Biological activities of Chromolena odorata (L.) King and Robinson (Asteraceae) collected from Sabah, Malaysia as protein phosphatase type-1 inhibitor

Chromolena Odorata has been traditionally used as wound healer in local community. The present study investigated the anti-kinase and anti-phosphatases activities on methanolic C. odorata extract. Mutant yeast strains used are MKK1P386, MKK1P386_MSG5, PAY704-1 and PAY700-4. Bioassay guided fractionation of C. odorata revealed positive activities of hexane, ethyl acetate and chloroform partitions. Column chromatography of all partitionates later confirmed fraction F2 from chloroform extract had most favorable activity with inhibitory zone ranged between 7±0.0 mm until 15±0.0 mm. Kinetic analysis including maximum enzyme velocity (Vm) and Michealis-Menten constant (Km) were evaluated and compared for both normal and inhibited reactions. Enzyme activity with DiFMUP as substrate showed fraction F2 act as PP1 enzyme inhibitor with the Km value 0.60 mM and Vm value 200 mM/min as compared to the normal enzymatic reaction. Results provided unveil the potential of C. odorata as an effective therapeutic agent.</jats:p

Peptide bonds affect the formation of haloacetamides, an emerging class of N-DBPs in drinking water: free amino acids versus oligopeptides

Haloacetamides (HAcAms), an emerging class of nitrogenous disinfection by-products (N-DBPs) of health concern, have been frequently identified in drinking waters. It has long been appreciated that free amino acids (AAs), accounting for a small fraction of the dissolved organic nitrogen (DON) pool, can form dichloroacetamide (DCAcAm) during chlorination. However, the information regarding the impacts of combined AAs, which contribute to the greatest identifiable DON portion in natural waters, is limited. In this study, we compared the formation of HAcAms from free AAs (tyrosine [Tyr] and alanine [Ala]) and combined AAs (Tyr-Ala, Ala-Tyr, Tyr-Tyr-Tyr, Ala-Ala-Ala), and found that HAcAm formation from the chlorination of AAs in combined forms (oligopeptides) significantly exhibited a different pattern with HAcAm formation from free AAs. Due to the presence of peptide bonds in tripeptides, Tyr-Tyr-Tyr and Ala-Ala-Ala produced trichloroacetamide (TCAcAm) in which free AAs was unable to form TCAcAm during chlorination. Moreover, peptide bond in tripeptides formed more tri-HAcAms than di-HAcAms in the presence of bromide. Therefore, the peptide bond may be an important indicator to predict the formation of specific N-DBPs in chlorination. The increased use of algal- and wastewater-impacted water as drinking water sources will increase health concerns over exposure to HAcAms in drinking water

Stability of astaxanthin-loaded nanostructured lipid carriers as affected by pH, ionic strength, heat treatment, simulated gastric juice and freeze–thawing

Nanostructured lipid carriers (NLCs) offer many potential benefits for incorporating lipophilic molecules into clear/opaque food systems. In this study, the influence of pH, ionic strength, thermal treatment, simulated gastric juice (SGJ), and freeze-thawing on the stability of astaxanthin-loaded NLCs (Ax-NLCs) was examined. Ax-NLCs (containing alpha-tocopherol and ethylenediaminetetraacetic acid as antioxidants) were stabilized with Tween 80 and lecithin (Z-average size: 94 nm), and studied for the above mentioned purpose. The size of Ax-NLCs increased at low pH values (= 50 mM), and slightly at SGJ, mainly because of decreasing the zeta-potential. Moreover, thermal treatment at 80/90 degrees C led to an increase in Ax-NLCs size. Glycerol was found as an appropriate cryoprotectant for preventing aggregation of Ax-NLCs during freeze-thawing. pH, ionic strength, heat and SGJ had no drastic effects on the chemical stability of astaxanthin in NLCs. These results have valuable implications for the utilization of food-grade NLCs