Structure, anti-inflammatory and anti-bacterial activities of novel pentacyclic triterpenoids and other constituents from the leaves of Pittosporum elevaticostatum.

The investigation of the leaves of Pittosporum elevaticostatum Chang et Yan led to the isolation of fifteen pentacyclic triterpenoids (1-15), including five previously undescribed ones (1-5), and nine others (16-24). The structures of compounds 1-5 were elucidated based on comprehensive spectroscopic techniques, including one dimension (1D) and 2D nuclear magnetic resonance (NMR), high resolution electrospray ionization mass spectroscopy (HR-ESI-MS), and other methods. Compounds 2 and 13 demonstrated significant inhibitory activity against Listeria monocytogenes (L. monocytogenes) with minimum inhibitory concentration (MIC) values of 32 µM. Scanning electron microscopy (SEM) observations revealed insights into the antibacterial mechanism, indicating that compounds 2 and 13 either prevent biofilm formation of dispersed the preformed cell membranes. Additionally, compounds 1, 5, 7, and 12 exhibited anti-inflammatory activity on lipopolysaccharide (LPS)-stimulated BV-2 microglial cells with IC50 values ranging from 11.27 to 17.80 µM.