Context: Pycnostachys abyssinica Fresen and Pycnostachys eminii Gürke (Lamiaceae) are used in traditional Ethiopian medicine against eye and skin infections, "Mitch disease", and dysentery.
Objective: Our study was aimed at characterizing essential oil (EO), phytochemical groups, and antimicrobial and anthelmintic activity of extracts to underscore the species' indigenous medicinal use.
Materials and methods: Plant organs of Pycnostachys species were subjected to hydrodistillation, and essential oils (EO) analyzed by GC-MS. Phytochemical compounds, antimicrobial (diffusion assay) and anthelmintic activity (bioassay) of gradient solvent extracts of different polarity were studied.
Results: In the stem and root EO of P. abyssinica, 25 (99%) and 30 (99.79%) compounds were detected respectively, with estragole (70.4%) (stem) and exo-fenchyl acetate (30.6%) (root) as the most abundant compounds. In leaf, stem and root EO of P. eminii, 30 (90.66%), 27 (90.59%) and 27 (99.96%) compounds were detected, respectively, with high levels of β-caryophyllene (from 18.08% to 28.85%) and germacrene D (from 15.1% to 22.06%). Alkaloids, saponins, phytosterols, flavonoids, polyphenols, diterpenoids and carotenoids were detected in Pycnostachys. Petroleum ether, chloroform and methanol extracts showed distinct antimicrobial effects with generally higher potential activity of lipophilic and semi-lipophilic fractions. Leaf and root methanol extracts of both species showed lethal activity against earthworms.
Discussion: Identified EO constituents and phytochemical groups underscore the observed antifungal, antibacterial and anthelmintic activity of Pycnostachys gradient solvent extracts.
Conclusion: EO analysis, phytochemical screening, and antimicrobial and anthelmintic assays indicate the biological potential of Pycnostachys species from Ethiopia, and emphasize their pharmacological and indigenous applications.