Dietary supplements: clinical cholesterol-lowering efficacy and potential mechanisms of action.

This review aims to analyse the efficacy of dietary supplements in reducing plasma cholesterol levels. Focusing on evidence from meta-analyses of randomised controlled clinical trials, with an emphasis on potential mechanisms of action as supported by human, animal, and cell studies. Certain dietary supplements including phytosterols, berberine, viscous soluble dietary fibres, garlic supplements, soy protein, specific probiotic strains, and certain polyphenol extracts could significantly reduce plasma total and low-density lipoprotein (LDL) cholesterol levels by 3-25% in hypercholesterolemic patients depending on the type of supplement. They tended to be more effective in reducing plasma LDL cholesterol level in hypercholesterolemic individuals than in normocholesterolemic individuals. These supplements worked by various mechanisms, such as enhancing the excretion of bile acids, inhibiting the absorption of cholesterol in the intestines, increasing the expression of hepatic LDL receptors, suppressing the activity of enzymes involved in cholesterol synthesis, and activating the adenosine monophosphate-activated protein kinase signalling pathway.

Characteristics of limestone soil collected from Gunung Lang, Perak and metagenomic analysis of the soil microbial community

Aims: This project was aimed to study the microbial diversity of the limestone soil and its correlation with the environment. Methodology and results: The study was carried out using samples obtained from Gunung Lang, Ipoh, Perak in August 2013. X-ray diffraction analysis of the rock structure confirmed that the samples were of limestone origin. Besides that, soil analysis revealed that this area was fertile and rich in nutrients. It therefore served as a suitable habitat for microorganismal diversity to flourish. This was proven by the 16S rDNA metagenomic analysis which targeted on 16S rDNA variable region V3-V5 using Illumina MiSeq sequencer. Using this approach, a variety of microorganisms was identified and many yet to be characterized microorganisms were detected from this area. Conclusion, significance and impact of study: This is the first study in Malaysia that aimed to study the microbial diversity of limestone soils through metagenomic approach. The study showed that limestone is rich in microbial diversity and it is a place worth looking for novel microbes and genes of interest in biotechnology.