From Chemical Composition to Biological Activity: Phytochemical, Antioxidant, and Antimicrobial Comparison of <em>Matricaria chamomilla</em> and <em>Tripleurospermum inodorum</em>

Matricaria chamomilla and Tripleurospermum inodorum are closely related Asteraceae plants that share morphology but differ in chemistry and bioactivity. This study investigated both species using an integrative approach combining microscopy, phytochemical profiling, and biological evaluations. Phenolic and flavonoid contents were quantified spectropho-tometrically, and essential oils analyzed by hydrodistillation–GC–MS. Antioxidant activity was determined using the DPPH assay, and antimicrobial effects assessed. Microscopy confirmed diagnostic differences. M. chamomilla contained more polyphenols (20.48 vs. 17.88 mg GAE/g DW), whereas T. inodorum showed higher flavonoid levels (15.93 vs. 13.87 mg RE/g DW). Their oils exhibited distinct chemotypes: in M. chamomilla, oxygenated ses-quiterpenes predominated (76.8%), mainly bisabolol oxide A (39.5%), bisabolol oxide B (18.7%), bisabolone oxide A (12.7%), β-farnesene (8.0%), trans-lachnophyllum ester (6.2%), and chamazulene (4.2%); in T. inodorum, the oil was dominated by β-farnesene (11.6%) and cis-lachnophyllum ester (11.6%), with a late signal tentatively assigned to 1,3-naphthalenediol. Antioxidant activity was moderate (IC₅₀ 17.7–21.5 µg/mL for M. chamomilla; 8.4–10.2 µg/mL for T. inodorum). Antimicrobial tests showed T. inodorum active against S. aureus and C. albicans, while M. chamomilla was effective only against C. albicans. These results underline chemical markers differentiating the taxa and support T. inodorum as a complementary source of bioactive compounds.