Abstract
This study compared hydrodistillation and steam distillation for the extraction of essential oil from Commiphora myrrha resin and evaluated differences in yield, chemical composition, antioxidant activity, and antimicrobial activity. Steam distillation produced a higher essential-oil yield (3.25%) than hydrodistillation (1.25%). Hydrodistillation produced a pale-yellow oil with a density of 0.8766 g/cm³, whereas steam distillation produced a golden-yellow oil with a density of 0.8791 g/cm³. GC-MS analysis identified 69 components in the steam-distilled oil and 76 components in the hydrodistilled oil. The principal constituents of the steam-distilled oil were alpha-pinene (24.54%), terpinen-4-ol (13.21%), beta-ocimene (11.80%), caryophyllene (4.50%), and humulene (4.11%). The hydrodistilled oil was characterised mainly by alpha-pinene (28.54%), 3-carene (16.24%), terpinen-4-ol (9.07%), sabinene (5.55%), and o-cymene (5.42%). In the DPPH assay, steam-distilled oil showed significantly greater radical-scavenging activity than hydrodistilled oil at all tested concentrations (p < 0.05). Total antioxidant capacity was also higher for steam-distilled oil (0.32 ± 0.019 mg ASAeq/mg dw) than for hydrodistilled oil (0.249 ± 0.003 mg ASAeq/mg dw). Antimicrobial responses varied according to microorganism and concentration; hydrodistilled oil produced larger inhibition zones in several bacterial comparisons and against Candida albicans at 25%, whereas some comparisons showed no significant difference. The findings demonstrate that the extraction method influenced oil yield, volatile composition, and the measured biological activities under the tested conditions.