UNAIR NEWS – “Silent killer ” seems to be the right designation for hypertension. Hypertension or high blood pressure is a disease that causes a heart attack and increases the risk of death without any symptoms.
Patients with hypertension generally have blood pressure at 140/90 mmHg or more and this condition is dangerous because it will cause the emergence of diseases such as stroke, kidney failure and heart failure.
“So as to overcome these problems a drug therapy is needed to reduce the blood pressure rate,” said Dwi Yuli Pujiastuti, S.Pi., MP, a lecturer of Faculty of Fisheries and Marine UNAIR.
Renin angiotensin aldosterone system (RAAS), provides an important role in regulating blood pressure and maintaining fluid balance so that it can be a therapeutic target for tackling the problem of hypertension.
“In RAAS , angiotensin-I converting enzyme (ACE) will catalyze angiotensin I ( Asp-Arg-Val-Tyr-Ile-His-Pro-Phe-His-Leu ) to angiotensin-II ( Asp-Arg-Val-Tyr) -Ile-His-Pro-Phe ), from decapeptide to octapeptide, “explained Pujiastuti.
“Angiotensin-II contributes to stimulation releasing aldosterone and antidiuretic hormone or vasopressin and increasing sodium and water retention and vasoconstrictors which directly increase blood pressure. So the work of this ACE must be inhibited by an inhibitor compound, ” she added
Some synthetic ACE inhibitors are captopril, lisinopril, enalapril, benazepril whose use has side effects such as dizziness, coughing, or rashes on the skin.
According to Puji, bioactive peptides are produced through enzymatic hydrolysis which usually uses digestive enzymes such as thermolysin, chymotrypsin and pepsin. In the digestive system, bioactive peptides can be easily absorbed through the intestine and enter the blood and provide health effects.
“Therefore, bioactive peptide is an important concern for researchers to continue to explore its potential, especially as a source of ACE inhibitors,” she explained.
The search for peptides that are able to inhibit ACE activity, has been intensified through emerging proven studies from fisheries and marine resources. Reliable testing to determine the ability of peptides to inhibit ACE activity has been a major concern.
The in vitro study of ACE inhibiting peptides is started by enzymatic digestion or microbial fermentation which is then followed by structural analysis and chemical synthesis of active peptides. The technique used to evaluate the ACE inhibitory activity of peptides must be simple, sensitive, and reliable.
Puji explained, several methods have been developed, such as spectrophotometry, high performance liquid chromatography (HPLC), fluorometric capillary electrophoresis, and radiochemistry.
This method, said Puji, involves hydrolysis of hippuryl-histidyl-leucine (HHL) by ACE into hippuric acid (HA).The amount of HA produced from HHL correlates directly with ACE activity. The amount of HA formed is determined by measuring absorbance at 228 nm (maximum absorption of HA). Although spectrophotometry is useful, it is time-consuming, complicated, and it cannot detect the number of traces of a sample.
Marine organisms produce several sources of functional ingredients such as bioactive peptides, enzymes, polyunsaturated fatty acids (PUFAs), vitamins, minerals, phenolic phlorotannins, and polysaccharides. In addition, marine organisms promise excellent prospects for industrial development such as pharmaceuticals, cosmetics, chemicals, nutritional supplements and therapeutic agents.
Puji’s research with noticed that natural inhibitors from fisheries and marine are believed to have no side effects, are safer and healthier compared to synthetic drugs.
“In recent years, research on the potential of fisheries and marine as an ACE inhibitor has been widely studied ranging from soft shelled turtle, fermented mackerel, sardine muscle, Alaskan Pollack skin, marine shrimp, salmon chum, yellowfin, collagen squid skin, Spirulina platensis, and Chlorella vulgaris , ” she explained
Marine organisms are a sustainable source of ACE inhibiting peptides for the production of drugs and nutraceuticals on an industrial scale. Because of the importance of ACE inhibition for the pharmaceutical and nutraceutical industries in the future, peptide refining techniques to produce pure peptides are very important.
“Therefore, the research on purifying bioactive peptides must continue to trigger researchers to conduct research,” she concluded.
Author: Fariz Ilham Rosyidi
Editor: Khefti Al Mawalia
Pujiastuti, D.Y.; Shih, Y.-H.; Chen, W.-L.; Sukoso; Hsu, J.-L. 2017. Screening of angiotensin-I converting enzyme inhibitory peptides derived from soft-shelled turtle yolk using two orthogonal bioassay-guided fractionations. Journal of Functional Foods, 28, 36–47.