What Is Lycopene Good For?

Lycopene is a lipophilic red or yellow carotenoid pigment with the molecular formula C40H56 and a relative molecular mass of 536.88[1]. Lycopene consists of eight isoprene units connected by regular head-to-tail bonds to form a symmetrical structure. It is insoluble in water, almost insoluble in methanol and ethanol, and soluble in organic solvents such as ether, petroleum ether, and chloroform. Lycopene is widely found in fruits and vegetables such as tomatoes, watermelons, plums, and papayas. The human body and animals cannot produce lycopene and need to obtain it through food.

After being ingested by the human body, lycopene is absorbed in the intestines at a rate of 7% to 10% along with dietary fat and is distributed to the body's tissues and organs. Among all carotenoids, lycopene has the strongest ability to capture singlet oxygen radicals, and its ability to quench singlet oxygen is 2 to 3 times that of beta-carotene [3]. Lycopene has antioxidant and physiological functional activity of scavenging free radicals[4-5]. Its antioxidant effect is beneficial for preventing and improving certain pathologies, and it has the functions of protecting the liver[6], protecting the cardiovascular system[7], resisting inflammation and radiation[8], and enhancing immune activity[9]. Therefore, it has been used in health foods and medical drugs.

1 Biological functions

1.1 Protecting the liver

Fatty liver is a disease caused by excessive fat accumulation in liver cells. Modern medical research has shown that one of the important factors leading to fatty liver is the initiation of lipid peroxidation chain reactions, which causes lipid peroxidation damage [10]. As the degree of lipid peroxidation damage increases, the antioxidant capacity decreases, the amount of free radicals produced increases, and liver damage occurs. Lycopene has the function of scavenging free radicals, can alleviate lipid peroxidation damage, and protect the liver [11]. Petyaev et al. [12] used a rat model of tramadol (TD)-induced liver tissue damage and orally administered lycopene. The results showed that the activity and gene expression of liver glutathione S-transferase (GST), superoxide dismutase (SOD), thioredoxin-1 (Txn-1) and catalase (CAT) activity and gene expression were higher than those in the model group, reducing fat degeneration and liver necrosis, and demonstrating that lycopene is related to the expression of mitogen-activated protein kinase (MAPK) proteins. It was concluded that lycopene alleviates the hepatotoxic effects induced by TD by preventing lipid peroxidation and activating the antioxidant pathway. Ana et al. [13] showed that lycopene ameliorates the damage caused by hepatotoxicity by inhibiting NADPH oxidase in the phosphoinositide signaling pathway (PKC pathway) and reducing the production of reactive oxygen species (ROS) in SK-Hep-1 cells.

1.2 Alleviating diabetic complications

Diabetes is a common chronic endocrine and metabolic disease with genetic characteristics, and the incidence of diabetes has been rising year by year in recent years. Diabetic patients often suffer from a variety of chronic complications involving multiple tissues and organs, which seriously affect human life, health and quality of life. Lycopene has strong antioxidant capacity, can improve oxidative stress and inflammation levels, and alleviate diabetic complications.

Liu Yanfeng et al. [14] prepared a diabetic rat model by intraperitoneal injection of streptozotocin to study the inhibitory effect of lycopene on renal inflammation in diabetic rats. The results showed that in the lycopene dose group, the fasting blood glucose level and renal index of rats decreased significantly, and the levels of inflammatory factors such as interleukin-1β (IL-1β), interleukin-6 (IL-6), intercellular adhesion molecule-1 (ICAM-1) and other inflammatory factors in rat plasma were significantly reduced, and renal tissue damage was significantly improved in a dose-dependent manner. Zheng et al. [15] used a rat model of diabetes induced by streptozotocin to conduct a lycopene gavage experiment and found that lycopene can lower fasting blood glucose levels in type 2 diabetic rats and and improved total antioxidant capacity. Erel et al. [16] used a rat model of diabetes induced by alloxan to evaluate the effect of lycopene on tissue pathology by gavage with different doses of lycopene, and measured indicators such as malondialdehyde (MDA), total oxidative status (TOS) and inflammatory markers. The results showed that lycopene has a significant effect in preventing complications caused by diabetes and oxidative stress.

Another theory on the alleviation of diabetic complications by lycopene is that it protects endothelial progenitor cells from damage caused by advanced glycation end products, reducing endothelial progenitor cell apoptosis and oxidative autophagy. Endothelial progenitor cells are a type of cell that can participate in the repair of vascular damage. They are widely found in the bone marrow and peripheral blood, and are of great significance for patients with diabetic vascular complications. Zeng et al. [17] showed that lycopene can maintain the number of endothelial progenitor cells in diabetic patients and maintain their normal function.

1.3 Protecting the cardiovascular system

Oxidative stress is considered to be an important pathogenic process in the development of cardiovascular diseases. Lycopene is a carotenoid antioxidant that protects the cardiovascular system. Studies have shown that lycopene has a beneficial effect on the cardiovascular and lymphatic systems of patients with cardiovascular disease (CVD) [18-19].

Zeng et al. [20] found that lycopene powder can significantly alleviate cardiac hypertrophy caused by stress overload by reducing the increase in reactive oxygen species (ROS) production during the hypertrophy process significantly alleviates cardiac hypertrophy caused by stress overload. Yue et al. [21] isolated primary cardiomyocytes, established an in vitro model of hypoxia/reoxygenation (H/R), and studied the possibility of lycopene protecting cardiomyocytes exposed to H/R. They further studied the interaction between lycopene and the mitochondrial-mediated apoptotic process, demonstrating the protective effect of lycopene on H/R cardiomyocytes. Seval et al. [22] studied the protective effect of lycopene on the cardiotoxic effects of aflatoxin B1 in rats. The study showed that lycopene can reduce malondialdehyde (MDA) levels and increase glutathione (GSH), glutathione-S-transferase (GST), catalase (CAT), glutathione peroxidase (GSH-Px), superoxide dismutase (SOD) and glucose-6-phosphate dehydrogenase (G6PD) activity in the heart tissue of model rats, thereby protecting the heart against toxicity.

1.4 Anti-cancer and anti-carcinogenic effects

Studies have shown that increasing the dietary intake of lycopene is negatively correlated with the risk of cancer [23]. Of the 72 studies on lycopene and cancer, 57 showed that blood levels of lycopene are negatively correlated with the risk of cancer [24]. Chai Xuzhe [25] used MG-63 cells, which are human osteosarcoma cells in the logarithmic growth phase, to explore the effect of lycopene on the proliferation and apoptosis of human osteosarcoma cells. The results showed that after intervention with lycopene dose groups, MG-63 cell proliferation was suppressed, the number of cells was significantly reduced, and the cell proliferation inhibition rate and apoptosis rate were significantly increased, proving that lycopene has the effect of inhibiting the proliferation of human osteosarcoma cells and promoting apoptosis.

Chen Kuili et al. [26] took human lung cancer A549 cells that were in the logarithmic growth period and cultured lung cancer A549 cells in vitro, intervened with lycopene in different dose groups, and calculated the inhibition rate of lung cancer A549 cell proliferation and the apoptosis status. The results showed that lycopene can increase the inhibition rate of lung cancer A549 cell proliferation and the apoptosis rate. Jelena et al. [27] studied the effect of lycopene on ferret lung cancer. The results showed that high doses of lycopene can significantly inhibit chronic bronchitis induced by the combination of tobacco carcinogens (NNK) and cigarette smoke (CS) and reduce lung tumor lesions. Magaly et al. [28] used a rat colon tumor model induced by azomethane and fed with lycopene, and found that lycopene can reduce the total number of tumors and the size of tumors in rats, suggesting that lycopene intake is negatively correlated with the incidence of colon cancer.

1.5 Alleviates neurodegenerative diseases

Oxidative stress is considered to be the main cause of brain aging, leading to memory and cognitive impairment. Lycopene can effectively improve oxidative stress damage and the decline in learning and memory ability. Cao et al. [29] used a rat model of hippocampal damage induced by aluminum chloride to study the neuroprotective effect and mechanism of lycopene on hippocampal damage. The results showed that lycopene can reduce cognitive impairment and hippocampal tissue damage in rats with hippocampal damage, reduce oxidative stress levels, and increase glutathione levels and superoxide dismutase activity. It was shown that lycopene can alleviate aluminum-induced hippocampal damage by inhibiting oxidative stress in rats.

Huang et al. [30] used a primary mouse neuron injury model induced by tert-butyl hydroperoxide (t-BHP) to investigate the effect of lycopene on t-BHP-induced neuronal damage. Lycopene was found to effectively enhance cell viability, improve neuronal morphology and restore mitochondrial membrane potential, and reduce the production of reactive oxygen species. It was concluded that lycopene can reduce oxidative stress and reduce t-BHP-induced apoptosis, and speculated that this effect was related to the activation of the phosphoinositide 3-kinase pathway (PI3K/Akt). Huang et al. [30] showed that lycopene improved the symptoms of Alzheimer's disease by reducing reactive oxygen species (ROS), inhibiting mitochondrial dysfunction, and inhibiting the expression of the NF-κB target gene Nucling in nerve cells to inhibit neuronal apoptosis.

2 Conclusions and prospects

Lycopene has a strong antioxidant effect, and studies have shown that many diseases begin with cellular oxidation. Lycopene can directly react with reactive oxygen species, and has multiple effects. However, the mechanism of lycopene in the body still needs further research. Identifying the target genes of lycopene from the perspective of genomics provides theoretical support for the future development of targeted drugs and health products.

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