Variations in chemical constituents and bioactivities of essential oils within <i>Elatostema stewardii</i> Merr. revealed by GC-MS-based metabolomics

Elatostema stewardii
Merr., an endemic species in China, is valued for its medicinal and food uses, yet its chemical compositions and biological activities remain unexplored. This study aims to analyze the essential oils (EOs) obtained from different plant parts (leaves, stems, and roots) of
E. stewardii
by gas chromatography-mass spectrometry (GC-MS)-based metabolomics. Collectively, 96 EO constituents were identified, primarily consisting of fatty acids (trace-61.56%), diterpenes (3.47-32.39%), alkanes (7.79-16.32%), and ketones (1.46-12.00%). Major constituents included
n
-hexadecanoic acid (trace-60.58%), 2-methyloctadecane (4.63-12.31%), phytol (0.19-12.00%), and 6,10,14-trimethyl-2-pentadecanone (1.39-9.92%). Multivariate analyses principal component analysis (PCA) and partial least squares-discriminant component analysis (PLS-DA) revealed significant EO chemical variations in plant parts, identifying 15 key differential constituents such as
n
-hexadecanoic acid, 3,5,11,15-tetramethyl-1-hexadecen-3-ol, and linoleic acid. Bioactivity assays demonstrated significant differences among the EOs, with the leaf-derived EO exhibiting the strongest cytotoxicity (IC
50
: 36.58-69.23 μg mL
-1
), anti-inflammatory effects (IC
50
: 47.03 μg mL
-1
for NO inhibition), and antioxidant capacity (IC
50
: 0.08, 0.33 mg mL
-1
for ABTS, DPPH scavenging, respectively; FRAP: 2.95 mmol Fe
2+
/mL). Correlation analysis showed that compounds like
β
-ionone-5,6-epoxide and neophytadiene were positively associated with these bioactivities. These findings highlight substantial chemical and bioactivity differences among
E. stewardii
EOs, identifying the leaf EO as a promising pharmaceutical candidate and demonstrating the effectiveness of GC-MS-based metabolomics in investigating
Elatostema
EOs.