Comparison of Nutritional Composition and Antioxidant Properties of Pulverized and Unutilized Portions of Waxy Barley.

To promote the use of waxy barley bran, an underutilized resource, samples of waxy barley were divided into three parts: polished waxy barley powder (PWBP), inner bran layer powder (IBLP), and outer bran layer powder (OBLP). The color and appearance, general properties, minerals, vitamins, ß-glucan, antioxidant properties, and aroma of each part were compared. In terms of appearance and color, IBLP and OBLP appeared more yellow than PWBP; general components that were more abundant in IBLP and OBLP compared with PWBP were protein, fat, and ash. IBLP and OBLP had characteristically high values of Mg and Zn, monounsaturated and polyunsaturated fatty acids, vitamin B1, total polyphenol content, H-ORAC, and DPPH. In particular, the vitamin B1 content of OBLP was approximately 10 times higher than that of PWBP, and Mg and Zn content was more than five times higher than in PWBP. The ß-glucan content of IBLP and OBLP was lower than that of PWBP, but relatively high. GC-MS analysis revealed that hexanal was the aroma component common to all three samples, and the peak areas were in the order of PWBP > OBLP > IBLP.

Safety evaluation of Chlorella sorokiniana strain CK-22 based on an in vitro cytotoxicity assay and a 13-week subchronic toxicity trial in rats.

The genus Chlorella contains unicellular green algae that have been used as food supplements. The purpose of this work was to evaluate the safety of the Chlorella sorokiniana strain CK-22 using powdered preparation (CK-22P) both by in vitro and in vivo assays. These included an experiment for cytotoxicity using Chinese hamster lung fibroblasts (V79 cells) and a 13-week repeated-dose oral toxicity trial using Wistar rats. The cytotoxicity was evaluated by MTT assay of a hot water extract (Hw-Ex) and 80% ethanol extract (Et-Ex) of CK-22P, and no effect on cell viability was observed. The 50% viability inhibitory effect (IC50) value for Hw-Ex and Et-Ex were estimated as greater than 73 and 17 µg/ml, respectively. In the subchronic toxicity test, pelleted rodent diet containing 0%, 2.5%, 5% or 10% CK-22P was given to Wistar rats (ten animals/sex/groups) for 13 weeks. During the experimental period, no CK-22P treatment-induced differences in general condition, body weight gain, food and water consumption, ophthalmology, urinalysis, hematology, clinical chemistry, gross pathology, organ weights, histopathology, or animal death were observed. The no-observed-adverse-effect levels (NOAEL) were estimated to be 5.94 g/kg body-weight/day for males and 6.41 g/kg body-weight/day for females.

Demethylation of methylmercury and the enhanced production of formaldehyde in mouse liver.

Methylmercury (MeHg) is gradually changed to inorganic Hg after demethylation in animal tissues, and a selective quantification of inorganic Hg in the tissues is necessary to detect the reaction. We detected inorganic Hg formation in liver and kidney of mouse as early as 24 hr after MeHg injection. As an example of biological demethylation, the cytochrome P450 (P450)-mediated N-demethylation of drugs has been well documented, and formaldehyde was detected as a reaction product. Here we incubated mouse liver homogenate with added MeHg and observed a dose-dependent production of formaldehyde, as well as inorganic Hg formation. Since the amount of formaldehyde was approx. 500 times higher than that of the inorganic Hg that formed, the formaldehyde production would be stimulated by inorganic Hg formed from MeHg. We observed that inorganic Hg caused formaldehyde production, and it was enhanced by L-methionine and sarcosine. Thus, some biomolecules with S-methyl and N-methyl groups may function as methyl donors in the reaction. Using subcellular fractions of mouse liver, we observed that microsomal P450 did not participate in the demethylation of MeHg, but the greatest activity was located in the mitochondria-rich fraction. The addition of superoxide anion in the reaction mixture significantly enhanced the formaldehyde production, whereas Mn-superoxide dismutase depressed the reaction. Our present findings demonstrated that inorganic Hg formed by MeHg demethylation in mouse liver stimulated the endogenous formaldehyde production, and we observed that MeHg demethylation could be estimated by a formaldehyde analysis. Our results also suggested that superoxide anion is involved in the reaction.

Effect of maternal Chlorella supplementation on carotenoid concentration in breast milk at early lactation.

Breast milk carotenoids provide neonates with a source of vitamin A and potentially, oxidative stress protection and other health benefits. Chlorella, which has high levels of carotenoids such as lutein, zeaxanthin and ß-carotene, is an effective dietary source of carotenoids for humans. In this study, the effect of maternal supplementation with Chlorella on carotenoid levels in breast milk at early lactation was investigated. Ten healthy, pregnant women received 6 g of Chlorella daily from gestational week 16-20 until the day of delivery (Chlorella group); ten others did not (control group). Among the carotenoids detected in breast milk, lutein, zeaxanthin and ß-carotene concentrations in the Chlorella group were 2.6-fold (p = 0.001), 2.7-fold (p = 0.001) and 1.7-fold (p = 0.049) higher, respectively, than those in the control group. Our study shows that Chlorella intake during pregnancy is effective in improving the carotenoid status of breast milk at early lactation.

Chlorella suppresses methylmercury transfer to the fetus in pregnant mice.

To investigate the effects of chlorella on methylmercury (MeHg) transfer to the fetus during pregnancy, female C57BL/6N mice (aged 10 weeks) were housed for 7 to 8 weeks, from 4 weeks before mating to birth, with diets containing 0% or 10% chlorella powder (CP) and MeHg-containing drinking water (2 µg Hg/ml). The consumption volume of the MeHg-containing water was limited to 15 ml/mouse/week throughout the experiment. Distilled water and a basal diet (0% CP) was given to control mice. Except for the mating period, during the 5(th) week, mice were housed individually until parturition. Two neonates were randomly selected from each mother mouse within 24 hr after parturition for Hg analysis of the blood, brain, liver, and kidneys. Mother mice were sacrificed on the same day as neonates to obtain tissue samples for Hg analysis. The blood and brain Hg levels of both neonates and mothers in the CP diet group were significantly lower than those in the basal diet group. Although the hepatic and renal Hg levels were not significant in mothers between the two dietary groups, in neonates, the CP diet group showed significantly lower Hg levels in these tissues than the basal diet group. The results obtained here revealed that continuous CP intake suppressed MeHg transfer to the fetus, in addition to effective suppressing MeHg accumulation in brains of the mothers.

Enhanced elimination of tissue methylmercury in Parachlorella beijerinckii-fed mice.

To investigate the influence of Chlorella (Parachlorella beijerinckii) on the excretion and tissue accumulation of methylmercury (MeHg), we orally administered 5 mg/kg of MeHg chloride (4 mg Hg/kg) to female C57BL/6N mice (aged 10 weeks). The mice were housed in metabolism cages to collect urine and feces for 3 weeks with diets containing 0%, 5%, or 10% P. beijerinckii powder (BP) in a basal diet (CE-2). The lowered blood Hg levels in the 5% and 10% BP groups became significant compared to those of the control group (0% BP) as early as day 7. During the 21 days of testing, significant increases in the cumulative Hg eliminations into urine (5% BP) and feces (5% and 10% BP) were found in the BP groups. Twenty-one days after administration, the organ Hg levels in both BP groups tended to decrease compared to that of the control group. The reduction of Hg levels in the kidney and brain were significant, whereas that in the liver was not. Although tissue Hg levels are known to be closely related to glutathione (GSH) metabolism, no difference was found in GSH levels in the blood or organs between the control group and the 10% BP group. These results suggest that continuous BP intake accelerates the excretion of MeHg and subsequently decreases tissue Hg levels in mice, with no alteration of GSH metabolism. We should conduct further research to elucidate details regarding the mechanism of BP-induced enhancement of MeHg excretion.

The influence of Parachlorella beyerinckii CK-5 on the absorption and excretion of methylmercury (MeHg) in mice.

Chlorella (Parachlorella beyerinckii CK-5), previously identified as Chlorella vulgaris CK-5, is a unicellular green algae that has for many years been used as a nutritional supplement. In order to investigate the effects of methylmercury (MeHg) detoxification by Chlorella, we examined the absorption and excretion of MeHg in mice. Female C57BL/6N mice were randomly divided into three groups of five, and were housed in metabolism cages. Mice were orally administered MeHg chloride at doses of 5 mg (4 mg Hg)/kg body weight with or without 100 mg/mouse of P. beyerinckii powder (BP), and were assigned to either a MeHg group or MeHg + BP group, accordingly. Twenty-four hr after oral administration, feces and urine were collected, and blood, liver, and kidney samples were obtained. Total mercury contents in the samples obtained were determined using an atomic absorption method. The amounts of Hg excreted in feces and urine of the MeHg + BP group were increased nearly 1.9 and 2.2-fold compared with those of the MeHg group. On the other hand, blood and organ Hg levels were not significantly different between two groups. These results suggest that the intake of BP may induce the excretion of Hg both in feces and urine, although it does not affect MeHg absorption from the gastrointestinal tract. The effect of BP on the tissue mercury accumulation may become evident in a long-term experiment.

Parachlorella beyerinckii accelerates lead excretion in mice.

The effect of Parachlorella beyerinckii CK-5, previously identified as Chlorella vulgaris, on gastrointestinal absorption of lead was investigated in mice. Female ICR mice aged 7 weeks were orally administered lead acetate solution at doses of 20 mg and 40 mg of lead per mouse, with or without 100 mg of P. beyerinckii powder (BP). The mice were bred for 24 hours. The amount of lead excreted in feces within 24 hours, and the lead levels of the blood, liver and kidney were analyzed by atomic absorption spectrometry. The percentage of total fecal excretion in mice administered BP increased by 27.7% in 20 mg lead administered mice and 17.2% in 40 mg lead administered mice in comparison to control mice, respectively. On the other hand, the lead levels of the blood, liver and kidney of BPadministered mice at 24 hours after lead administration were 48-63% lower as compared with those of control mice. The lead adsorption ability of BP and the pepsin non-digestive residue of BP (dBP) were investigated in vitro. One hundred mg of BP and dBP could adsorb 10.6 mg and 6.0 mg of lead in a 20 mg per 10 mL of lead solution, respectively. The lead absorption abilities of BP and dBP were considered to contribute to the prevention of gastrointestinal absorption of lead and the promotion of the excretion of lead. These results suggested that BP treatment might be useful in animals and humans exposed to lead.