Comparative Chemical Composition and Antimicrobial Activities of The Essential Oils and Solvent Extracts of The Flower, Leaf, And Stem of Epilobium angustifolium Growing in Türkiye

Volatile organic compounds (VOCs) of essential oils (EOs) and solid phase microextract (SPME) obtained from the flower, leaf, and stem of Epilobium angustifolium L. were analyzed by GC-FID/MS. The EOs and SPMEs consist mainly of monoterpenes and aldehydes, which are major classes of compounds. Limonene was found to be a major compound in flower (HD: 42.9% vs. SPME: 95.5%), in leaf (HD: 60.3% vs. SPME: 4.7%), and in stem (HD: 49.06% vs. SPME: 93.6%). The antimicrobial activity of EOs and the solvent extracts (n-hexane, acetonitrile, and methanol) of E. angustifolium were screened in vitro against nine microorganisms. The EO of the leaf showed the best activity (10.2 µg/mL MIC) against Mycobacterium smegmatis. All the EOs and the solvent extracts gave moderate activity against the Staphylococcus aureus, Bacillus cereus, and M. smegmatis within the range of 10.2-1300.0 µg/mL MIC values. The best antibacterial activity was observed against S. aureus and B. cereus in the n-hexane extract of stem and methanol extract of flower samples.