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PubMed2003

Attenuating effect of chlorella supplementation on oxidative stress and NFkappaB activation in peritoneal macrophages and liver of C57BL/6 mice fed on an atherogenic diet.

This study was designed to investigate whether chlorella supplementation may ameliorate oxidative stress and nuclear factor kappa B (NFkappaB) activation in peritoneal macrophages and liver of C57BL/6 mice fed on an atherogenic diet. The animals were maintained on an atherogenic diet (control), or an atherogenic diet supplemented with 3% (w/w) chlorella or 5% (w/w) chlorella for 12 wks. The plasma and hepatic lipid levels were not affected by chlorella supplementation. Hepatic thiobarbituric acid-reactive substances and superoxide anion production in peritoneal macrophages were significantly lower in the 5% chlorella group (p<0.05), but the glutathione level was not altered by chlorella supplementation. The hepatic antioxidative enzyme activities of Cu, Zn-superoxide dismutase and catalase were higher in the mice fed on the 5% chlorella diet (p<0.05). The plasma aspartate aminotransferase activity was lower in the mice fed on the chlorella-containing diets (p<0.05), whereas the alanine aminotransferase activity was not affected by chlorella supplementation. The NFkappaB nuclear binding activities of peritoneal macrophages and liver were significantly lower in the 5% chlorella groups (p<0.05). These results suggest that chlorella supplementation may attenuate oxidative stress by reducing reactive oxygen production and increasing antioxidative processes, thus suppressing inflammatory mediator activation in peritoneal macrophages and liver.

Animals↗
PubMed2005

Therapeutic potentials of unicellular green alga Chlorella in advanced glycation end product (AGE)-related disorders.

Reducing sugars can react non-enzymatically with amino groups of protein to form Amadori products. These early glycation products undergo further complex reaction such as rearrangement, dehydration, and condensation to become irreversibly cross-linked, heterogeneous fluorescent derivatives, termed advanced glycation end products (AGEs). The formation and accumulation of AGEs in various tissues has been known to progress at an accelerated rate under hyperglycemic conditions in diabetes. Recent understanding of this process has revealed that AGEs have been implicated in the development of many of the pathological sequelae of diabetes and aging, such as atherosclerosis and diabetic microangiopathy. Furthermore, recently, AGE-their receptor (RAGE) interaction was also involved in neurodegenerative diseases, melanoma growth, expansion and metastasis. These observations suggest that blockade of AGE formation may be a novel promising target for therapeutic intervention in these devastating AGE-related disorders. We have recently found that unicellular green alga Chlorella inhibited the formation of AGEs in vitro. Since several lines of evidence have shown anti-atherogenic effects of Chlorella on animal models, we hypothesize here that the beneficial aspects of Chlorella on atherosclerosis could be ascribed, at least in part, to its AGE inhibitory property and that Chlorella may have therapeutic potentials in treatment of patients with other AGE-related disorders such as diabetic microangiopathy and Alzheimer's disease. In this paper, we would like to propose the possible ways of testing our hypotheses. Does daily intake of Chlorella reduce the risk of the incidence and progression of diabetic vascular complications including atherosclerosis? Does Chlorella treatment prevent the development of Alzheimer's disease and/or improve the cognitive impairment of patients with this disorder? If the answers are yes, are plasma or tissue levels of AGE in these patients actually suppressed by Chlorella treatment? And, does the extent of the AGE reduction by Chlorella predict the beneficial effects of Chlorella on these disorders? These prospective studies will provide further valuable information whether blockade by Chlorella of the AGE formation could be clinically relevant.

Administration, Oral↗
PubMed2005

Potential hypoglycemic effects of Chlorella in streptozotocin-induced diabetic mice.

Chlorella, a type of unicellular fresh water algae, has been a popular foodstuff in Japan and Taiwan. Chlorella has been shown to produce hypoglycemic effects in alloxan-induced diabetic animals. However, there are no other reports of the effects of this substance in other diabetic animal models. Here we have used streptozocin (STZ)-induced diabetic mice to study the thypoglycemic effects of Chlorella. Diabetes was induced in ICR strain mice by the i.p. injection of STZ. Vehicle-treated ICR mice were used as normal control animals and glibenclamide was used as a positive drug control. The effects of Chlorella on basal blood glucose, exogenous insulin sensitivity test and plasma insulin levels were measured. In normal mice Chlorella produced a transient hypoglycemic effect at 90 min after acute administration; whereas glibenclamide produced a more sustained hypoglycemic effect between 90 min and 180 min after acute administration. Chlorella did not affect the basal blood glucose level in STZ mice. However, Chlorella enhanced and prolonged the hypoglycemic effects of injected insulin in STZ mice for a further 60 min compared to the normal vehicle-treated group. Plasma insulin levels were increased in normal mice after treatment with glibenclamide, whereas Chlorella had no such effect. The current results indicate that Chlorella enhances the hypoglycemic effects of exogenous insulin at a dose which does not produce hypoglycemia in STZ mice, suggesting that insulin sensitivity is increased in these mice.

Administration, Oral↗
PubMed2005

Improving glycogenesis in Streptozocin (STZ) diabetic mice after administration of green algae Chlorella.

Chlorella, a type of unicellular fresh water algae, has been a popular foodstuff in Japan and Taiwan. Studies have shown the hypoglycemic effects of Chlorella in alloxan-induced and Streptozocin (STZ)-induced diabetic animals. However, the mechanisms by which Chlorella treatment affects blood glucose homeostasis have not been studied. Diabetes in ICR mice was induced by injection of STZ. Lipogenesis in vivo was measured by incorporating 3H-H2O into lipids in brown and white adipose tissues. Glucose uptake in the liver and soleus muscles was measured by assaying 2-deoxy-D-[1,2-3H] glucose levels. The effects of Chlorella on serum non-esterified fatty acids (NEFA) were measured with commercial assay kits. Insulin-stimulated lipogenic rates in brown and white adipose tissues were unaffected by Chlorella. However, Chlorella increased 2-deoxyglucose uptake in the livers and soleus muscles in normal and STZ mice compared to that in their respective controls (p < 0.01). In addition, fasting NEFA levels were lower in Chlorella-treated STZ mice compared to H2O-treated STZ mice (p < 0.005). The current results suggest that the hypoglycemic effects of Chlorella are due to an enhancement of glucose uptake in the liver and in soleus muscles. The improved insulin sensitivity after Chlorella treatment could be also due to lower NEFA levels, since insulin sensitivity is usually blunted by elevated NEFA in diabetes.

Adipose Tissue↗
PubMed1985

Correlations between characteristics of some free-living Chlorella sp. and their ability to form stable symbioses with Hydra viridis.

Aposymbiotic polyps of Hydra viridis were infected with 17 strains of in vitro cultured Chlorella sp. Larvae of Artemia fed with the chlorellae were used as an infecting vector. Of the 17 strains, seven formed stable symbioses and one formed a transient infection that disappeared within several weeks. Chlorellae of the nine other strains were cleared out of the infected hydra within 2-3 days. There was a distinct correlation between the ability of the chlorellae to form stable symbioses and their ability to adapt and grow in media enriched with 0.5% proteose peptone. Only strains that grew in the latter medium formed symbioses with the hydra. The symbioses formed with the different strains of chlorellae differed from one another. Hydra infected with some strains greened completely while those infected with other strains greened only partially. The degree of infection varied also within each population, and there were differences in the distribution of the various chlorellae along the stalk and inside the digestive cells of the hydra. Growth rates of the infected hydra were all less that those of aposymbiotic hydra or of hydra hosting native zoochlorellae. We conclude that adaptability to a nutrient-rich environment inside the perialgal vacuole of the digestive cell and a sufficient growth rate therein are crucial to the ability of chlorellae to form stable symbioses with H. viridis. In time, co-adaptation of hydra and chlorellae would restore the normal growth rate of the former and bring about regularity to the form and extent of infection by the latter.

Cells, Cultured↗
PubMed2003

Antioxidant and anti-cataract effects of Chlorella on rats with streptozotocin-induced diabetes.

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-diphenyl-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 11 wk. At the end of the experiment, Chlorella had decreased the blood glycated hemoglobin (hemoglobin A1c) 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 Chlorella has antioxidant activity and may be beneficial for the prevention of diabetic complications such as cataracts.

Animals↗
PubMed2005

Symbiotic association in Chlorella culture.

Chlorella sorokiniana IAM C-212 has long been maintained in slant culture as a mixed strain, representing an associated natural microbial consortium. In this study, the consortium was separated and five nonalgal constituents, a fungal strain (CSSF-1), and four bacterial strains (CSSB-1, CSSB-2, CSSB-3, and CSSB-4) were isolated and identified. 16S rDNA sequence analysis revealed that strains CSSB-1, CSSB-2, CSSB-3, and CSSB-4 were close to Ralstonia pickettii (99.8% identity), Sphingomonas sp. DD38 (99.4% identity), Microbacterium trichotecenolyticum (98.6% identity), and Micrococcus luteus (98.6% identity) respectively. 18S rDNA sequence analysis revealed that strain CSSF-1 resembled Acremonium-like hyphomycete KR21-2 (98.8%). The fungal strain CSSF-1 and one of the bacterial strains, CSSB-3, were found to promote the growth of Chlorella while the presence of bacterial strains CSSB-1 and CSSB-2 had no effect. Strain CSSB-4 could not be subcultured so its role was not elucidated. These results show that the interaction between Chlorella and its symbionts under photoautotrophic conditions involved both mutualism and commensalisms. The chlorophyll content of mixed strain was stable in long-term cultivation (7 months) while the chlorophyll content of a pure culture showed a marked decline. Electron microscopic analysis showed the two bacterial strains CSSB-2 and CSSB-3 were harbored on the sheath excreted by Chlorella, while the fungal strain CSSF-1 and the bacterial strain CSSB-1 directly adhered to the Chlorella cell surface. This report is the first observation of a symbiotic relationship among fungus, bacteria, and Chlorella, and the first observation of direct adhesion of fungus and bacteria to Chlorella in a consortium.

Bacteria↗
PubMed2006

Genotype versus phenotype variability in Chlorella and Micractinium (Chlorophyta, Trebouxiophyceae).

The most recent revision of the genus Chlorella, based on biochemical and SSU rDNA analyses, suggested a reduction to a set of four "true" spherical Chlorella species, while a growing number of morphologically different species such as Micractinium (formerly Micractiniaceae) were found to cluster within the clade of "true"Chlorella. In this study, the generic concept in Chlorellaceae to Chlorella and Micractinium was evaluated by means of combined SSU and ITS-2 rDNA sequence analyses and biotests to induce development of bristles on the cell wall. Molecular phylogenetic analyses of Chlorella and Micractinium strains confirmed their separation into two different genera. In addition, non-homoplasious synapomorphies (NHS) and compensatory base changes (CBC) in the secondary structures of SSU and ITS-2 rDNA sequences were found for both genera using this approach. The Micractinium clade can be differentiated into three different genotypes. Using culture medium of the rotifer Brachionus calyciflorus, phenotypic plasticity in Chlorella and Micractinium was studied. Non-bristled Micractinium cells developed bristles during incubation with Brachionus culture medium, whereas Chlorella did not produce bristles. Grazing experiments with Brachionus showed the rotifer preferred to feed on non-bristled cells. The dominance of colonies versus solitary cells in the Micractinium culture was not correlated with the "Brachionus factor". These results suggest that morphological characteristics like formation of bristles represent phenotypic adaptations to the conditions in the ecosystem.

Adaptation, Physiological↗
PubMed2002

Nutritional supplementation with Chlorella pyrenoidosa for mild to moderate hypertension.

Pharmacological treatment of hypertension reduces the risk of cardiovascular disease; however, randomized, controlled clinical trials and population studies have also shown that abnormally high blood pressure (BP) can be lowered with diet modification and exercise. The objective of this pilot study was to determine whether daily dietary supplementation with 10 g Chlorella tablets and 100 ml Chlorella extract for 2 months would reduce BP in subjects with a mean sitting diastolic BP (SiDBP) between 90 and 115 mm Hg. Thirty-three people were enrolled and underwent a 4-week washout period from all antihypertensive medications, during which they consumed placebo. At completion of this washout/placebo period, 24 subjects were considered evaluable (i.e., had a SiDBP between 90 and 115 mm Hg) and were continued in the study. After 1 or 2 months of dietary Chlorella supplementation, the average heart rate, sitting systolic BP, and SiDBP changed only slightly; after 2 months of Chlorella consumption, the group's mean SiDBP was 96.5 +/- 6.6. However, a heterogenous response pattern to Chlorella existed, with 25% (6/24) of the subjects achieving their BP goal (SiDBP less than 90 mm Hg). Furthermore, the BP of nonresponders did not increase significantly above washout values. Quality-of-life questionnaires indicated an overall perception that health had significantly improved in conjunction with Chlorella consumption. The results indicate that, for some subjects with mild to moderate hypertension, a daily dietary supplement of Chlorella reduced or kept stable their SiDBP.

Adult↗
PubMed1999

Chlorella accelerates dioxin excretion in rats.

We investigated the effects of Chlorella on fecal excretion of polychlorinated dibenzo-p-dioxin (PCDD) congeners and polychlorinated dibenzofuran (PCDF) congeners in Wistar rats administered the rice oil that caused Yusho disease, as a substitute for purified dioxin. The rats were fed 4 g of a control diet or a 10% Chlorella diet containing 0.2 mL of the rice oil once during the 5-d experimental period. The amounts of PCDD and PCDF congeners excreted in feces from d 1 to 5 in the group fed 10% Chlorella were 0.2-11.3 and 0.3-12.8 times greater (P < 0.05), respectively, than those of the control group. We then investigated the fecal excretion of PCDD and PCDF congeners from d 8 to 35 in rats administered 0.5 mL of the rice oil. Rats consumed the basal diet for 1 wk. After 1 wk, they consumed either the basal diet or the 10% Chorella diet. The fecal excretions of PCDD and PCDF congeners in the group fed 10% Chlorella were 0.3-3.4 and 0.5-2.5 times greater (most, P < 0.05), respectively, than those of the control group. Thus, the fecal excretions of PCDD and PCDF congeners were greater in rats fed Chlorella. These findings suggest that the administration of Chlorella may be useful in preventing gastrointestinal absorption and for promoting the excretion of dioxin already absorbed into tissues. Moreover, these findings suggest that Chlorella might be useful in the treatment of humans exposed to dioxin.

Animals↗
PubMed1995

Subcellular localization of the inducible Chlorella HUP1 monosaccharide-H+ symporter and cloning of a Co-induced galactose-H+ symporter.

The unicellular green alga Chlorella kessleri can induce monosaccharide-H+ symport catalyzing the energy-dependent transport of D-glucose (D-Glc) and several other pentoses and hexoses across the plasmalemma. The gene coding for the inducible HUP1 monosaccharide-H+ symporter has been cloned and the protein has been characterized previously. The data presented in this paper demonstrate that the presence of the HUP1 gene product alone is not sufficient to cover the broad substrate specificity of monosaccharide transport in induced Chlorella cells. Two other HUP genes are shown to be co-induced in Chlorella in response to D-Glc in the medium. The cloning of HUP2 and HUP3 cDNA and genomic sequences is described, both being very homologous to HUP1. Modification of the 5' untranslated sequences of full-length cDNA clones of HUP2 and HUP3 allowed the functional expression of both transporters in Schizosaccharomyces pombe. HUP2 was shown to be a galactose-H+ symporter, whereas the substrate specificity of the HUP3 gene product is very similar to that of the HUP1 protein. However, HUP3 does not seem to be induced to high levels in Glc-treated Chlorella cells. Results are also presented proving that the product of the HUP1 gene is localized in the plasmalemma of D-Glc-induced Chlorella cells and is absent in plasma membranes of noninduced cells. Incubation of thin sections of Chlorella cells with anti-HUP1 antibodies and a fluorescence-labeled, second antibody yielded a ring of fluorescence on the surface of Glc-induced Chlorella cells.

Base Sequence↗
PubMed1999

Evidence for a novel Chlorella virus-encoded alginate lyase.

To clone the genes encoding lysis protein from a Chlorella virus, water samples were collected from 13 aquatic environments located in the Kanto area of Japan. Eight water samples contained plaque-forming viruses on Chlorella sp. NC64A, but no virus was detected in the other five samples. A novel Chlorella virus, CVN1, was isolated from the Inba-numa marsh sample. CVN1 genomic DNA was partially digested and shotgun cloned into pUC118 to identify the genomic region responsible for the lytic phenotype on Chlorella sp. NC64A. A DNA fragment which encoded two ORFs, ORF1 and ORF2, was obtained by antialgal assay. The ORF2 gene product, CL2, consisted of 333 amino acids showing antialgal activity not only on the original host of Chlorella sp. NC64A, but also on the heterogeneous hosts of Chlorella vulgaris C-27 and C. vulgaris C-207. CL2 showed a weak homology (19.8% amino acid identity) to mannuronate lyase SP2 from Turbo cornutus. CL2 in Escherichia coli cells was purified using a nickel chelate column. Lyase activity of purified CL2 on alginic acid was observed in an enzyme assay. The specific activity of purified CL2 was 2.1x10(-2) U mg(-1), the optimum pH for enzymatic activity was 10.5, and Ca(2+) was required for enzyme activity. This is the first report of a Chlorella virus protein with lyase activity.

Alginates↗
PubMedDate not supplied

A review of recent clinical trials of the nutritional supplement Chlorella pyrenoidosa in the treatment of fibromyalgia, hypertension, and ulcerative colitis.

CONTEXT: It has been suggested that the consumption of natural "whole foods" rich in macronutrients has many healthful benefits for those who otherwise ingest a normal, nonvegetarian diet. One example is dietary supplements derived from Chlorella pyrenoidosa, a unicellular fresh water green alga rich in proteins, vitamins, and minerals. OBJECTIVE: To find evidence of the potential of chlorella dietary supplements to relieve signs and symptoms, improve quality of life, and normalize body functions in people with chronic illnesses, specifically fibromyalgia, hypertension, and ulcerative colitis. DESIGN: Double-blind, placebo-controlled, randomized clinical trials. SETTING: Virginia Commonwealth University's Medical College of Virginia. PATIENTS: Fifty-five subjects with fibromyalgia, 33 with hypertension, and 9 with ulcerative colitis. INTERVENTION: Subjects consumed 10 g of pure chlorella in tablet form and 100 mL of a liquid containing an extract of chlorella each day for 2 or 3 months. MAIN OUTCOME MEASURES: For fibromyalgia patients, assessments of pain and overall quality of life. For hypertensive patients, measurements of sitting diastolic blood pressure and serum lipid levels. For patients with ulcerative colitis, determination of state of disease using the Disease Activity Index. RESULTS: Daily dietary supplementation with chlorella may reduce high blood pressure, lower serum cholesterol levels, accelerate wound healing, and enhance immune functions. CONCLUSIONS: The potential of chlorella to relieve symptoms, improve quality of life, and normalize body functions in patients with fibromyalgia, hypertension, or ulcerative colitis suggests that larger, more comprehensive clinical trials of chlorella are warranted.

Chlorella↗
PubMed1999

Biodegradation capacity of tributyltin by two Chlorella species.

Two microalgal species, Chlorella vulgaris and Chlorella sp., which showed high tributyltin (TBT) tolerant ability were investigated for their capabilities in degrading TBT at sublethal concentration. The distribution of TBT and its degraded products dibutyltin (DBT) and monobutyltin (MBT) in the incubation medium, extracellular surface and intracellular fraction were monitored during an exposure period of 14 days. Results showed that biosorption of TBT by the algal cell wall was the major mechanism in reducing 40% of the initial TBT from the medium in the first 2 days. The half-life of TBT incubated with C. vulgaris was 60 h while that of Chlorella sp. was 80 h. The occurrence of DBT at Day 1 in the culture medium provided direct evidence to the biodegradation of TBT by both Chlorella species. At the end of the experimental period, 27 and 41% of the original TBT were recovered as DBT and MBT in cultures of C. vulgaris, respectively. In contrast, DBT appeared to be the only degradation product of Chlorella sp. and only 26% of the original TBT was transformed to DBT. Despite the same genus, TBT was debutylated to a greater extent to MBT by C. vulgaris, while DBT was the end degradation product by Chlorella sp. The capability of such debutylating process therefore accounted for the higher tolerant ability of C. vulgaris than Chlorella sp.

Journal Article↗