Detection Of Antimicrobial Compounds Research Articles

Antimicrobial Activities of Essential Oils Extracted from the Leaf Materials of Selected Zingiberaceae Plants of Vizianagaram District, AP, India and Detection of Antimicrobial Compounds

Antimicrobial Activities of Essential Oils Extracted from the Leaf Materials of Selected Zingiberaceae Plants of Vizianagaram District, AP, India and Detection of Antimicrobial Compounds

TLC-Bioautographic Detection of Antimicrobial Compounds in Essential Oils of Selected Ocimum Species

:The present study was intended to identify antimicrobial compounds of Ocimum basilicum, Ocimum gratissimum and Ocimum sanctum using TLC-bioautography, followed by gas chromatography-high resolution mass spectrometry analysis. Antimicrobial screening was performed with disc diffusion and broth dilution methods using 16 bacterial strains and a fungal strain Candida albicans. Among three test oils O. gratissimum was found to be potentially antimicrobial followed by O. basilicum and O. sanctum. TLC-bioautographic studies revealed that, eugenol, linalool and citral have been identified as major antimicrobial compounds. In order to substantiate the results of TLC-bioautography, all the three commercially procured major compounds were tested individually and combinatorially. Among them; citral found to be potentially active antimicrobial followed by eugenol and linalool. The activities of tested compound combination were nearly matched with the individual essential oil. In the test bacteria, A. baumannii found to be the most sensitive to all test oils; the zone of inhibition (ZOI) ranging from 46±1.73 to 30.3±1.53 mm and the most resistant were K. pneumonia, E. faecalis and P. aeruginosa. Potential anticandidal activity was also observed with all three test oils and the ZOI ranging from 41±2 to 18.3±0.58 mm. The results of broth dilution confirmed the results of disc diffusion with certain deviations.

Detection of antimicrobial compounds by bioautography of different extracts of leaves of selected South African tree species.

The hexane, acetone, dichloromethane and methanol extracts of Combretum vendae A.E. van Wyk (Combretaceae), Commiphora harveyi (Engl.) Engl. (Burseraceae), Khaya anthotheca (Welm.) C.DC (Meliaceae), Kirkia wilmsii Engl. (Kirkiaceae), Loxostylis alata A. Spreng. ex Rchb. (Anacardiaceae), Ochna natalitia (Meisn.) Walp. (Ochnaceae) and Protorhus longifolia (Bernh. Ex C. Krauss) Engl. (Anacardiaceae) were screened for their antimicrobial activity. The test organisms included bacteria (Enterococcus faecalis, Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus), and fungi (Aspergillus fumigatus, Candida albicans, Cryptococcus neoformans, Microsporum canis and Sporothrix schenckii). A simple bioautographic procedure, involving spraying suspensions of the bacteria or fungi on thin layer chromatography (TLC) plates developed in solvents of varying polarities was used to detect the number of antibacterial and antifungal compounds present in the extracts. All the extracts had antimicrobial activity against at least one of the test microorganisms. This activity was denoted by white spots against a red-purple background on the TLC plates after spraying with tetrazolium violet. Twenty seven TLC plates; 9 for each solvent system and 3 different solvent systems per organism were tested in the bioautographic procedure. Of the bacteria tested, S. aureus was inhibited by the most compounds separated on the TLC plates from all the tested plants. Similarly, growth of the fungus C. neoformans was also inhibited by many compounds present in the extracts. Loxostylis alata appeared to be the plant extract with the highest number of inhibition bands when compared with other plants tested against both bacteria and fungi. This species was selected for in depth further study.