Infections caused by bacteria represent an emerging public health threat due to the development of antibiotic resistance in bacteria. Curcumin (CUR), a naturally derived substance, is found to be effective against several bacteria. However, its use is limited by its low water solubility and rapid degradation profile. Polymeric nanocapsules (NCs) represent an interesting drug delivery system with high incorporation rates due to their liquid core. The present study aimed to develop poly-(lactic-co-glycolic acid) (PLGA) NCs for the delivery of CUR for enhancing its solubility and antibacterial activity. The particle size, polydispersity index (PDI), zeta potential and drug entrapment efficiency of CUR NCs with optimal formulation were 158 nm, 0.156, −29.1 mV and 92.64%, respectively. The water solubility of CUR in NCs increased about 1500 fold compared to that of free CUR. TEM and AFM images proved the core–shell structure of PLGA NCs with narrow size distributions. The in vitro release profile of CUR from PLGA NCs showed a burst release in the initial 24 h followed by a sustained release of the interior CUR over 10 days. In vitro antibacterial experiments demonstrate that the minimum inhibitory concentrations (MICs) of CUR NCs were lower than those of free CUR for all different bacterial strains, especially for Gram-negative bacteria. CUR NCs exhibited broad-spectrum antibacterial effects compared with free CUR. These data suggest that these CUR-loaded PLGA NCs may provide a promising strategy as novel antibacterial agents.

Oridonin isolated from Rabdosia rubescens, a plant used to treat cancer in Chinese folk medicine, is one of the most important antitumor active ingredients. Previous studies have shown that oridonin has anti- tumor activities in vivo and in vitro, but little is known about cell cycle effects of oridonin in gastric cancer. MTT assay was adopted to detect the proliferation inhibition of SGC-7901 cells, the cell cycle was assessed by flow cytometry and protein expression by Western blotting. Oridonin could inhibit SGC-7901 cell proliferation, the IC50 being 15.6 μM, and blocked SGC-7901 cell cycling in the G2/M phase. The agent also decreased the protein expression of cyclinB1 and CDK1. Oridonin may inhibit SGC-7901 growth and block the cells in the G2/M phase by decreasing Cdk1 and cyclinB1 proteins.

Bacteria and bacterial components possess multifunctional properties, making them attractive natural bio-nanocarriers for cancer diagnosis and targeted treatment. The inherent tropic and motile nature of bacteria allows them to grow and colonize in hypoxic tumor microenvironments more readily than conventional therapeutic agents and other nanomedicines. However, concerns over biosafety, limited antitumor efficiency, and unclear tumor-targeting mechanisms have restricted the clinical translation and application of natural bio-nanocarriers based on bacteria and bacterial components. Fortunately, bacterial therapies combined with engineering strategies and nanotechnology may be able to reverse a number of challenges for bacterial/bacterial component-based cancer biotherapies. Meanwhile, the combined strategies tend to enhance the versatility of bionanoplasmic nanoplatforms to improve biosafety and inhibit tumorigenesis and metastasis. This review summarizes the advantages and challenges of bacteria and bacterial components in cancer therapy, outlines combinatorial strategies for nanocarriers and bacterial/bacterial components, and discusses their clinical applications.

Long-term manganese exposure causes a neurodegenerative disorder referred to as manganese poisoning, but the mechanism remains unclear and no specific treatment is available. Oxidative stress is widely recognised as one of the main causes of manganese-induced neurotoxicity. In recent years, the role of histone acetylation in neurodegenerative diseases has been widely concerned. curcumin is a natural polyphenol compound extracted from the rhizome of turmeric and exhibits both antioxidant and neuroprotective properties. Therefore, we aimed to investigate whether and how curcumin protects against manganese-induced neurotoxicity from the perspective of histone acetylation, based on the reversibility of histone acetylation modification. In this study, rats were treated with or without curcumin and subjected to long-term manganese exposure. Results that treatment of manganese decreased the protein expression of H3K18 acetylation and H3K27 acetylation at the promoters of oxidative stress-related genes and inhibited the expression of these genes. Nevertheless, curcumin increased the H3K27 acetylation level at the manganese superoxide dismutase (SOD2) gene promoter and promoted the expression of SOD2 gene. Oxidative damage in the rat striatum as well as learning and memory dysfunction were ameliorated after curcumin treatment. Taken together, our results suggest that the regulation of oxidative stress by histone acetylation may be a key mechanism of manganese-induced neurotoxicity. In addition, curcumin ameliorates Mn-induced neurotoxicity may be due to alleviation of oxidative damage mediated by increased activation of H3K27 acetylation at the SOD2 gene promoter.