Allium sativum linn. contains linear alkylbenzene sulfonates that alter membrane fluidity for the inhibition of Mycobacterium tuberculosis H37RA

Abstract

Objectives: The purpose of the study is to characterize antimycobacterial phytoconstituent from ethyl acetate extract of dried bulbs of Allium sativum Linn. (Alliaceae) and elucidating the probable mode of action of the bioactive molecule. Methods: Serial extraction, Mycobacterium tuberculosis assay by agar well diffusion method, minimal inhibitory concentration by microplate alamar blue assay, Fourier Transform Infrared (FT-IR), Nuclear Magnetic Resonance (NMR) spectroscopy, Liquid Chromatography (LC)-electrospray ionization (ESI)-mass spectrometry (MS)/MS, cell leakage assay, Scanning Electron Microscopy (SEM), inhibition property of Linear Alkylbenzene Sulfonate (LAS) in the presence of rifampicin on M. tuberculosis were performed. Results: Ethyl acetate extract displayed significant inhibition properties against M. tuberculosis H37Ra (MTCC 300). Subsequently, the bioactivity-guided fractionation was employed to purify the phytochemical. Analysis of FT-IR, LC-MS (ESI), ¹H and ¹³C-NMR spectrum revealed that the bioactive phytochemicals are the variants of LAS, with C₁₂-alkyl being predominant, and the minimum inhibitory concentration was found to be 5.56 μg/ml. Morphological examination by SEM and cell leakage assay indicated that these molecules change the membrane fluidity. Conclusion: The results thus suggest the possibility of using low concentrations of LAS to effect changes in membrane fluidity, thereby enhancing the efficacy of antibiotic treatment.