Cordiasecosides G-J, 9,10-Seco-29-norcycloartane glycosides isolated from Cordia lutea and their antibacterial activities

Four undescribed secocycloartane monoglycosides (1–4) were isolated from an ethanolic extract of the dry flowers of Cordia lutea Lam. Their structural assignment is based on NMR and MS analysis. Their stereochemistry is confirmed by molecular modelling studies using DFT-NMR calculations done for compound 3. In vitro antibacterial activity of the four compounds was moderate on Helicobacter pylori (MIC = 15.6 μg/mL), and much weaker on Staphylococcus aureus, Pseudomonas aeruginosa or Escherichia coli (MIC >125 μg/mL). Toxicity evaluated against RAW 264.7 cells was weak (IC₅₀ values ranging from 24 to 41 μM i.e. 15 to 24 μg/mL), but in the same range as anti-Helicobacter activity.