• Journal of the Korean Society of Food Science and Nutrition
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• v.39 no.5
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• pp.769-775
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• 2010

The genus Lespedeza belonging to Leguminosae is an annual or perennial herb, which has been used as a Chinese herbal medicine. Antioxidant activity on DPPH ((1,1)-diphenyl-2-picrylhydrazyl) and ABTS (2,2'-azino-bis(3-ethylenebenzothiazoline-6-sulfonic acid) radicals and the contents of total polyphenol and flavonoid were analyzed with 12 methanol extracts from six Lespedeza genus plants with different plant parts. The highest content of total polyphenol was detected in the leaves of Lespedeza$\times$robusta (194.6 mg GAE/g), while the highest content of total flavonoid existed in the aerial part of Lespedeza thunbergii var. intermedia (47.9 mg QE/g). Generally, the amounts of polyphenol and flavonoid compounds were higher in the leaves than in the stems. The $SC_{50}$ value of DPPH radical scavenging activity ranged from 10.16 to 90.94 ppm, of which the strongest activity was determined in the leaves of L. robusta. Most ABTS radical scavenging activities from the investigated methanol extracts were higher than that of L-ascorbic acid, implying the excellent antioxidant activity. The radical scavenging activity in this study showed high correlation with the amount of total polyphenol rather than that of total flavonoid. These data suggest that the methanol extracts from these Lespedeza spp. could be potential candidates for natural antioxidants.

• Korean Journal of Materials Research
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• v.7 no.1
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• pp.57-61
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• 1997

Formation of fluorite structure and other related crystal structures in the $Y_{0.8}Ta_{0.2}O_{1.7}$-MO(M=Ba, Sr, Ca and Mg) system has been studied $Ba_2YTaO_6,\;Sr_2YTaO_6$ of cubic perovskite type ordered structure anti $Y_2O_3$ of cubic structure were produced besides the defect fluorite structure when 4 moIob of BaO or SrO was added to $Y_{0.8}Ta_{0.2}O_{1.7}$ When CaO more than 8 nlol"/o was added to $Y_{0.8}Ta_{0.2}O_{1.7}$, monoclinic: $Ca_2YTaO$, and cubic $Y_2O_3$ were pri~tlucecl ;IS this sec:onci phases hesides the main fluorite truc,ture. Smglc phase of fluorite structure \vas 1)roduc:ciI when MgO was added up to 12 mol%, however, MgO appeared as the second phase besides the main fluorire structure when MgO was added more than lti moI0'. Consquently, it is considered rh;it the formation of tluorite structure is related with the formation of the cubic perovskite type ordered structure of $A_2(B'B")O_6$ as well as the cation radii of the additives.additives.