Biochemical Aspect, Antimicrobial and Antioxidant Activities of Melaleuca and Syzygium Species (Myrtaceae) Grown in Egypt

The objective of the present work was to establish the antimicrobial activity of four species of Melaleuca (i.e. Melaleuca leucandron, Melaleuca armillaris, Melaleuca linarifolia, & Melaleuca ericifolia) methanolic extracts and five species of Syzygium (i.e., Syzygium samaragense, Syzygium jambos, Syzygium gratum, Syzygium paniculatum & Syzygium malaccense). To research the chemical composition of the most promising extracts, as well. The antimicrobial activity was evaluated against four pathogenic microbial strains, namely Staphylococcus aureus, Escherichia coli, Candida albicans and Aspergillus niger, the antioxidant activity was evaluated by 2,2'-diphenyl-1-picrylhydrazyl radical (DPPH), while the chemical composition was calculated by gas chromatography coupled to a mass spectrometry method (GC/MS). For the genus of Melaleuca, S. After therapy, aureus pathogens were inhibited with their methanolic extracts with an 8.0-20.0 mm range of inhibition zones, E. Coli with a 0.0-21.0 mm inhibition zone size, C. Albicans with an inhibition zone size of 9.0-18.0 mm, and A. Niger with an inhibition zone scale of 0.0-15.0 mm. Whereas, for the genus Syzygium, S. After treatment with their methanolic extracts, aureus pathogens were inhibited with a 10.0-20.0 mm range of inhibition zones, E. Coli, with an inhibition zone size of 0.0-14.0 mm, C. Albicans with an inhibition zone size of 0.0-21.0 mm, and A. Niger with a range of inhibition zones of 0.0-9.0 mm. The IC50 values in the DPPH assay ranged from 34.60 to 60.97μg/ml for the species Melaleuca. The IC50 values for the Syzygium species ranged from 29.81 to 52.95μg/ml compared to 7.35μg/ml for the normal ascorbic acid. GC/MS research showed that Syzygium gratum's methanolic extract consists of 39 compounds comprising 99.08 percent, with Veridiflorol (7.16 percent) and 2-methyl, 3-Hexanone being the main compounds (5.74 percent ). While Melaleuca armillaris' methanolic extract consists of 30 compounds comprising 97.66%, with Veridiflorol (18.36%) and Globulolol compounds being the key compounds (12.57 percent ).