Treatment for tumors depends on host immune system. The antitumor and immunoregulatory activities of Ulva lactuca polysaccharide (ULP) were evaluated in H22 tumor‐bearing mice and cyclophosphamide‐induced immunosuppressed mice, respectively. The structural properties of ULP were identified through multi‐angle laser light scattering, high‐performance liquid chromatography, Fourier‐transformed infrared, and nuclear magnetic resonance. It was composed of α‐D‐Manp‐(1→, →2,4)‐β‐L‐Rhap‐(1→, β‐D‐GlcpA‐(1→, β‐GalpA‐(1→, →2,4)‐α‐D‐Glcp‐(1→, and →6)‐β‐D‐Galp‐(1→ with the molecular weight of 1.46 × 10⁵ Da. Its antioxidant, anti‐inflammatory, and antitumor effects were determined. Liver and tumor tissues were collected for histopathological, immunohistochemical, and western blotting analysis. ULP showed the great tumor growth inhibition of 74.41% compared with cyclophosphamide, which has side effects on immune system. ULP enhanced the expression of p53 to inhibit tumorigenesis, promoted the activation of IKKα, and inhibited the activation of p65 within the NF‐κB pathway. ULP inhibited the tumor growth through downregulating the expressions of PI3K/Akt and mTOR, and promoting BAX/Bcl‐2 ratio. The inhibition of TRAF2/TNF‐α and CD31/VEGF achieved a direct killing effect on tumor cells and inhibited tumor proliferation by inhibiting angiogenesis, respectively. Moreover, ULP increased the levels of immunoglobulin M and total superoxide dismutase, decreased the level of methane dicarboxylic aldehyde, and inhibited the activation of PI3K/AKT/mTOR/p70S6k pathways. The results showed that ULP exhibited pronounced antitumor activity and immunoregulatory effect.

Diabetes mellitus is a metabolic disease with a high mortality rate worldwide. MicroRNAs (miRNAs), and other small noncoding RNAs, serve as endogenous gene regulators through binding to specific sequences in RNA and modifying gene expression toward up‐ or down‐regulation. miRNAs have become compelling therapeutic targets and play crucial roles in regulating the process of insulin resistance. Fucoidan has shown potential function as an α‐amylase inhibitor, which may be beneficial in the management of type 2 diabetes mellitus. In recent years, many studies on fucoidan focused on the decrease in blood glucose levels caused by ingesting low‐glucose food or glucose‐lowering components. However, the importance of miRNAs as regulators of antidiabetic effects was rarely recognized. Hence, this review emphasizes the antidiabetic mechanisms of fucoidan through regulation of miRNAs. Fucoidan exerts a vital antidiabetic effect by regulation of miRNA expression and thus provides a novel biological target for future research.

This study investigates the antibacterial activities of food-derived dihydrochalcone and flavone flavonoids against Porphyromonas gingivalis and their mechanisms of antibacterial action through a comparative transcriptomic analysis.

Porphyromonas gingivalis is a key periodontal pathogen whose cysteine proteases, gingipains (Rgp and KGP), are essential for nutrient acquisition and virulence. Targeting gingipains may attenuate bacterial pathogenicity and prevent related systemic diseases. This paper aimed to review advances in food-derived natural products that inhibit P. gingivalis or gingipains, with emphasis on mechanisms, potency, and translational potential. A literature search of several databases identified 64 studies on food-derived compounds demonstrating in vitro, in vivo, or clinical effects against P. gingivalis or gingipains. The results showed that tea polyphenols and dihydrochalcones (e.g., phloretin and phlorizin) inhibited gingipain activity, and a variety of food-derived natural products (especially polyphenols and polysaccharides) suppressed the growth, survival, biofilm formation, and virulence of P. gingivalis. Structure–activity relationships suggest galloyl moieties and dihydrochalcone scaffolds enhance gingipain inhibition. Polysaccharides and alkaloids exhibited anti-adhesion or protease inhibition, though with limited potency data. In summary, food-derived natural products represent promising gingipain inhibitors. These inhibitors have potential structure–activity relationships, indicating that food-derived natural products have considerable research prospects. Future research should prioritize structure-based discovery and structure optimization to realize their therapeutic potential.

Porphyromonas gingivalis is crucial for the pathogenesis of periodontitis. This research investigated the effects of the fruit-derived flavonoid phloretin and its analogs on the growth of pure P. gingivalis and the flora of P. gingivalis mixed with the symbiotic oral pathogens Fusobacterium nucleatum and Streptococcus mitis. The results showed that the tested flavonoids had little effect on the biofilm amount of pure P. gingivalis, but significantly reduced the biofilm amount of mixed flora to 83.6~89.1%. Biofilm viability decreased to 86.7~92.8% in both the pure- and mixed-bacterial groups after naringenin and phloretin treatments. SEM showed that phloretin and phlorizin displayed a similar and remarkable destructive effect on P. gingivalis and the mixed biofilms. Transcriptome analysis confirmed that biofilm formation was inhibited by these flavonoids, and phloretin significantly regulated the transcription of quorum sensing. Phlorizin and phloretin reduced AI-2 activity to 45.9% and 55.4%, respectively, independent of the regulation of related gene transcription. This research marks the first finding that these flavonoids possess anti-biofilm properties against P. gingivalis and its intricate bacterial community, and the observed performance variations, driven by structural differences, underscore the existence of intriguing structure–activity relationships.