The plant Aconitum ouvrardianum HAND.-MAZZ. grows in Diqing country of Yunnan province in China at an elevation of 3000 m. Biological activity studies performed on diterpenoid alkaloids of "CaoWu" species have shown analgesia, anti-imflammatory and antiarrhythmic action. 1,2) To our knowledge, no phytochemical study of this plant has previously been undertaken. These reasons and our interest in the species prompted us to work with the A. ouvrardianum. In the course of our studies on the alkaloids of this plant, a new C 19 -diterpenoid alkaloid, ouvrardiantine (1) and two new C 20 -diterpenoid alkaloids, ouvrardiandines A (2) and B (3) have been isolated from the root of A. ouvrardianum. This paper describes the separation and structural elucidation of these new alkaloids.
Results and DiscussionOuvrardiantine (1) The configuration of 2-OH was a-orientation, based on the downfield shift of C-19 (d C 51.8 t) in the 13 C-NMR spectra of compound 1. In this case, there was a hydrogen bond formed between N atom and 2a-OH group (Fig. 2). 4) Finally, all the evidence given above led to assignment of the structure of ouvrardiantine as 1.Ouvrardiandine A (2) was isolated as a white amorphous powder, A new C 19 -diterpenoid alkaloid, ouvrardiantine (1) and two new C 20 -diterpenoid alkaloids, ouvrardiandines A (2) and B (3) were isolated from the root of Aconitum ouvrardianum HAND.-MAZZ. The structure of the new alkaloids was established on the basis of spectral data (1D-and 2D-NMR, HR-MS).