In vitro screening of angiotensin converting enzyme and hydroxymethylglutaryl-coenzyme A reductase inhibitory activities in lactic acid bacteria and yeasts isolated from fermented sorghum gruels

Abstract

Background 3-hydroxyl-3-methylglutaryl-coenzyme A (HMG-CoA) reductase and angiotensin converting enzyme (ACE) are implicated in the pathogenesis of hyperlipidemia and hypertension, which are oxidative-stress linked conditions of public health importance. The adverse effects associated with standard clinical drugs used to inhibit these enzymes have prompted the search for alternative sources. This study was designed to investigate the <i>in vitro</i> inhibitory activities of lactic acid bacteria (LAB) and yeasts isolated from fermented sorghum gruels. Material and methods LAB and yeast isolates were obtained and characterized using standard methods. The HMG-CoA reductase and ACE inhibitory activities of the microbial isolates were evaluated using established protocols. Results Screening of LAB for HMG-CoA reductase and ACE inhibitory activities revealed that at concentrations (mg/ml) of 6, 12, 24, and 48, <i>Lactobacillus pentosus</i> WSL5 exhibited the highest %HMG-CoA reductase inhibition of 3.21, 6.42, 9.17, and 12.84, with corresponding ACE inhibitory activities of 6.38, 13.17, 18.13, and 23.47, respectively. At concentrations (mg/ml) of 1, 2, 4, and 8, the yeast isolates <i>Trichomonascus ciferri</i> RSY53 demonstrated %HMG-CoA reductase inhibition of 7.71, 11.47, 14.68, and 16.97, with corresponding ACE inhibitory activities of 11.83, 20.91, 34.73, and 48.28, respectively. Furthermore, <i>L. pentosus</i> WSL5 recorded the lowest HMG-CoA reductase half-maximal inhibitory concentration (IC<sub>50</sub>) of 219.72 µg/ml and ACE IC<sub>50</sub> of 116.22 µg/ml, while <i>T. ciferri</i> RSY53 had even lower IC<sub>50</sub> values of 29.55 µg/ml for HMG-CoA reductase and 7.03 µg/ml for ACE inhibition compared to the controls. Conclusions <i>L. pentosus</i> WSL5 and <i>T. ciferri</i> RSY53 can be considered potential starter cultures for the fermentation of functional foods aimed at supporting cardiovascular health.