Al-Gharaibeh, M. | Search bioRxiv

bioRxiv2025

Hypericum triquetrifolium Essential Oil: Chemical Composition, Hierarchical Cluster Analysis, and Antibacterial Activity

Plant species belonging to the genus Hypericum are well known for their profound pharmacological activities. This study evaluated the in vitro antibacterial activity and the chemical composition of the essential oil of Hypericum triquetrifolium Turra (Hypericaceae) that was collected from the Northern part of Jordan. The aerial parts of H. triquetrifolium were subjected to hydrodistillation to obtain a yellowish essential oil with a yield of 0.023% (w/w of dried material). The chemical composition of the oil was explored using gas chromatography-mass spectrometry (GC-MS). Forty-five compounds accounting for 99.5% of the oil composition were identified. The main classes identified were monoterpenes with 52.3% (49.6% as monoterpene hydrocarbons and 2.7% as oxygenated monoterpenes), aliphatic hydrocarbons 35.4%, and sesquiterpenes 11.8% (10.9% as sesquiterpene hydrocarbons and 0.9% as oxygenated sesquiterpenes). The oil was predominated with -pinene (40.0%), which was identified as a chemotype for Jordanian H. triquetrifolium. Other major constituents included n-nonanal (10.1%), nonane (9.0%), 4Z-hepten-1-ol (5.8%), 4-methyl-pentanol (5.1%), and {beta}-pinene (4.6%). The antimicrobial activity of the oil was evaluated using a micro broth dilution assay against a set of Gram-positive and Gram-negative pathogens. The oil exhibited antimicrobial activity against the tested strains with minimum bactericidal concentration (MBC)/minimum inhibitory concentration (MIC) values of 12.5/6.25, 6.25/3.125, 6.25/3.125 and 3.125/1.56 g/L, respectively. Finally, Hierarchical Cluster Analysis of the essential oil composition of H. triquetrifolium from different geographical locations in the world has identified the oil from Jordan to be more similar to those obtained from Italy, Greece, and Crete.

pharmacology and toxicology↗

bioRxiv2023

Clinal variation in drought response is consistent across life stages but not between native and non-native ranges

Clinal variation, i.e., intraspecific variation that corresponds to environmental gradients, is common in widely distributed species. Studies on clinal variation across multiple ranges and life stages are lacking, but can enhance our understanding of specie[s] adaptive potential to abiotic environments and may aid in predicting future species distributions. This study examined clinal variation in drought responses of 59 Conyza canadensis populations across large aridity gradients from the native and non-native ranges in three greenhouse studies. Experimental drought was applied to recruitment, juveniles, and adult stages. Drought reduced growth at all three life stages. However, contrasting patterns of clinal variation emerged between the two ranges. Native populations from xeric habitats were less inhibited by drought than mesic populations, but such clinal variation was not apparent for non-native populations. These range-specific patterns of clinal variation were consistent across the life stages. The experiments suggest that invaders may succeed without complete local adaptation to their new abiotic environments, and that long-established invaders may still be evolving to the abiotic environment. These findings may explain lag times in some invasions and raise concern about future expansions.

evolutionary biology↗