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Gene & Protein in Disease Natural carotenoids prevent prostate cancer

1.5. Link between carotenoids and PCa β-carotene, lycopene, lutein, and β-cryptoxanthin.

Numerous epidemiological studies have indicated that Specifically, α-carotene, β-carotene, and lycopene belong
increased carotenoid serum levels are linked to a reduced to the class of carotenes and are fat soluble, while lutein
risk of PCa incidence and progression. In a prospective and β-cryptoxanthin belong to the class xanthophylls and
are relatively water soluble due to the presence of hydroxyl
study involving 450 PCa patients and 450 healthy 73
individuals, the relationship between plasma carotenoids or keto groups at the end rings. In general, carotenoids
and PCa occurrence was investigated using blood samples are considered lipophilic and non-polar due to their large
and dietary habit questionnaires. The results indicated hydrocarbon structure. Figure 1B and C illustrate the
that, except for elderly participants and those without a main skeleton structure, which can be modified through
cancer-related family history, elevated plasma lycopene cyclization, hydronation, or the addition of one or more
oxygens. In fact, carotenoids that contain one or more
concentrations were significantly associated with a lower oxygens are known as xanthophylls. Carotenoids can
risk of PCa. In addition, the findings imply that diets high in be further classified as cis or trans isomers based on the
β-carotene might help prevent the development of PCa in different configurations around the C-C bond. The presence
younger men. In another cas–control study, blood serum of isomers can be indicated by their different melting points,
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samples from 118 non-hispanic Caucasian males and 52 solubility, and ultraviolet properties. Additional properties
controls were analyzed using high-performance liquid include different molecular geometry, thermostability, and
chromatography to assess plasma carotenoid levels and the absorption properties. 74-76 Since carotenoids are often found
risk of PCa. The study found that high concentrations of in ester or diester form, saponification is required after the
cis-lycopene isomers were adversely associated with PCa extraction of pigments. To date, more than 600 carotenoids
risk, whereas high plasma levels of alpha-carotene, beta- have been identified, but only approximately 40 of them
carotene, alpha-cryptoxanthin, lutein, and zeaxanthin are present in the human diet. Figure 1 demonstrates the
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were correlated with a 50% reduced risk compared to chemical structure of α-carotene, β-carotene, lycopene,
men with lower levels. Similar findings were reported in lutein, and β-cryptoxanthin.
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a population-based case–control study involving 193 PCa
patients and 197 healthy men, which showed that elevated 2.2. Consumption
serum levels of lycopene, lutein, and beta-cryptoxanthin Carotenoid consumption is generally well tolerated
were associated with a reduced PCa risk. Umesawa et al. by the majority of the global population. According
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investigated the link between vegetable and carotene to García-Closas et al., root vegetables and green leafy
consumption and PCa risk in a Japanese prospective study vegetables, such as spinach, chard, and lettuce, are the
involving 15,471 male participants. A questionnaire that main sources of α-carotene, β-carotene, and lutein, while
included questions on food consumption was administered, tomatoes and citrus fruits contribute to the majority of
leading to the identification of 143 cases of incident prostate lycopene and β-cryptoxanthin intake. However, the main
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malignancies. While vegetables were not associated with a source of carotenoid intake may differ from country to
risk for PCa, moderate-to-high consumption of α-carotene country, depending on their fruit and vegetable consumption
may be related to a decreased risk. In another Dutch patterns. A cross-sectional Spanish cohort study revealed that
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cohort study involving 58,279 participants, the link between carotenoid consumption in the United States is one-fifth of
carotenoids, retinol, vitamins E and C, and PCa risk was that in Spain, reflecting the difference in carotenoid intake.
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examined. A total of 642 incident PCa cases were included For instance, an average adult in the United States consumes
in the study. Only β-cryptoxanthin had a beneficial 4.5 mg of lycopene and 1.5 mg of lutein daily. As a point of
association with a lowered risk of disease, whereas the reference, one serving of tomato sauce provides 6.9 mg of
consumption of vitamins E, C, and retinol had no impact. 71 lycopene, while one egg yolk provides approximately 1 mg

2. Overview of carotenoids of lutein. Safety levels for carotenoid intake are established at
75 mg of lycopene and 20 mg of lutein per day. 80
2.1. Substance It is important to note that the biological activity of
Carotenoids are natural isoprenoid compounds commonly carotenoids is highly dependent on their absorption
found in flowers, leaves, and seeds in nature, as well as mechanisms. Owing to their lipophilic and non-polar
in fruits and vegetables within the human diet. Due to nature, the absorption of carotenoids requires the
their characteristic color, carotenoids are often referred presence of dietary fat. This process is facilitated by their
to as pigments. For instance, β-carotene, a precursor incorporation into lipid droplets, which are then absorbed
to vitamin A, imparts the orange color to carrots. The by enterocytes. Such absorption is aided by bile salts and
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most commonly studied carotenoids include α-carotene, calcium, which promote micellization and reduce the size

Volume 3 Issue 1 (2024) 7 https://doi.org/10.36922/gpd.2827