Abstract

Neelofar Khanam*, G. K. Sharma

ABSTRACT

The present study evaluates and compares the efficiency of two widely used antimicrobial susceptibility testing methods, namely the disc diffusion method and the minimum inhibitory concentration (MIC), in determining the antimicrobial potential of Aloe vera L. extracts. Various clinically significant microorganisms, including bacteria (Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, etc.), fungi (Aspergillus spp.), and yeast (Candida spp.), were selected for the investigation. Crude extracts were prepared from both whole leaf and inner gel of Aloe vera L., derived from in vivo grown and in vitro regenerated plants. Different solvents such as ethyl acetate, methanol, chloroform, n-hexane, and water were used for extraction. Antimicrobial activity was assessed using the Kirby-Bauer disc diffusion technique, while MIC values were determined using the agar dilution method. Comparative analysis revealed that ethyl acetate extracts exhibited the highest antimicrobial activity against most tested pathogens, followed by methanol, chloroform, and n-hexane extracts. Aqueous extracts showed negligible or no inhibitory effect. The results obtained from both disc diffusion and MIC methods were largely consistent, although minor variations were observed due to differences in microbial susceptibility, extract diffusion, and solvent properties. The study confirms that Aloe vera L. possesses significant broad-spectrum antimicrobial properties, attributed to its bioactive phytochemicals. Furthermore, the findings highlight that MIC provides a more precise quantitative evaluation, whereas disc diffusion offers a rapid qualitative assessment. Overall, this comparative study supports the potential application of Aloe vera L. extracts in developing alternative antimicrobial agents and emphasizes the importance of method selection in antimicrobial testing.