Advanced glycation end products (AGEs) are substances composed of amino groups of proteins and reducing sugars. The initial and propagation phases of the glycation process are accompanied by the production of a large amount of free radicals, carbonyl species, and reactive dicarbonyl species, of which, methylglyoxal (MG) is the most reactive and can cause dicarbonyl stress, influencing normal physiological functions. In the advanced phase, the production of AGEs and the interaction between AGEs and their receptor, RAGE, are also considered to be among the causes of chronic diseases, oxidative stress, and inflammatory reaction. Till date, multiple physiological activities of polyphenols have been confirmed. Recently, there have been many studies discussing the ability of polyphenols to suppress the MG and AGEs formation, which was also confirmed in some in vivo studies. This review article collects recent literatures concerning the effects of polyphenols on the generation of MG and AGEs through different pathways and discusses the feasibility of the inhibition of glycative stress and dicarbonyl stress by polyphenols.
The lysyl oxidase (LOX) family of oxidases contains a group of extracellular copper-dependent enzymes that catalyze the cross-linking of collagen and elastin by oxidation, thus maintaining the rigidity and structural stability of the extracellular matrix (ECM). Aberrant expression or activation of LOX alters the cellular microenvironment, leading to many diseases, including atherosclerosis, tissue fibrosis, and cancer. Recently, a number of studies have shown that LOX is overexpressed in most cancers and that it is involved in the regulation of tumor progression and metastasis. In contrast, a few reports have also indicated the tumor-suppressing role of LOX. In this short review, we discuss recent research on the correlations between LOX and cancer. Further, the role of LOX in tumor microenvironment remodeling, tumorigenesis, and metastasis and the underlying mechanisms have also been elucidated.
Hinokitiol is a natural component isolated from Chamacyparis taiwanensis. It has anti-microbial activity, and has been used in oral care products. The minimal inhibitory concentration (MIC) and minimal microbicidal concentration (MMC) of hinokitiol against MRSA, Aggregatibacter actinomycetemcomitans, Streptococcus mutans, and Candida albicans were determined by the agar and broth dilution method (MIC: 40-110μM; MMC: 50-130μM); the paradoxical inhibition phenomenon (PIP) was observed in A. actinomycetemcomitans and S. mutans. The PIP can be described as microbial growth occurring in the presence of both high and low concentrations of a compound, between which microbial growth is inhibited. The PIP was confirmed using a kinetic microplate and inhibition zone methods. The PIP was also observed in MRSA. The low autolysin activity somehow correlated to the PIP positive. The cell diameter was increased in all the pathogens, and the transition was inhibited in C. albicans following hinokitiol treatment. Hinokitiol is also a potential anticancer drug. The 200μM of hinokitiol has significant antimicrobial and cytotoxic activities against oral pathogens and oral squamous cell carcinoma cell lines, respectively, and lower cytotoxic effects for normal human oral keratinocytes, indicating that hinokitiol displays a high potential for safe and effective applications in oral health care.
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