H2S biosynthesis and catabolism: new insights from molecular studies

Hydrogen sulfide (H2S) has profound biological effects within living organisms and is now increasingly being considered alongside other gaseous signalling molecules, such as nitric oxide (NO) and carbon monoxide (CO). Conventional use of pharmacological and molecular approaches has spawned a rapidly growing research field that has identified H2S as playing a functional role in cell-signalling and post-translational modifications. Recently, a number of laboratories have reported the use of siRNA methodologies and genetic mouse models to mimic the loss of function of genes involved in the biosynthesis and degradation of H2S within tissues. Studies utilising these systems are revealing new insights into the biology of H2S within the cardiovascular system, inflammatory disease, and in cell signalling. In light of this work, the current review will describe recent advances in H2S research made possible by the use of molecular approaches and genetic mouse models with perturbed capacities to generate or detoxify physiological levels of H2S gas within tissue

Antioxidant dietary fiber from the bran of five Philippine pigmented rice varieties

Pigmented rice varieties are considered rich sources of antioxidant dietary fiber (ADF); consuming them may have health benefits. In this study, bran samples of five Philippine pigmented rice varieties namely, Red-64, Black Rice, Calatrava, Arabon, and Dinorado were analyzed for their ADF contents. The bulk of dietary fiber in the bran of the five varieties is insoluble dietary fiber (IDF), while a very minimal amount is soluble dietary fiber. Calatrava (CL) exhibited the highest total dietary fiber (52.5%), consisting primarily of 50 percent IDF. The CL IDF exhibited the highest total phenolic content (1.8 mg gallic acid equivalents [GAE]/gram dry weight [DW]) and total anthocyanin content (0.524 mg cyanidin-3-glucoside /100 g DW). The CL IDF also displayed the highest antioxidant activity in terms of ferric ion-reducing antioxidant power (17.72 μmol trolox equivalents/gram DW), ABTS*+ radical scavenging activity (33%), and DPPH radical quenching activity (76.7%, 3.9 mg ascorbic acid per gram DW). The majority of the phenolics associated with CL IDF is in the bound form amounting to 6.9 mg GAE/g DW. High-performance liquid chromatography revealed the presence of gallic acid, resorcinol, vanillin, ferulic acid, salicylic acid, and quercetin in the bound phenolic extract. As this study has established that the CL IDF is an ADF believed to possess many health-promoting properties, it can be valorized for potential applications in nutraceuticals and functional foods