I analyzed the uploaded 2024 research paper, “Evaluation of Colorless Carotenoids from White Heirloom Tomato for Regeneration of Skin Cells via Reduction of Inflammation and Stress.” The study investigates a white heirloom tomato powder rich in phytoene (PT) and phytofluene (PTF) using HaCaT human keratinocyte cells and evaluates cell viability, oxidative stress, inflammatory markers, VEGF, MMP-12, MDA, glutathione reductase and GSH.

Below is a substantially rewritten article. I have preserved the study's findings but changed the language, organization, and presentation rather than simply substituting words sentence by sentence.

White Heirloom Tomato Carotenoids and Skin Health: Potential Roles in Antioxidant Defence, Inflammation and Cellular Recovery

Abstract

Interest in nutritional approaches to skin health has increased considerably, particularly for naturally occurring compounds capable of protecting cells from oxidative and environmental stress. Carotenoids are among the most extensively investigated plant-derived antioxidants, and two lesser-known members of this family—phytoene and phytofluene—are attracting attention because of their distinctive biological and physicochemical characteristics.

White heirloom tomatoes provide a source of these colourless carotenoids. Unlike strongly pigmented carotenoids such as lycopene and β-carotene, phytoene and phytofluene have little visible colour yet may contribute to antioxidant defence and cellular protection.

A recent laboratory investigation evaluated phytoene- and phytofluene-rich white heirloom tomato powder in human HaCaT keratinocyte cells subjected to oxidative stress. The study assessed cellular viability and recovery together with lactate dehydrogenase (LDH), vascular endothelial growth factor (VEGF), matrix metalloproteinase-12 (MMP-12), tumour necrosis factor-alpha (TNF-α), malondialdehyde (MDA), reduced glutathione (GSH), and glutathione reductase (GR).

The findings demonstrated concentration-dependent effects of the tomato preparation. At appropriate concentrations, treatment was associated with improved recovery of oxidatively stressed cells, lower LDH release, increased VEGF, reduced MMP-12 and TNF-α, decreased MDA, and increased glutathione reductase and GSH. These findings provide preliminary mechanistic evidence supporting further investigation of white tomato-derived colourless carotenoids for nutritional skin-health applications. However, because the investigation was conducted in cultured cells rather than humans, clinical studies are required before these findings can be translated into demonstrated oral skin benefits.

Keywords: White tomato; Solanum lycopersicum; phytoene; phytofluene; colourless carotenoids; glutathione; oxidative stress; skin health; photoprotection; inflammation.

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1. Introduction

Skin is continuously exposed to environmental factors capable of generating oxidative stress. Ultraviolet radiation is particularly important because excessive exposure can promote the formation of reactive oxygen species and initiate biological processes associated with inflammation, cellular injury, pigmentation and premature skin ageing.

Nutrition may provide an additional means of supporting the skin's natural defence mechanisms. This concept, sometimes described as nutritional photoprotection, has encouraged scientific interest in plant-derived compounds such as carotenoids and flavonoids.

Tomatoes are a particularly important dietary source of phytochemicals. They contain flavonoids and numerous carotenoids, of which lycopene is perhaps the best known. However, tomatoes also contain the relatively overlooked colourless carotenoids phytoene (PT) and phytofluene (PTF). The paper notes that these compounds have increasingly attracted scientific attention because of their bioavailability and potential biological properties.

Phytoene and phytofluene are intermediates in carotenoid biosynthesis. Their structures and light-absorption characteristics differ from those of strongly coloured carotenoids, which historically contributed to their receiving less research attention. Nevertheless, emerging evidence has stimulated interest in their antioxidant activity and potential applications in nutritional and cosmetic science.

This is especially relevant to the expanding field of nutricosmetics or “beauty from within,” where dietary compounds are investigated for their ability to support skin appearance and physiology following ingestion.

White heirloom tomatoes are of particular interest because they can contain appreciable quantities of phytoene and phytofluene while having substantially less visible carotenoid pigmentation than conventional red tomatoes.

The study under review therefore examined whether a colourless-carotenoid-rich white heirloom tomato preparation could protect and support human skin cells exposed to oxidative injury.

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2. White Tomato as a Source of Colourless Carotenoids

The tomato preparation investigated in the study was produced from organic white heirloom tomato fruit.

According to the researchers, the heirloom tomatoes originated from plant seeds maintained without crossbreeding for at least 50 years and were characterized by their distinctive colour and other phenotypic characteristics. The fruits were processed by washing and decontamination followed by freeze-drying to produce tomato fruit powder.

The preparation was characterized principally by its content of the colourless carotenoids:

Phytoene (PT)
and
Phytofluene (PTF)

These compounds formed the central scientific basis of the investigation.

White tomato is particularly interesting from a skin-health perspective because phytoene and phytofluene may participate in antioxidant mechanisms while also possessing absorption characteristics different from conventional coloured carotenoids.

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3. Experimental Approach

The researchers used HaCaT cells, an immortalized human keratinocyte cell line frequently employed as an experimental model for epidermal biology.

Cells were cultured under controlled conditions and subsequently exposed to different concentrations of white heirloom tomato powder:

100 µg/mL
200 µg/mL
500 µg/mL
1,000 µg/mL
2,000 µg/mL

Treatment was carried out for 24 hours before various cellular and biochemical parameters were evaluated.

A series of assays was then used to examine several aspects of cellular health.

Cell viability

An MTT assay was employed to determine whether different concentrations of the tomato preparation affected cellular viability.

Cellular injury

LDH release was measured as an indicator of cellular membrane damage and injury.

Inflammation and tissue-related markers

The researchers measured:

TNF-α – an inflammatory mediator

MMP-12 – a matrix metalloproteinase associated with extracellular matrix degradation

VEGF – a signalling protein associated with angiogenic processes.

Oxidative stress

Malondialdehyde (MDA) was measured as an indicator associated with lipid peroxidation and oxidative damage.

Endogenous antioxidant system

The researchers also measured:

Reduced glutathione (GSH)

and

Glutathione reductase (GR).

These measurements are particularly relevant because glutathione represents an important component of intracellular antioxidant defence.

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4. Determining an Appropriate Concentration

An important part of the investigation was determining the concentration range at which white tomato powder could be used without adversely affecting cellular viability.

The MTT results showed that lower concentrations had relatively little cytotoxic effect, whereas concentrations of approximately 1 mg/mL and 2 mg/mL produced greater cytotoxicity.

Based on these findings, the investigators identified 100 µg/mL as the optimal concentration in their experimental system.

This concentration-response relationship is scientifically important. A natural ingredient should not automatically be assumed to become more beneficial simply as its concentration increases.

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5. Recovery Following Oxidative Injury

The researchers next created an oxidative-stress model by exposing HaCaT cells to 6 mM hydrogen peroxide (H₂O₂) for three hours.

Hydrogen peroxide exposure produced a substantial decrease in cellular viability. When the injured cells were subsequently treated with the white heirloom tomato preparation, cellular viability increased significantly, indicating recovery following oxidative injury.

LDH measurements provided additional information.

Damaged or stressed cells can release LDH following disruption of the cellular membrane. Compared with H₂O₂-injured cells, tomato-treated groups demonstrated lower LDH release within the effective concentration range.

Based on the combined cell-viability and LDH results, the researchers identified approximately 100–500 µg/mL as the effective experimental range, with 100 µg/mL described as optimal.

These observations suggest that components within white heirloom tomato powder may help cells recover from experimentally induced oxidative stress.

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6. Influence on VEGF

The study also examined vascular endothelial growth factor (VEGF).

Oxidative injury reduced VEGF levels in the experimental model. Treatment with white heirloom tomato powder was associated with increased VEGF compared with H₂O₂-stressed cells.

The authors interpreted this increase as evidence of improved angiogenic potential following treatment.

In the context of cellular recovery, this observation may be relevant to tissue repair mechanisms. Nevertheless, the experiment was conducted in cultured keratinocytes, so it should not be interpreted as demonstrating improved human skin circulation or wound healing after oral supplementation.

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7. Reduction in Inflammatory Markers

One of the more interesting observations concerned TNF-α, a well-recognized inflammatory mediator.

Oxidatively stressed cells demonstrated increased inflammatory activity. Following treatment with white heirloom tomato powder, TNF-α levels decreased.

The researchers also examined MMP-12, an enzyme capable of degrading extracellular matrix components, including elastin.

Treatment with the tomato preparation resulted in reduced MMP-12 levels compared with H₂O₂-stressed cells. The authors therefore proposed that the preparation may possess properties relevant to protecting cells from inflammation and extracellular-matrix degradation.

The results shown in the paper's Figure 3 further illustrate that H₂O₂ stress increased TNF-α and MMP-associated measurements, whereas treatment shifted these values closer to those observed in untreated control cells.

This provides a potential mechanistic link between white tomato carotenoids and processes relevant to environmentally induced skin ageing.

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8. XIOMATO™ White Tomato and Oxidative Stress

Another important measurement was malondialdehyde (MDA).

MDA is commonly used experimentally as a marker associated with lipid peroxidation. Elevated levels can therefore indicate increased oxidative damage to cellular lipids.

In the study, H₂O₂ exposure increased MDA activity. Treatment with white heirloom tomato powder significantly reduced MDA in post-treated HaCaT cells.

This result supports the hypothesis that phytoene- and phytofluene-rich tomato preparations may help counter oxidative processes at the cellular level.

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9. A Particularly Interesting Finding: Glutathione Reductase

One of the most noteworthy findings relates to the body's glutathione antioxidant system.

Glutathione exists primarily in reduced and oxidized states. Reduced glutathione (GSH) participates in antioxidant reactions and can become oxidized to GSSG. The enzyme glutathione reductase (GR) helps regenerate reduced glutathione, thereby contributing to maintenance of cellular antioxidant capacity.

The researchers measured both GSH and GR following oxidative stress and tomato treatment.

White heirloom tomato powder produced a substantial increase in glutathione reductase activity.

The paper reports GR activity increasing from approximately:

0.784 ± 0.139 mU/mL

before treatment to

5.07 ± 0.323 mU/mL

following treatment with 500 µg/mL of the tomato preparation.

Increasing the tomato concentration further to 1 or 2 mg/mL did not produce additional increases, and the authors identified the 100–500 µg/mL range as optimal in this cell model.

This finding deserves attention because it suggests that white tomato's antioxidant effects may potentially involve not only direct antioxidant activity but also interaction with an endogenous antioxidant recycling system.

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10. Relationship Between Glutathione and Skin Pigmentation

The paper goes further by connecting its GR findings with the biology of glutathione.

Reduced glutathione participates in protection against oxidative stress through both enzymatic and non-enzymatic pathways. During peroxide reduction, GSH becomes oxidized to GSSG, after which glutathione reductase can convert GSSG back into GSH.

Glutathione has also been discussed in scientific literature in connection with melanogenesis.

The paper proposes the following relationship:

Phytoene + Phytofluene-rich White Tomato

↓

Increase in Glutathione Reductase

↓

Improved regeneration of reduced Glutathione (GSH)

↓

Greater cellular antioxidant defence

↓

Potential influence on oxidative-stress-associated melanogenesis

↓

Potential support for skin tone

The authors specifically propose that increased glutathione reductase could increase reduced glutathione and thereby potentially influence skin tone over time.

However, this point requires careful interpretation.

The experiment demonstrated changes in GR and GSH in cultured cells. It did not demonstrate that oral consumption of this white tomato powder increases glutathione in humans or clinically improves pigmentation.

That distinction is important if the research is being used to support a nutraceutical product.

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11. Why Phytoene and Phytofluene in XIOMATO™ Are Interesting for Skin Nutrition

Phytoene and phytofluene differ from many conventional carotenoids because they are essentially colourless.

Their potential value in skin nutrition can be considered through several interconnected mechanisms:

Antioxidant activity may help protect cellular components against oxidative damage.

Photoprotective potential makes dietary carotenoids interesting in the context of UV-associated skin stress.

Inflammatory modulation is suggested by the reduction in TNF-α observed in this cell study.

Extracellular matrix protection may be relevant because MMP-12 was reduced following treatment.

Endogenous antioxidant support is suggested by increased glutathione reductase and GSH.

Together, these observations provide a more comprehensive scientific rationale for white tomato than simply describing it as a “skin whitening” ingredient.

A better scientific framework is:

White Tomato → Antioxidant Defence → Cellular Protection → Skin Health

This positioning is more consistent with what the experiment actually demonstrated.

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12. Potential Role in Healthy Skin Ageing

Oxidative stress and chronic inflammation are two important contributors to environmentally associated skin ageing.

Reactive oxygen species generated following environmental exposure can affect cellular lipids, proteins and extracellular-matrix components. Increased activity of matrix metalloproteinases can further contribute to degradation of structural proteins.

The study demonstrated several potentially relevant effects simultaneously:

↓ LDH release
indicating reduced cellular injury;

↓ TNF-α
indicating reduced inflammatory signalling;

↓ MMP-12
suggesting reduced matrix-degrading activity;

↓ MDA
suggesting reduced oxidative lipid damage;

↑ GSH and glutathione reductase
indicating improvement in antioxidant defence;

and

↑ VEGF
which the authors associated with recovery and angiogenic activity.

The paper summarizes these collective findings as evidence of cellular recovery following oxidative injury.

This multi-pathway activity makes white tomato-derived colourless carotenoids interesting candidates for further investigation in healthy-ageing and skin-health nutrition.

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13. Relevance to Oral Nutricosmetics

The study discusses phytoene and phytofluene in the context of nutricosmetics, where nutritional ingredients are intended to support skin physiology from within.

This is particularly relevant to an oral white-tomato formulation.

However, there is a major scientific limitation that should not be overlooked:

This particular study was not an oral human clinical trial.

The researchers applied white heirloom tomato powder directly to HaCaT cells in vitro.

Therefore, the study supports statements such as:

White heirloom tomato carotenoids demonstrated antioxidant, anti-inflammatory and cytoprotective activity in an experimental keratinocyte model.

It does not, by itself, establish statements such as:

Oral white tomato clinically treats hyperpigmentation or melasma.

Nor can the concentrations of 100–500 µg/mL used in cell culture be directly converted into a human oral dose.

That would require pharmacokinetic and human clinical evidence.

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14. Scientific Interpretation

The study provides an interesting mechanistic model for understanding how white tomato-derived phytoene and phytofluene might contribute to skin health.

The proposed biological sequence can be summarized as:

White Heirloom Tomato

↓

Phytoene + Phytofluene

↓

Antioxidant activity

↓

Reduction in oxidative stress and lipid peroxidation

↓

Lower MDA

•  

Reduction in inflammatory signalling

↓

Lower TNF-α

•  

Reduction in matrix-degrading activity

↓

Lower MMP-12

•  

Enhanced glutathione antioxidant system

↓

Higher GR + GSH

↓

Improved cellular resilience and recovery

↓

Potential support for healthier skin

The strength of this study is therefore not evidence of a single “whitening mechanism.” Instead, it suggests that white tomato carotenoids may influence several biological pathways relevant to skin stress and cellular recovery simultaneously.

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15. Limitations of the Research

Although the findings are promising, several limitations should be considered.

Most importantly, this was an in-vitro investigation using HaCaT keratinocytes, not a randomized human oral supplementation trial. The authors themselves state that future human clinical investigations are needed to validate the proposed skincare benefits.

Secondly, the experiment investigated a whole white heirloom tomato powder. Consequently, the findings should not automatically be attributed exclusively to phytoene or phytofluene unless those individual compounds are separately evaluated under comparable conditions.

Thirdly, cellular concentrations cannot be directly extrapolated to an oral human dose.

Fourthly, biochemical improvements such as higher glutathione reductase or lower MDA do not automatically establish a visible improvement in pigmentation, melasma, skin brightness or ageing in humans.

These questions require appropriately designed clinical studies.

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16. Conclusion

White tomato represents an intriguing natural source of the colourless carotenoids phytoene and phytofluene.as in brand XIOMATO™

In the reported HaCaT keratinocyte model, white heirloom tomato powder demonstrated several biological effects relevant to skin health. Appropriate concentrations were associated with improved recovery following hydrogen-peroxide-induced injury, reduced LDH release, lower inflammatory and matrix-associated markers, decreased MDA, increased VEGF and enhanced glutathione-related antioxidant activity.

Particularly interesting was the observed increase in glutathione reductase and GSH, suggesting that the biological activity of the tomato preparation may extend beyond direct antioxidant effects to interaction with endogenous cellular antioxidant systems.

Taken together, these findings provide a mechanistic basis for further investigation of phytoene- and phytofluene-rich XIOMATO™ white tomato preparations as nutritional ingredients for skin health, antioxidant defence and protection against environmental stress.

The results should nevertheless be interpreted as preclinical evidence. Human oral clinical studies are necessary to establish bioavailability, effective dosage and clinically meaningful effects on skin parameters such as pigmentation, photoprotection, elasticity, hydration and overall appearance. The original authors likewise identify human clinical investigation as an important next step.