Air pollution is a very critical issue worldwide, particularly in developing countries. Particulate matter (PM) is a type of air pollution that comprises a heterogeneous mixture of different particle sizes and chemical compositions. There are various sources of fine PM (PM_2.5), and the components may also have different effects on people. The pathogenesis of PM_2.5 in several diseases remains to be clarified. There is a long history of epidemiological research on PM_2.5 in several diseases. Numerous studies show that PM_2.5 can induce a variety of chronic diseases, such as respiratory system damage, cardiovascular dysfunction, and diabetes mellitus. However, the epidemiological evidence associated with potential mechanisms in the progression of diseases need to be proved precisely through in vitro and in vivo investigations. Suggested mechanisms of PM_2.5 that lead to adverse effects and chronic diseases include increasing oxidative stress, inflammatory responses, and genotoxicity. The aim of this review is to provide a brief overview of in vitro and in vivo experimental studies of PM_2.5 in the progression of various diseases from the last decade. The summarized research results could provide clear information about the mechanisms and progression of PM_2.5-induced disease.

Polyphenols have been widely recognized for their potential anti-obesity effects. This study aimed to evaluate the impact of a polyphenol compound-epigallocatechin-3-gallate, quercetin, and rutin (EQR) on obesity-related parameters and gut microbiota composition. After four weeks of high-fat diet (HFD) induction, the obese Wistar male rats received EQR treatment for an additional four weeks. EQR supplementation significantly reduced body weight gain, feed efficiency, adipose tissue accumulation, and liver lipid content in obese rats. Additionally, it enhanced fecal short-chain fatty acid (SCFA) levels and modulated gut microbiota composition. Specifically, EQR treatment significantly induced Fusobacteria, Fusobacteriaceae, Christensenellaceae, Christensenellaceae R-7 group, Lachnoclostridium, Enterorhabdus, and Parvibacter levels and reduced Deferribacteres and Mucispirillum levels. Gene expression analysis in liver, white adipose tissue (WAT), and brown adipose tissue (BAT) revealed that EQR upregulated the expression of liver PPAR-α, WAT SIRT-1, and BAT PGC-1α, while downregulating liver PPAR-γ, liver FATP-1, and WAT FAS, indicating its role in promoting fatty acid oxidation and thermogenesis, as well as suppressing lipid synthesis and transport. In conclusion, EQR demonstrated significant anti-obesity effects by modulating gut microbiota and lipid metabolism, suggesting its potential as a functional ingredient for obesity management.

Background/Objectives: Obesity represents a critical risk factor for various chronic illnesses and metabolic dysfunctions, underscoring the urgency of identifying safe, food-based interventions to curb fat over-accumulation. Mesona procumbens Hemsl. (Hsian-tsao) is a traditional Chinese herb known for its antioxidant and health-promoting properties; however, it remains unclear how its phenolic acid profiles contribute to anti-obesity activity. This research explored the anti-adipogenic potential of various Hsian-tsao ethanol extracts, focusing on how their phenolic profiles influence lipid suppression in 3T3-L1 adipocytes. Methods: Ethanol extracts prepared using different ethanol concentrations were analyzed for total polyphenol content, antioxidant capacity, and phenolic acid profiles. Adipocytes were exposed to 0, 100, and 250 μg/mL of Hsian-tsao ethanol extract for 48 h duration to monitor changes in cell count and intracellular triglyceride levels. Results: Among all fractions, the 40% ethanol extract (40EEHT) possessed the most robust antioxidant capacity and highest polyphenol content, specifically showing enriched levels of caffeic acid, p-coumaric acid, and total phenolic acids. Notably, while 40EEHT influenced cell density at certain concentrations, it significantly and specifically reduced intracellular triglyceride content, indicating a potent inhibitory effect on lipid storage independent of changes in cell number. Comparative analysis using phenolic acid standards revealed that caffeic acid exerted the strongest inhibitory effect on lipid accumulation, suggesting that it is a key contributor to the anti-adipogenic activity of 40EEHT. Conclusions: Collectively, these findings demonstrate that phenolic acid profiles, particularly caffeic acid enrichment, critically contribute to the potential anti-adipogenic effects of specific ethanol extracts of M. procumbens. Therefore, Hsian-tsao ethanol extracts represent a promising natural source for the development of functional ingredients targeting obesity and related metabolic disorders.