The antioxidant activities of Chlorella in vitro and in vivo were investigated. Chlorella showed a strong antioxidant effect compared to various vegetables in a 1,1-diphe nyl-2-picrylhydrazyl (DPPH) radical scavenging assay. To evaluate the antioxidant and anti cataract effects in vivo, a 7.3% Chlorella powder was fed to rats with Streptozotocin-induced diabetes for 11wk. At the end of the experiment, Chlorella had decreased the blood glycated hemoglobin (hemoglobin Alc) and serum cholesterol levels significantly, however, it had not affected the serum glucose concentration. The serum lipid peroxide value (TBARS value) in the rats fed Chlorella was lower than that of the control rats. In the liver and kidney, Chlorella also reduced chemiluminescent intensities. In addition, it delayed the development of lens opacities. The lens lipid peroxide content of the rats fed Chlorella was lower than that of the control rats, however the differences were not significant. These results indicate that Chlo rella has antioxidant activity and may be beneficial for the prevention of diabetic complica tions such as cataracts.

SummaryThe effects of Chlorella regularis powder (CP) and Chlorella regularis indigestible fraction (CIF) on serum and liver lipid concentrations and on fecal steroid excretion were es timated in rats fed diets containing 5g/kg cholesterol and 2.5g/kg sodium cholate. The in gestion of 12.7% CP or 5.3% CIF did not influence food intake or growth. CP and CIF de creased the levels of serum cholesterol, but had no effect on the levels of serum triacylglyc erol and phospholipid. Liver cholesterol contents were lower in the CP and CIF groups than in the control group, but CP and CIF did not affect liver triacylglycerol content. CP and CIF increased the total amount of fecal neutral steroids excreted, but did not modify the total bile acid excretion. However, the soluble bile acid concentrations of reconstituted fecal water in the rats fed CP and CIF diets were lower than the control value. Moreover, CP and CIF had a high bile acid binding capacity in vitro. These results indicated that CIF had a hypocholes terolemic effect and enhanced fecal neutral steroid excretion while decreasing the soluble fecal bile acid concentration.

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We investigated an improved method for the separation of high-purified lutein from a commercially available spray-dried Chlorella powder (CP) using fine grinding by jet mill and flash column chromatography on a silica gel. Saponification and extraction of lutein were enhanced 2.3-2.9-fold in jet mill-treated CP (mean particle size, 20 microm) as compared to untreated CP (mean particle size, 67 microm). The carotenoid extract was dissolved in ether-hexane (1:1 v/v) and subjected to flash column chromatography on silica gel. A mixture of alpha- and beta-carotene was eluted with hexane, followed by elution with hexane-acetone-chloroform (7:2:1 v/v). Lutein (dark-orange band) was collected after the elution of an unknown colorless compound (detected based on UV absorbance). The purity of lutein in this fraction was over 99%, and the yield was 60%. The present study provides key information for obtaining highly purified lutein using flash column chromatography on a silica gel.

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