# A New Ursane-Type Pentacyclic Triterpenoid from the Tree Bark of Sandoricum koetjape: Antibacterial, DFT, and Molecular Docking Study

## TL;DR

A new triterpenoid compound from Sandoricum koetjape tree bark shows antibacterial properties and was studied using various scientific methods.

## Contribution

A new ursane-type pentacyclic triterpenoid compound with antibacterial activity was isolated and studied.

## Key findings

- Compound 7 inhibited bacterial growth with inhibition zones of 7.5–9 mm at 1 mg/mL.
- DFT analysis revealed electronic properties like HOMO-LUMO gaps and electrophilicity.
- Molecular docking suggested a potential antibacterial mechanism for compound 7.

## Abstract

Natural products have played an important role in the discovery and development of antibacterial agents. This paper described the isolation of a new ursane-type pentacyclic triterpenoid, (18β,19αH)-3-oxo-urs-12-en-27α-oic acid (2), from the tree bark of Sandoricum koetjape Merr. Along with this, five known compounds—β-caryophyllene oxide (1), bryononic acid (3), 7-deacetylgedunin (4), 7-deacetyl-7-oxogedunin (5), and 12,20-dihydroxydammar-24-en-3-one (6)—were successfully isolated, and one compound, 12β-hydroxydammarenolic acid (7), was reported in our previous report. All compounds (1–7) were tested with their antibacterial properties against two Gram-positive (Enterococcus faecalis and Staphylococcus saprophyticus) and two Gram-negative (Citrobacter freundii and Salmonella enterica) bacteria. The structures of the isolated compounds were elucidated using NMR spectroscopy and mass spectrometry data. A preliminary antibacterial assay showed that only compound 7 inhibited the growth of the tested bacteria, with an inhibition zone diameter of 7.5–9 mm at a concentration of 1 mg/mL. DFT analyses explained electronic profiles with HOMO-LUMO gaps (4.54–6.34 eV) and electrophilicity from 1.73 to 4.39 eV. To elucidate the antibacterial mechanism of compound 7, a molecular docking study was conducted. The findings from both in vitro and in silico analyses suggest that compound 7 is a promising antibacterial candidate for further investigation.