Anti-quorum sensing, antibiofilm, and antibacterial activities of extracts of Centella asiatica L. leaves, and in vitro derived leaves-calli through tissue culture: a potential for biofouling-prevention

Abstract

Extracts of Centella asiatica leaves (LEs), and in-vitro leaf-calli (CEs), were investigated for antibacterial, antibiofilm, and anti-quorum sensing activities. Ethyl acetate extracts from leaves (EALE), leaf-calli (EACE), methanolic extracts from leaves (MELE), and leaf-calli (MECE) showed antibacterial activity; the minimum inhibitory concentrations (MICs) of LEs and CEs ranged from 0.312–2.50 mg ml⁻¹ and 0.625 − 2.50 mg ml⁻¹, respectively. The MICs of EALE and EACE were 2.50 mg ml⁻¹, each, for C. violaceum 12742, and P. aeruginosa PAO1. At sub-MIC levels, EALE and EACE showed anti-quorum sensing (anti-QS) activity, demonstrated by concentration dependent pigment inhibition of C. violaceum 12742. Similarly, EALE and EACE inhibited QS-controlled virulence factors in P. aeruginosa PAO1 (biofilm, pyocyanin, and pyoverdin); again, the inhibition was concentration-dependent. The best effect was at immediate sub-MIC concentration i.e. 1250 µg ml⁻¹. GC-MS analyses revealed the presence of compound 9,12-Octadecadienoic acid, and in silico docking study suggested interactions with QS-receptors CviR', LasI, and LasR proteins for anti-QS activity.

Keywords:

• Centella asiatica
• quorum sensing
• antibiofilm
• phytoconstituents
• GC-MS

Acknowledgements

The authors are grateful to the Advanced Instrumentation & Research Facility (AIRF), JNU, New Delhi for the GC/MS analysis of the plant extract. We are also thankful to AMU's University Sophisticated Instruments Facility (USIF) for electron and confocal microscopic analysis. Mo Ahamad Khan is grateful to the University Grants Commission (UGC) in New Delhi, India, for granting a Non-NET fellowship. The secretarial assistance by Tomy Kaitharath is highly appreciated. The numerical calculations reported in this paper were partially performed at TUBITAK ULAKBIM, High Performance and Grid Computing Center (TRUBA resources). This work is a part of Ph.D. experimentation of Mo Ahamad Khan under the supervision of Prof. Mohammad Shahid and Prof. H.M. Khan.

Authors’ contribution

MS and MAK conceptualized the idea. MAK, IBG, and SK collected the specimens. MAK, IBG, IC, and SK mainly undertook the experimental work. IBG and AS mainly performed tissue culture-related experimentation and its analyses. MS, HMK, MAK, and SK analyzed and interpreted the bacterial identification and antibiotics susceptibility data. MAK and IC analyzed the molecular data. MS and MAK analyzed and interpreted the QS-related data. MS and MAK wrote the first draft of the manuscript. MS edited, modified, and prepared the final draft. All authors reviewed, verified, and approved the final draft for submission.

Disclosure statement

No potential conflict of interest was reported by the authors.

Funding

The author(s) reported there is no funding associated with the work featured in this article.