Thin-layer chromatography in bioassays of antimicrobial compounds from plants

Growing antibiotic resistance creates a need to find new antimicrobial agents characterized by diverse chemical structures and pharmaceutical activity. The higher plants synthesize many specialized metabolites as a part of their normal metabolic activity and have been extensively used for centuries in treatment of different diseases. They have a wide activity range depending on the species, topography and climate, and may have different categories of active principles. In contrast to conventional antimicrobial techniques, planar chromatography in combination with biological detection can be an appropriate method of choice for fast, simple, and low-cost screening of plant extract for successful detection of antimicrobial agents which can be good candidates for lead compounds. To date, all bioautography steps such as chromatographic separation, detection with bacteria cells, incubation, and visualization of bioactive bands were improved and optimized. This review gives an overview of bioautography procedure from extraction to structure elucidation of antimicrobial compounds from plants.