Sesquiterpene lactones from Centaurea tougourensis

Cytotoxic and chemotaxonomic study of isolated metabolites from Centaurea aegyptiaca

The aerial parts of Centaureaa egyptiaca afforded 10 secondary metabolites including four sesquiterpene lactones; chlorohyssopifolin A (centaurepensin) (1), rediolpidetriol (2), linichlorinA (3), and sinaicin (4), one monoterpene; loliolid (5), one phenolic: tyrosol (6), three lignans; arctigenin (7), matairesinol (8), and pinoresinol (9), and one steroid; ergosta‐5,22‐dien‐3‐ol (10). The cluster analysis of 32 Centaurea species revealed that C. aegyptiaca is closely related to C. repens and C. solstitialise. The isolated compounds (1–10) were screened against CCRF‐CEM‐leukemia, MDA‐MB‐231‐pcDNA3 breast cancer, and HCT116 (p53+/+) colon carcinoma cell lines. Compounds1 and 2 were the most potent compounds against both leukemia and breast carcinoma cell lines.

Wild and Cultivated Centaurea raphanina subsp. mixta: A Valuable Source of Bioactive Compounds

Centaurea raphanina subsp. mixta (DC.) Runemark is a wild edible species endemic to Greece. This study evaluated the chemical composition and bioactive properties of wild and cultivated C. raphanina subsp. mixta plants. Wild plants had higher nutritional value than cultivated ones, whereas cultivated plants contained more tocopherols. Glucose and sucrose were higher in cultivated plants and trehalose in wild ones. Oxalic and total organic acids were detected in higher amounts in cultivated samples. The main fatty acids were α-linolenic, linoleic and palmitic acid, while wild plants were richer in polyunsaturated fatty acids. Two pinocembrin derivatives were the main phenolic compounds being detected in higher amounts in wild plants. Regarding the antioxidant activity, wild and cultivated plants were more effective in the oxidative haemolysis (OxHLIA) and thiobarbituric acid reactive substances (TBARS) assays, respectively. Moreover, both extracts showed moderate cytotoxicity in non-tumor cell lines (PLP2), while cultivated plants were more effective against cervical carcinoma (HeLa), breast carcinoma (MCF-7) and non-small lung cancer (NCI-H460) cell lines. Finally, wild plants showed higher antimicrobial activity than cultivated plants against specific pathogens. In conclusion, the cultivation of C.raphanina subsp. mixta showed promising results in terms of tocopherols content and antiproliferative effects, however further research is needed to decrease oxalic acid content.

Centaurea pumilio L. extract and nanoparticles: A candidate for healthy skin

Centaurea pumilio was the subject of phytochemical and biological studies, and its extract was used in the green synthesis of silver nanoparticles (AgNPs). Liquid chromatography/electrospray ionization mass spectrometry allowed the tentative identification of twenty-nine phytoconstituents of C. pumilio methanolic extract (CME), while column chromatography led to the identification of eight phenolic compounds. The neutral red uptake method showed the safety of CME and AgNPs on skin cells (HaCaT cell lines), while their high antioxidant potentials were demonstrated based on their oxygen radical absorbance capacity, and these results were confirmed in vivo. Additionally, CME and AgNPs had promising abilities to retard the ageing process and combat dark spots by potently inhibiting collagenase, elastase and tyrosinase, in addition to antimicrobial activity against skin infection-causing strains, especially Staphylococcus aureus, which was further confirmed by the significant phagocytic activity of neutrophils via engulfment. This study presents C. pumilio as a candidate for healthy skin.

Chemical profiling of Centaurea bornmuelleri Hausskn. aerial parts by HPLC-MS/MS and their pharmaceutical effects: From nature to novel perspectives

Ethnobotanical evidences substantiate the use of several Centaurea species to treat and/or manage several human ailments. In the present study, the phytochemical profile of the ethyl acetate, methanol, and aqueous extracts (prepared by infusion and decoction) of Centaurea bornmuelleri Hausskn. aerial parts was established. The enzyme inhibitory and antioxidant properties were also determined by in vitro bioassays. Methanol extract (38.58 mg gallic acid equivalent/g extract) and ethyl acetate extract (38.83 mg rutin equivalent/g extract) possessed the highest concentration of phenolics and flavonoids, respectively. Aqueous extract prepared following traditional infusion method showed potent DPPH (38.54 mg TE/g extract) and ABTS (57.75 mg TE/g extract) scavenging abilities. The methanol extract (101.46 mg TE/g extract) of C. bornmuelleri exhibited potent reducing activity in the CUPRAC assay while the aqueous extract obtained by infusion was more active in the FRAP assay (69.81 mg TE/g extract). Ethyl acetate extract of C. bornmuelleri inhibited both acetylcholinesterase (1.14 mg galantamine equivalent [GALAE]/g extract), butyrylcholinesterase (0.63 mg GALAE/g extract), tyrosinase (69.84 mg kojic acid equivalent/g extract), amylase (19.90 mg acarbose equivalent [ACAE]/g extract), and glucosidase (33.12 mg ACAE/g extract). The phytochemical profile of C. bornmuelleri has been characterized and the main components quantified in order to provide scientific base to design innovative products including pharmaceuticals, cosmetics or nutraceuticals although further investigation concerning the isolation of the main bioactive compounds would be required.

Natural sesquiterpenoids

This review covers the isolation, structural determination, synthesis and chemical and microbiological transformations of natural sesquiterpenoids. The literature from January to December 2012 is reviewed, and 471 references are cited.