Phytochemical Screening and Antimicrobial Activity of Aqueous Stem Extract of Aloe vera on Some Common Pathogenic Bacteria

Abstract

Aloe vera is one of the most popular ethnomedicinal plants commonly used in treating many infectious diseases. However, the knowledge of the spectrum of antimicrobial activity of the plant and its bioactive components is still inadequate. In this study, we carried out an automated determination of phytochemical components in the aqueous extract (AE) of Aloe vera whole stem by GC-MS (Gas Chromatography-Mass Spectrometry), determined the in vitro antimicrobial activity of the extract on some common pathogenic bacteria, including Escherichia coli, Salmonella typhi, Enterococcus faecalis, and Staphylococcus aureus by the agar well diffusion method, and determined the minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) by the agar dilution method. The results showed that the extract has strong antimicrobial activity against all the test organisms. No resistance was observed. The ranges for zones of inhibition, MIC, and MBC were 12.33 ± 0.33–28.67 ± 0.60 mm, 25 mg/mL–50 mg/mL, and 50 mg/mL–100 mg/mL, respectively. The most susceptible isolate was S. typhi (MBC = 50 mg/mL), and the least sensitive isolate was E. faecalis (MBC = 150 mg/mL). The GC-MS analysis of the extract revealed nine different compounds, of which 82.82% were Palmitic acid methyl ester, (7Z)-7-Tetradecenal, Palmitin, 1,2-di-, 2-aminoethyl hydrogen phosphate, and Decyl hexanoate, with peak areas of 34.40%, 20.48%, 15.46%, and 12.48%, respectively. In conclusion, Aloe vera contains many broad-spectrum antimicrobially active compounds that can be further purified to produce new antimicrobial agents, particularly effective against S. typhi, S. aureus, and E. coli.