Chiang Mai Journal of Science

 The emergence and spread of antimicrobial resistance (AMR) is a serious threat to public human health. The challenge now is an urgent need to new potent antibiotics combating AMR which can be an effective way to solve the crisis. A new potent antibacterial activity of diptoindonesin D, together with four known compounds as hopeafuran, α-viniferan, hopeahainol A and hopeahainol C were isolated from the stem bark of Shorea roxburghii G. Don in Khon Kaen province, Thailand. Diptoindonesin D were screened for antimicrobial activity and possesses significant activity minimum inhibitory concentrations (MIC) values of 4.68 and 9.37 μg/mL against Staphylococcus epidermidis and Staphylococcus aureus, respectively. The absolute configuration of diptoindonesin D were evaluated by circular dichroism (ECD) calculations. The ECD results indicated that the possible configuration of diptoindonesin D should be R-configuration. Furthermore, reverse docking was performed to identify the protein target of diptoindonesin D based on four scoring functions using GOLD program. This investigation is the first time that reveals interaction between diptoindonesin D and its binding with cell wall synthesis protein targets. The results highlighted that, penicillin-binding protein 2a (PBP2a), an antibacterial cell wall, might be the potential target for the binding of diptoindonesin D. The obtained results can be useful as a guideline for the development of effective diptoindonesin D as a PBP2a inhibitor.