Measurements of the second-order rate constants and the singlet oxygen absorption capacity (SOAC) values for the reaction of singlet oxygen (1O2) with 23 kinds of food extracts were performed in ethanol/chloroform/D2O (50:50:1, v/v/v) solution at 35 °C. It has been clarified that the SOAC method is useful to evaluate the 1O2-quenching activity (i.e. the SOAC value) of food extracts having two orders of magnitude different rate constants from 3.18 × 104 L g−1 s−1 for tomato to 1.55 × 102 for green melon. Furthermore, comparison of the observed rate constants for the above food extracts with the calculated ones based on the concentrations of seven kinds of carotenoids included in the food extracts and the rate constants reported for each carotenoids was performed, in order to ascertain the validity of the SOAC assay method developed and to clarify the ratio of the contribution of principal carotenoids to the SOAC value.

Radical scavenging and singlet oxygen quenching activities of 32 kinds of fruits and vegetables typically consumed in Japan were evaluated using both the oxygen radical absorbance capacity (ORAC) and singlet oxygen absorption capacity (SOAC) methods. Total-ORAC and SOAC values correlated with total polyphenol (r = 0.92) and carotenoid (r = 0.85) contents. From the data of daily fruit and vegetable intake (110.0 and 286.4 g, respectively) in the National Health and Nutrition Survey in Japan, daily ORAC and SOAC intakes were estimated to be 3177.7 µmol trolox equivalents/day and 1610.3 µmol α-tocopherol equivalents/day, respectively. The major contributors to ORAC intake were apples, Satsuma mandarins, edible burdock, and onions, accounting for 44.3% of the total; whereas Japanese squash, carrots, tomatoes, and spinach accounted for 73.2% of total SOAC intake. Total antioxidant capacity assessment of foods may facilitate the identification of relationships between antioxidant intake and disease risk reduction.

Maintaining normal vascular endothelial function is important for preventing arteriosclerosis. Flow-mediated dilatation (FMD) is widely used to evaluate vascular endothelial function. Lycopene, a carotenoid abundant in tomatoes, has been reported to improve FMD, but its effect after 4 weeks of intake remains unclear. We conducted a randomized, placebo-controlled, double-blind, parallel-group trial to assess the effects of lycopene. Seventy-five healthy adults with borderline FMD (4–7%) were randomly assigned to placebo juice (0.7 mg lycopene), tomato juice (TJ, 15.0 mg), or high-lycopene tomato juice (HLTJ, 26.7 mg) groups. FMD, serum lycopene, oxidative stress markers (malondialdehyde, 8-hydroxy-2′-deoxyguanosine, 8-iso-prostaglandin F2α), and nitrogen oxide concentrations were measured every 4 weeks over a 12-week intervention. The participants analyzed included 23 (placebo), 25 (TJ), and 24 (HLTJ). Data were analyzed using a linear mixed effects model adjusting for baseline covariates and a post hoc Dunnett's test with Bonferroni correction for intergroup comparisons. At week 12, FMD was significantly higher in the TJ (6.1 ± 0.5%, p < 0.001) and HLTJ groups (7.0 ± 0.7%, p < 0.001) than in the placebo group (5.4 ± 0.6%). In the HLTJ group, FMD at weeks 4 (6.2 ± 1.0%, p < 0.001) and 8 (6.7 ± 0.7%, p < 0.001) was significantly higher than in the placebo group (5.4 ± 0.9% and 5.3 ± 0.6%, respectively). Serum lycopene concentrations were significantly increased in TJ and HLTJ groups than in the placebo group. No significant differences were observed in oxidative stress or nitrogen oxide levels. These findings suggest that lycopene intake improves vascular endothelial function, though the mechanism remains unclear. Trial registration: UMIN000051176.

Falcarindiol, a typical polyacetylene compound found in Apiaceae vegetables, activates peroxisome proliferator-activated receptor γ (PPARγ). However, whether it induces the browning of adipocytes through PPARγ activation is unclear. In this study, we aimed to clarify the effects of falcarindiol on adipocyte browning and mitochondrial respiration in human preadipocyte-derived adipocytes. Human primary cultured cells were differentiated for 8 days in the presence of falcarindiol. The expression of PPARγ target and beige adipocyte-related genes was measured using quantitative real-time PCR, and the accumulation of lipid droplets and uncoupling protein 1 (UCP1) protein expression were evaluated using immunohistochemistry. The oxygen consumption rate was measured using a Seahorse flux analyzer. Falcarindiol increased the expression of PPARγ target genes, including PPARγ, FABP4, SLC2A4, and ADIPOQ. It also increased the expression of beige adipocyte-related genes, such as PPARGC1A, PPARA, CITED1, and TBX1, and increased the expression of UCP1 protein. Falcarindiol also significantly increased basal respiration, ATP-linked respiration, maximal respiration, spare capacity, and proton-leak respiration, and significantly decreased the coupling efficiency in a concentration-dependent manner. These results indicate that falcarindiol promotes a beige adipocyte-like phenotype and oxygen consumption of adipocytes in vitro, suggesting that dietary intake of falcarindiol and falcarindiol-containing Apiaceae vegetables may be effective in obesity prevention.

The present study involves the precise identification and safety evaluation of Enterococcus casseliflavus KB1733, previously identified using 16S rRNA analysis, through whole-genome sequencing, phenotypic analysis, and preclinical toxicity studies. Analyses based on the genome sequencing data confirm the identity of KB1733 as E. casseliflavus and show that the genes related to vancomycin resistance are only present on the chromosome, while no virulence factor genes are present on the chromosome or plasmid. Phenotypic analyses of antibiotic resistance and hemolytic activity also indicated no safety concerns. A bacterial reverse mutation test showed there was no increase in revertant colonies of heat-killed KB1733. An acute toxicity test employing heat-killed KB1733 at a dose of 2000 mg/kg body weight in rats resulted in no deaths and no weight gain or other abnormalities in the general condition of the animals, with renal depression foci and renal cysts only occurring at the same frequency as in the control. Taking the background data into consideration, the effects on the kidneys observed in the current study were not caused by KB1733. Our findings suggest that KB1733 is non-pathogenic to humans/animals, although further studies involving repeated oral toxicity tests and/or clinical tests are required.