Sesquiterpene Lactones and Flavonoids from Psephellus pyrrhoblepharus with Antiproliferative Activity on Human Gynecological Cancer Cell Lines

Plant Extracts and Phytochemicals from the Asteraceae Family with Antiviral Properties

Asteraceae (Compositae), commonly known as the sunflower family, is one of the largest plant families in the world and includes several species with pharmacological properties. In the search for new antiviral candidates, an in vitro screening against dengue virus (DENV) was performed on a series of dichloromethane and methanolic extracts prepared from six Asteraceae species, including Acmella bellidioides, Campuloclinium macrocephalum, Grindelia pulchella, Grindelia chiloensis, Helenium radiatum, and Viguiera tuberosa, along with pure phytochemicals isolated from Asteraceae: mikanolide (1), eupatoriopicrin (2), eupahakonenin B (3), minimolide (4), estafietin (5), 2-oxo-8-deoxyligustrin (6), santhemoidin C (7), euparin (8), jaceidin (9), nepetin (10), jaceosidin (11), eryodictiol (12), eupatorin (13), and 5-demethylsinensetin (14). Results showed that the dichloromethane extracts of C. macrocephalum and H. radiatum and the methanolic extracts prepared from C. macrocephalum and G. pulchella were highly active and selective against DENV-2, affording EC50 values of 0.11, 0.15, 1.80, and 3.85 µg/mL, respectively, and SIs of 171.0, 18.8, >17.36, and 64.9, respectively. From the pool of phytochemicals tested, compounds 6, 7, and 8 stand out as the most active (EC50 = 3.7, 3.1, and 6.8 µM, respectively; SI = 5.9, 6.7, and >73.4, respectively). These results demonstrate that Asteraceae species and their chemical constituents represent valuable sources of new antiviral molecules.

Two new compounds from endemic Centaurea paphlagonica (Bornm.) Wagenitz and their cytotoxic activities

Centaurea paphlagonica (Bornm.) Wagenitz is an endemic plant in Turkey. Pyrocatechol, vanillic acid, 3,4-dihydroxy benzoic acid, 5-O-caffeoylshikimic acid, tamarixetin, chlorogenic acid methyl ester, quercetin, 1,3-dicaffeoylquinic acid, tamarixetin-7-O-β-D-glucopyranoside, quercimetrin, daucosterin, paphlagonicanin B, tamarixetin-7-O-β-rutinoside, rutin, chlorogenic acid, isoorientin, orientin, 3-O-feruloylquinic acid, quercetagetin-3-methyl ether 6-O-β-glucopyranoside, diosmetin 6-C-β-glucopyranoside, quercetagetin 4'-methyl ether 7-O-β-glucopyranoside, paphlagonicanin A, nepetin, cirsiliol, desacylcynaropicrin, and 8α-O-(2',3'-dihydroxyisobutyryl) desacylcynaropicrin were isolated from both flower and aerial parts of C. paphlagonica. These compounds were identified using 1D and 2D NMR methods and ESI-MS. The MTT assay assessed the antiproliferative activities of all isolated (known and new compounds) compounds on Caco-2, LNCaP, A549, HeLa, and HEK-293 cell lines. The 8α-O-(2',3'-dihydroxyisobutyryl) desacylcynaropicrin demonstrated the highest activity against CaCo-2 and HeLa cancer cell lines.

Three sesquiterpene lactones suppress lung adenocarcinoma by blocking TMEM16A-mediated Ca2+-activated Cl- channels

Transmembrane protein TMEM16A, which encodes calcium-activated chloride channel has been implicated in tumorigenesis. Overexpression of TMEM16A is associated with poor prognosis and low overall survival in multiple cancers including lung adenocarcinoma, making it a promising biomarker and therapeutic target. In this study, three structure-related sesquiterpene lactones (mecheliolide, costunolide and dehydrocostus lactone) were extracted from the traditional Chinese medicine Aucklandiae Radix and identified as novel TMEM16A inhibitors with comparable inhibitory effects. Their effects on the proliferation and migration of lung adenocarcinoma cells were examined. Whole-cell patch clamp experiments showed that these sesquiterpene lactones potently inhibited recombinant TMEM16A currents in a concentration-dependent manner. The half-maximal concentration (IC50) values for three tested sesquiterpene lactones were 29.9 ± 1.1 μM, 19.7 ± 0.4 μM, and 24.5 ± 2.1 μM, while the maximal effect (Emax) values were 100.0% ± 2.8%, 85.8% ± 0.9%, and 88.3% ± 4.6%, respectively. These sesquiterpene lactones also significantly inhibited the endogenous TMEM16A currents and proliferation, and migration of LA795 lung cancer cells. These results demonstrate that mecheliolide, costunolide and dehydrocostus lactone are novel TMEM16A inhibitors and potential candidates for lung adenocarcinoma therapy.

Chemical constituents from Centaurothamnus maximus and their antimicrobial activity

A new sesquiterpene lactone, 3β,10α-dihydroxy-10β-(hydroxymethyl)-8α-(4-hydroxymethacrylate)-1αH,5αH,6βH,7αH-guai-4(15), 11(13)-dien-6,12-olide (1), along with twenty-one known compounds, were identified from the aerial parts of Centaurothamnus maximus. The structures of the isolated compounds were elucidated on the basis of spectroscopic evidences and correlated with known compounds. Compounds (2, 3, 5‒13 and 15‒22) were identified from C. maximus for the first time. Antibacterial and antifungal activities of the isolated compounds were tested using the agar disc diffusion method. Compounds that demonstrated promising antimicrobial activity were evaluated for their minimum inhibitory concentration (MIC). The results showed that compounds 3 and 7 were the most effective antibacterial compounds against B. subtilis ATCC 6633, S. aureus ATCC 25923 and S. pyogenes ATCC 27736, with MIC estimates between 8 and 32 mg/mL. In addition, compound 2 exhibited the strongest antifungal activity against C. albicans ATCC 14243 and C. krusei ATCC 14243 with MIC 8 mg/mL.

Byproducts of Globe Artichoke and Cauliflower Production as a New Source of Bioactive Compounds in the Green Economy Perspective: An NMR Study

The recovery of bioactive compounds from crop byproducts leads to a new perspective way of waste reutilization as a part of the circular economy. The present study aimed at an exhaustive metabolite profile characterization of globe artichoke and cauliflower byproducts (leaves, stalks, and florets for cauliflower only) as a prerequisite for their valorization and future implementations. The metabolite profile of aqueous and organic extracts of byproducts was analyzed using the NMR-based metabolomics approach. Free amino acids, organic acids, sugars, polyols, polyphenols, amines, glucosinolates, fatty acids, phospho- and galactolipids, sterols, and sesquiterpene lactones were identified and quantified. In particular, globe artichoke byproducts are a source of health-beneficial compounds including chiro-inositol (up to 10.1 mg/g), scyllo-inositol (up to 1.8 mg/g), sesquiterpene lactones (cynaropicrin, grosheimin, dehydrocynaropicrin, up to 45.5 mg/g in total), inulins, and chlorogenic acid (up to 7.5 mg/g), whereas cauliflower byproducts enclose bioactive sulfur-containing compounds S-methyl-L-cysteine S-oxide (methiin, up to 20.7 mg/g) and glucosinolates. A variable content of all metabolites was observed depending on the crop type (globe artichoke vs. cauliflower) and the plant part (leaves vs. stalks). The results here reported can be potentially used in different ways, including the formulation of new plant biostimulants and food supplements.

Feature-Based Molecular Networking for the Exploration of the Metabolome Diversity of Common Egyptian Centaurea Species in Relation to Their Cytotoxic Activity

Centaurea is a genus compromising over 250 herbaceous flowering species and is used traditionally to treat several ailments. Among the Egyptian Centaurea species, C. lipii was reported to be cytotoxic against multidrug-resistant cancer cells. In this context, we aimed to explore the metabolome of C. lipii and compare it to other members of the genus in pursuance of identifying its bioactive principles. An LC-MS/MS analysis approach synchronized with feature-based molecular networks was adopted to offer a holistic overview of the metabolome diversity of the Egyptian Centaurea species. The studied plants included C. alexandrina, C. calcitrapa, C. eryngioides, C. glomerata, C. lipii, C. pallescens, C. pumilio, and C. scoparia. Their constitutive metabolome showed diverse chemical classes such as cinnamic acids, sesquiterpene lactones, flavonoids, and lignans. Linking the recorded metabolome to the previously reported cytotoxicity identified sesquiterpene lactones as the major contributors to this activity. To confirm our findings, bioassay-guided fractionation of C. lipii was adopted and led to the isolation of the sesquiterpene lactone cynaropicrin with an IC₅₀ of 1.817 µM against the CCRF-CEM leukemia cell line. The adopted methodology highlighted the uniqueness of the constitutive metabolome of C. lipii and determined the sesquiterpene lactones to be the responsible cytotoxic metabolites.

Iphiona mucronata (Forssk.) Asch. & Schweinf. A Comprehensive Phytochemical Study via UPLC-Q-TOF-MS in the Context of the Embryo- and Cytotoxicity Profiles

Iphiona mucronata (Family Asteraceae) is widely distributed in the Eastern desert of Egypt. It is a promising plant material for phytochemical analysis and pharmacologic studies, and so far, its specific metabolites and biological activity have not yet been thoroughly investigated. Herein, we report on the detailed phytochemical study using UPLC-Q-TOF-MS approach. This analysis allowed the putative annotation of 48 metabolites belonging to various phytochemical classes, including mostly sesquiterpenes, flavonoids, and phenolic acids. Further, zebrafish embryotoxicity has been carried out, where 100 µg/mL extract incubated for 72 h resulted in a slow touch response of the 10 examined larvae, which might be taken as a sign of a disturbed peripheral nervous system. Results of in vitro testing indicate moderate cytotoxicity towards VERO, FaDu, and HeLa cells with CC50 values between 91.6 and 101.7 µg/mL. However, selective antineoplastic activity in RKO cells with CC50 of 54.5 µg/mL was observed. To the best of our knowledge, this is the first comprehensive profile of I. mucronata secondary metabolites that provides chemical-based evidence for its biological effects. A further investigation should be carried out to precisely define the underlying mechanisms of toxicity.

Chemometrics applied to 1H NMR and UV-Vis spectroscopy as a way to evaluate solid-liquid extraction of leaves of artichoke

Artichoke has several biological actions, which are related to the synergistic action of its bioactive compounds. Solid-liquid extraction influence the type and quantity of compounds extracted and, consequently, the biological activity of the plant extract. This study aims to investigate which extraction method (maceration, infusion, or Soxhlet) and which green solvent (ethanol or acetone) would be more suitable to obtain bioactive artichoke extracts. All solid-liquid procedures were carried out in triplicate, using 3.0 g of artichoke leaves and 200 mL of solvent. After drying, samples were analyzed by UV-Vis and ¹H NMR. Chemometrics was applied to spectroscopic data, and the PCA analysis showed that they were specially separated according to the solvent extractor. The sesquiterpene lactone cynaropicrin was identified as the major compound of the extracts, and this allowed us to conclude that the best solid-liquid procedure was Soxhlet, using ethanol as solvent.

Secondary metabolites from Bacillus sp. MERNA97 extract attenuates the oxidative stress, genotoxicity and cytotoxicity of aflatoxin B1 in rats

This study aimed to determine the bioactive compounds of Bacillus sp. MERNA97 extract and to evaluate their efficacy against the oxidative damage, genotoxicity, chromosomal aberration and DNA fragmentation in rats treated with AFB₁. Sixty male Sprague-Dawley rats were divided into 6 groups and treated for 6 weeks and included the control group, AFB₁-treated group (80 μg/kg b. w), the groups treated with Bacillus extract (BE) at low (2 mg/kg b.w) or high (4 mg/kg b.w) dose and the groups treated with AFB₁ plus BE at the two doses. Blood and tissues samples were collected for different assays. The GC-MS results revealed the isolation of 44 compounds belong to different classes. The in vivo results showed that AFB₁ disturbs all the biochemical parameters, oxidative stress markers, cytokines gene expression chromosomal aberration and DNA fragmentation along with the histological changes in the liver tissue. BE at the two tested doses induced a significant improvement in all parameters tested and the histological picture in a dose dependent manner. It could be concluded that the extract of Bacillus sp. MERNA97 isolated from the marine environment in the Red Sea is a promise as a source of novel compounds with therapeutically benefits.

Galangin, a Flavonoid from Lesser Galangal, Induced Apoptosis via p53-Dependent Pathway in Ovarian Cancer Cells

Among women worldwide, ovarian cancer is one of the most dangerous cancers. Patients undergoing platinum-based chemotherapy might get adverse side effects and develop resistance to drugs. In recent years, natural compounds have aroused growing attention in cancer treatment. Galangin inhibited the growth of two cell lines, A2780/CP70 and OVCAR-3, more strongly than the growth of a normal ovarian cell line, IOSE 364. The IC₅₀ values of galangin on proliferation of A2780/CP70, OVCAR-3 and IOSE 364 cells were 42.3, 34.5, and 131.3 μM, respectively. Flow cytometry analysis indicated that galangin preferentially induced apoptosis in both ovarian cancer cells with respect to normal ovarian cells. Galangin treatment increased the level of cleaved caspase-3 and -7 via the p53-dependent intrinsic apoptotic pathway by up-regulating Bax protein and via the p53-dependent extrinsic apoptotic pathway by up-regulating DR5 protein. By down-regulating the level of p53 with 20 μM pifithrin-α (PFT-α), the apoptotic rates of OVCAR-3 cells induced by galangin treatment (40 μM) were significantly decreased from 18.2% to 10.2%, indicating that p53 is a key regulatory protein in galangin-induced apoptosis in ovarian cancer cells. Although galangin up-regulated the expression of p21, it had little effect on the cell cycle of the two ovarian cancer cell lines. Furthermore, the levels of phosphorylated Akt and phosphorylated p70S6K were decreased through galangin treatment, suggesting that the Akt/p70S6K pathways might be involved in the apoptosis. Our results suggested that galangin is selective against cancer cells and can be used for the treatment of platinum-resistant ovarian cancers in humans.