Ethnobotany, Biological Activities and Phytochemical Compounds of Some Species of the Genus Eryngium (Apiaceae), from the Central-Western Region of Mexico

Chemical Composition of the Essential Oils of the Iberian Peninsula Endemic Species Eryngium dilatatum Lam

Eryngium dilatatum Lam. is a thorny Iberian Peninsula endemic species belonging to the Apiaceae family that has not been previously analysed from a chemical point of view. Following our studies on this genus, we characterized the chemical composition of the essential oils from the different parts (inflorescences, stems + leaves, and roots) of this species; these parts were gathered in Cádiz (Spain). The specimens were collected in July during the flowering period and air-dried before the oil extraction by hydro-distillation. The essential oils were analysed by gas chromatography and gas chromatography coupled with mass spectrometry. The different parts of the plant yielded low amounts of pale yellow oil, with the roots being the fraction that provided the lowest amount of oil. The chemical characterization of the essential oils showed qualitative and quantitative differences between the fractions examined, but all of them showed the same principal compound, germacrene D (9.1-46.5%). Similarly, all the fractions shared most of their representative constituents, with their percentage compositions being different from one sample to the other: α-cadinol (3.8%), bicyclogermacrene (3.5%), octanal (3.1%), and spathulenol (2.5%) were found in the inflorescences; octanal (8.1%), α-cadinol (3.7%), δ-cadinene (3.6%), (E)-caryophyllene (2.6%), bicyclogermacrene (2.5%), and spathulenol (2.4%) were found in the stems and leaves; and spathulenol (4.6%), α-cadinol (4.4%), khusinol (3.2%), α-muurolol (3.1%), and δ-cadinene (2.6%) were found in the roots. As far as we know, this is the first report about the chemical composition of this endemic species of the Iberian Peninsula. It contributes to the knowledge of this species and to the genus to which it belongs. This species could be considered as a natural source of germacrene D, which is a sesquiterpene hydrocarbon with active properties.

Identification of the chemical profile and evaluation of the antimicrobial effect of Eryngium billardieri Delar essential oil component against bacterial species of agricultural and food interest

Studies on the antibacterial activity of the essential oil of E. billardieri are limited. In this study, we identified this herb as a natural complex effective against several bacteria by employing disk diffusion and broth microdilution susceptibility methods. Primary estimation of the antimicrobial effect of this herbal compound by disk diffusion method showed that the oil could inhibit the growth of the tested bacteria by the appearance of haloes between 8.25 and 21.25 mm. In the next step, the oil was found to be active against all 24 tested Gram-negative and Gram-positive bacteria in the broth media, at minimum inhibitory concentrations ranging from 0.67 to 34.17 g L-1. Furthermore, Enterococcus faecalis and Curtobacterium flaccumfaciens pv. flaccumfaciens were the most sensitive food and plant pathogenic bacteria, respectively. Gas chromatography-mass spectrometry analysis was conducted to assign the ingredients present in the oil; 34 different components representing 95.71% of the total oil were identified, with n-hexadecanoic acid being the dominant component, followed by 2-Pentadecanone, 6,10,14-trimethyl, 1H-Indene, 1-ethylideneoctahydro-, and Cinnamyl tiglate. These findings demonstrate, for the first time, a broad spectrum of the antibacterial capacity of E. billardieri. Based on these observations, the oil could be applied as a natural preservative with the potential for designing novel products. Its bioactive agents can also be isolated for further use in the food and agricultural industries.

Effects of Annual Growth Conditions on Phenolic Compounds and Antioxidant Activity in the Roots of Eryngium montanum

Medicinal plants grown in natural settings are exposed to different adverse environmental conditions that determine their growth and development as well as the composition and concentration of secondary metabolites in their organs. The objective of this study was to evaluate the effects of environmental conditions associated with localities and annual growth cycles on the contents of phenolic compounds and flavonoids, antioxidant activity and potentially bioactive phenolic acids in the roots of Eryngium montanum, a medicinal species from temperate Mexico. The samples for composition analysis were collected using a bifactorial design: Factor A consisted of the localities (Morelos and La Unión de San Martin Huamelulpam, Mexico) and Factor B was represented by the annual growth cycle (2020 and 2021). In each sample, the contents of polyphenols and equivalent flavonoids of quercetin and catechin and antioxidant activity were evaluated using spectrophotometry. Subsequently, chlorogenic, caffeic and rosmarinic acids were identified and quantified using high-performance liquid chromatography with diode-array detection (HPLC-DAD). The annual growth conditions and, to a lesser extent, the locality of origin of the samples significantly influenced the contents of phenolic compounds and antioxidant activity. The environmental conditions that occurred in 2021 favored an increase in the contents of phenolic compounds compared to those in 2020, and the same pattern was observed for chlorogenic acid; however, for caffeic and rosmarinic acids, the opposite pattern was observed. The content of phenolic acids in the roots of E. montanum follows different and independent patterns between cycles based on the interaction between the locality of origin and annual growth cycle. This study quantifies the magnitude of the total environmental effect on the phenolic compound concentrations in E. montanum roots, which was measured via sampling during two annual growth cycles, where the sampling locations factor had little influence. The bioactive compounds identified in E. montanum roots have the potential for use as alternative medicines, as mentioned by different families from Oaxaca, Mexico.