Sesquiterpene-Rich Essential Oil From Magnolia officinalis Stem Bark: Chemical Composition, Biological Activities,...

The stem bark essential oil of Magnolia officinalis (M. officinalis) Rehder & E.H. Wilson was investigated for its chemical composition, biological activities, and in silico interactions. From the GC-FID/MS analysis, the sample was dominated by sesquiterpene hydrocarbons (85.38% ± 0.04%). The major constituents were (E)-caryophyllene (21.69% ± 0.020%), α-selinene (10.13% ± 0.016%), (Z)-β-farnesene (7.07% ± 0.011%), β-selinene (6.81% ± 0.006%), γ-muurolene (6.15% ± 0.008%), α-humulene (6.13% ± 0.007%), and δ-cadinene (5.26% ± 0.006%). Remarkably, this is the first report demonstrating the α-glucosidase inhibitory activity of M. officinalis stem bark essential oil, which exhibited significant activity (IC₅₀ = 188.98 ± 5.60 µg/mL), exceeding that of the standard compound acarbose (IC₅₀ = 240.06 ± 4.32 µg/mL). In addition, the essential oil possessed cytotoxicity against MCF-7 and HepG2 cancer cell lines, DPPH radical scavenging, anti-inflammatory activity against NO and PGE2 productions, and antimicrobial activities. Molecular docking analysis revealed that the major compounds exhibited moderate to strong binding affinities toward α-glucosidase, with binding energies ranging from -5.6 to -6.9 kcal/mol, comparable to acarbose, and predominantly stabilized by hydrophobic interactions. In addition, γ-muurolene and δ-cadinene emerged as the most promising candidates, combining strong binding affinity with optimal ADMET characteristics.