Anti-proliferative and computational studies of two new pregnane glycosides from Desmidorchis flava

• Two new metabolites named desmiflavasides C and D were isolated from Desmidorchis flava.
• Two new structures were elucidated by 1D-, 2D-NMR, and ESIMS experiments.
• Desmiflavasides C and D showed anticancer activity against breast and ovarian cancer cells.
• Docking studies of tested compounds were carried out in order to predict any important binding orientations.

Two new pregnane glycosides named desmiflavasides C (1) and D (2) were isolated from the sap of Desmidorchis flava (N.E.Br.) Meve & Liede and have had their structures confirmed from 1D and 2D NMR spectroscopic techniques and mass spectrometry (ESIMS). Further, the effects of desmiflavasides C (1) and D (2) on the proliferation of breast and ovarian cancer cells as well as normal breast epithelial cells in culture were examined. Interestingly, desmiflavasides C (1) and D (2) were able to cause a substantial decline in the viability of cancer cells in a concentration-dependent manner. Moreover, treatment of normal cells with compound 2 resulted in no significant growth inhibition, indicating that its cytotoxicity was selective towards cancer cells. Furthermore, the activity of compound 2 against cancer as well as normal epithelial cells was found to be similar to that of a previously reported pregnane glycoside, nizwaside (3). Molecular docking studies of desmiflavasides C (1) and D (2) and nizwaside (3) were carried out to ascertain if it was possible to predict any important binding orientations required of small molecule drug candidates with suggested protein target molecules for the purposes of being able to predict the affinity and activity to an acceptable degree by such compounds. Desmiflavaside D (2) showed a relatively good binding affinity (−22.4449 kcal/mol) as compared to the other two compounds viz., nizwaside (3) (−20.0319 kcal/mol), and desmiflavaside C (1) (−19.4042 kcal/mol). Docking results of the three pregnane glycosides viz., 1–3 revealed that these ligand molecules can accurately interact with the target protein.

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