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(+)-Catechin derivatives with different alkyl chain lengths were synthesized from (+)-catechin and various straight chain alkylaldehydes in the presence of methyl mercaptan, and their antibacterial activities against Gram-positive bacteria were evaluated. The antibacterial activity increased markedly with elongation of the alkyl chain lengths of the derivatives and reached a maximum at a chain of four to seven carbons. Subsequently, interaction of the (+)-catechin derivatives with a model membrane using liposome was investigated. The derivatives with a chain of three carbons or more were found to have very strong affinity for the membrane. The injury action of the derivatives against the membrane was examined with liposome in which calcein was enclosed as a fluorescent indicator. The leakage was observed in the derivatives with chain lengths of four carbons or more. Particularly the derivatives with chains longer than five carbons are considered to destroy the liposome membrane judging from the degree of the fluorescent leakage. These results implied that the lipophilicity and disrupting ability of the (+)-catechin derivatives to the liposome membrane participate in their antibacterial activity.

Green tea contains a high concentration of such catechins as (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), and (-)-epigallocatechin gallate (EGCg). Their biological activities have been evaluated by in vitro experiments using cultured cells or bacteria, but the order of activity of the various catechins differed with the study. We have been studying the interaction of tea catechins with lipid bilayers, and clarified that the number of hydroxyl groups on the B-ring, the presence of the galloyl moiety, and the stereochemical structure of each catechin govern their affinity for lipid bilayers. We investigated in this present study the effects of various external factors on the affinity of tea catechins for lipid bilayers by using liposomes as model membranes. The amount of tea catechins incorporated into the lipid bilayers increased with increasing salt concentration in an aqueous medium and decreased with increasing negative electric charge of the lipid bilayers. Furthermore, the amount of EGCg or ECg incorporated into the lipid bilayers increased with increasing EC concentration. These results reveal that the salt concentration in an aqueous medium, the electric charge of the membrane, and the presence of other catechins governed the affinity of tea catechins for the lipid bilayers.

Interaction of tea catechins with lipid bilayers has been investigated with liposome systems. Epicatechin gallate had the highest affinity for lipid bilayers, followed by epigallocatechin gallate, epicatechin, and epigallocatechin. Epicatechin gallate and epigallocatechin gallate in the surface of lipid bilayer perturbed the membrane structure.

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The Dietary Approaches to Stop Hypertension (DASH) diet is recommended by the American Heart Association to lower blood pressure (BP); however, its effects in Japanese participants have not been rigorously studied. We assessed the effects of the DASH-Japan Ube Modified diet Program (DASH-JUMP), a modified DASH diet, on cardiometabolic and inflammatory biomarkers in Japanese participants with untreated high-normal BP or stage 1 hypertension. Fifty-eight participants (30 men and 28 women; mean age 54.1±8.1 years) with untreated high-normal BP or stage 1 hypertension followed the DASH-JUMP (salt 8.0 g per day) for 2 months. After the intervention period, they resumed their usual diets for 4 months. The DASH-JUMP significantly decreased the participants' body mass index values (24.6±3.5 kg m−2 at baseline→23.2±3.3 kg m−2 at 2 months, P=0.000), BP (153±14/91±11 mm Hg at baseline→130±16/80±9 mm Hg at 2 months, P=0.000 and 139±16/85±10 mm Hg at 6 months, P=0.000), fasting serum glucose level (100±26 mg dl−1→94±15 mg dl−1 at 2 months, P=0.003) and fasting insulin level (6.9±5.9 μIU ml−1→4.4±2.7 μIU ml−1 at 2 months, P=0.000). The mean compliance of the participants for the DASH-JUMP diet was 88.5%. The DASH-JUMP diet reduced cardiovascular risk factors and may be an effective nutritional strategy for preventing cardiovascular events.

Various folk remedies employ certain odorous compounds with analgesic effects. In fact, linalool, a monoterpene alcohol found in lavender extracts, has been found to attenuate pain responses via subcutaneous, intraperitoneal, intrathecal, and oral administration. However, the analgesic effects of odorous compounds mediated by olfaction have not been thoroughly examined. We performed behavioural pain tests under odourant vapour exposure in mice. Among six odourant molecules examined, linalool significantly increased the pain threshold and attenuated pain behaviours. Olfactory bulb or epithelium lesion removed these effects, indicating that olfactory sensory input triggered the effects. Furthermore, immunohistochemical analysis revealed that linalool activated hypothalamic orexin neurons, one of the key mediators for pain processing. Formalin tests in orexin neuron-ablated and orexin peptide-deficient mice showed orexinergic transmission was essential for linalool odour-induced analgesia. Together, these findings reveal central analgesic circuits triggered by olfactory input in the mammalian brain and support a potential therapeutic approach for treating pain with linalool odour stimulation.