Variation of medicinal components in a unique geographical accession of horny goat weed Epimedium sagittatum Maxim. (Berberidaceae).

Herbal Epimedium species have been widely in Traditional Chinese Medicine for sexual enhancement, immunity improvement, anticancer and anti-aging treatment, with flavonoids and polysaccharides being the major active components. However, exhaustive depletion of wild sources warrants germplasm evaluation and quality resource exploration. A preliminarily analysis had previously indicated that a specific local geographic accession of Epimedium sagittatum found in Luotian (LT) county of Hubei Province (China) had a much higher content of total flavonoids and polysaccharides. In this study, we further investigated the medicinal component variation in the LT type under different light intensities and in different regions by the common-garden experiment. The results indicated a light intensity range of 40-160 μmol/m²/s was the most suitable for the synthesis and accumulation of total flavonoids, while polysaccharide accumulation was negatively correlated with the light intensity. Icariin was the component displaying the highest content among flavonoids, and the content of major flavonoid bioactive components was relatively stable in the third year after cultivation. There was significant correlation between the major flavonol glycoside constituents and the geographic location, and Central China followed by Northern China were the highly suitable regions for cultivation of LT type E. sagittatum. The results revealed that there was a functional balance between flavonoids and polysaccharides at different developmental stages, and the best harvesting stage should consider the primary contents of interest. This study provides important information on the exploration of quality resources, further breeding approaches and cultivation practices of E. sagittatum, and thus the important insights to enhance our understanding of quality control of traditional medicinal plants.