Study on molecular identification of water extracts from Gelsemium elegans and Lonicera japonica and its close species by specific PCR amplification Chemical constituents of aerial parts of Gelsemium elegans Chemical constituents from Gelsemium elegans Chemical constituents from Gelsemium elegans Isolation and purification of gelsenicine and gelsevirine from Gelsemium elegans by high-speed counter-current chromatography Non-alkaloid constituents of Gelsemium elegans Investigation on the additional alkaloid-types on Gelsemium elegans