Athamanta L. is a small genus of the Apiaceae family, comprising only sixteen species and subspecies, which are distributed in the Canary Islands, Central Europe, and the Mediterranean basin. Background/Objectives: Since the time of Dioscurides, the species of this genus have been reported to have had several ethnopharmacological activities, and some of them are also used currently. Athamanta sicula L., growing in Italy, Tunisia, Algeria, and Morocco, is the only species of this genus present in Sicily. To further explore the phytochemical profile and biological properties of this species, the present study focused on the essential oil (EO) extracted from the aerial parts of wild A. sicula populations collected in central Sicily. Methods: The chemical composition of the EO, obtained by hydrodistillation, was determined by GC–MS analysis. The presence of myristicin was confirmed by isolation and by ¹H-NMR spectroscopic characterization. Results: The EO and its main constituents have been tested for possible antimicrobial properties against several bacterial strains, showing MIC values in the of 15–30 mg/mL range, and the mechanism of action was further investigated, revealing membrane-targeting effects consistent with outer membrane permeabilization. In addition, antibiofilm activity (with up to ~80% inhibition of biofilm formation at sub-MICs), antioxidant potential (demonstrating dose-dependent radical scavenging activity), and biocompatibility with eukaryotic cells were assessed to provide a comprehensive pharmacological profile of A. sicula EO. Specifically, the most abundant constituent was myristicin (62.2%), the principal representative of the phenylpropanoid class (64.4%). Hydrocarbon monoterpenes represented the second class of the EO (27.4%), with β-phellandrene (12.2%) as the main compound. Conclusions: Myristicin emerged as the key contributor to the antimicrobial and antibiofilm activity of the EO. The obtained results highlight the relevance of A. sicula EO as a myristicin-rich essential oil with notable in vitro biological activity.

Helichrysum Mill. is one of the largest genera in the Asteraceae family, and in Madagascar, a plant paradise with ca 14,000 species, 111 Helichrysum species are known, 110 of which are endemic. In this work, the essential oil of endemic Helichrysum manopappoides Humbert, obtained by steam distillation, was investigated chemically and biologically. The spectrometric data obtained by GC-MS (Gas Chromatography–Mass Spectrometry) analysis highlighted the presence of three major compounds, such as eucalyptol (7.38 ± 0.36%), α-humulene (14.75 ± 0.79%), and β-caryophyllene (19.78 ± 0.89%), which were also structurally confirmed by NMR (Nuclear Magnetic Resonance) spectroscopic investigation. Biological results showed potential antimicrobial, antioxidant, and antibiofilm effects of both the H manopappoides essential oil and the main components identified by GC-MS, enhancing an interesting approach for intestinal infections, being active against Escherichia coli, Listeria monocytogenes, Shigella sonnei, and Salmonella enterica ser. typhimurium strains.

The increasing problem of antibiotic resistance is a critical global health issue, necessitating the development of alternative therapeutic strategies to manage infections effectively. Among the promising solutions are human antimicrobial peptides (AMPs), naturally occurring molecules known for their broad spectrum of antimicrobial activity. Background/Objectives: This study investigates the potential of some AMPs, selected through a bioinformatic approach, as alternatives to conventional antibiotics, particularly focusing on their efficacy against species within the Bacteroidota phylum. These species, including pathogens such as Porphyromonas gingivalis, Capnocytophaga ochracea, and Capnocytophaga canimorsus, are well known for their roles in various human infections and related diseases. Non-pathogenic environmental species, such as Flavobacterium johnsoniae, are also included in this group, frequently used as a model organism. Methods: By analyzing the antimicrobial efficacy, mechanisms of action, and potential therapeutic applications of human AMPs, this research underscores their significance in addressing the challenge of antibiotic resistance. Results: This study identified three peptides, KTL24, LIR23, and MFP22, as particularly interesting. These peptides are derived from specific human proteins, namely SPI1, NAPSA and SCUB1. Conclusions: Their notable antimicrobial potential suggests that AMPs could serve either as a complementary treatment alongside traditional antibiotics or as a standalone therapy, mitigating the ongoing spread of antibiotic resistance and offering an alternative in global health strategies.

The complex genus Achillea L. comprises more than 140 species distributed widely throughout the Northern Hemisphere. Several species are widely used in traditional medicine for their therapeutic properties, yet few studies have correlated their biological properties with the plant’s phytochemical composition. Among these, Achillea setacea Waldst. & Kit. is a perennial species traditionally used to treat digestive and inflammatory disorders. In this study, the essential oil of A. setacea, collected wild in North Macedonia, was analyzed spectrometrically and spectroscopically by GC-MS and NMR, respectively. A total of nineteen compounds were identified, with camphor (31.3%), 4-terpineol (11.3%), and eucalyptol (10.6%) being the main constituents. Furthermore, the biological activities of pure oil were evaluated, showing notable antioxidant properties, as well as antimicrobial effects against a panel of clinically relevant microorganisms, including Gram-positive and Gram-negative bacteria. Furthermore, its impact on human intestinal epithelial (Caco-2) cells was assessed, highlighting its potential relevance for gastrointestinal applications, in agreement with the traditional use of Achillea species for digestive disorders.

Several species of the genus Athamanta L. (Apiaceae) have been used since ancient times for their remarkable therapeutic properties and biological potential. Among them, Athamanta sicula L. is the only species of this genus found in Sicily, Italy. This study highlights the chemotaxonomic variability of the essential oils of this species by correlating chemical results with environmental and geographical data. Chemical analysis by GC-MS confirmed the predominance of apiol (47.5%), while spectroscopic analysis confirmed both the spectrometric characterization of the entire essential oil and the analytical purity of the isolated apiol. Biological assays showed that the apiol-rich essential oil retained antimicrobial and antibiofilm activities comparable to those of the previously characterized myristicin-rich chemotype, while displaying enhanced activity against Pseudomonas aeruginosa. Membrane-permeabilization assays supported membrane damage as a major antibacterial mechanism, whereas antioxidant tests revealed a more efficient scavenging response of the apiol-rich chemotype at lower concentrations. Overall, these findings suggest that climate-associated chemotypic variation modifies specific functional traits without substantially compromising the biological activity of the essential oil.