Variation in contents of major bioactive compounds in Glechoma longituba related to harvesting time and geographic distribution

Abstract

Glechoma longituba (Nakai) Kupr. (Labiatae) is an important medicinal plant with various pharmacological activities. Current study was carried out to establish the variation pattern in the contents of ethanol-soluble extractive, total flavonoids, ursolic acid (UA) and oleanolic acid (OA) in G. longituba in relation to harvesting time and geographical origin. G. longitubawas harvested at one month interval during ontogenetic development phases and twenty-nine populations were collected from different distribution areas in China. The results showed that the contents of ethanol-soluble extractive, total flavonoids, UA and OA in G. longituba were related to harvesting time and distribution origin. The optimum harvesting time should be in mid-April in terms of the contents of ethanol-soluble extractive and total flavonoids, and be in mid-August or in mid-March in terms of the contents of UA and OA. Populations of G. longituba showed remarkable differences in chemical composition depending on the provenance of plants. And the differences among 29 populations are likely to be genetically controlled since all populations were grown under uniform conditions. Our results on seasonal and environmental factors will be useful for commercial producers of G. longituba in determining the optimum harvesting time and the most appropriate plants for germplasm evaluation and breeding. Key words: Glechoma longituba (Nakai) Kupr., harvesting time, inter-populational variability, total flavonoids, ursolic acid, oleanolic acid.