To explore the influence of pH values on the properties of a compound system containing tea polyphenols (TPs) and low acyl gellan gum (LGG), the color, texture characteristics, rheological properties, water holding capacity (WHC), and microstructure of the compound system were measured. The results showed that the pH value noticeably affects the color and WHC of compound gels. Gels from pH 3 to 5 were yellow, gels from pH 6 to 7 were light brown, and gels from pH 8 to 9 were dark brown. The hardness decreased and the springiness increased with an increase in pH. The steady shear results showed that the viscosity of the compound gel solutions with different pH values decreased with increasing shear rates, indicating that all of the compound gel solutions were pseudoplastic fluids. The dynamic frequency results showed that the G′ and G″ of the compound gel solutions gradually decreased with increasing pH and that G′ was higher than G″. No phase transition occurred in the gel state under heating or cooling conditions at pH 3, indicating that the pH 3 compound gel solution was elastic. The WHC of the pH 3 compound gel was only 79.97% but the WHC of compound gels pH 6 and pH 7 was almost 100%. The network structure of the gels was dense and stable under acidic conditions. The electrostatic repulsion between the carboxyl groups was shielded by H⁺ with increasing acidity. The three-dimensional network structure was easily formed by an increase in the interactions of the hydrogen bonds.

Antimicrobial peptides (AMPs) have caught the attention of researchers over the last couple of years due to their unique membrane lytic mechanism for combating antibiotic resistance, which differs from the molecular targets of traditional antibiotics. Although natural AMPs exhibit potential antimicrobial activity against a wide range of microorganisms, some drawbacks, such as toxicity, low antibacterial activity, and high production costs limit their clinical application. To enhance the antimicrobial activity of a series of HSP peptides derived from the natural peptide HSP-1, this study optimized them using a variety of strategies, including net charge, hydrophobic moment, hydrophobicity, and helicity. Optimizing the antimicrobial action of HSP peptides depended mostly on net charge, hydrophobic moment, and hydrophobicity rather than helicity. HSP-M4 may be designed to combat microbial infections because the antimicrobial activity and cytotoxicity assays showed that they exhibited low cytotoxicity and prominent antimicrobial activity, respectively.

The imbalance of the renin–angiotensin system (RAS), characterized by the overactivation of the pro-tumor ACE/AngII/AT1R axis, is closely linked to tumor growth, angiogenesis, metastasis, and poor prognosis. Natural polyphenols, such as EGCG and resveratrol, exert anti-cancer effects by dual-regulating RAS: they inhibit the pro-tumor axis by blocking renin, ACE activity, and AT1R expression, while simultaneously activating the protective ACE2/Ang(1-7)/MasR axis. Furthermore, polyphenols and their autoxidation products (e.g., EAOP) modify thiol-containing transmembrane proteins (such as ADAM17 and integrins) and interact with RAS components, further disrupting oncogenic pathways (including MAPK and PI3K/Akt/mTOR) to induce apoptosis, suppress invasion, and reduce oxidative stress. Notably, EAOP exhibits stronger RAS-modulating efficacy than its parent polyphenols. However, challenges such as low bioavailability, insufficient targeting, and limited clinical evidence impede their application. This review provides a comprehensive overview of the anti-cancer mechanisms of polyphenols through RAS regulation, discusses the associated challenges, and proposes potential solutions (including nanodelivery and structural modification) and strategies to advance natural product-based adjuvant treatments.