Ephedra is one of the oldest known medicinal plants and the largest genera of the Ephedraceae family. In vivo antitumor evaluation of Ephedra foeminea revealed that ethyl acetate (EtOAc) was the most bioactive fraction. Bio-guided fractionation of EtOAc fraction afforded nine compounds isolated for the first time from the plant species. Macrocyclic spermine alkaloids (1,9), proanthocyanidins (2,4,5), quinoline alkaloids (7,8), phenolic (3), and nucleoside (6) were identified and elucidated by spectroscopic analyses including 1D and 2D NMR, ESI-MS-MS spectrometry. The tested compounds exhibited moderate anticancer activity, except for the kynurenic acid derivative (6-mKYNA) which showed significant cytotoxicity and remarkable inhibition of CA-19.9 and CA-125 tumor biomarkers. In-silico study was conducted to determine the anti-proliferative mechanism of 6-mKYNA by using the CK2 enzyme active site. Moreover, the ADME computational study suggested that 6-mKYNA is an effective candidate with a promising pharmacokinetic profile and therapeutic potential against various types of cancer.
Keywords: 6-methoxykynurenic acid; ADME; Ephedra foeminea; alkaloids; in silico; proanthocyanidins; tumor marker.