Left, right, or both? On the configuration of the phenanthroindolizidine alkaloid tylophorine from Tylophora indica.

The alkaloid (-)-tylophorine was isolated from a sample of Tylophora indica, and the crude extract was analyzed by HPLC/MS(n) and chiral HPLC/MS. While the literature states that the naturally occurring form of this alkaloid is the R-enantiomer and that its S-antipode is usually not found in nature, we confirmed the hypothesis of Govindachari and Nagarajan that natural levorotatory tylophorine is indeed a nearly racemic mixture with a slight excess of the R-enantiomer.