Publications by authors named "Naofumi Umigai"

The corneal epithelium is located at the outermost layer of the ocular surface and continuously exposed to environmental factors, such as ultraviolet (UV) radiation from sunlight. UV irradiation causes excessive production of reactive oxygen species (ROS) in cells, which results in oxidative damage to membrane-bound organelles such as mitochondria, eventually leading to cell death. Crocetin, a natural carotenoid found in plants, has various biological properties including antioxidant activity.

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Background: Paprika ( L.) is a good source of carotenoids, including capsanthin, β-carotene, β-cryptoxanthin, and zeaxanthin. Several epidemiological studies have shown a beneficial association of intake of these carotenoids or their blood concentration with bone mineral density (BMD) and fracture risk.

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Objectives: The aim of the present study was to investigate the effect of crocetin on sleep architecture and subjective sleep parameters in healthy adult participants with mild sleep complaints.

Design: A randomized, double-blind, placebo-controlled, crossover study with two intervention periods of 14 days each, separated by a 14-day wash-out period.

Interventions: Thirty participants were randomly assigned to one of two sequence groups.

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Paprika oleoresin is obtained by solvent extraction from Capsicum annuum L. fruits and contains multiple carotenoids, such as capsanthin, β-carotene, zeaxanthin, and β-cryptoxanthin, which are considered protective against various diseases. Herein, we investigated the effect of paprika oleoresin supplementation on plasma carotenoid accumulation and evaluated the safety of the oleoresin.

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Crocetin, the aglycone of crocin, is a carotenoid found in fruits of gardenia (Gardeina jasminoides Ellis) and saffron (Crocus sativus L.). We investigated the protective effects of crocetin against ultraviolet-A (UV-A)-induced skin damage and explored the underlying mechanism.

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Crocetin, an aglycone of crocin, is found both in the saffron crocus (Crocus starus L.) and in gardenia fruit (Gardenia jasminoides Ellis). We evaluated the protective effects of crocetin against the retinal ischemia induced by 5h unilateral ligation of both the pterygopalatine artery (PPA) and the external carotid artery (ECA) in anesthetized mice.

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Crocetin, an aglycone of crocin, is found in stigmas of the saffron crocus (Crocus starus L.) and has been used in traditional medicine. We investigated the effects of oral administration of crocetin on damage induced by N-methyl-D-aspartate (NMDA) in the murine retina.

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We evaluated the protective effects of crocetin against angiogenesis induced by vascular endothelial growth factor (VEGF). Crocetin, the aglycone of crocin carotenoids, is found in saffron crocus (Crocus sativus L.) and gardenia fruit (Gardenia jasminoides Ellis).

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Crocetin is a natural carotenoid compound of gardenia fruits and saffron, which has various effects in biological systems. In this study, we investigated the antioxidant effects of crocetin on reactive oxygen species such as hydroxyl radical using in vitro X-band electron spin resonance and spin trapping. Crocetin significantly inhibited hydroxyl radical generation compared with the control.

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Crocetin is a carotenoid that is the aglicone of crocin, which are found in saffron stigmas (Crocus sativus L.) and gardenia fruit (Gardenia jasminoides Ellis). In this study, we investigated the effects of crocetin on retinal damage.

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Potassium channels, which control the passage of K+ across cell membranes, have two transmembrane segments, M1 and M2, separated by a hydrophobic P region containing a highly conserved signature sequence. Here we analyzed the membrane topogenesis characteristics of the M1, M2, and P regions in two animal and bacterial two-transmembrane segment-type K+ channels, Kir 2.1 and KcsA, using an in vitro translation and translocation system.

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