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[in Japanese]

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Antioxidant-related activities was examined in ethanol extracts of 53 parts of 36 species of the plants cultivated and used as edible and medicinal plants in food culture of Okinawa. The activities examined in this study were DPPH radical scavenging, inhibition of AAPH-induced lipid oxidation, and inhibition of H₂O₂-induced oxidative cell death. Strong DPPH radical scavenging activity was observed in the extracts from the rhizomes of Alpinia speciosa, the leaves of Mallotus japonicus, the branches of Heritiera littoralis, the leaves of Psidium guajava, the leaves of Eucalyptus robusta, and the underground part of Hypericum chinense var. salicifolia. Potent inhibitory activity of lipid peroxidation was observed in the extracts from the leaves of M. japonicus, the leaves of Nandina domestica, the leaves of H. chinense var. salicifolia, the leaves of P. guajava, and the fruits and the rhizomes of A. speciosa. Strong inhibition against oxidative cell death was observed in the extracts from the leaves of P. guajava, the leaves of H. chinense var. salicifolia, the fruits and the rhizomes of A. speciosa, the branches of H. littoralis, the branches of Elaeagnus glabra, the branches of Citrus depressa, and the tuberous roots of Ipomoea batatas. From the results of these three assays, P. quajava, H. chinense var. salicifolia, and A. speciosa were selected as the plants having potent antioxidant ability. Interestingly, the extracts from tuberous roots of two cultivated species of I. batatas showed strong protective activity against oxidative cell death, whereas the other activities were very week and their phenol contents were not high.

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The effect of shiitake (Lentinus edodes, LE) and autolyzed(fermented) shiitake (AutolyzedLE) on blood pressure and serum fat levels of spontaneously hypertensive rats (SHR) were studied. Powdered LE or Autolyzed-LE was fed to SHR at the levels of 2% in a 1% NaCl (control) diet for 21 days. The blood pressure was measured by tail cuff. The animals of the AutolyzedLE group showed significantly lower blood pressure compared to the control or LE group. The serum levels of total cholesterol (TC), triglyceride and phospholipid of the groups fed with LE and AutolyzedLE were lower than those of the control group, and atherogenic index [(TCHDLC)/HDLC] improved significantly in 21 days. It was suggested that the serum TC decline is the action of eritadenine that is contained in the shiitake. An inhibitory activity of the angiotensin Iconverting enzyme (ACE) was compared between of LE and AutolyzedLE. The IC50 of LE and AutolyzedLE for ACE were 2500 and 490μg/ml, espectively. AutolyzedLE showed higher inhibitory activity than LE against the ACE. These phenomena suggested that the hypotensive action of AutolyzedLE was due to concomitant ACE inhibitory activities of peptides and γaminobutyric acid contained in higher amounts during the autolysis of LE.

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[in Japanese]

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[in Japanese]

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[in Japanese]

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[in Japanese]

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