The aim of this study was to purify proanthocyanidins from areca nut seeds (P-AN) and to investigate the bactericidal activity and mechanism of the purified products against S. mutans. UPLC-Q-TOF-MS, FT-IR, MADLI-TOF-MS and thiolysis experiment were used for P-AN chemical analysis. Time-kill analysis and glycolytic pH drop were used to evaluate the activity of S. mutans in vitro. Meanwhile, the investigation of the bacteriostatic mechanism included membrane protein, fluidity, permeability and integrity tests. The results showed that P-AN was a kind of proanthocyanidins mainly composed of B-type proanthocyanidin and their polymers. Moreover, MADLI-TOF-MS and thiolysis experiments demonstrated that the degree of polymerization (DP) of P-AN was 13. The time-kill analysis showed that P-AN had strong bactericidal activity against S. mutans. P-AN at MIC concentrations was able to induce S. mutans death, while complete lethality occurred at 2 MIC. Glycolysis test showed that P-AN significantly inhibited S. mutans acid production (p < 0.01). The morphological changes of S. mutans were observed by SEM and TEM experiments, which indicated that P-AN destroyed the cellular structure of S. mutans. At the same time, significant changes were observed in membrane proteins, fluidity, permeability and integrity. P-AN can effectively inhibit the activity of S. mutans. P-AN can reduce the erosion of the tooth surface by the acid of S. mutans. P-AN could break the structure of cell membrane protein of S. mutans. P-AN could destroy the integrity of membrane, resulting in the death of S. mutans.

In this study, the active components in the seed of Mangifera indica L. were isolated, the main chemical components were identified, and then their antioxidant activities and their effects on liver injury and intestinal microbiota were evaluated. The results showed that all the components of mango column chromatography exhibited antioxidant activity. F2 had the lowest IC₅₀ value of 93.61 μg/mL and exhibited the strongest DPPH radical scavenging activity. Given its superior overall antioxidant activity, F2 was selected for further compositional analysis and activity evaluation. UPLC-MS/MS analysis showed that the isolated components of mango F2 contained 11 active ingredients, including mangiferin, gallic acid and quercetin. The results showed that specific mango fractions significantly reduced serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) levels, and showed a protective effect on liver injury induced by alcohol. rRNA sequencing analysis showed that high alcohol intake could reduce the species diversity of intestinal microbiota in mice, and mango fractions could effectively alleviate this phenomenon. High alcohol intake decreases the relative abundance of Bacteroidota and increases the abundance of Bacillota and Thermodesulfobacteriota phyla. The high-dose mango group alleviated the above changes, which was manifested by an increase in the relative abundance of Bacteroidota and Thermodesulfobacteriota bacteria. The relative abundance of families such as Muribaculaceae in the high-dose mango group decreased compared to the model group. This study provides a scientific basis for the analysis and high-value utilization of mango components, and provides a new alternative for protecting against alcoholic liver injury and regulating intestinal microbiota.

Mango fruits are popular for their flavor. Sugar, a key component of fruit nutrition and flavor, determines fruit quality via its composition and content. While many studies explore molecular regulatory pathways of sugar metabolism in various fruits, large-scale physiological screening of related enzymes via advanced mathematical methods is largely neglected, and the physiological mechanism of sugar accumulation in mango remains unclear. This study analyzed glucose, fructose, sucrose and starch contents, and the activities of 11 sugar metabolism-related enzymes (adenosine diphosphate glucose pyrophosphorylase (AGP); sucrose synthase (SS); sucrose phosphate synthase (SPS); protein kinase (PK); starch debranching enzyme (DBE); phosphoglucomutase (PGM); α-amylase; β-amylase; isoamylase (ISA); sucrose invertase (INV); acid invertase (AI)) from fruit growth to post-ripening stages of mango cultivar ‘Renong No.1’, determined the correlations among soluble sugar, starch and enzyme activities, and constructed mathematical models of inter-group relationships using R language. The results showed that glucose, fructose and starch accumulated during fruit growth, while sucrose accumulated during post-ripening. Fructose content was significantly positively correlated with AGP, α-amylase, AI, β-amylase and SPS activities; so was glucose content and AGP activity; sucrose content and AGP, AI, PK, α-amylase, ISA, INV and SPS activities; and sweetness value and AGP, α-amylase, AI, SPS, SS and β-amylase activities. AI, AGP and α-amylase were identified as the key enzymes influencing sweetness value. Ultimately, a new visualizing and digitizing statistical approach for roles of eleven key enzymes in sweet value and soluble sugar component content during mango development was shown.

Cuminaldehyde (CA), a major bioactive constituent of cumin essential oil, was incorporated into gelatin/konjac glucomannan (Gel/KGM) composite films at different levels, expressed relative to the polymer content (mL/g polymer), to investigate its effects on film structure, physicochemical properties, and antioxidant activity. Structural characteristics of the films were examined using Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy, X-ray diffraction (XRD), and scanning electron microscopy (SEM). Mechanical properties, surface wettability, optical properties, water sensitivity, and antioxidant activity were also determined. Spectroscopic analyses indicated changes in the molecular interactions of the Gel/KGM matrix following CA incorporation, while XRD and SEM analyses showed reduced structural order and a more heterogeneous microstructure at higher CA levels. Representative contact-angle observations showed an initial angle of 40.2° for the Control and 58.0° for CA-10, suggesting a tendency toward reduced surface wettability after CA incorporation. The addition of CA also improved UV-shielding properties and enhanced antioxidant responses, although the magnitude and trend of the antioxidant effect depended on the assay. In contrast, higher CA levels significantly reduced tensile strength and increased water solubility, whereas the tensile strength of films containing 1 mL CA did not differ significantly from that of the control (p > 0.05). These results demonstrate that the structural, physicochemical, and functional responses of Gel/KGM composite films varied with the nominal CA loading. Among the tested formulations, CA-3 represented a possible compromise between structural integrity and functional performance. Further studies using real food matrices are required to validate its practical applicability under actual food-packaging conditions.