Biological Activities and GC-MS Analysis of Aloe vera and Opuntia ficus-indica Extracts

To evaluate the potential antimicrobial activity, Aloe vera and Opuntia ficus-indica plants were collected from the Jeddah, Al Baha, and Taif areas of the Kingdom of Saudi Arabia (SA), and their ethanolic extracts were screened by gas chromatography mass spectrometry (GC-MS/MS). The di(2-propylpentyl) ester and hexadecenoic acid ethyl ester of phthalic acid were the most abundant compounds in the A. vera extract, and 1-(benzyloxy)-3,5-dinitrobenzene and phenol, 5-ethenyl-2-methoxy were the most abundant compounds in the O. ficus-indica extract. The antimicrobial activity of aqueous and ethanolic extracts of these plants against seven fungi and five pathogenic bacteria was also tested. Among all the tested fungi, A. chevalieri showed the largest inhibition zone when treated with the A. vera gel ethanolic extract, followed by P. funiculosum and P. minioluteum, which were more sensitive to and showed larger inhibition zones upon treatment with aqueous extract. For the O. ficus-indica ethanolic extract, T. funiculosus showed the largest inhibition zone. The aqueous extract of the O. ficus-indica showed low antimicrobial activity against all tested fungi. By contrast, both the A. vera and O. ficus-indica extracts showed antibacterial activity against S. aureus, Shigella sp., E. coli, and MRSA except S. typhimurium, which was the most resistant bacterium to both the aqueous and ethanol extracts of A. vera and O. ficus-indica.