chinensis were fermented by Lactobacillus fermentum SM 605 and the fermented sauce presented high ACE inhibitory activity. The minimum IC(50) value (3.37 +/- 0.04 mg/mL) was achieved by response surface methodology with optimized process parameters such as fermentation time of 24.19 h, incubation temperature at 38.10 degrees C, and pH 6.12. Three ACE inhibitory peptides are purified by ultrafiltration, gel filtration, and reverse-phase high performance liquid chromatography. Identified by mass spectrometry, their amino acid sequences are Asp-Pro, Gly-Thr-Gly, and Ser-Thr, with IC(50) values of 2.15 +/- 0.02, 5.54 +/- 0.09, and 4.03 +/- 0.10 microM, respectively. Also, they are all novel ACE inhibitory peptides. Compared with protease digestion, fermentation is a simpler and cheaper method to produce ACE inhibitory peptides from shrimp A. chinensis.