Yasuo Nagata

The leaves and bark of Litsea species have traditionally been used as folk medicine to treat pain, headache, inflammation, diarrhea, and gastroenteritis. This study investigated whether dietary supplementation with Litsea cubeba leaves could preserve key functional components of the colonic barrier in a mouse model of dextran sulfate sodium (DSS)-induced ulcerative colitis. Male C57BL/6J mice were fed a control diet or a diet supplemented with L. cubeba leaves (20 g/kg diet) for 2 weeks, and colitis was induced by administering 3% (w/v) DSS in drinking water during the final week. Dietary L. cubeba leaf supplementation significantly attenuated DSS-induced body weight loss and suppressed the increase in Disease Activity Index. In addition, L. cubeba leaf supplementation attenuated DSS-induced reduction in fecal immunoglobulin A content and significantly prevented the reduction in fecal mucin content, which are key functional components of the colonic barrier. Furthermore, plasma levels of the inflammatory chemokine monocyte chemoattractant protein-1 were significantly decreased by L. cubeba leaf supplementation, accompanied by a reduction in plasma alanine aminotransferase activity, a marker of liver injury. These findings suggest that dietary L. cubeba leaf supplementation alleviates DSS-induced ulcerative colitis in mice, at least in part, by preserving key functional components of the colonic barrier rather than predominantly through direct suppression of colonic inflammatory gene expression.

Perilla frutescens (L.) Britton var. frutescens (egoma in Japan) is a traditional oilseed that has several varieties with different photoperiod responses. Although egoma pomace, industrial waste produced during oil extraction, is a rich source of macro- and micro-nutrients such as protein, fiber, minerals, and polyphenols, it has not yet been used for purposes other than livestock feeding. To find out a better use of perilla pomace and its function, we selected four varieties of egoma originating from different regions with different photoperiod responses: two varieties were from Japan, which are broadly cultivated for oilseed and are highly sensitive to light and temperature. The other two varieties from Nepal, which are tolerant to low light and low temperature. Rosmarinic acid-3-O-glucoside, rosmarinic acid, and apigenin-7-O-glucoside were detected as the main polyphenolic constituents in every variety, while apigenin and luteolin were present only in perilla pomace from Japan. In IgE-sensitized RBL-2H3 cells, polyphenols derived from two varieties of Japan suppressed degranulation of mast cells, but those derived from the two varieties of Nepal did not, indicating that apigenin and luteolin may be in part responsible for the anti-allergic response. In addition, it was found that proteins involved in the degranulation signaling pathway, such as PLCγ2, Syk, and Akt, were less phosphorylated in cells treated with the egoma pomace extracts of Japanese origin. Taken together, pomace from egoma varieties derived from different regions may differently modulate allergic response in part due to the difference in polyphenol composition and may be applied to develop nutraceuticals and functional foods fortified with anti-allergic properties.

Lotus root is a traditional food ingredient used primarily in Asia and is rich in polyphenols. To determine its potential use in antiphotoaging, polyphenols were extracted from lotus root with 50% ethanol, and the activity of matrix metalloproteinase (MMP) was measured in dermal cells treated with ultraviolet A (UVA). UVA exposure increased the gene expression of IL-1α, the mRNA levels of MMP-1, and hence, the levels of MMP-1 protein in HaCaT cells, whereas cells treated with lotus polyphenol (LP) normalized these values to the control. In the presence of LP at concentrations of 1 and 10 μg/mL, both the secretion of IL-1α and protein levels of MMP-1 in human keratinocyte cells significantly reduced. Similarly, in the LabCyte EPI-MODEL24, irradiation with UVA caused an increase in mRNA expression of IL-1α and MMP-1, which was prevented by adding LP to the cells. Our results with three different skin cells accordingly showed that LP may help maintain skin health through decreased levels of MMP-1 activity via its anti-inflammatory properties.

The leaf of Perilla frutescens (L.) Britton var. frutescens (egoma) is a rich source of polyphenolic compounds, including rosmarinic acid. However, there is still a lack of detailed information concerning the content of phenolic compounds in these leaves. Since some flavonoids were found as a conjugated form, leaves were used untreated or hydrolyzed using β-glucuronidase for analysis. Enzymatic hydrolysis method successfully identified some polyphenols, which have not been reported before. Scutellarin, a flavone glucuronide with a molecular mass similar to that of luteolin 7-O-glucuronide, was present in egoma leaves. Scutellarin was the second most abundant polyphenolic compound, after rosmarinic acid. Egoma leaves at the top of the plant contained a higher amount of rosmarinic acid and scutellarin compared to that in the leaves below. The difference in plant growth stage also influenced the rosmarinic acid and scutellarin contents, while the time of harvesting during the day did rosmarinic acid contents only. This is the first time that scutellarin, a traditional Chinese medicine, widely used for the treatment of cerebrovascular disease, was quantitatively determined in egoma leaves. The present study may help adding value to egoma leaves, developing dietary supplements, functional foods, and cosmetics.

BACKGROUND: Rare sugars including d‐allulose, d‐tagatose, and d‐sorbose are present in limited quantities in nature; some of these rare sugars are now commercially produced using microbial enzymes. Apart from the anti‐obesity and anti‐hyperglycaemic activities of d‐allulose, effects of these sugars on lipid metabolism have not been investigated. Therefore, we aimed to determine if and how d‐tagatose and d‐sorbose modulate lipid metabolism in rats. After feeding these rare sugars to rats, parameters on lipid metabolism were determined.RESULTS: No diet‐related effects were observed on body weight and food intake. Hepatic lipogenic enzyme activity was lowered by d‐allulose and d‐sorbose but increased by d‐tagatose. Faecal fatty acid excretion was non‐significantly decreased by d‐allulose, but significantly increased by d‐sorbose without affecting faecal steroid excretion. A trend toward reduced adipose tissue weight was observed in groups fed rare sugars. Serum adiponectin levels were decreased by d‐sorbose relative to the control. Gene expression of cholesterol metabolism‐related liver proteins tended to be down‐regulated by d‐allulose and d‐sorbose but not by d‐tagatose. In the small intestine, SR‐B1 mRNA expression was suppressed by d‐sorbose.CONCLUSION: Lipid metabolism in rats varies with rare sugars. Application of rare sugars to functional foods for healthy body weight maintenance requires further studies. © 2017 Society of Chemical Industry