Nutraceutical interest of phytoecdysteroid in Microsorum species of French Polynesia
Ferns belonging to the genus Microsorum (Polypodiaceae), have always played an important role in the everyday life of Polynesians as ornamental and medicinal plants. Among them, M. scolopendria and M. membranifolium, called locally „Metuapua'a“, used in a great number of remedies in Polynesian traditional medicine, were found to contain ecdysteroids . Ecdysteroids are known to possess many pharmacological effects in mammals/humans such as anabolic, hypoglycaemic, hypocholesterolemic, tonic, hepatoprotective, antidepressant and considered as „adaptogen“ compounds . Thus, high ecdysteroid content Microsorum species present a nutraceutical interest worth to investigate. A chemical survey of the six species of Microsorum from French Polynesia (M. scolopendria, M. membranifolium, M. maximum, M. punctatum, M. commutatum and M. rubidium) had been performed to establish their ecdysteroid content and pattern. Sample of fronds from these species were collected and analysed by HPLC and their main constituents were isolated and identified by spectroscopic techniques.
Except M. rubidium, the five other species are found to contain ecdysteroid (0.02 to 1.66 %) and the major ones are: ecdysone, 20-hydroxyecdysone and 2-deoxy-20-hydroxyecdysone. Interestingly, the highest ecdysteroid concentrations were found in the two species M. scolopendria (0.47%) and M. membranifolium (1.66%), i.e. the ones mostly used in Polynesian traditional medicine. In conclusion, both M. scolopendria and M. membranifolium, used for centuries in French Polynesia, can indeed be considered as rich sources of ecdysteroids, especially of ecdysone (0.14 to 0.49%) which is rarely present as a major component in plants. Thus, they could be proposed as good candidates for nutraceutical ingredients.
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