Serum melatonin levels and antioxidant capacities after consumption of pineapple, orange, or banana by healthy male volunteers

Abstract

Melatonin is a naturally occurring molecule biosynthesized by the pineal gland of vertebrates; it also has been identified in many plants. It is considered an important antioxidant and may retard the development of some neurodegenerative diseases and cancer. Previous studies in humans have measured melatonin metabolites in urine and have indicated that melatonin-containing foods may provide dietary melatonin. This study tested whether the consumption of fruits or fruit juice containing melatonin would influence the serum melatonin concentration and antioxidant status. In this crossover study, 12 healthy male volunteers took either juice extracted from one kilogram of orange or pineapple or two whole bananas, with a 1-wk washout period between the fruit or fruit juices. An enzyme-linked immunosorbent (ELISA) assay was used to determine the serum melatonin concentration. Serum antioxidant capacity was determined by ferric reducing antioxidant power (FRAP) assay and oxygen radical antioxidant capacity (ORAC) assay. The highest serum melatonin concentration was observed at 120 min after fruit consumption, and compared with before consumption levels, their values were significantly increased for pineapple (146 versus 48 pg/mL P = 0.002), orange (151 versus 40 pg/mL, P = 0.005), and banana (140 versus 32 pg/mL, P = 0.008), respectively. Serum antioxidant capacity following fruit consumption also significantly increased in both the FRAP (7-14% increase, P ≤ 0.004) and ORAC (6-9% increase, P = 0.002) assays. Both the serum FRAP and ORAC values strongly correlated with serum melatonin concentration for all three fruits. These findings suggest that tropical fruit consumption increases the serum melatonin concentrations and also raises the antioxidant capacity in the serum of healthy volunteers in proportion to serum melatonin levels.

Melatonin production in Escherichia coli by dual expression of serotonin N-acetyltransferase and caffeic acid O-methyltransferase

“…For the first time, we were able to produce a large quantity of melatonin (1.46 μg/mL) in E. coli by dual expression of sheep SNAT and rice COMT. This melatonin level is 7300-fold higher than the peak melatonin level (200 pg/mL) in human serum at night (Sae-Teaw et al 2013). In comparison, transgenic rice and tomato plants overexpressing SNAT (Kang et al 2010) and ASMT (Wang et al 2014a) produced only 2.5 and 75 ng/g fresh weight, respectively.…”

Melatonin, an underestimated natural substance with great potential for agricultural application

“…The high level of this compound was found in flower buds of Datura metel L. but it decreased following the floral development (Murch et al 2009a). MEL was found also in fruits such as strawberries, kiwis, pineapples, bananas, apples and in grapes (Hattori et al 1995;Iriti et al 2006;Sae-Teaw et al 2013) as well as tart cherries (Manchester et al 2000) and tomatoes (Van Tassel and O'Neill 2001;Okazaki and Ezura 2009). This may be related to their high sensitivity to environmental stresses including UV radiation during buds development and plant growth (Murch et al 2009a).…”

Pathophysiology of Depression: Molecular Regulation of Melatonin Homeostasis – Current Status

“…The review prepared by Meng et al [98] presents a detailed list of products containing melatonin. It has been proven that products rich in melatonin such as pineapple, orange, or banana increase the concentration of circulating melatonin in human serum [99]. Unfortunately, we do not have such detailed knowledge about the bioavailability of melatonin in other food products.…”