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An adequate immune system is required to prevent diarrhoea in neonates, and IgA provides protection against microbial antigens on mucosal surfaces. Although β-carotene supplementation has been expected to enhance the retinoic acid (RA)-mediated immune response in neonates, the exact mechanism of the enhancement of mucosal IgA production in the small intestine by β-carotene is still unclear. In the present study, we investigated the effect of supplemental β-carotene on the concentrations of IgA, the numbers of IgA antibody-secreting cells (ASC) and the mRNA expressions of IgA C-region, CCL25, retinoid X receptor (RXR) α, retinoic acid receptor (RAR) α and RARγ in the jejunum and ileum of weanling mice. Weanling mice were fed rodent feed or 50 mg/kg β-carotene-supplemented rodent feed for 7, 14 or 21 d. The concentrations of IgA and the numbers of IgA ASC in the jejunum and ileum of mice increased markedly with age, and supplemental β-carotene increased the concentrations of IgA, the numbers of IgA ASC and the mRNA expressions of IgA C-region, CCL25 and RARγ in the jejunum after 14 and 21 d of treatment. Supplemental β-carotene increased the numbers of IgA ASC in the ileum after 14 and 21 d of treatment, but the concentrations of IgA in the ileum were not affected by β-carotene supplementation. The mRNA expressions of RXRα and RARα in the jejunum and those of RXRα and RARγ in the ileum after 21 d of treatment were enhanced by β-carotene supplementation. These results indicate that β-carotene supplementation in weanling mice is effective to enhance mucosal IgA induction in the jejunum or ileum and that the effects are mainly due to the RA-mediated immune response.

Mortality of neonates continues to be a major problem in humans and animals. IgA provides protection against microbial antigens at mucosal surfaces. Although β-carotene supplementation has been expected to enhance retinoic acid-mediated immune response in neonates, the exact mechanism by which β-carotene enhances IgA production is still unclear. We investigated the effect of supplemental β-carotene for maternal mice during pregnancy and lactation on IgA antibody-secreting cells (ASC) in mammary gland and guts and on IgA transfer from milk to neonatal mice. Pregnant mice were fed untreated or 50 mg/kg β-carotene-supplemented diets from 6·5 d postcoitus (dpc) to 14 d postpartum (dpp). Supplemental β-carotene increased the numbers of IgA ASC in mammary gland (P < 0·05) and ileum (P < 0·001), and also mRNA expression of IgA C-region in ileum (P < 0·05) of maternal mice at 14 dpp, but few IgA ASC were detected in mammary gland at 17·5 dpc. IgA concentration in stomach contents, which represents milk IgA level, was significantly higher (P < 0·01) in neonatal mice born to β-carotene-supplemented mothers at 7 and 14 dpp, and IgA concentration in serum, stomach contents and faeces increased (P < 0·001) drastically with age. These results suggest that β-carotene supplementation for maternal mice during pregnancy and lactation is useful for enhancing IgA transfer from maternal milk to neonates owing to the increase in IgA ASC in mammary gland and ileum during lactation.

The polyene carotenoids β-carotene and lycopene are antioxidants that not only quench singlet oxygen but also inhibit lipid peroxidation. Tri-n-butyl borane (TBB) is used as an initiator for dental resin materials and is extremely reactive with oxygen and reactive oxygen species (ROS). This reactionability of TBB may be analogous to that of carotenoids with ROS. To clarify the biological activity of such ROS scavengers, we investigated the anti-inflammatory activity of β-carotene, lycopene and TBB in terms of the expression of RNA for lipopolysaccharide (LPS)-induced cyclooxygenase-2 (Cox2), nitric oxide synthase 2 (Nos2) and tumor necrosis factor-alpha (Tnfa), and mRNA expression and up-regulation of heme oxygenase 1 (Hmox1) mRNA in RAW264.7 cells. mRNA expression was investigated using real-time reverse transcriptase-polymerase chain reaction (PCR). The antioxidant activity of carotenoids was evaluated using the induction period method in the azobisisobutyronitrile or benzoyl peroxide-methyl methacrylate system. Hmox1 mRNA, but not Cox2 and Nos2 mRNA, was up-regulated by 100 μM β-carotene and lycopene, and by 0.125% TBB. LPS-stimulated Cox2, Nos2 and Tnfa gene expression was inhibited by 50 μM β-carotene and lycopene, and by 0.5-1% TBB. Both β-carotene and lycopene had weak antioxidant activity, but β-carotene showed pro-oxidant activity at higher concentrations. The anti-inflammatory activity of β-carotene, lycopene and TBB may be related to their ROS-scavenging activity. Additionally, the activity of carotenoids and TBB may be attributed to the electrophilicity of ROS-induced carotenoid intermediates and boranes, respectively. Their anti-inflammatory activity may be attributable to enhancement of the potency of the electrophile/antioxidant response element transcription system in view of their up-regulation of Hmox1 mRNA expression.

Lettuce ( Lactuca sativa ) is commonly produced in vertical farms. The levels of nutritionally important phytochemicals such as beta-carotene (precursor to vitamin A) are generally low in lettuce. In this study, we investigated the benefits of variable lighting strategy (i.e., varying the light quality during production) on maintaining plant growth and increasing the biosynthesis of beta-carotene and anthocyanin. We tested two variable lighting methods, using green and red romaine lettuce, namely (i) providing growth lighting (supports vegetative growth) initially (21 days) followed by a high percentage of blue light (supports biosynthesis of phytochemicals) at final stages (10 days) and (ii) providing a high percentage of blue light initially followed by growth lighting at final stages. Our results indicate that the variable lighting method with initial growth lighting and high percentage of blue at final stages can maintain vegetative growth and enhance phytochemicals such as beta-carotene in green romaine lettuce while both variable lighting methods were not effective in red romaine lettuce. In green romaine lettuce, we did not observe a significant reduction in shoot dry weight but there was an increase in beta-carotene (35.7%) in the variable compared to the fixed lighting method with growth lighting for the entire duration. The physiological bases for differences in vegetative growth and synthesis of beta-carotene and anthocyanin in the variable and fixed lighting methods are discussed.

Enzymes are essential catalysts in biological systems. Substrate inhibition, once dismissed, is now observed in 20% of enzymes 1 and is attributed to the formation of an unproductive enzyme-substrate complex, with no structural evidence of unproductivity provided to date 1 , 2 , 3 , 4 , 5 – 6 . This study uncovers the molecular mechanism of substrate inhibition in tobacco glucosyltransferase Nb UGT72AY1, which transfers glucose to phenols for plant protection. The peculiarity that β-carotene strongly attenuates the substrate inhibition of Nb UGT72AY1, despite being a competitive inhibitor, allows to determine the conformational changes that occur during substrate binding in both active and substrate-inhibited complexes. Crystallography reveals structurally different ternary enzyme-substrate complexes that do not conform to classical mechanisms. An alternative pathway suggests substrates bind randomly, but the reaction occurs only if a specific order is followed (asymmetric cooperativity). This unreported paradigm explains substrate inhibition and reactivation by competitive inhibitors, opening new research avenues in metabolic regulation and industrial applications. This study proposes an unreported molecular mechanism of substrate inhibition in enzymes. It shows that a competitive inhibitor reduces substrate inhibition and identifies unique enzyme-substrate complexes, suggesting an unreported paradigm for enzyme regulation.

β-carotene (β-C) is a hydrophobic compound, easily degradable by light and oxygen and with low solubility, limiting its applications. β-cyclodextrin (β-CD) can encapsulate β-C, protecting it from degradation and maintaining its bioactivity. Therefore, this research aimed to characterize and determine the antioxidant and erythroprotective activity of β-C/β-CD inclusion complexes. The co-precipitation technique was used to elaborate β-C/β-CD in a 40:60 ratio, obtaining a high yield (94.10%), an entrapment efficiency of 82.47%, and a loading efficiency of 11.92%. The moisture of β-C/β-CD was 2.93%. β-C release increased over the time of 216 h (80.8%, 92.8%, and 97.4% at 8 °C, 25 °C, and 37 °C, respectively). A UV–visible analysis confirmed the presence of β-carotene in the inclusion complex, indicating successful encapsulation without significant structural changes. According to the adsorption–desorption isotherms, the complexes showed a type II isotherm. The FT-IR and Raman spectroscopy confirmed the formation of the inclusion complex, which interacted by hydrogen bonds, hydrophobic interactions, or van der Waals forces. The DSC showed an endothermic peak at 118 °C in the β-C/β:CD. The TGA revealed reduced water loss in the β-carotene/β-cyclodextrin complex, indicating limited water binding due to encapsulation. The microscopic surface morphologies observed by the SEM of β-C/β-CD were irregular-shaped clumps in the surface with a particle average size of 8.09 µm. The X-ray diffraction showed a crystalline structure of the complex. The zeta potential determination indicated a negative charge (−23 and −32 mV). The ABTS, DPPH, and FRAP demonstrated the antioxidant activity of β-C/β:CD (34.09%, 21.73%, and 8.85. mM ET/g, respectively), similar to pure β-C (34.64%, 22.63%, and 9.12 μM ET/g, respectively). The complexes showed an erythroprotective effect inhibiting hemolysis (64.09%). Therefore, with these characteristics, β-CD is a good encapsulant for β-C, and this complex could be applied in the food and pharmaceutical industries.

For a long time, the increased consumption of fruits and vegetables was considered critical in protecting humans against a number of diseases, such as cancer, diabetes, neurodegenerative diseases, and heart and brain vascular diseases. Presently, it is thought that the protective properties of these foods result from the presence of low-molecular antioxidants that protect the cells and their structures against oxidative damage. The alleged effect of reducing the risk for many diseases is not only due to the effect of individual antioxidants, such as α-tocopherol, ascorbic acid, or β-carotene, but also may be the result of antioxidant compounds not yet known or synergy of several different antioxidants present in fruits and vegetables. Studies on macromolecules (DNA, nucleotides, proteins) free-radical–related damage showed that diets enriched with extra servings of fruits and vegetables rich in β-carotene, tocopherols, and ascorbic acid had only limited effect on the inhibition of oxidation processes. A number of studies have shown, however, that consuming less common fruits and vegetables contribute much more to the reduction of free-radical processes, most likely because they contain a large amount of non-vitamin antioxidants, such as polyphenols and anthocyanins.

Purpose The aim is to evaluate the effect of β-carotene for osteoporosis and provide quantitative evidence. Method PubMed, Embase, Web of Science, and Cochrane Library were searched for eligible studies. Fifteen studies were included. Random-effect model was applied to pool the odds ratio (OR). The risk of osteoporosis and fracture were compared between low β-carotene intake group and high β-carotene intake group. Result The intake of β-carotene was unassociated with the overall risk of osteoporosis [OR = 0.733, 95% Cl (0.528, 1.018), p  = 0.064]. Subgroup analysis showed that the intake of β-carotene was negatively associated with the risk of osteoporosis in both male subgroup [OR = 0.7, 95% Cl (0.549, 0.893), I 2  = 40.40%, p  = 0.004] and female subgroup [OR = 0.684, 95% Cl (0.487, 0.960), I 2  = 86.40%, p  = 0.028]. There was also a negative association between β-carotene intake and osteoporosis in Asia subgroup [OR = 0.512, 95% Cl (0.403, 0.650), I 2  = 0.00%, p  = 0], whereas no association was observed in Western subgroup [OR = 1.107, 95% Cl (0.908, 1.350), I 2  = 2.30%, p  = 0.314]. In addition, random-effect model was adopted to pool the standard mean difference (SMD), and the results showed that β-carotene intake was positively associated with overall bone mineral density (BMD) [SMD =  − 0.213, 95% Cl (− 0.391, − 0.034), I 2  = 87.30%, p  = 0.019]. Subgroup analysis showed that β-carotene intake was positively associated with BMD in Asian participants [SMD =  − 0.394, 95% Cl (− 0.461, − 0.328), I 2  = 0, p  = 0], while unassociated in Western participants [SMD =  − 0.047, 95% Cl (− 0.314, 0.219), I 2  = 78.9%, p  = 0.727]. Conclusion β-carotene may improve BMD and reduce the risk of osteoporosis and fracture. However, these effects could vary by gender and race and need to be further validated by longitudinal studies.

This work was intended to investigate the targeting potential of fructose-tethered lipid-polymeric hybrid nanoparticles (F-BC-MTX-LPHNPs) co-loaded with beta carotene (BC) and methotrexate (MTX) in breast cancer therapeutics and find out the possible protective role of BC on MTX-induced toxicity. F-BC-MTX-LPHNPs were fabricated using self-assembled nano-precipitation technique. Fructose was conjugated on the surface of the particles. The cytotoxicity, sub-cellular localization and apoptotic activity of F-BC-MTX-LPHNPs were evaluated against MCF-7 breast cancer cells. The antitumor potential of F-BC-MTX-LPHNPs was further studied. Outcomes suggested that F-BC-MTX-LPHNPs induced the highest apoptosis index (0.89) against MCF-7 cells. Following 30 days of treatment, the residual tumor progression was assessed to be approximately 32%, in animals treated with F-BC-MTX-LPHNPs. F-BC-MTX-LPHNPs are competent to selectively convey the chemotherapeutic agent to the breast cancers. Beta carotene ameliorated MTX-induced hepatic and renal toxicity.

Biological sex is a fundamental determinant of physiological differences, including metabolic processes and disease susceptibility. β-carotene (BC), a provitamin A carotenoid, is known for its health benefits, but its sex-specific effects on its metabolism remain largely unexplored. This study investigated male and female BALB/c mice receiving BC or vehicle control via oral gavage for 11 weeks. Hepatic and circulating lipid levels, serum retinol, and the expression of BC cleavage enzymes (Bco1 and Bco2) and estrogen receptors (Esr1 and Esr2) in the liver and gonadal fat were analyzed. BC supplementation increased the hepatic Bco1 and Bco2 expression in males, accompanied by higher serum retinol, while downregulating expressions of these enzymes in male gonadal fat. Additionally, BC supplementation significantly reduced gonadal fat mass and adipogenic gene expression in males, with Cebpa and Esr1/Esr2 positively correlated, suggesting a role for estrogen receptor signaling in adipogenesis. These findings demonstrate that BC exerts sex- and tissue-specific effects on lipid metabolism, with strong regulatory interactions between BC metabolism, lipid homeostasis, and sex hormone signaling in males. The results provide novel insights into the mechanisms underlying sex-dependent differences in lipid metabolism following BC supplementation, with potential implications for metabolic health and disease prevention.