Essential Oil from Magnolia braianensis (Gagnep.) Figlar leaves growing wild in Vietnam: Chemical Analysis, Antimicrobial, and Antioxidant Activities

Magnolia braianensis (Gagnep.) Figlar is an endemic species native to Vietnam. To date, its essential oil's chemical composition and biological activity have not been studied. This study aimed to investigate the chemical composition and biological activities of the leaf essential oil from M. braianensis. The chemical composition was analyzed using GC/MS, while antimicrobial activity was evaluated through a microdilution broth assay. Additionally, the ABTS+ and DPPH scavenging assays were conducted to assess the essential oil's antioxidant potential. The results show that twenty‐four compounds were identified in the essential oil, with oxygenated sesquiterpenes being dominant at 53.6%. The major compounds were α‐selinene (17.9%), flourensadiol (13.7%), germacrene D (10.0%), globulol (9.7%), β‐elemene (8.4%), carotol (5.7%), and pogostol (5.7%). The essential oil inhibited only B. subtilis and S. aureus (IC50: 61.28 ± 2.7 μg/mL and 169.5 ± 7.98 μg/mL, respectively), showing minimal effect on other strains. The essential oil demonstrated significant DPPH radical scavenging activity, with an SC50 value of 98.81 µg/mL. However, it exhibited poor antioxidant activity in the ABTS assay, as indicated by an SC50 value exceeding 100 µg/mL. For the first time, this report explores the chemical composition, antimicrobial, and antioxidant potential of essential oils extracted from M. braianensis leaves.