OBJECTIVEThis study investigated the effects of allylpyrocatechol (APC), the major component in ethanolic extract of Piper betle, on key oxidative stress resistance enzymes important for the survival of Staphylococcus aureus, a major pathogen in the human host.

METHODSEffects of APC on expressions of genes encoding catalase (katA), superoxide dismutases (SODs), including sodA and sodM, and alkyl hydroperoxide reductase (ahpC) in Saureus were quantitated by RT-qPCR in reference to gyrA and 16S rRNA. Corresponding activities of the enzymes were also investigated. The Livak analysis was performed for verification of gene-fold expression data. Effects of APC on intracellular and extracellular reactive oxygen species (ROS) levels were determined using the nitroblue tetrazolium (NBT) reduction assay.

RESULTSAPC-treated Saureus cells had higher sodA and sodM transcripts at 1.5-fold and 0.7-fold expressions respectively with corresponding increase in total SOD activity of 12.24 U/mL compared to untreated cells, 10.85 U/mL (P<0.05). Expression of ahpC was highest in APC-treated cells with 5.5-fold increased expression compared to untreated cells (P<0.05). Correspondingly, ahpC activity was higher in APC-treated cells at 0.672 (A) compared to untreated cells which was 0.394 (A). In contrast, katA expression was 1.48-fold and 0.33-fold lower respectively relative to gyrA and 16S rRNA. Further, APC-treated cells showed decreased catalase activity of 1.8 ×10(U/L or μmol/(min·L)) compared to untreated cells, which was 4.8 ×10U/L (P<0.05). Absorbance readings (A) for the NBT reduction assay were 0.709 and 0.695 respectively for untreated and treated cells, which indicated the presence of ROS. APC-treated Saureus cells had lower ROS levels both extracellularly and intracellularly, but larger amounts remained intracellularly compared to extracellular levels with absorbances of 0.457 and 0.137 respectively (P<0.05).

CONCLUSIONAPC induced expressions of both sodA and sodM, resulting in increased total SOD activity in Saureus. Higher sodA expression indicated stress induced intracellularly involving O, presumably leading to higher intracellular pools of HO. A concommittant decrease in katA expression and catalase activity possibly induced ahpC expression, which was increased the highest in APC-treated cells. Our findings suggest that in the absence of catalase, cells are propelled to seek an alternate pathway involving ahpC to reduce stress invoked by Oand HO. Although APC reduced levels of ROS, significant amounts eluded its antioxidative action and remained intracellularly, which adds to oxidative stress in treated cells.

Commonly referred to as ‘daun rerama’, Christia vespertilionis has increased in popularity in traditional and modern medicine. This review aims to report the relevance of this plant in terms of its traditional uses, pharmacological actions, phytoconstituents, extractions methods, and identify the research gaps and future potentials. The review is conducted as per PRISMA guidelines; a database search was conducted in Web of Science, Science Direct, Scopus and Google Scholar from 1996 to 2021. Results show that to date, phytochemicals such as alkaloids, flavonoids, quinones, and others have been identified, corresponding to its range of pharmacological activities that include anti-cancer, anti-malaria, and antioxidant. There have also been claims of antidiabetic activity but not supported by enough scientific evidence. Study on molecular and gene expression was still lacking. There is a good future in the research of this plant with many potential aspects to be investigated.

Prediabetes is a condition in which blood glucose level is above the normal but below the diagnostic value of diabetes mellitus. Hyperglycaemia can upregulate markers of chronic inflammation and contribute to the overproduction of reactive oxygen species (ROS), which ultimately causes increased oxidative stress. This leads to beta-cell dysfunction and insulin resistance, which are involved in the pathogenesis of prediabetes status. Proper treatment of hyperglycaemia, inhibition of ROS overproduction, and suppression of inflammation are crucial for delaying the onset of diabetes. Therefore, it is essential to determine and understand the mechanisms involved in prediabetes. This review discusses the relationship between oxidative stress and prediabetes, along with the inflammation’s role in prediabetes. Additionally, the effects of some biomarkers of oxidative stress in prediabetes, inflammatory markers, and their influence on chronic inflammation are also briefly reviewed. Finally, the role of antioxidant and anti-inflammatory markers are discussed.