Computational study and biological evaluation of isolated saponins from the fruits of gleditsia aquatica and gleditsia caspica

Phytochemical study of the ethanolic extract of the fruits of Gleditsia aquatica and Gleditsia caspica resulted in the isolation of the triterpene saponins; aquaticasaponin A (1), aquaticasaponin B (2), caspicaoside L (3) and caspicaoside M (4). Compound (1) showed good activity against methicillin resistant Staphylococcus aureus (MRSA) (IC₅₀ =16.3 μg/mL) and Staphylococcus aureus (non-MRSA), (IC₅₀ =12.2 μg/mL) and it expressed considerable cytotoxic activity against BT-549 (Human Ductal Carcinoma, Breast), KB (Human Epidermal Carcinoma, Oral) and SK-MEL (Human Malignant Melanoma) with IC₅₀ values of 8.3, 10.0 and 3.3 μg/mL, respectively. Compounds (2) and (3) showed potent cytotoxicity against BT-549 with IC₅₀ values of 5.3 and 7.3 μg/mL, and against SK-MEL with IC₅₀ values of 4.3 and 3.1 μg/mL, respectively. Compound (4) showed good cytotoxicity against KB with IC₅₀ value of 7.3 μg/mL. In consistent, the study of molecular determinates of cytotoxic activity of these new scaffolds showed close high docking scores to CD81 (Cluster of Differentiation 81) human antigen which could be of great importance for the development of new cytotoxic candidates. The structure identification of isolated metabolites was carried out using 1D and 2D NMR and mass spectra.