Melatonin in Montmorency cherries

What is melatonin?  

Melatonin (N-acetyl-5-methoxytryptamine) is a biologically active substance produced in the pineal gland of humans and animals that performs a variety of functions. It is also synthesized in various parts of plants, such as fruits, leaves, stems, roots, and seeds. In plants, melatonin acts as a messenger that is produced under certain conditions and regulates various processes ​(1) ​. 

The body's natural production of melatonin can be impaired by unhealthy habits such as smoking, drinking alcohol, drinking too much coffee, and taking certain medications that suppress melatonin production. In addition to reducing these factors, natural melatonin production can be supported by eating foods rich in melatonin ​(2, 3) ​. 

What function does melatonin fulfill in the human body?  

The best known and most important function of melatonin is the regulation of the sleep-wake cycle . Melatonin is mainly secreted at night , and its release depends on the duration of darkness. In this way, it prepares the body for the night's rest phase and sleep. 

As mentioned above, melatonin is synthesized and secreted in the pineal gland. This process depends on two precursors of melatonin. First, the amino acid tryptophan is taken up from the bloodstream and converted into serotonin . Melatonin is then produced from serotonin by the enzymes serotonin N-acetyltransferase and hydroxyindole-O-methyltransferase ​(4) ​. 

The highest melatonin levels in the blood can usually be measured between 2:00 and 4:00 am and are around 60 to 70 pg/mL. However, these values ​​are individual and can vary greatly from person to person. The rhythm and the concentration released remain relatively constant in a person under normal circumstances ​(5) ​. 

However, melatonin is not only involved in sleep regulation, but also in numerous other functions in the human body. These include the regulation of body temperature, the immune system, blood clotting and blood sugar levels (4) . 

What function does melatonin fulfill in plants?  

Melatonin also plays an important role in the immune system in plants. Its release increases in response to stress such as extreme temperature fluctuations, drought, toxins or fungal infections. In addition, the release of melatonin activates other proteins and enzymes that can strengthen the plant's defenses against pathogens and neutralize harmful oxidation processes (1) . 

Melatonin is also crucial for maintaining the functions of various enzymes and receptors . These are responsible for communication between cells and play an important role in the plant's response to external influences as well as in the distribution of nutrients within the plant. 

A key role of melatonin is to regulate plant growth and the development of roots, flowers and fruits. In addition, melatonin also influences the ripening of fruits , even after harvest. Thanks to the antioxidant properties of melatonin, chlorophyll is better preserved and the leaves retain their green color for longer ​(6) ​. 

How much melatonin do Montmorency cherries contain?  

Natural sources of melatonin include various fruits, vegetables and herbs. Sour cherries are considered to be a type of fruit that is particularly rich in melatonin. Today, 74 varieties of sour cherries are known ​(7) ​, which, in addition to melatonin, are considered particularly healthy due to their numerous other ingredients such as vitamins, minerals and polyphenols ​(8) ​. 

Of these numerous varieties, one has proven to be particularly valuable due to its high melatonin concentration: the Montmorency sour cherry. It contains 13.46 ng/g of melatonin, followed by the Balaton sour cherry, which also contains a relevant but significantly lower amount of melatonin at 2.06 ng/g ​(3) ​. In addition, sour cherries contain the amino acid tryptophan, which serves as a precursor to the formation of melatonin ​(9) ​. 

The Montmorency sour cherry can be traced back to an old French variety, "Chateau de Moreille", which is over 400 years old . This sour cherry variety is now mainly grown in Michigan, USA . Since other sour cherry varieties contain smaller amounts of health-promoting ingredients, it is advisable to take a closer look at the origin of the fruit when buying sour cherry products​ (8) ​. Due to their sour taste, sour cherries are often used in various products that are often sweetened. However, valuable nutrients are lost during this type of processing. In contrast, sour cherry juice and concentrate, when prepared gently, offer the highest content of melatonin and other valuable nutrients​ (10) ​. 

What other foods are rich in melatonin?  

Melatonin levels vary not only from plant to plant, but also between different parts of the same plant. For example, flowers and leaves of a plant often contain different amounts of melatonin. In addition, melatonin levels can vary depending on the region in which the plant is grown, influenced by factors such as temperature differences and soil pH ​(2) ​. The table below lists some foods that are rich in melatonin, in addition to sour cherries. 

Groceries	part of the plant	amount of melatonin in ng/g
Black pepper	Sheet	1093
turmeric	root	120
almond	core	39
strawberry	fruit	11.3
pomegranate	fruit	5.5
St. John's wort	blossom	4

Tab. 1: Melatonin content in selected plants ​( 11 ) 

The most important things in brief

literature 

1. Saroj N, Prasad K, Singh SK, Kumar U, Lal MK, Maurya S et al. Regulatory Role of Melatonin in Flowering, Fruit Setting, and Ripening. In: Kumar R, Altaf MA, Lal MK, Tiwari RK, eds. Melatonin in Plants: A Regulator for Plant Growth and Development. 1st ed. 2023. Singapore: Springer Nature Singapore; Imprint Springer; 2023. pp. 67–79.
2. Koca Çalişkan U, Aka C, Bor E. Melatonin in Edible and Non-Edible Plants. Turk J Pharm Sci 2017; 14(1):75–83. doi: 10.4274/tjps.33043.
3. Burkhardt S, Tan DX, Manchester LC, Hardeland R, Reiter RJ. Detection and Quantification of the Antioxidant Melatonin in Montmorency and Balaton Tart Cherries (Prunus cerasus). Journal of Agricultural and Food Chemistry 2001; 49(10):4898–902. doi: 10.1021/jf010321.
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5. Arendt J, Aulinas A, Feingold KR, Anawalt B, Blackman MR, Boyce A et al. Physiology of the Pineal Gland and Melatonin. South Dartmouth (MA); 2000.
6. Sun C, Liu L, Wang L, Li B, Jin C, Lin X. Melatonin: A master regulator of plant development and stress responses. J Integr Plant Biol 2021; 63(1):126–45. doi: 10.1111/jipb.12993.
7. Blando F, Oomah BD. Sweet and sour cherries: Origin, distribution, nutritional composition and health benefits. Trends in Food Science & Technology 2019; 86:517–29. doi: 10.1016/j.tifs.2019.02.052.
8. Ferretti G, Bacchetti T, Belleggia A, Neri D. Cherry antioxidants: from farm to table. Molecules 2010; 15(10):6993–7005. doi: 10.3390/molecules15106993.
9. Garrido M, Espino J, Toribio-Delgado AF, Cubero J, Maynar-Mariño JI, Barriga C et al. A jerte valley cherry-based product as a supply of tryptophan. Int J Tryptophan Res 2012; 5:9-14. doi: 10.4137/IJTR.S9394.
10. Ou B, Bosak KN, Brickner PR, Iezzoni DG, Seymour EM. Processed tart cherry products--comparative phytochemical content, in vitro antioxidant capacity and in vitro anti-inflammatory activity. J Food Sci 2012; 77(5):H105-12. doi: 10.1111/j.1750-3841.2012.02681.x.
11. Salehi B, Sharopov F, Fokou PVT, Kobylinska A, Jonge L de, Tadio K et al. Melatonin in Medicinal and Food Plants: Occurrence, Bioavailability, and Health Potential for Humans. Cells 2019; 8(7). doi: 10.3390/cells8070681.