Structural elucidation of possible lutein oxidation products mediated through peroxyl radical inducer 2,2′-Azobis (2-methylpropionamidine) dihydrochloride: Antioxidant and cytotoxic influence of oxidized lutein in HeLa cells

Lutein Production and Extraction from Microalgae: Recent Insights and Bioactive Potential

Microalgae have been reported to be excellent producers of bioactive molecules. Lutein is a pigment reported to have various beneficial effects for humans, and especially for eye well-being. In the current review, we summarize various methods that have been developed to optimize its extraction and bioactivities reported for human health. Several protective effects have been reported for lutein, including antioxidant, anticancer, anti-inflammatory, and cardioprotective activity. This review also reports attempts to increase lutein production by microalgae by changing culturing parameters or by using pilot-scale systems. Genetic engineering lutein production is also discussed. Considering the increasing aging of the worldwide population will create an increased need for lutein, a viable economic and eco-sustainable method to produce lutein is needed to face this market demand.

Prevention of aspirin-mediated secondary toxicity by combined treatment of carotenoids in macrophages

Upon understanding the boosting role of carotenoids on the endogenous anti-inflammatory system, it is vital to explore their role in reducing the use of high doses of non-steroidal anti-inflammatory drug (NSAIDs), and their mediated secondary toxicity during the treatment of chronic diseases. The current study investigates the carotenoids potential on inhibition of secondary complications induced by NSAIDs, aspirin (ASA) against lipopolysaccharide (LPS) stimulated inflammation. Initially, this study evaluated a minimal cytotoxic dose of ASA and carotenoids (β-carotene, BC/lutein, LUT/astaxanthin, AST/fucoxanthin FUCO) in Raw 264.7, U937, and peripheral blood mononuclear cells (PBMCs). In all three cells, carotenoids + ASA treatment reduced the LDH release, NO, and PGE2 efficiently than an equivalent dose of carotenoid or ASA treated alone. Based on cytotoxicity and sensitivity results, RAW 264.7 cells were selected for further cell-based assay. Among carotenoids, FUCO + ASA exhibited an efficient reduction of LDH release, NO, and PGE2 than the other carotenoids (BC + ASA, LUT + ASA, and AST + ASA) treatment. FUCO + ASA combination decreased LPS/ASA induced oxidative stress, pro-inflammatory mediators (iNOS, COX-2, and NF-κB), and cytokines (IL-6, TNF-α, and IL-1β) efficiently. Further, apoptosis was inhibited by 69.2% in FUCO + ASA, and 46.7% in ASA than LPS treated cells. A drastic decrease in intracellular ROS generation with the increase in GSH was observed in FUCO + ASA compared to LPS/ASA groups. The results documented on the low dose of ASA with a relative physiological concentration of FUCO suggested greater importance for alleviating secondary complications and optimize prolonged chronic disease treatments with NSAID's associated side effects.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-023-03632-w.

Antiobesity drug-likeness properties and pancreatic lipase inhibition of a novel low molecular weight lutein oxidized product, LOP6

Elevated expression of peroxisome proliferator-activated receptor-gamma (PPAR-γ), a key regulator of adipogenesis, leads to lipid accumulation and obesity. Although orlistat is effective for obesity, flatus with discharge, faecal urgency, oily evacuation and other allied side effects limit its usage. Thus, natural product-based drug intervention is the future of research and development of novel treatment. We synthesized and characterized total lutein oxidized products (LOPs) by exposing lutein to direct sunlight with a solar intensity of 5.89 kW h m^-2 day^-1 and at 31 ± 2 °C for 1-10 days. Total LOPs were analyzed on C₁₈ and structural elucidation was carried on LCMS/MS-TOF. The pancreatic lipase inhibition kinetics was estimated. The binding effects of LOP6 (fragmented peak 6) on PPAR-γ, pancreatic lipase, pharmacokinetic properties and inhibition studies were analysed. Histological evaluation of liver and adipose tissues was performed to confirm the antiobesity effect of total LOPs. The yield of extracted lutein purified from shade-dried marigold flower petals was 6%. Total LOPs were formed on the 10th day upon exposure of lutein to direct sunlight. Total LOPs on the C₁₈ column fragmented into eight oxidized products (LOP1 to LOP8). The total LOPs showed significant inhibition of pancreatic lipase activity with an IC₅₀ of 1.6953 μg ml^-1, and K_m and V_max of 3.05 μg and 1.19 μg s^-1 respectively following mixed type of inhibition. The LOP6 [4-((1E,3E,5E)-3,7-dimethylocta-1,3,5,7-tetraen-1-yl)-3,5,5-trimethylcyclohex-3-enol] with an approximate molecular mass of 274.25 showed a binding energy of -5.40 kcal mol^-1 with a K_i of 109.43 μM for PPAR-γ and a docking score of -5.35 kcal mol^-1 with a K_i of 119.4 μM for pancreatic lipase. The IC₅₀ of LOP6 was 11.8420 μg ml^-1, and K_m and V_max were 2.519 μg and 1.294 μg s^-1. The pharmacokinetic properties such as solubility, permeability, bioavailability, and topological polar surface area when tested with LOP6 were significantly better than those of lutein alone. The histological examination of the liver and adipose tissue revealed that all three doses of total LOPs were effective in alleviating the ballooning and vesicular degeneration of hepatocytes and invasion of inflammatory cells in the adipose tissue. Total LOPs and LOP6 inhibited pancreatic lipase activity in vitro. LOP6 showed a better docking score for PPAR-γ and pancreatic lipase in comparison to orlistat. Histological data showed that the total LOPs exerted antiobesity activity. Thus, LOPs might provide a novel treatment approach for obesity.

Lutein and Zeaxanthin and Their Roles in Age-Related Macular Degeneration-Neurodegenerative Disease

Lutein and zeaxanthin belong to the xanthophyll family of carotenoids, which are pigments produced by plants. Structurally, they are very similar, differing only slightly in the arrangement of atoms. Key sources of these carotenoids include kale, savoy cabbage, spinach, broccoli, peas, parsley, corn, and egg yolks. The recommended daily intake of lutein is approximately 10.0 mg and that of zeaxanthin is 2 mg. Lutein intake in adults varies, with average intakes being 1–2 mg/day. Due to the lack of synthesis of consumption of these compounds in humans, these substances are extremely important for the proper functioning of certain organs of the body (eye, skin, heart, intestines). Eating a lot of dark leafy vegetables and some fruits can help to prevent our bodies from developing diseases. The protective effects of carotenoids are mainly related to their defense against oxidative stress and their ability to scavenge free radicals. Lutein and zeaxanthin are the only dietary carotenoids that accumulate in the retina, specifically the macula, and are called macular pigments. These carotenoids are concentrated by the action of specific binding proteins such as StARD3, which binds lutein, and GSTP1, which binds zeaxanthin and its dietary metabolite, mesozeaxanthin. It has been shown that supportive therapy with lutein and zeaxanthin can have a beneficial effect in delaying the progression of eye diseases such as age-related macular degeneration (AMD) and cataracts. This article presents the current state of knowledge on the role of lutein and zeaxanthin, especially from human studies targeting their metabolism and bioavailability, with recommendations to consume xanthophyll-rich foods.

Lutein plus Water Chestnut (Trapa bispinosa Roxb.) Extract Inhibits the Development of Cataracts and Induces Antioxidant Gene Expression in Lens Epithelial Cells

Age-related cataract (ARC) is the major cause of blindness worldwide. The most significant factors are the maximal exposure of the eye lens to environmental stressors, including oxidative and glycative load. The administration of antioxidant and antiglycative supplements may reduce the risk of cataract progression. In this study, the effects of lutein (LU) and water chestnut (Trapa bispinosa Roxb.) extract (TBE) on cataracts and the expression of antioxidant-related genes were assessed in Shumiya cataract rats (SCRs). LU+TBE or castor oil (COil) as a control was administered to 6- or 9-week-old cataractous SCRs and noncataractous SCRs via a feeding needle for 3 or 4 weeks. Five-week-old SCRs were provided ad libitum access to solid regular chow containing LU, TBE, LU+TBE, or the same chow without LU and/or TBE for 3 weeks. Lenses from all rats were then extracted and photographed. The right eyes of the rats were processed for histological observation, and the left eyes were used for total RNA extraction from lens epithelial cells (LEC). The mRNA levels of antioxidant proteins, peroxiredoxin 6, and catalase were examined using real-time quantitative polymerase chain reaction. Lens opacity appeared in all cataractous SCRs that began receiving LU+TBE at 9 weeks of age. However, compared to the COil group, lens opacity was decreased in the cataractous LU+TBE SCRs in all experiments. The mRNA expression levels of peroxiredoxin 6 and catalase in LECs of cataractous SCRs and cultured human LECs increased after the administration of LU+TBE. Collectively, our results highlight the anticataract and antioxidative effects of LT+TBE in SCRs. LT+TBE supplementation may, thus, be useful in delaying cataract progression.

Fractionation and Characterization of Lycopene-Oxidation Products by LC-MS/MS (ESI)+: Elucidation of the Chemopreventative Potency of Oxidized Lycopene in Breast-Cancer Cell Lines

Lycopene (LYC) has been correlated with the reduction of certain cancers and chronic diseases. However, the existence and biofunctionality of degraded, oxidized, and biotransformed LYC products in vivo have not been revealed. Therefore, this study aimed to screen and elucidate the potential bioactive lycopene-derived products in breast-cancer and non-cancerous cells. LYC-oxidation or -cleavage products were generated using KMnO₄. These oxidation products were separated as fractions I-III by silica column chromatography using gradient solvent systems. Further, LC-MS/MS (ESI)⁺ was used to elucidate their possible fragmentation patterns and structures. Fraction II showed higher cytotoxicity (IC₅₀ value of 64.5 μM), cellular uptake, and apoptosis-inducing activity in MCF-7 cells. This fraction consists of major peak m/ z 323, identified as apo-8,6'-carotendial. The cytotoxicity-inducing activity may be due to partial ROS generation with mitochondrial dysfunction. Further, the role of apo-8,6'-carotendial in the induction of apoptosis is demonstrated for the first time. These results illustrated that LYC-oxidation derivatives or metabolites are involved in growth inhibition of cancer cells. Exploration of specific oxidized-carotenoid products will give further insight into the field of nutritional biochemistry.

Low-dose doxorubicin with carotenoids selectively alters redox status and upregulates oxidative stress-mediated apoptosis in breast cancer cells

The combination of carotenoids and doxorubicin (DOX) selectively alters oxidative stress-mediated apoptosis in breast cancer cells. Primarily, cytotoxic efficiency of carotenoids (β-carotene, BC; lutein, LUT; astaxanthin, AST; or fucoxanthin, FUCO) either with or without a minimal cytotoxic dose of DOX was evaluated in MCF-7 (0.12 μM) and MDA-MB-231 cells (0.28 μM). The higher cell growth inhibition of BC and/or LUT with DOX was selected for testing in further cell-based assays. Low-dose DOX significantly enhanced cytotoxicity in carotenoid (<5 μM)-treated cells compared to high-dose DOX (>1 μM) or carotenoid (20 μM) treatment alone. Depleted glutathione, increased lipid peroxides and increased ROS levels in cells confirmed the cytotoxic effect. Furthermore, mitochondrial dysfunction, cell growth arrest at G0/G1 phase and caspase cascades as well as up- and down-regulated expression levels of related proteins (p21, p27, Bax, p53, Bcl-2, and cyclin D1) revealed the synergistic effect of carotenoid and DOX treatment on ROS-mediated apoptosis. These observations demonstrated increased apoptosis in BC + DOX/LUT + DOX-treated cells due to the pronounced pro-oxidant action. Interestingly, normal breast epithelial cells (MCF 10A) exposed to similar treatments resulted in non-significant cytotoxicity. These newly observed mechanistic differences of anticancer drugs on the mitigation of toxicity with carotenoids may provide insight into the targeting of cancer therapy.

Astaxanthin from shrimp efficiently modulates oxidative stress and allied cell death progression in MCF-7 cells treated synergistically with β-carotene and lutein from greens

This study investigated the synergistic efficacy of keto-carotenoid astaxanthin (AST, from shrimp) plus hydrocarbon (β-carotene, BC) and hydroxyl (lutein, L) carotenoids (from greens) on molecular events in MCF-7 cells. MCF-7 cells were treated with either of carotenoid (20 μM, AST or BC or L) separately or the mixture of them (an equimolar concentration of carotenoids mixture, CM) or saponified carotenoid extract from shrimp (SSCE) for 48 h and analyzed cellular uptake, cytotoxicity, and apoptosis. The IC₅₀ and combination-index values of AST co-treatment with a lower concentration of BC and L (5 μM) exhibited enhanced cytotoxicity and oxidative stress as compared with individual carotenoids or SSCE. Further, higher cellular uptake/accumulation of AST along with BC and L found to synergistically induce apoptosis through modulation of cyclin D1, p53, Bax and Bcl-2 expressions by arresting cell cycle at G0/G1 phase. Further, CM or SSCE treatments are unlikely to affect proliferation of normal breast epithelial cells (MCF-10A). The results of selective killing of MCF-7 cells demonstrated a greater insight on the synergistic effect of shrimp AST plus BC and L. It is concluded that consumption of shrimp along with green leafy vegetables helps in combating cancer chemoprevention.

The Pharmacological Effects of Lutein and Zeaxanthin on Visual Disorders and Cognition Diseases

Lutein (L) and zeaxanthin (Z) are dietary carotenoids derived from dark green leafy vegetables, orange and yellow fruits that form the macular pigment of the human eyes. It was hypothesized that they protect against visual disorders and cognition diseases, such as age-related macular degeneration (AMD), age-related cataract (ARC), cognition diseases, ischemic/hypoxia induced retinopathy, light damage of the retina, retinitis pigmentosa, retinal detachment, uveitis and diabetic retinopathy. The mechanism by which they are involved in the prevention of eye diseases may be due their physical blue light filtration properties and local antioxidant activity. In addition to their protective roles against light-induced oxidative damage, there are increasing evidences that L and Z may also improve normal ocular function by enhancing contrast sensitivity and by reducing glare disability. Surveys about L and Z supplementation have indicated that moderate intakes of L and Z are associated with decreased AMD risk and less visual impairment. Furthermore, this review discusses the appropriate consumption quantities, the consumption safety of L, side effects and future research directions.

Neuroprotective Effect of Carnosine on Primary Culture of Rat Cerebellar Cells under Oxidative Stress

Dipeptide carnosine (β-alanyl-L-histidine) is a natural antioxidant, but its protective effect under oxidative stress induced by neurotoxins is studied insufficiently. In this work, we show the neuroprotective effect of carnosine in primary cultures of rat cerebellar cells under oxidative stress induced by 1 mM 2,2'-azobis(2-amidinopropane)dihydrochloride (AAPH), which directly generates free radicals both in the medium and in the cells, and 20 nM rotenone, which increases the amount of intracellular reactive oxygen species (ROS). In both models, adding 2 mM carnosine to the incubation medium decreased cell death calculated using fluorescence microscopy and enhanced cell viability estimated by the MTT assay. The antioxidant effect of carnosine inside cultured cells was demonstrated using the fluorescence probe dichlorofluorescein. Carnosine reduced by half the increase in the number of ROS in neurons induced by 20 nM rotenone. Using iron-induced chemiluminescence, we showed that preincubation of primary neuronal cultures with 2 mM carnosine prevents the decrease in endogenous antioxidant potential of cells induced by 1 mM AAPH and 20 nM rotenone. Using liquid chromatography-mass spectrometry, we showed that a 10-min incubation of neuronal cultures with 2 mM carnosine leads to a 14.5-fold increase in carnosine content in cell lysates. Thus, carnosine is able to penetrate neurons and exerts an antioxidant effect. Western blot analysis revealed the presence of the peptide transporter PEPT2 in rat cerebellar cells, which suggests the possibility of carnosine transport into the cells. At the same time, Western blot analysis showed no carnosine-induced changes in the level of apoptosis regulating proteins of the Bcl-2 family and in the phosphorylation of MAP kinases, which suggests that carnosine could have minimal or no side effects on proliferation and apoptosis control systems in normal cells.

Lutein derived fragments exhibit higher antioxidant and anti-inflammatory properties than lutein in lipopolysaccharide induced inflammation in rats

In the present study, we appraise the anti-inflammatory efficacy of lutein oxidative degradation derivatives mediated through UV-irradiation over lutein in counteracting the inflammation induced by lipopolysaccharide (LPS) in rats (n = 5 per group). UV-irradiated lutein fragments were identified as anhydrolutein (B, C40H54O), 2,6,6-trimethylcyclohexa-1,4-dienylium (M1, C9H13), (2E,4E,6E,8E)-9-(4-hydroxy-2,6,6-trimethylcyclohex-1-1en-1-yl)-3,7-dimethylnona-2,4,6,8-tetraen-1-ylium (M2, C20H29O), 4-[(1E,3E,5E,7E)-3,7,-dimethyldeca-1,3,5,7-tetraen-1-yl]-3,5,5-methylcyclohex-3-en-1-ol (M3, C21H30O) and zeaxanthin (M4, C40H56O) and its isomers as 13'-Z zeaxanthin, 13'-Z lutein, all-trans zeaxanthin, and 9-Z lutein. Induction of inflammation by LPS significantly increased the production of nitrites (3.3 fold in the serum and 2.6 fold in the liver), prostaglandin E2 (26 fold in the serum), and pro-inflammatory cytokines like tumor necrosis factor-α (6.6 fold in the serum), and interleukin-6 (4.8 fold in the serum). Oxidative derivatives of lutein, especially M1, M2 and M3, ameliorated acute inflammation in rats by inhibiting the production of nitrites, malondialdehyde (MDA), PGE2, TNF-α, and IL-6 cytokines more efficiently than lutein in rats. The anti-inflammatory mechanism of derivatives might be related to the decrease of inflammatory cytokines and the increase of antioxidant enzymes (superoxide dismutase, catalase, glutathione peroxidase, glutathione S transferase, glutathione reductase), which would result in the reduction of iNOS, COX-2 and MDA and subsequently inflammatory responses.

Role of different vehicles in carotenoids delivery and their influence on cell viability, cell cycle progression, and induction of apoptosis in HeLa cells

The objective of the present study was to determine the role of different vehicles in carotenoids delivery and their influence on cell viability, cell cycle progression and induction of apoptosis in HeLa cells. Cells (5 × 10(3)) were treated with different concentrations (25-100 µM) of β-carotene (BC) or lutein (L) or astaxanthin (AST) dissolved in 0.5% of tetrahydrofuran (THF), dimethylsulfoxide (DMSO), and fetal bovine serum (FBS), respectively. The effect of delivery vehicle on carotenoids uptake, cytotoxicity, oxidative status, cell cycle distribution, and apoptosis was examined after 48 h of incubation. The results shown that, cell viability reduced significantly in a dose- and time-dependent manner irrespective of carotenoid delivered in vehicles. Cellular uptake of BC delivered in THF was higher by 49.1, 29.7% and L delivered through THF was higher by 41.7 and 37.5% than DMSO and FBS, respectively. While, AST delivered through DMSO was higher by 36.1 and 43.7% than the THF and FBS, respectively. In case of cells treated either with BC or L delivered through THF and AST in DMSO decreased the glutathione and increased the malondialdehyde levels. The net increase in the G 2/M phase percentage of cell cycle progression was observed in carotenoid-treated cells. The % induction of apoptosis by BC or L delivered with THF and AST in DMSO was higher than other treated groups. In conclusion, choice of suitable vehicle for specific carotenoids delivery is essential that in turn may influence on cell proliferation and cell-based assays.

Evaluation of in vitro anticancer activity of Ocimum basilicum, Alhagi maurorum, Calendula officinalis and their parasite Cuscuta campestris

The present investigation was carried out to study the relationship between presence of cytotoxic compounds in Ocimum basilicum, Alhagi maurorum, Calendula officinalis and their parasite Cuscuta campestris. The cytotoxic activity of the pure compounds was performed by MTT assay against breast cancer cell lines (MCF-7 and MDA-MB-231) and normal breast cell line (MCF 10A). The induction of apoptosis was measured by the expression levels of p53, bcl-2, bax and caspase-3 genes using quantitative Real Time PCR. Three active fractions were detected by nuclear magnetic resonance as lutein, lupeol and eugenol, respectively, in C. officinalis, A. maurorum and O. basilicum. These compounds and their epoxidized forms were also detected in their parasite C. campestris. The cytotoxic activity of lutein epoxide, lupeol epoxide and eugenol epoxide was significantly more than lutein, lupeol and eugenol. The mRNA expression level of p53, caspase-3 and bax genes were increased in both cancer cells treated with all pure compounds. However, bcl-2 gene expression decreased in treated breast cancer cells. In conclusion, all the data indicated that the epoxide forms of lupeol, lutein and eugenol are potential drug candidates for inducing apoptosis in human breast cancer cells.

Formulation development and in vivo hepatoprotective activity of self nanoemulsifying drug delivery system of antioxidant coenzyme Q10

Coenzyme Q10 (CQ10) is known as an endogenous cellular antioxidant, naturally found in every cell of the human body and plays an important role in maintaining human health. It is widely used as a nutritional supplement and pharmaceutical drug for various disorders like diabetes mellitus, carcinomas, neurodegenerative disorders etc. However, CQ10 is practically insoluble even in the presence of 5 % sodium lauryl sulfate in water and poorly absorbed from the gastrointestinal tract. The present research is aimed to formulate and evaluate self nanoemulsifying drug delivery system (SNEDDS) of CQ10 primarily to improve its aqueous solubility, dissolution velocity as well as hepatoprotective activity and thus enhancing its nutraceutical and pharmaceutical values. Robustness to dilution, thermodynamic stability study, droplet size analysis and drug release were adopted to optimize liquid SNEDDS. Droplet size of the SNEDDS was found to be size less than 200 nm and appeared round in shape without aggregation under transmission electron microscopy examination. Liquid SNEDDS were adsorbed on porous carrier to get solid SNEDDS (S-SNEDDS). S-SNEDDS gave rapid (>90 %) drug release within 30 min while pure drug was not practically dissolved within 1 h. In vivo hepatoprotective activity showed that S-SNEDDS achieved the most liver protection as compared to the pure drug. Further S-SNEDDS was successfully converted to self nanoemulsifying mouth dissolving tablet. The enhanced solubility, dissolution velocity as well as hepatoprotective activity of CQ10, unravels the potential of S-SNEDDS as suitable carrier for enhancing nutraceutical and pharmaceutical values of CQ10.

Association between lutein and zeaxanthin status and the risk of cataract: a meta-analysis

The purpose of this meta-analysis was to evaluate the relationship between blood lutein and zeaxanthin concentration and the risk of age-related cataract (ARC). MEDLINE, EMBASE, ISI and Cochrane Library were searched to identify relevant studies up to April 2013. Meta-analysis was conducted to obtain pooled relative risks (RRs) for the highest-versus-lowest categories of blood lutein and zeaxanthin concentrations. One cohort study and seven cross-sectional studies were included in the meta-analysis. There were significant inverse associations between nuclear cataract and blood lutein and zeaxanthin concentrations, with the pooled RRs ranging from 0.63 (95% confidence interval (CI): 0.49, 0.77) for zeaxanthin to 0.73 (95% CI: 0.59, 0.87) for lutein. A stronger association between nuclear cataract and blood zeaxanthin might be noted for the studies conducted in the European Nations. Blood lutein and zeaxanthin were also noted to lead towards a decrease in the risk of cortical cataract and subcapsular cataract; however, these pooled RRs were not statistically significant, with the exception of a marginal association between lutein and subcapsular cataract. Our results suggest that high blood lutein and zeaxanthin are significantly associated with a decrease in the risk of nuclear cataract. However, no significant associations were found for ARC in other regions of the lens.