Thiophenes from Echinops latifolius

Evaluation of antioxidant and antibacterial properties of dehydrocostus lactone isolated from Echinops kebericho root

Background and Aim

Echinops kebericho, an endemic plant to Ethiopia, traditionally used to treat infectious as well as noninfectious diseases. The primary objective of this study was isolating dehydrocostus lactone (DHCL) from E. kebericho and evaluating antibacterial activities on selected human pathogenic bacteria.

Methods

Extraction method used in this study was maceration. Based on the bioassay information methanol extract of the root of E. kebericho was subjected to column chromatography on silica gel by increasing solvent gradients to isolate DHCL. Optimized amount isolation of DHCL was done by dissolving methanol crude extract by hexane followed by recrystallization at room temperature in the dark place. Different concentrations of the extract were subjected by disc diffusion method against tested bacterial species and antioxidant activity test.

Results

The phytochemical analysis of E. kebericho revealed a high presence of terpenoids, which are diverse natural compounds known for their antimicrobial and antioxidant properties. This suggests that terpenoids contribute significantly to the pharmacological effects of E. kebericho. In antibacterial testing, Escherichia coli was the most sensitive bacterium among all extracts and concentrations. The methanol extract displayed higher antioxidant activity compared to ethyl acetate and hexane extracts, indicating a higher concentration of antioxidant compounds. Notably, the isolated compound DHCL showed promising activity against tested pathogens and significant antioxidant activity. The higher activity of DHCL compared to the crude extracts suggests its responsibility for the observed effects, indicating that the isolation and purification process may have concentrated its beneficial properties. These findings highlight the potential of E. kebericho and DHCL as sources of bioactive compounds for therapeutic applications.

Conclusion

All tested extracts and pure compound showed higher inhibition than positive controls in both bioassay. DHCL the principal bioactive component in the root extract of the plant and it displayed potent antibacterial and antioxidant activity.

Echinops taeckholmiana Amin: Optimization of a Tissue Culture Protocol, Biological Evaluation, and Chemical Profiling Using GC and LC-MS

There have been no reports published on the rare Echinops taeckholmiana growing wildly in Egypt. So, this study aimed to preserve it through method optimization of in vitro seed germination, besides callus formation from induced seedlings. Chemical profiling using gas chromatography-mass spectrometry (GC-MS) analysis of the n-hexane fraction afforded 29 identified components, mainly fatty acids esters, sesquiterpenes, triterpenes, one thiophene, and bis(2-ethylhexyl) phthalate. Ultra-performance liquid chromatography-electron spray ionization/tandem mass spectrometry (UPLC-ESI/MS-MS) analysis of total alcoholic root and induced calli extracts resulted in 68 metabolites. Taraxeryl acetate, β-sitosterol, stigmasterol-3β-d-glucoside, and 1,1,1-kestopentaose were identified from the defatted root extract, which inhibited α-amylase (IC50 54.6 μg/mL) and α-glucosidase (60.4 μg/mL) enzymes compared with acarbose (IC50 values of 30.57 and 34.71 μg/mL, respectively). Moreover, it showed moderate activity against HepG2 (IC50 31.1 ± 1.4 μg/mL) and no activity against M-NFS-60 cell lines compared to cisplatin (IC50 3.25 ± 1.4 and 8.37 ± 0.25, respectively).

Novel Bithiophene Dimers from Echinops latifolius as Potential Antifungal and Nematicidal Agents

Three novel dimeric bithiophenes, echinbithiophenedimers A-C (1-3), along with two known thiophenes, 4 and 5, were obtained from Echinops latifolius, and their structures were identified through extensive spectroscopic analysis and electronic circular dichroism calculations. Compounds 1-3 possessed new carbon skeletons; they are dimeric bithiophenes with 1 and 2 featuring an unprecedented 1,3-dioxolane ring system and 3 featuring an unusual 1,4-dioxane ring. These compounds are the first examples of bithiophene dimers furnished by different cyclic diethers. Dimeric bithiophenes 1-3 had good antifungal activities against five phytopathogenic fungi, and compound 3 showed excellent activity against Alternaria alternate and Pyricularia oryzae, with a minimal inhibitory concentration value of 8 μg/mL, which was close to or higher than that of carbendazim. Moreover, its effect on the mycelial morphology was observed by scanning electron microscopy. Compounds 1-3, which were demonstrated to be nonphototoxic thiophenes, exhibited better nematicidal activity than the commercial nematicide ethoprophos against Meloidogyne incognita. This study revealed that dimeric bithiophenes containing 1,3-dioxolane or 1,4-dioxane rings could be used as novel antifungal and nematicidal agents for controlling plant fungal and nematode pathogens.

Pharmacokinetics study of 16 active ingredients from Tabson-2 decoction in normal and d-galactose induced osteoporosis rats by liquid chromatography-tandem mass spectrometry

Tabson-2 decoction is the traditional Mongolian formula for anti-osteoporosis, and the ambiguous of active ingredient is an important factor in restricting its modernization and globalization. Although pharmacokinetic profiles research is a viable approach to find the components being responsible for formula efficacy, the pharmacokinetics study of Tabson-2 decoction has not been elucidated yet. Owing to the existence of isomers, low bioavailability of some small molecule and interference of endogenous, the pharmacokinetics study of Tabson-2 decoction are more difficult than that of chemical drugs. In our experiment, a specific and sensitive liquid chromatography-tandem mass spectrometry method was developed and validated for simultaneous determination of 16 active ingredients in Tabson-2 decoction, which could fulfill the requirements of multi-compounds pharmacokinetic study of Tabson-2 decoction. Additionally, the ingredients with significant distributions in rats were gentianic acid, chlorogenic acid, and aucubin, which could be the main potential active components in Tabson-2 decoction. The components with a significant bioavailability difference between normal and d-galactose induced osteoporosis rats were achieved as well. These data offer useful information for screening the active ingredients in Tabson-2 decoction, and assessing the bioavailability of these active ingredients in different physiological status, which might provide a possible mechanism of anti-osteoporosis efficacy of Tabson-2 decoction.

The Genus Echinops: Phytochemistry and Biological Activities: A Review

The genus Echinops belongs to the family of Asteraceae and comprises about 130 species. Many species belonging to the genus Echinops are traditionally used as medicinals mainly in Africa and Asia. The genus is reported to contain diverse secondary metabolites. The aim of this review is to critically evaluate the available research reports on the genus and systematically organize the findings. Information for this study was obtained using various search engines including PubMed and Google Scholar. This review revealed that the genus is used traditionally to treat pain, inflammation, respiratory diseases, diseases caused by different microorganisms, as an aphrodisiac, to fasten expulsion of placenta, and for removal of renal stones. More than 151 secondary metabolites have been reported from the genus in which thiophenic compounds held the biggest share. Various extracts, essential oils, and isolated compounds from members of this genus are shown to exhibit different biological effects mainly anti-microbial, anti-proliferative, and anti-inflammatory. However, there are a number of species in this genus that are claimed to have traditional medicinal uses but their biological effect not yet been evaluated.

Identification of Larvicidal Constituents of the Essential Oil of Echinops grijsii Roots against the Three Species of Mosquitoes

The screening of Chinese medicinal herbs for insecticidal principles showed that the essential oil of Echinops grijsii Hance roots possessed significant larvicidal activity against mosquitoes. The essential oil was extracted via hydrodistillation and its constituents were determined by gas chromatography-mass spectrometry (GC-MS) analysis. GC-MS analyses revealed the presence of 31 components, with 5-(3-buten-1-yn-1-yl)-2,2'-bithiophene (5-BBT, 27.63%), αterthienyl (α-T, 14.95%),1,8-cineole (5.56%) and cis-β-ocimene (5.01%) being the four major constituents. Based bioactivity-directed chromatographic separation of the essential oil led to the isolation of 5-BBT, 5-(4-isovaleroyloxybut-1-ynyl)-2,2'-bithiophene (5-IBT) and αT as active compounds. The essential oil of E. grijsii exhibited larvicidal activity against the fourth instar larvae of Aedes albopictus, Anopheles sinensis and Culex pipiens pallens with LC50 values of 2.65 μg/mL, 3.43 μg/mL and 1.47 μg/mL, respectively. The isolated thiophenes, 5-BBT and 5-IBT, possessed strong larvicidal activity against the fourth instar larvae of Ae. albopictus(LC50 = 0.34 μg/mL and 0.45 μg/mL, respectively) and An. sinensis(LC50 = 1.36 μg/mL and 5.36 μg/mL, respectively). The two isolated thiophenes also had LC50 values against the fourth instar larvae of C. pipiens pallens of 0.12 μg/mL and 0.33 μg/mL, respectively. The findings indicated that the essential oil of E. grijsii roots and the isolated thiophenes have an excellent potential for use in the control of Ae.albopictus, An. sinensis and C. pipiens pallens larvae and could be used in the search for new, safer and more effective natural compounds as larvicides.

A New Bithiophene from the Root of Echinops grijsii

A new bithiophene, 5-(4-hydroxy-3-methoxy-1-butyny)-2,2′-bithiophene (1), and sixteen known thiophenes: 2-(3,4-dihydroxybut-1-ynyl)-5-(penta-1,3-diynyl)thiophene (2), α-terthienyl (3), 5-(3,4-dihydroxybut-1-ynyl)-2,2′-bithiophene (4), 5-acetyl-2,2′-bithiophene (5), 5-formyl-2,2′-bithiophene (6), methyl 2,2′-bithiophene-5-carboxylate (7), 5-(but-3-en-1-ynyl)-2,2′-bithiophene (8), 5-(4-isovaleroyloxybut-1-ynyl)-2,2′-bithiophene (9), cardopatine (10), isocardopatine (11), 5-(3-hydroxy-4-isovaleroyloxybut-1-ynyl)-2,2′-bithiophene (12), 5-(3-hydroxymethyl-3-isovaleroyloxyprop-1-ynyl)-2,2′-bithiophene (13), 5-(4-hydroxy-1-butynyl)-2,2′-bithiophene (14), 5-(4-acetoxy-1-butynl)-2,2′-bithiophene (15), 2,2′-bithiophene-5-carboxylic acid (16) and 2-(4-hydroxybut-1-ynyl)-5-(penta-1,3-diynyl)thiophene (17) were isolated from the roots of Echinops grijisii Hance. Among them, compounds 6, 7 and 16 were isolated from a natural source for the first time. Compounds 2, 4 and 14 exhibited significant anti-inflammatory activity against nitrite of LPS-stimulated production in the RAW 264.7 cell line.

Essential oils from the roots of Echinops bannaticus Rochel ex Schrad. and Echinops sphaerocephalus L. (Asteraceae): chemotaxonomic and biosynthetic aspects

Herein, we report, for the first time, the results of detailed chemical and statistical analyses of the essential oils from the roots of two Echinops species (Asteraceae), E. bannaticus Rochel ex Schrad., and E. sphaerocephalus L., from the weed flora of Serbia. Among 106 and 81 constituents, respectively, S-containing polyacetylene compounds and triquinane sesquiterpenoids made up ca. 80% of the oils. Several of these compounds are reported here as new metabolites for the two species or even for the genus Echinops. A multivariate statistical comparison of the essential-oil composition data for these two and additional six taxa of this genus available from the literature permitted an examination of the mutual relationships of the taxa within this morphologically highly uniform genus. Principal component analysis (PCA) and agglomerative hierarchical clustering revealed a grouping of E. bannaticus and E. sphaerocephalus (both belonging to the section Echinops), and their close relationship with E. grijsii, suggesting a circumscription of this Chinese taxon to the section Echinops. PCA Correlation matrix offered valuable insight into the biosynthetic links between essential-oil constituents, and these agreed excellently with the currently proposed ones for the polyacetylene S-containing compounds, triquinanes, and monoterpenes.

GC-MS Analysis of Insecticidal Essential Oil of Aerial Parts ofEchinops latifoliusTausch

The roots ofEchinops latifoliusTausch (Asteraceae) have been used in the traditional medicine. However, no report on chemical composition and insecticidal activities of the essential oil of this plant exists. The aim of this research was to determine chemical composition and insecticidal activities of the essential oil ofE. latifoliusaerial parts against maize weevils (Sitophilus zeamaisMotschulsky) for the first time. Essential oil ofE. latifoliusaerial parts at flowering stage was obtained by hydrodistillation and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 35 components of the essential oil ofE. latifoliusaerial parts were identified. The major compounds in the essential oil were 1,8-cineole (19.63%), (Z)-β-ocimene (18.44%), andβ-pinene (15.56%) followed byβ-myrcene (4.75%) and carvone (4.39%). The essential oil ofE. latifoliuspossessed contact toxicity againstS. zeamaiswith an LD50value of 36.40 µg/adult. The essential oil also exhibited fumigant toxicity againstS. zeamaiswith an LC50value of 9.98 mg/L. The study indicates that the essential oil ofE. latifoliusaerial parts has a potential for development into a natural insecticide/fumigant for control of insects in stored grains.