2-Hydroxy-4-methoxybenzaldehyde from Hemidesmus indicus is antagonistic to Staphylococcus epidermidis biofilm formation

Abstract

Staphylococcus epidermidis (SE) is an opportunistic nosocomial pathogen that accounts for recalcitrant device-related infections worldwide. Owing to the growing interest in plants and their secondary metabolites targeting bacterial adhesion, this study was intended to uncover the anti-biofilm potential of Hemidesmus indicus and its major constituent 2-hydroxy-4-methoxybenzaldehyde (HMB) against SE. The minimum biofilm inhibitory concentration (MBIC) of H. indicus root extract and HMB were found to be 500 and 250 µg ml⁻¹, respectively. The results of time-dependent biofilm inhibition and mature biofilm disruption assays confirmed that HMB targets initial cell adhesion. Furthermore, interference by HMB in the expression of adhesin genes (icaA, aap and bhp) and biofilm components was associated with an increased susceptibility of SE to oxidative stress and antibiotics. To conclude, this study reports for the first time HMB as a potential drug against SE biofilms.

Keywords:

• Anti-biofilm
• Hemidesmus indicus
• 2-hydroxy-4-methoxybenzaldehyde
• Staphylococcus epidermidis

Disclosure statement

The authors declare that they have no conflict of interest.

Additional information

Funding

The computational and bioinformatics facility was provided by the Alagappa University, Bioinformatics Infrastructure Facility (funded by DBT, GOI, File No. BT/BI/25/012/2012, BIF). The instrumentation facilities were provided by the Department of Science and Technology—Fund for Improvement in S&T Infrastructure (DST-FIST) (grant no. SR/FST/LSI-639/2015(C)), University Grants Commission—Special Assistance Programme—the Department Research Support (UGC SAP-DRS-II) (grant no. F.5-1/2018/DRS-II (SAP-II)), and the Department of Science and Technology—Promotion of University Research and Scientific Excellence Grant (DST-PURSE) (grant no. SR/PURSE Phase 2/38 (G)). Financial support was rendered through RUSA 2.0 (grant no. F. 24-51/2014-U, Policy [TNMulti-Gen], Department of Education, GoI). Financial assistance was given to AR. Kannappan by the University Grants Commission in the form of an UGC-BSR Fellowship (grant no. F.25-1/2014-15(BSR)/7-326/2011(BSR)).