Malaysian brown seaweeds Sargassum siliquosum and Sargassum polycystum: Low density lipoprotein (LDL) oxidation, angiotensin converting enzyme (ACE),α-amylase, and α-glucosidase inhibition activities.
Food Res Int. 2017 09 ;99(Pt 2):950-958. Epub 2017 Jan 27. PMID: 28847432
Two Malaysian brown seaweeds, Sargassum siliquosum and Sargassum polycystum were first extracted using methanol to get the crude extract (CE) and further fractionated to obtain fucoxanthin-rich fraction (FRF). Samples were evaluated for their phenolic, flavonoid, and fucoxanthin contents, as well as their inhibitory activities towards low density lipoprotein (LDL) oxidation, angiotensin converting enzyme (ACE),α-amylase, and α-glucosidase. In LDL oxidation assay, an increasing trend in antioxidant activity was observed as the concentration of FRF (0.04-0.2mg/mL) and CE (0.2-1.0mg/mL) increased, though not statistically significant. As for serum oxidation assay, significant decrease in antioxidant activity was observed as concentration of FRF increased, while CE showed no significant difference in inhibitory activity across the concentrations used. The ICvalues for ACE inhibitory activity of CE (0.03-0.42mg/mL) were lower than that of FRF (0.94-1.53mg/mL). When compared to reference drug Voglibose (ICvalue of 0.61mg/mL) in the effectiveness in inhibitingα-amylase, CE (0.58mg/mL) gave significantly lower ICvalues while FRF (0.68-0.71mg/mL) had significantly higher ICvalues. Theα-glucosidase inhibitory activity of CE (ICvalue of 0.57-0.69mg/mL) and FRF (ICvalue of 0.50-0.53mg/mL) were comparable to that of reference drug (ICvalue of 0.54mg/mL). Results had shown the potential of S. siliquosum and S. polycystum in reducing cardiovascular diseases related risk factors following their inhibitory activities on ACE,α-amylase and α-glucosidase. In addition, it is likelihood that FRF possessed antioxidant activity at low concentration level.