Green tea extract protects against early alcohol-induced liver injury in rats

Oxidants have been shown to be involved in alcohol-induced liver injury. This study was designed to test the hypothesis that the antioxidant polyphenolic extract of green tea, comprised predominantly of epigallocatechin gallate, protects against early alcohol-induced liver injury in rats. Male Wistar rats were fed high-fat liquid diets with or without ethanol (10-14 g kg(-1) day(-1)) and green tea (300 mg kg(-1) day(-1)) continuously for 4 weeks using an intragastric enteral feeding protocol. Mean body weight gains (approximately 4 g/day) were not significantly different between treatment groups, and green tea extract did not the affect average concentration or the cycling of urine ethanol concentrations (0-550 mg dl(-1) day(-1)). After 4 weeks, serum ALT levels were increased significantly about 4-fold over control values (35+/-3 IU/l) by enteral ethanol (114+/-18); inclusion of green tea extract in the diet significantly blunted this increase (65+/-10). Enteral ethanol also caused severe fatty accumulation, mild inflammation, and necrosis in the liver. While not affecting fat accumulation or inflammation, green tea extract significantly blunted increases in necrosis caused by ethanol. Furthermore, ethanol significantly increased the accumulation of protein adducts of 4-hydroxynonenal, a product of lipid peroxidation and an index of oxidative stress; green tea extract blocked this effect almost completely. TNFalpha protein levels were increased in liver by alcohol; this phenomenon was also blunted by green tea extract. These results indicate that simple dietary antioxidants, such as those found in green tea, prevent early alcohol-induced liver injury, most likely by preventing oxidative stress.     

Retinol-deficient rats can convert a pharmacological dose of astaxanthin to retinol: antioxidant potential of astaxanthin, lutein, and β-carotene

Retinol (ROH) and provitamin-A carotenoids are recommended to treat ROH deficiency. Xanthophyll carotenoids, being potent antioxidants, can modulate health disorders. We hypothesize that nonprovitamin-A carotenoids may yield ROH and suppress lipid peroxidation under ROH deficiency. This study aimed to (i) study the possible bioconversion of astaxanthin and lutein to ROH similar to β-carotene and (ii) determine the antioxidant potential of these carotenoids with reference to Na(+)/K(+)-ATPase, antioxidant molecules, and lipid peroxidation (Lpx) induced by ROH deficiency in rats. ROH deficiency was induced in rats (n = 5 per group) by feeding a diet devoid of ROH. Retinol-deficient (RD) rats were gavaged with astaxanthin, lutein, β-carotene, or peanut oil alone (RD group) for 7 days. Results show that the RD group had lowered plasma ROH levels (0.3 μmol/L), whereas ROH rose in astaxanthin and β-carotene groups (4.9 and 5.7 μmol/L, respectively), which was supported by enhanced (69% and 70%) intestinal β-carotene 15,15'-monooxygenase activity. Astaxanthin, lutein, and β-carotene lowered Lpx by 45%, 41%, and 40% (plasma), respectively, and 59%, 64%, and 60% (liver), respectively, compared with the RD group. Lowered Na(+)/K(+)-ATPase and enhanced superoxide dismutase, catalase, and glutathione-S-transferase activities support the lowered Lpx. To conclude, this report confirms that astaxanthin is converted into β-carotene and ROH in ROH-deficient rats, and the antioxidant potential of carotenoids was in the order astaxanthin > lutein > β-carotene.     

Carotenoid-containing unilamellar liposomes loaded with glutathione: a model to study hydrophobic-hydrophilic antioxidant interaction

Unilamellar liposomes are used as a simple two-compartment model to study the interaction of antioxidants. The vesicle membrane can be loaded with lipophilic compounds such as carotenoids or tocopherols, and the aqueous core space with hydrophilic substances like glutathione (GSH) or ascorbate, mimicking the interphase between an aqueous compartment of a cell and its surrounding membrane.

Unilamellar liposomes were used to investigate the interaction of GSH with the carotenoids lutein, β-carotene and lycopene in preventing lipid peroxidation. Lipid peroxidation was initiated with 2,2′-azo-bis-[2,4-dimethylvaleronitrile] (AMVN). Malondialdehyde (MDA) formation was measured as an indicator of oxidation; additionally, the loss of GSH was followed. In liposomes without added antioxidant, MDA levels of 119 ± 6 nmol/mg phospholipid were detected after incubation with AMVN for 2 h at 37°C. Considerably lower levels of 57 ± 8 nmol MDA/mg phospholipid were found when the liposomal vesicles had been loaded with GSH. Upon incorporation of β-carotene, lycopene or lutein, the resistance of unilamellar liposomes towards lipid peroxidation was further modified. An optimal further protection was observed with 0.02 nmol β-carotene/mg phospholipid or 0.06 nmol lycopene/mg phospholipid. At higher levels both these carotenoids exhibited prooxidant effects. Lutein inhibited lipid peroxidation in a dose-dependent manner between 0.02 and 2.6 nmol/mg phospholipid. With increasing levels of lycopene and lutein the consumption of encapsulated GSH decreased moderately, and high levels of β-carotene led to a more pronounced loss of GSH.

The data demonstrate that interactions between GSH and carotenoids may improve resistance of biological membranes towards lipid peroxidation. Different carotenoids exhibit specific properties, and the level for optimal protection varies between the carotenoids.     

Carotenoid-containing unilamellar liposomes loaded with glutathione: a model to study hydrophobic-hydrophilic antioxidant interaction

Unilamellar liposomes are used as a simple two-compartment model to study the interaction of antioxidants. The vesicle membrane can be loaded with lipophilic compounds such as carotenoids or tocopherols, and the aqueous core space with hydrophilic substances like glutathione (GSH) or ascorbate, mimicking the interphase between an aqueous compartment of a cell and its surrounding membrane.

Unilamellar liposomes were used to investigate the interaction of GSH with the carotenoids lutein, β-carotene and lycopene in preventing lipid peroxidation. Lipid peroxidation was initiated with 2,2'-azo-bis-[2,4-dimethylvaleronitrile] (AMVN). Malondialdehyde (MDA) formation was measured as an indicator of oxidation; additionally, the loss of GSH was followed. In liposomes without added antioxidant, MDA levels of 119 ± 6 nmol/mg phospholipid were detected after incubation with AMVN for 2 h at 37°C. Considerably lower levels of 57 ± 8 nmol MDA/mg phospholipid were found when the liposomal vesicles had been loaded with GSH. Upon incorporation of β-carotene, lycopene or lutein, the resistance of unilamellar liposomes towards lipid peroxidation was further modified. An optimal further protection was observed with 0.02 nmol β-carotene/mg phospholipid or 0.06 nmol lycopene/mg phospholipid. At higher levels both these carotenoids exhibited prooxidant effects. Lutein inhibited lipid peroxidation in a dose-dependent manner between 0.02 and 2.6 nmol/mg phospholipid. With increasing levels of lycopene and lutein the consumption of encapsulated GSH decreased moderately, and high levels of β-carotene led to a more pronounced loss of GSH.

The data demonstrate that interactions between GSH and carotenoids may improve resistance of biological membranes towards lipid peroxidation. Different carotenoids exhibit specific properties, and the level for optimal protection varies between the carotenoids.     

Bioavailability of lutein in humans from intrinsically labeled vegetables determined by LC-APCI-MS

The aim of the investigation was to assess a stable isotope method for determining the relative bioavailability of food-derived lutein in humans. Subjects were administered a single dose of deuterium-labeled carotenoids from intrinsically labeled spinach or collard green; 10 mL blood samples were drawn at various time points over a 34 days period. The vegetables had been hydroponically grown using 25 atom-% deuterated water. Lutein molecules in the vegetables were partially deuterated with a highest abundance isotopomer at M(0) + 8 (unlabeled molecular mass, M(0,) plus 8 additional mass units from 8 deuterium atoms in the molecules). This allowed labeled lutein to be distinguished from endogenous lutein in serum samples after consuming the labeled meal. The presence of labeled lutein in the circulation was determined by liquid chromatography-mass spectrometry (LC/MS) equipped with an atmospheric pressure chemical ionization (APCI) interface. The quantification of the labeled lutein in serum samples enabled the calculation of the enrichment for each time point after the dose; these values were plotted vs. time to generate absorption-clearance curves for each of the subjects. Area under the curve analyses of four different subjects (integrated over 29 days) yielded serum lutein responses of 128, 145, 149, and 262 microg-day/mg dietary lutein, following an acute dose of spinach containing 15.4, 18.8, 18.8 and 9.8 mg labeled lutein, respectively. This technique will facilitate the study of lutein bioavailability from different foods of diverse carotenoid composition and/or following various food preparation procedures.     

Comparison of dietary supplementation with lutein diacetate and lutein: a pilot study of the effects on serum and macular pigment

The responses of subjects taking a 20 mg/day lutein diacetate supplement were compared with that for a 20 mg/day crystalline lutein or a placebo. Ten subjects, assigned to each of three groups, lutein diacetate (group 1), lutein (group 2), and a placebo (group 3), were supplemented for 24 weeks. Groups 1 and 2 consumed a dose equivalent to 20 mg per day of free lutein. Serum samples, collected at baseline, and at weeks 6, 12, 18, and 24 were analyzed by HPLC. Macular Pigment Optical Density (MPOD) was obtained by heterochromatic flicker photometry at baseline and weeks 6, 12, 18 and 24. Results: The average serum lutein concentrations for weeks 6 to 24 expressed as a ratio to the baseline value (±S.D.) were 5.52 ± 2.88 for group 1, 4.43 ± 1.61 for group 2, and 1.03 ± 0.25 for group 3. The median rate of macular pigment increase (milli-absorbance units/week) for groups 1, 2, and 3 were 2.35, 1.55, and 0.19 mAU/wk, respectively. P-values for these serum and MPOD increases are both highly significant when compared to placebo. The average serum response was about 25% higher for group 1 compared with group 2 and, the median MPOD response was 52% higher for group 1 than group 2. P-values calculated for the differences in these increases were, p = 0.066, marginally significant, for serum, and p = 0.09 approaching significance, for MPOD.     

Oxidant induced injury of erythrocyte—Role of green tea leaf and ascorbic acid

Oxidant and free radical-generating system were used to promote oxidative damage in erythrocytes. Among the oxidants used, phenylhydrazine represents one of the most investigated intracellular free radical-generating probes, which in the presence of haemoglobin autooxidises and give rise to hydroxyl radical, a marker for cellular damage. Erythrocyte, as a single cell, is a good model to be used for studying the haemolytic mechanism of anaemia. Our present investigations reveal increased lipid peroxidation of erythrocyte using phenylhydrazine as well as other oxygen-generating systems (hydrogen peroxide, iron with hydrogen peroxide). It has further been observed that not only lipid peroxidation, phenylhydrazine causes significant elevation in methemoglobin formation, catalase activity and turbidity, in the above system, which are the typical characteristics of haemolytic anaemia. However, exogenous administration of green tea leaf extract and ascorbic acid as natural antioxidants and free radical scavengers were shown to protect separately increased lipid peroxidation caused by phenylhydrazine, though the degree of protection is more in case of green tea leaf extract than ascorbic acid. Results suggest that oxidative damage in vivo due to haemolytic disease may be checked to some extent by using natural antioxidants. (Mol Cell Biochem 276: 205–210, 2005)     

Green tea polyphenols inhibit cognitive impairment induced by chronic cerebral hypoperfusion via modulating oxidative stress

Responses to oxidative stress contribute to damage caused by chronic cerebral hypoperfusion, which is characteristic of certain neurodegenerative diseases. We used a rat model of chronic cerebral hypoperfusion to determine whether green tea polyphenols, which are potent antioxidants and free radical scavengers, can reduce vascular cognitive impairment and to investigate their underlying mechanisms of action. Different doses of green tea polyphenols were administered orally to model rats from 4 to 8 weeks after experimentally induced cerebral hypoperfusion, and spatial learning and memory were assessed using the Morris water maze. Following behavioral testing, oxygen free radical levels and antioxidative capability in the cortex and hippocampus were measured biochemically. The levels of lipid peroxidation and oxidative DNA damage were assessed by immunohistochemical staining for 4-hydroxynonenal and 8-hydroxy-2′-deoxyguanosine, respectively. Rats that received green tea polyphenols 400 mg/kg per day had better spatial learning and memory than saline-treated rats. Green tea polyphenols 400 mg/kg per day were found to scavenge oxygen free radicals, enhance antioxidant potential, decrease lipid peroxide production and reduce oxidative DNA damage. However, green tea polyphenols 100 mg/kg per day had no significant effects, particularly in the cortex. This study suggests that green tea polyphenols 400 mg/kg per day improve spatial cognitive abilities following chronic cerebral hypoperfusion and that these effects may be related to the antioxidant effects of these compounds.     

Dose-dependent response of serum lutein and macular pigment optical density to supplementation with lutein esters

We conducted a study to determine the effect of different doses of a lutein supplement on serum lutein concentration and macular pigment optical density (MPOD). Lutein is one of the major components of human macular pigment. Eighty-seven subjects received daily doses of 5, 10, or 20 mg of lutein, or a placebo, over a 140 day period. Serum lutein concentration was determined by HPLC and MPOD by heterochromatic flicker photometry (HFP). Serum lutein responded positively, except in the placebo group, reaching a plateau that, averaged for each dosage group, was linearly dependent on dose. Likewise MPOD, on average, increased at a rate that varied linearly with dose. For subjects deemed more proficient at HFP, approximately 29% of the variability in MPOD response could be attributed to a linear dependence on the fractional change in serum lutein concentration. We did not detect any significant influence of age on serum lutein uptake or MPOD response.     

Plasma carotenoid and malondialdehyde levels in ischemic stroke patients: relationship to early outcome

An association between ischemic stroke and increased oxidative stress has been suggested from animal studies. However, there is a lack of evidence with respect to this association in humans. Here, the time course of plasma levels of six carotenoids, which are lipophilic micronutrients with antioxidant properties, as well as of malondialdehyde (MDA), a marker of lipid peroxidation, was followed in ischemic stroke patients. Plasma levels of lutein, zeaxanthin, beta-cryptoxanthin, lycopene, alpha- and beta-carotene, as well as MDA were measured by high-performance liquid chromatography in 28 subjects (19 men and nine women aged 76.9+/-8.7 years) with an acute ischemic stroke of recent onset (<24h) on admission, after 6 and 24 h, and on days 3, 5, and 7. Carotenoid and MDA levels in patients on admission were compared with those of age- and sex-matched controls. Plasma levels of lutein, lycopene, alpha- and beta-carotene were significantly lower and levels of MDA were significantly higher in patients in comparison with controls. Significantly higher levels of MDA and lower levels of lutein were found in patients with a poor early-outcome (functional decline) after ischemic stroke as compared to patients who remained functionally stable. These findings suggest that the majority of plasma carotenoids are lowered immediately after an ischemic stroke, perhaps as a result of increased oxidative stress, as indicated by a concomitant rise in MDA concentrations. Among the carotenoids, only lutein plasma changes are associated with a poor early-outcome.     

Synergistic interactions of Ferulic acid with Ascorbic acid: Its cardioprotective role during isoproterenol induced myocardial infarction in rats

Studies on the lipid peroxidation and antioxidant changes and their significance during myocardial injury have provided a new insight into the pathogenesis of heart disease. The heart failure subsequent to myocardial infarction may be associated with an antioxidant deficit as well as increased myocardial oxidative stress. The present study was designed to evaluate the effect of the combination of ferulic acid and ascorbic acid on antioxidant defense system and lipid peroxidation against isoproterenol (ISO)-induced myocardial infarction in rats. Induction of rats with isoproterenol (150 mg/kg body weight daily, i.p.) for 2 days resulted in a marked elevation in lipid peroxidation, serum marker enzymes (LDH, CPK, GOT, and GPT), and a significant decrease in activities of endogenous antioxidants (SOD, GPx, GST, CAT, and GSH). Pre-co-treatment with the combination of ferulic acid (20 mg/kg body weight/day) and ascorbic acid (80 mg/kg body weight/day) orally for 6 days, significantly attenuated these changes when compared to the individual treatment groups. Histopathological observations were also in correlation with the biochemical parameters. Thus, ferulic acid and ascorbic acid significantly counteracted the pronounced oxidative stress effect of ISO by the inhibition of lipid peroxidation, restoration of antioxidant status, and myocardial marker enzymes levels. In conclusion, these findings indicate the synergistic protective effect of ferulic acid and ascorbic acid on lipid peroxidation and antioxidant defense system during ISO-induced myocardial infarction and associated oxidative stress in rats.     

Protective effect of Operculina turpethum against 7,12-dimethyl benz(a)anthracene induced oxidative stress with reference to breast cancer in experimental rats

Reactive oxygen species (ROS) directly or indirectly involves in multistage process of carcinogenesis. Antioxidant activity of methanolic extract of Operculina turpethum stems (MEOT) on 7,12 dimethylbenz(a)anthracene (DMBA) induced breast cancer was investigated in female Sprague-Dawley rats. Changes in the levels of lipid peroxidation and antioxidants system was evaluated in addition to tumour development. Twenty four female rats were divided into four groups: control, DMBA, DMBA + MEOT and MEOT. In the DMBA group, rats were intragastrically administered with 20 mg of DMBA using corn oil as vehicle. Animals of DMBA + MEOT group received a single dose of 20 mg of DMBA dissolved in corn oil intragastrically followed by O. turpethum extract (100 mg/kg body weight), while MEOT group received O. turpethum extract (100 mg/kg body weight) intragastrically daily for a period of 45 days. After the experimental period of 45 days, oxidative stress parameters were assessed in serum, liver and breast of both control and experimental groups. In addition to this, tumour weight of breast was also assessed. A significant increase in lipid peroxidation levels were observed in the tested samples of cancer induced rats while the activities of enzymic antioxidants such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and non-enzymic antioxidants like glutathione (GSH), ascorbic acid (Vitamin C) and α-tocopherol (Vitamin E) were decreased in cancer-bearing animals when compared to control animals. A significant (P < 0.05) increase in the tumour weight was observed in the breast of DMBA group and the breast tumour weight decreased significantly (P < 0.05) in the DMBA + MEOT groups. Oral administration of MEOT remarkably reduced the lipid peroxidation activity and increased the antioxidants level in drug treated animals and decreased the tumour weight significantly (P < 0.05). This result suggests that MEOT shows antioxidant activity and play a protective role against DMBA induced breast cancer.     

Modification of biochemical parameters of gentamicin nephrotoxicity by coenzyme Q10 and green tea in rats

The present study was designed to investigate the possible potential protective role of coenzymeQ10 (CoQ10; 10 mg/kg/day, ip) and/or green tea (GT; 25mg/kg/day, po) against gentamicin (GM) nephrotoxicity. Marked increase in the level of serum urea. creatinine and lipid peroxidation (LPO) content was found after administration of gentamicin (80 mg/kg/day, ip) for eight days along with significant decrease in the antioxidant enzymes, superoxide dismutase (SOD), reduced glutathione (GSH), catalase (CAT) as well as brush border enzymes (Na+/K+ ATPase, Mg(+2)ATPase and Ca2+ ATPase).Treatment with CoQ10 or green tea alone with GM showed significant decrease in serum urea, creatinine and tissue LPO content and significant increase in antioxidant and membrane bound enzymes. Combined treatment with CoQ10 and green tea was more effective in mitigating adverse effect of GM nephrotoxicity. The present work indicated that CoQ10 and green tea due to their antioxidant activity modified the biochemical changes occurred during gentamicin nephrotoxicity and thus had a potential protective effect.     

Green tea protection of hypoxia/reoxygenation injury in cultured cardiac cells

Antioxidant-rich diets exert a protective effect in diseases involving oxidative damage. Among dietary components, green tea is an excellent source of antioxidants. In this study, cultured neonatal rat cardiomyocytes were used to clarify the protective effect of a green tea extract on cell damage and lipid peroxidation induced by different periods of hypoxia followed by reoxigenation. Cultures of neonatal rat cardiomyocytes were exposed to 2--8 hr hypoxia, eventually followed by reoxygenation, in the absence or presence of alpha-tocopherol or green tea. LDH release and the production of conjugated diene lipids were measured, and appeared linearly related to the duration of hypoxia. During hypoxia, both LDH release and conjugated diene production were reduced by alpha-tocopherol and, in a dose dependent manner, by green tea, the 50 &mgr;g/ml being the most effective dose. Reoxygenation caused no further increase in LDH leakage, while it caused a significant increase in conjugate dienes, which absolute value was lower in antioxidant supplemented cells. Anyway, the ratio between conjugated diene production after hypoxia and after reoxygenation was similar in all groups, indicating that the severity of free radical-induced reoxygenation injury is proportional to the severity of previous hypoxic injury. Since hypoxic damage is reduced by alpha-tocopherol and green tea, our data suggest that any nutritional intervention to attenuate reoxygenation injury must be directed toward the attenuation of the hypoxic injury. Therefore, recommendations about a high dietary intake of antioxidants may be useful not only in the prevention, but also in the reduction of cardiac injury following ischemia.     

Antioxidant properties and cytotoxic effects of selected edible plants in Southeast Asia for further use as phytogenic antioxidant additives

Excessive free radicals in human and animal bodies can cause oxidative stress (OS) which damages cells and tissues. Plant materials with high antioxidant potential would resolve the OS problem. Thus, this study proposed to investigate the total phenolic (TPC) and flavonoid contents (TFC), antioxidant capacities and cytotoxicity in 17 edible plant materials from herbs, fruits, vegetables and plant by-products available in Southeast Asia for future use in the food or feed industry. Among 17 plant materials, Syzygium aromaticum (clove), Camellia sinensi (green tea pomace) from the beverage industry and Persicaria odorata (Vietnamese coriander) showed a prominent amount of TPC and TFC. These three plants and their combination (1:1:1 ratio, v:v:v) also possessed a remarkable antioxidant function in terms of DPPH, ABTS and FRAP, as well as showing a strong ROS inhibition through HepG2 cells. The cytotoxicity test of the crude extract of clove, green tea pomace and Vietnamese coriander, or their combination can be used between 0.032 and 0.255, 0.011 to 0.088, 0.022 to 0.178 and 0.021 to 0.346 mg/mL, respectively, without impeding cell viability. A combined mixture of clove, green tea pomace and Vietnamese coriander revealed the synergistic properties of antioxidants and cell safety. This indicates that there is a potential use of various antioxidant bioactive compounds in plant materials tested for use as phytogenic antioxidant additives.     

Characterization,extraction and purification of lutein produced by an indigenous microalga Scenedesmus obliquus CNW-N

This study aimed to improve the commercial viability of microalgae-based lutein production using an isolated microalga Scenedesmus obliquus CNW-N possessing a high lutein content of over 0.25%. Effective lutein extraction protocols, appropriate storage methods, and purification procedures were developed. Disruption of microalgae cells was most efficient with a bead-beater. The conventional saponification step was modified to reduce the overall extraction time by 24 h. Diethyl ether exhibited the best lutein extraction efficiency. Storage of the lutein extract at low temperature (4 or −20 °C) with antioxidant addition (around 0.01% BHT) can maintain 90% lutein stability after 80 days. Addition of a suitable amount of the antioxidant could promote the stability of lutein extracts under the exposure of light. The protocol developed in this work allows efficient lutein extraction from S. obliquus CNW-N at a lower cost. Further purification was employed to elevate the purity of lutein and its commercial value.     

Inhibition of human LDL lipid peroxidation by phenol-rich beverages and their impact on plasma total antioxidant capacity in humans

Mounting evidence shows that phenol-rich beverages exert strong antioxidant activity. However, in vivo evidence has produced conflicting results. In the present study, we studied the impact of the ingestion of 300 mL of black and green tea, alcohol-free red wine, alcohol-free white wine, or water on plasma total antioxidant capacity in five healthy volunteers. Red wine has the highest content of phenolics (3.63 +/- 0.48 g QE/L), followed by green tea (2.82 +/- 0.07 g QE/L), black tea (1.37 +/- 0.15 g QE/L), and white wine (0.31 +/- 0.01 g QE/L). Plasma total antioxidant capacity values of subjects who drank green tea rose at 30 min (P < 0.05). After black tea and red wine ingestion, the peaks were at 50 min (P < 0.05 and P < 0.01, respectively). No changes were observed in the control and white wine groups. Red wine and green tea were the most efficient in protecting low density lipoprotein from oxidation driven by peroxyl and ferril radicals, respectively. Phenol-rich beverages are a natural source of antioxidants; however, the phenolic content alone cannot be considered an index of their in vivo antioxidant activity.     

Simultaneous enhancement of CO2 fixation and lutein production with thermo-tolerant Desmodesmus sp. F51 using a repeated fed-batch cultivation strategy

This study aimed to improve lutein production using a thermo-tolerant lutein-rich microalga Desmodesmus sp. F51. To achieve this goal, four fed-batch cultivation strategies were investigated for CO₂ fixation and lutein production of Desmodesmus sp. F51. Among them, Fed-batch IV showed the best performance, giving the highest CO₂ fixation rate and lutein productivity of 1582.4 mg/L/d and 3.91 mg/L/d, respectively. Both increasing the light intensity and limiting the nutrients led to a lower carotenoids content in the microalga, with a higher proportion of lutein and lower proportion of β-carotene being obtained in the carotenoids. The carotenoid present in the biomass was mainly lutein, accounting for 50–66% of total carotenoids. Repeated operations of the Fed-batch IV strategy could effectively improve CO₂ fixation and lutein production of Desmodesmus sp. F51, giving the best results of 1826.0 mg/L/d, and 4.61 mg/L/d, respectively. This performance is better than most of the previously reported values.