Two new sesquiterpene lactone glycosides from Cnicus benedictus

Dracotangusions A and B, two new sesquiterpenes from Dracocephalum tanguticum Maxim. with anti-inflammatory activity

Two new guaiane sesquiterpenoids were isolated from the dried aerial parts of Dracocephalum tanguticum Maxim., named as dracotangusions A (1) and B (2), together with four known sesquiterpenoids, which were identified as Curcumenone (3), (4Z,7Z,9Z)-11-Hydroxy-4,7,9-germacratriene-1,6-dione (4), Kobusone (5), and (1S,10S), (4S, 5S)-(+)-germacrone-1(10)-4-diepoxide (6). The structures of isolates were determined by UV, IR, HR-ESI-MS, and NMR analysis. What is noteworthy is that four known sesquiterpenoids were isolated for the first time from the genus of Dracocephalum L. All compounds inhibited the extremely significant difference (p < 0.01) in anti-inflammatory activity, suggesting that these compounds may be promising candidates as an anti-inflammatory agent.

HPLC/ESI-MS Characterization of Phenolic Compounds from Cnicus benedictus L. Roots: A Study of Antioxidant, Antibacterial, Anti-Inflammatory, and Anti-Alzheimer's Activity

The phenolic composition of Cnicus benedictus roots from four Algerian regions was investigated. Extractions were performed in both hydro-methanolic (30 : 70, v/v) and hydro-ethanolic (30 : 70, v/v) solvents. Their efficiency was determined in terms of the qualitative and quantitative composition in phenolic compounds by HPLC-LC/MS of the different extracts isolated from C. Benedictus roots. Cnicus benedictus roots extract have been characterized by high content of phenolic compounds, where the trans chalcone, 2,3-dihydro flavone, 3-hydroxy flavone and cinnamic acid constitute the major components, in addition to fourteen minor acidic compounds and flavonoids as rutin. The hydro-methanolic extract was the richest in phenolic compounds yield from C benedictus. On the other hand, hydro methanolic (30 : 70, v/v) and hydro ethanolic (30 : 70, v/v) extracts exhibited a high anti-inflammatory activity by in vitro 5-lipoxygenase inhibitory activity (IC50 : 6.05±94.16 μg/mL) as well as by in silico docking according two methods. Likewise, anti-Alzheimer activity of extracts was confirmed by this last technique taking into account the major compounds identified. Antibacterial tests revealed interesting results compared to amoxicillin for the different regions studied with a high content in trans chalcone and 3-hydroxy Flavone.

Simultaneous determination and characterization of flavonoids, sesquiterpene lactone, and other phenolics from Centaurea benedicta and dietary supplements using UHPLC-PDA-MS and LC-DAD-QToF

Simultaneous identification and quantification of phenolic acid (chlorogenic acid), sesquiterpene lactone (cnicin), lignan (arctiin), and flavonoids (bracteoside, 6-methoxybracteoside, isokaempferide, and viscosine) in mixed parts of Centaurea benedicta (Syn. Cnicus benedictus) were performed for the first time. The liquid chromatography method showed an adequate performance for the separation of seven compounds. The method was validated for linearity (0.5-100 μg/mL), precision, accuracy, limit of detection (LOD), and limit of quantification (LOQ) as well as robustness. Cnicin and arctiin were detected at concentrations as low as 0.25 µg/mL. Remaining flavonoids and chlorogenic acid were detected at 0.025 μg/mL. The method demonstrated good performance in terms of intra- and inter-day precision (0.1-3.4%), accuracy (98.0-105.0%), lower and upper limits of quantification for all compounds. Analysis of various samples showed considerable variation of 0.9-10.3 mg/g for the marker compound, cnicin. Twenty-one dietary supplements, claiming to contain C. benedictus extract, were analyzed for authenticity. Thirteen (62%) of 21 products showed the presence of all analyzed compounds and were confirmed to contain C. benedictus. A liquid chromatography-tandem mass spectrometry method coupled with electrospray ionization (ESI) is described for the identification of compounds in plant samples. This method involved the use of protonated, deprotonated, and adduct ions for compounds in positive and negative ion modes with extractive ion chromatogram (EIC). The application of liquid chromatography-quadrupole time of flight mass spectrometry (LC-QToF) provided useful information to characterize sixty-four compounds. The developed methods were also applicable for quality assessment of raw materials and dietary supplements containing C. benedictus.

Cnicin as an Anti-SARS-CoV-2: An Integrated In Silico and In Vitro Approach for the Rapid Identification of Potential COVID-19 Therapeutics

Since the emergence of the SARS-CoV-2 pandemic in 2019, it has remained a significant global threat, especially with the newly evolved variants. Despite the presence of different COVID-19 vaccines, the discovery of proper antiviral therapeutics is an urgent necessity. Nature is considered as a historical trove for drug discovery, especially in global crises. During our efforts to discover potential anti-SARS CoV-2 natural therapeutics, screening our in-house natural products and plant crude extracts library led to the identification of C. benedictus extract as a promising candidate. To find out the main chemical constituents responsible for the extract's antiviral activity, we utilized recently reported SARS CoV-2 structural information in comprehensive in silico investigations (e.g., ensemble docking and physics-based molecular modeling). As a result, we constructed protein-protein and protein-compound interaction networks that suggest cnicin as the most promising anti-SARS CoV-2 hit that might inhibit viral multi-targets. The subsequent in vitro validation confirmed that cnicin could impede the viral replication of SARS CoV-2 in a dose-dependent manner, with an IC50 value of 1.18 µg/mL. Furthermore, drug-like property calculations strongly recommended cnicin for further in vivo and clinical experiments. The present investigation highlighted natural products as crucial and readily available sources for developing antiviral therapeutics. Additionally, it revealed the key contributions of bioinformatics and computer-aided modeling tools in accelerating the discovery rate of potential therapeutics, particularly in emergency times like the current COVID-19 pandemic.