Studies On The Distribution Of Melatonin In Medicinal Plants And Foods

Melatonin (N-acetyl-5-methoxytryptamine) is an indole hormone in the human and secreted by the pineal gland of human or other mammals. It is mainly used to regulate sleep with pg (1×10-12 g) level. Its content changes with daily rhythmicity in vivo.5 to 10 times more production at night than during the day time, the largest secrete at 3 AM to 4 AM at early morning.This hormone was isolate from bovine pineal gland first by professor Lerner in 1958, and named melatonin. Studies have shown that melatonin have functions like anti-aging, adjust the jet lag, immunoregulation, anti-tumor, mean while it has very important significance on regulating sleep. Presence of melatonin at varying concentrations in algaes and foods including seeds, fruits, beverages has been previously reported. Since the importantance biological activity of melatonin figure out the distribution of melatonin in medicinal plants and food has an important significance for the explanation about the mechanism of drug treatment and diet.Melatonin in Chinese herbs was determined by using high performance liquid chromatography system coupled to fluorescence detector. Methanol-water and acetonitrile-water were used as mobile phase with isocratic elution. The flow rate was 0.8 mL/min, the column temperature was set at 40℃, the injection volume was 10 μL. The excitation wavelength of fluorescence detector was set at 285nm and emission wavelength was set at 345nm. Melatonin in Chinese herbs had good chromatograms within 10 min. In the given concentration range (100 pg/mL ～1 μg/mL), good linear correlation (R2=0.9998) was obtained with the RSD of precision at 1.02%, RSD of stability at 1.18% and RSD of repeatability at 1.19%, sample recovery rate was 98.8% and RSD at 1.21%. The results of the experimental shown that this method can be used to detect melatonin in traditional Chinese medicine and plants. And the method was used to detect the 24 hour rhythmic change of melatonin in leaf and root in medicinal plant and some commonly used food.The experimental results shown that most traditional Chinese medicine with improve sleep function contain melatonin, such as Mai Dong (Ophiopogon japonicus (Linn.f.)) Ker-Gawl. 9025.60±10.02ng/g, Dan Shan (Salvia miltiorrhiza Bge.) 3222.68±3.27 ng/g, Shi Chang Pu (Acorus tatarinowii) 6317.73±8.34 ng/g. Melatonin also existed in five lichens. These experimental results show that melatonin is likely to be one of the material base of YangXinAnShen traditional Chinese medicine. Experiments for the rhythmic with correlation photoperiod of melatonin in various plants had also studied. Light has an influence to melatonin in excised leaf and root tissues of Mai Dong (Ophiopogon japonicus) plant. Foods such as millet, chrysanthemum tea and seaweed contain melatonin, and can be used in daily diet regimen.