Influence of ascorbic acid and α-tocopherol on the autoxidation and in vitro antifungal activity of amphotericin B

Mohammed Habib Belhachemi, Zahia Boucherit-Otmani, Kebir Boucherit, Sara Belmir

Curr Med Mycol . 2021 Mar;7(1):12-18. doi: 10.18502/cmm.7.1.6178.


Background and purpose: Amphotericin B (AmB) is the standard treatment for systemic fungal infections; however, the formation of reactive oxygen species reduces the efficacy and stability of this molecule. The present study aimed to evaluate the effect of the combination of AmB with ascorbic acid and α-tocopherol on its autoxidation and antifungal activity.

Materials and methods: The antifungal activity against Candida albicans was evaluated by the viable cell counting method and checking their morphological changes with a scanning electron microscope. Monomer state of AmB was assessed by scanning the UV absorbance in the range of 300-450 nm and the lipid peroxidation was measured using quantification of thiobarbituric acid reactive-substances (TBARS).

Results: Based on the findings, the addition of ascorbic acid (3×102 µg/mL) and α-tocopherol (16 µg/mL) to the reaction medium of AmB increased its antifungal activity while maintaining its molecular stability. Moreover, the level of TBARS formed in the reaction medium of AmB was significantly reduced after combination with ascorbic acid and α-tocopherol.

Conclusion: Given their availability, their anti-free radical activity, and their low toxicity, the incorporation of ascorbic acid and α-tocopherol into the reaction medium of AmB seems to be a promising approach to obtain an effective antifungal formulation.

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How COVID-19 revitalized interest in familiar letter vitamins

Back-to-basics As, Bs, and Cs (and Ds, and Ks, and Es) are basking in vitamins’ newfound glow.

Jia Zhang Lee, executive director, Davos Life Science (Singapore), notes that his company has seen a steady increase in demand for vitamin E tocotrienols in particular. “Research studies have shown that tocotrienols have positive health benefits in the management of hypertension, heart disease, and diabetes,” Lee notes. “These chronic conditions predispose individuals to the more severe form of COVID-19, and therefore there’s been growing interest in tocotrienol supplementation to help promote the prevention of these chronic diseases.”

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Vitamin E analogs limit in vitro oxidant damage to bovine mammary endothelial cells

M J Kuhn, L M Sordillo

J Dairy Sci . 2021 Mar 24;S0022-0302(21)00448-3. doi: 10.3168/jds.2020-19675. Online ahead of print.


Diseases that occur during the transition period are exacerbated when cows are unable to cope with an increased pro-oxidant load that results in oxidative stress. Dairy cattle are routinely supplemented with the vitamin E analog α-tocopherol to mitigate the severity of oxidative stress. Nonetheless, oxidative stress remains a disease predisposing condition for many dairy cattle. A better method of optimizing the antioxidant functions of vitamin E is needed. α-Tocopherol is only 1 of 8 analogs of vitamin E, all of which have varying antioxidant properties in other mammals, albeit a shorter physiological half-life compared with α-tocopherol. A primary bovine mammary endothelial cell oxidant challenge model was used to determine functions of certain vitamin E analogs. The aim of this study was to determine if other analogs, namely γ-tocopherol or γ-tocotrienol, have antioxidative functions in bovine cells and if these functions may protect cellular viability and endothelial function from oxidant damage. Physiological (10 μM) and supraphysiological (50 μM) concentrations of γ-tocopherol and γ-tocotrienol had a greater capacity to reduce accumulated reactive oxygen species derived from a nitric oxide donating pro-oxidant antagonist, when compared with α-tocopherol, after 30 min to 6 h of treatment. Further, γ-tocotrienol (10 μM) decreased cell cytotoxicity to a greater amount than other analogs at like concentrations, whereas γ-tocopherol (10 μM) reduced lipid peroxidation and apoptosis more effectively than other analogs. Last, α-tocopherol (5 and 10 μM) and γ-tocopherol (5 and 10 μM) significantly slowed pro-oxidant induced loss of endothelial cell barrier integrity over a 48-h period using an electrical cell-substrate impedance sensing system. Concerningly, γ-tocotrienol drastically reduced the endothelial barrier integrity at only 5 μM despite no apparent effect on cellular viability at like concentrations. γ-Tocotrienol, however, was also the only analog to show significant cytotoxicity and reductions in viability at supraphysiological doses (25 and 50 μM). Our results suggest that γ-tocopherol has antioxidant activities that reduces cellular damage and loss of function due to oxidant challenge as effectively as α-tocopherol. These data set the foundation for further investigation into the antioxidant properties of vitamin E analogs in other bovine cells types or whole animal models.

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Singapore palm oil giant dispels “myths” and pushes health credentials

Singaporean palm oil company, Golden Agri-Resources (GAR), which is among the world’s largest palm oil-based agribusinesses, has stepped up efforts to “dispel misperceptions” while raising awareness about the health benefits of palm oil. These moves come amid the increase in consumer concerns about food safety and nutrition amid the COVID-19 pandemic.

Depending on the degree of refining – Wassell highlights that palm oil is a natural source of beta-carotene and tocotrienols (vitamin E).

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Vitamin E delta-tocotrienol and metabolite 13′-carboxychromanol inhibit colitis-associated colon tumorigenesis and modulate gut microbiota in mice

Chao Yang, Yiying Zhao, Suji Im, Cindy Nakatsu, Yava Jones-Hall, Qing Jiang

J Nutr Biochem . 2021 Mar;89:108567. doi: 10.1016/j.jnutbio.2020.108567. Epub 2021 Jan 9.


The gut microbiota play important roles in colon cancer. Vitamin E δ-tocotrienol (δTE) and its metabolite δTE-13′-carboxychromanol (δTE-13′) are known to have cancer-preventive effects, but their impact on gut flora during tumorigenesis and the role of the metabolite in δTE’s beneficial effects remain to be determined. In the murine colitis-associated colon cancer (CAC) induced by azoxymethane (AOM) and dextran sulfate sodium (DSS), we show that δTE and δTE-13′ inhibited the multiplicity of large adenomas (>2 mm2) by 34% (P<.05) and 55% (P<.01), respectively, compared to the control diet. δTE-13′ diminished AOM/DSS-increased GM-CSF and MCP-1, and δTE decreased IL-1β. Using 16S rRNA gene sequencing of fecal DNAs, we observe that δTE and δTE-13′ modulated the composition but not the richness of gut microbes compared to the control. Both δTE and δTE-13′ enhanced potentially beneficial Lactococcus and Bacteroides. The elevation of Lactococcus positively correlated with fecal concentrations of δTE-13′ and its hydrogenated metabolite, suggesting that the metabolite may contribute to δTE’s modulation of gut microbes. Furthermore, δTE-13′ counteracted AOM/DSS-induced depletion of Roseburia that is known to be decreased in patients with inflammatory bowel diseases. δTE uniquely elevated (Eubacterium) coprostanoloigenes. Our study demonstrates that δTE and δTE-13′ inhibited tumorigenesis, suppressed pro-inflammatory cytokines and modulated gut microbiota in a murine CAC model. These findings uncover new and distinct activities of δTE and δTE-13′ and support the notion that the metabolite may play a role in δTE’s anticancer and modulation of gut microbes.

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