Purification of angiotensin converting enzyme inhibitory peptides and antihypertensive effect generated from Indonesian traditional fermented beef (Cangkuk)

Abstract

Objective: Traditional fermented meat products can be considered a source of bioactive peptides.Cangkuk, a traditional Indonesian fermented beef product is one source of ACE inhibitory peptides.This study aimed to identify ACE-inhibitory peptides from Cangkuk and analyze their antihypertensive effects. Methods:The water-soluble fraction of Cangkuk was fractionated to obtain ACE-inhibitory peptides using an ethanol solvent at several concentrations and solid-phase extraction with an OASIS HLB cartridge followed by purification with RP-HPLC. HPLC-MS was used to identify target peptides, followed by automatic protein sequencer analysis to detect peptide sequences. Antihypertensive effects were analyzed on the water-soluble fraction and synthesized peptides. The animal model was comprised of 14-16-week-old male spontaneously hypertensive rats (SHRs) [~320 g average body weight] with mean systolic blood pressures (SBPs) higher than 190 mm Hg. All oral doses of peptides were 1 mL in volume. Distilled water was used as a control. The antihypertensive activities of the sample and control were observed by measuring the SBP at 0, 2, 4, 6, 8 and 24 h after oral administration.Results: Two sequences of ACE inhibitory peptides were found, EAPLNPKANR (IC50 value of 44.6 µmol L -1 ) and IVG (IC50 value of 97.3 µmol L -1 ). The water-soluble fraction demonstrated an antihypertensive effect on SHRs after oral administration at 100 mg kg -1 body weight, maximally lowering the SBP by 14.9 mm Hg 8 h after administration. The tripeptide IVG showed the highest reduction of SBP, 24.76±2.1 mm Hg 8 h after administration. The decapeptide EAPLNPKANR showed the highest reduction of SBP, 21.0 ±1.9 mm Hg, 8 h after administration. All the samples differed significantly from the control (p<0.01). Conclusion:Cangkuk has potential as a functional food ingredient acting as an antihypertensive agent.