Melatonin in Chinese medicinal herbs.
Melatonin is a highly conserved molecule that not only exists in animals, but also is present in bacteria, unicellular organisms and in plants. Since melatonin is an antioxidant, in plants melatonin was speculated to protect them from intrinsic and environmental oxidative stress. More importantly, melatonin in edible plants inevitably enters animals and human through feed and food. In this study, more than 100 Chinese medicinal herbs were analyzed using the methods of solid phase extraction and HPLC-FD on-line with MS to determine whether melatonin is present in these commonly used herbs. Melatonin was detected in majority of these plants. Sixty-four of them contain melatonin in excess of 10 ng per gram dry mass. Melatonin levels in several herbs are in excess of 1000 ng/g. It is well known that normal average physiological plasma levels of melatonin are only 10-60 pg/mL. These high level-melatonin containing plants are traditionally used to treat diseases which presumably involve free radical damage. The current study provides new information concerning one potentially effective constituent present in a large number of medicinal herbs. The results suggest that these herbs should be reevaluated in reference to their nutritional and medicinal value.
Dalian Institute of Chemistry and Physics, Chinese Academy of Sciences, 161 Zhong Shan Road, Dalian 116011, China.
Guofang
G
Chen
Yushu
Y
Huo
Dun Xian
DX
Tan
Zhen
Z
Liang
Weibing
W
Zhang
Yukui
Y
Zhang
D000975:Antioxidants / Q000032:analysis*; D002851:Chromatography, High Pressure Liquid; D004365:Drugs, Chinese Herbal / Q000032:analysis*; D013058:Mass Spectrometry; D008550:Melatonin / Q000032:analysis*; D010946:Plants, Medicinal / Q000737:chemistry*; D011786:Quality Control; D012997:Solvents; D013050:Spectrometry, Fluorescence
D000975:Antioxidants; D004365:Drugs, Chinese Herbal; D012997:Solvents; D008550:Melatonin