[Modification of the analytical method for rotenoids in plants].

Rotenoids are the active ingredients of some botanical insecticides and prospective candidates as anticancer agents. The proper isolation and determination of rotenoids in plants is of great importance for their further research and development. However, the HPLC method available for this purpose was developed particularly for the detection and determination of rotenone, so it appears to be unsuitable for the analysis of other rotenoids such as deguelin, elliptone and their analogues. By checking the UV spectra, it has been found that four types of UV absorption patterns occurred among the major rotenoids isolated from the roots of Derris elliptica and leaves of Tephrosia vogelii, and that the detection wavelength at 240 nm is more adequate for the analysis of a complex of rotenoids than at 280 nm-300 nm, which is used for rotenone detection. The extraction of rotenoids from plants is conveniently carried out by CHCl3-MeOH(9:1, V/V) and the purification can be accomplished by filtration of the crude residue through a C18 reversed-phase cartridge. Rotenoids can be isocratically eluted by MeOH-H2O(66:34, V/V). The results showed that rotenone, deguelin, elliptone, and their 12a-hydroxy- and 6a,12a-dehydro-analogs can be easily detected by the modified method, along with a satisfactory peak separation. The rotenoid components might be characterized by their retention times and relative retention times based on rotenone, which were at a range of 3.26 min-39.42 min and 40.4%-489.1% respectively.