This study aimed to determine the chemical compositions and antioxidant and
antimicrobial activities of thyme (Thymus vulgaris L.) and oregano (Origanum
vulgare L.) cultivated in Egypt. The results conducted that the major constituents of the thyme essential oil were thymol (45.19%), p-cymene (13.59%), carvacrol (7.65%)and γ-terpinene (6.82%), while carvacrol (52.46%), terpine-4-ol (7.43%), terpineol,cis-beta (5.64%) and γ-terpinene (4.73%) were the major components of oregano essential oil by GC-MS analysis. The essential oils of thyme and oregano contained appreciable levels of total phenolic contents (228.78 and 129.43 mg PE/g) and showed good activity in DPPH radical scavenging with IC50 (68.95 and 96.47
mg/mL). Both extracts contained lower total phenolic contents (123.68 and 138.26 mg
PE/g) than the essential oils but exhibited very strong DPPH radical scavenging
capacity with IC50 (0.438 and 0.984 mg/mL, respectively). In addition, extracts and
the essential oils proved great antimicrobial properties against human and plant
pathogenic microorganisms. Klebsiella pneumonia was the most sensitive
microorganism of oregano and thyme extracts (200μg/mL) with 35.8±0.89 and
37±0.47 mm inhibition zones, respectively. Thyme essential oil had the highest effect on Rhodotorula mucilaginosa with 25.7±0.27 mm, while oregano 16.5±0.24 mm on
Aspergillus flavus.