Peptides, antihypertensive bioactive

Biochemical and nutritional aspects of seaweed proteins have been reported. Enzymatic degradation of algal fibers could be attempted to improve protein digestibility (Fleurence, 1999) and also to prepare bioactive peptides. A great deal of interest has been developed nowadays to isolate antihypertensive bioactive peptides, which act as angiotensin-con-verting enzyme (ACE) inhibitors because of their numerous health beneficial effects (Wijesekara and Kim, 2010). 

Bioactive peptides as products of hydrolysis of diverse marine invertebrate (shellfish, crustacean, rotifer, etc.) proteins are the focus of current research. After much research on these muscles and byproducts, some biologically active peptides were identified and applied to useful compounds for human utilization. This chapter reviews bioactive peptides from marine invertebrates in regarding to their bioactivities. Additionally, specific characteristics of antihypertensive, anti-Alzheimer, antioxidant, antimicrobial peptide enzymatic production, methods to evaluate bioactivity capacity, bioavailability, and safety concerns of peptides are reviewed. 

According to Lee et al. (2010), the peptide Gly-Asp-Leu-Gly-Lys-Thr-Thr-Thr-Val-Ser-Asn-Trp-Ser-Pro-Pro-Lys-Try-Lys-Asp-Thr-Pro, derived from big-eye tuna frame protein hydrolysate, showed a strong suppressive effect on the systolic blood pressure of SHRs, while its antihypertensive activity was similar to that of captopril, a commercially available antihypertensive drug. Further, they reported no side effects after the administration of this antihypertensive peptide to rats. In addition, these marine antihypertensive peptides exhibit stronger antihypertensive activity in vivo than in vitro. The exact mechanisms underlying this phenomenon have yet to be identified however, it was suggested that bioactive peptides have a higher tissue affinity and are eliminated more slowly than captopril (Fujita and Yoshikawa, 1999). 

Great amount of marine fish species have been identified with potential nutraceutical and medicinal values. Consequently, a number of bioactive compounds have been identified including fish muscle proteins, peptides, collagen and gelatin, fish oil, fish bone. Bioactive peptides derived from various fish muscle proteins have shown various biological activities including antihypertensive, antibacterial, anticoagulant, anti-inflammatory, and antioxidant activities, and hence they may be a potential material for biomedical and... 

Marine Fish-Derived Bioactive Peptides as Potential Antihypertensive Agents... 

III. Antihypertensive Activity of Bioactive Peptides Derived from Marine Fishes... 

Recently, marine fish-derived bioactive peptides have been shown to possess many physiological functions including antihypertensive, antioxidant, antimicrobial, antiproliferative, antitumor, anticoagulant, and immunomodulatory activities. Among these, antihypertensive peptides act as ACE inhibitors are of particular interest for prevention and treatment of hypertension (Kobayashi et ah, 2008). 

III. ANTIHYPERTENSIVE ACTIVITY OF BIOACTIVE PEPTIDES DERIVED FROM MARINE FISHES... 

Exogenous ACE inhibitors having an antihypertensive effect in vivo were first discovered in snake venom (Ondetti et al., 1971). Afterwards, various ACE-inhibitors have been found from enzymatic hydrolysates and related synthetic peptides of food proteins. These food proteins include such as bovine and human casein and whey, zein, gelatin, yeast and corn (Ariyoshi, 1993 Yamamoto, 1997 FitzGerald andMeisel, 2000 Pihlanto-Leppala, 2001). So far, ACE-inhibitory peptides are the most commonly known group of bioactive peptides of food protein origin. Some examples of these peptides are presented in Table III. 

When the ultimate objective is to produce bioactive peptides for particular purposes, such as antioxidative or antihypertensive activities, the purification of target peptides from protein hydrolysate can be carried out using UF membranes with or without chromatographic techniques. Jun et al (2004) reported successful preparation of protein hydrolysates from yellowfin sole frame by first using extracted mackerel intestine crude enzyme at pH 10.0 and 50 °C, followed by treatment with pepsin at pH 2.0 and 37 °C. The resultant hydrolysate was further fractionated through five different UF membranes with... 

Bioactive peptides released by enzymatic proteolysis of various proteins that act as potential physiological modulators of metabolism during intestinal digestion have been reported in recent reports. These peptides usually contain 3-20 amino acid residues, and their activity depends on their amino acid composition and sequence (Pihlanto-Leppala, 2001). Based on their structural, compositional, and sequential properties, they may exhibit different kinds of bioactivities such as antioxidative (Jimg et al., 2005 Kim et al., 2001), antihypertensive (Suetsima et ah, 2004), and immunomodulatory effects (Qien et al., 1995 Tsuruki et al., 2003). 

III. Edible Seaweeds as Potential Sources of Bioactive Peptides A. In vitro and in vivo evaluation of antihypertensive 330... 

Eisenia species of brown algae. The ACE-inhibitory properties of phlorofu-cofuroeckol A, dieckol, and eckol ranked high, with IC50 values of 12.74 0.15, 34.25 3.56, and 70.82 0.25 pM, respectively. Summarizing, other bioactive compoimds, besides peptides, may be responsible for the antihypertensive capacity of seaweeds. 

Bioactive peptides have been defined as specific protein fragments that have a positive impact on body functions or conditions and may influence health. Upon oral administration, bioactive peptides, may affect the major body systems—namely, the cardiovascular, digestive, immune, and nervous systems. The beneficial health effects may be classified as antimicrobial, antioxidative, antithrombotic, antihypertensive, antimicrobial, and immunomodulatory [87,88]. 

Saito, T. (2008). Antihypertensive peptides derived from bovine casein and whey proteins. In Z. Bdsze (Ed.), Advances in experimental medicine and biology Bioactive components of milk Vol.606. (pp. 295-317). Springer. 

Tsai, J., Chen, T., Pan, B. S., Gong, S., Chung, M. (2008). Antihypertensive effect of bioactive peptides produced by protease-facilitated lactic acid fermentation of milk. Food Chemistry, 106, 552-558. 

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