Quantitative analysis of camptothecin derivatives in Nothapodytes foetida using ¹H-NMR method

A quantitative analysis using ¹H-NMR has been developed for the determination of camptothecin derivatives and trigonelline in Nothapodytes foetida root, stems and leaves. In the region of δ 9.5-5.5, the signals of H-7 of camptothecin (1), H-10 of 9-methoxycamptothecin (2), H-19 of pumiloside (3) and H-2 of trigonelline (4), were well separated from each other in DMSO-d₆. The quantity of the compounds was calculated by the ratio of the intensity of each compound to the known amount of internal standard 3,4,5-trimethoxybenzaldehyde. These results were compared with the conventional HPLC method. The advantages of the method are that no reference compounds are required for calibration curves, the quantification could be directly realized on a crude extract, an overall profile of the preparation could be directly obtained, and a very significant time-gain could be achieved, in comparison to conventional HPLC methods, for instance.