Phytochemical Analysis and Anti-Cancer Properties of Extracts of Centaurea castriferrei Borbás & Waisb Genus of Centaurea L.

The Centaurea L. (Asteraceae) genus includes many plant species with therapeutic properties. Centaurea castriferrei Borbás & Waisb is one of the least known and least described plants of this genus. The aim of the study was the phytochemical analysis of water and methanol-water extracts (7:3 v/v) obtained from the aerial parts of the plant as well as evaluation of their anticancer activity. Quantitative determinations of phenolic compounds and flavonoids were performed, and the antioxidant potential was measured using the CUPRAC method. The RP-HPLC/DAD analysis and HPLC-ESI-QTOF-MS mass spectroscopy were performed, to determine the extracts' composition. The antiproliferative activity of the obtained extracts was tested in thirteen cancer cell lines and normal skin fibroblasts using MTT test. Regardless of the extraction method and the extractant used, similar cytotoxicity of the extracts on most cancer cell lines was observed. However, the methanol-water extracts (7:3 v/v) contained significantly more phenolic compounds and flavonoids as well as showing stronger antioxidant properties in comparison to water extracts. Centaurea castriferrei Borbás & Waisb is a rich source of apigenin and its derivatives. In all tested extracts, chlorogenic acid and centaurein were also identified. In vitro research revealed that this plant may be a potential source of compounds with anticancer activity.

Phytochemical Profile and Biological Activity of the Ethanolic Extract from the Aerial Part of Crocus alatavicus Regel & Semen Growing Wildly in Southern Kazakhstan.

The composition of the ethanolic extract from the aerial parts of Crocus alatavicus Regel & Semen from southern Kazakhstan spontaneous flora was analyzed together with the determination of its antibacterial, antifungal, antiviral and anticancer activity. The phytochemical profile analysis by high-performance liquid chromatography-electrospray ionization-quadrupole-time of flight-mass spectrometry (HPLC/ESI-QTOF-MS) revealed the presence of multiple kaempferol derivatives. High-performance reverse-phase liquid chromatography combined with a photodiode-array detection (RP-HPLC/PDA) found that kaempferol 3-O-dihexoside and kaempferol 3-O-acyltetrahexoside accounted for 70.5% of the kaempferol derivatives. The minimum inhibitory concentration (MIC) values of the extract for all the tested reference microorganisms were high, reaching 10 mg/mL for yeasts and 20 mg/mL for bacteria. In contrast, antiviral activity was observed at 2 mg/mL, resulting in the inhibition of the HSV-1-induced cytopathic effect and the reduction in virus infectious titer by 1.96 log, as well as the viral load by 0.85 log. Among the tested prostate cancer cell lines, significant cytotoxic activity of the extract was noted only on the LNCaP cell line, with an IC50 value of 1.95 mg/mL. The LNCaP cell line treated with 2 mg/mL of the extract showed a noticeably reduced number of spindle-shaped cells with longer cellular projections, a significant increase in the peak corresponding to the population of apoptotic cells in the sub-G1 phase and a decreased intracellular glutathione (GSH) level, suggesting the prooxidative properties of the extract. The obtained data provide novel information about the flavonoids present in the aerial part of C. alatavicus and suggest its potential application as a source of the compounds active against HSV-1 and metastatic, androgen-sensitive prostate cancer.

Cytotoxic activity of methanolic fractions of different Marrubium spp. against melanoma cells is independent of antioxidant activity and total phenolic content.

The Marrubium genus (horehound) has proved to be an abundant source of biologically active compounds, but there is little knowledge about its potential anticancer activity. Moreover, some Marrubium species have not been the subject of study in this regard. In this study, we performed comparative analysis of phenolic acid (PhA) content and total phenolic content in fractions obtained from methanolic extracts of Marrubium vulgare L. (common horehound), Marrubium cylleneum Boiss. & Heldr. and Marrubium friwaldskyanum Boiss herbs. We examined the cytotoxicity of these fractions against a human melanoma cancer cell line (A375) and normal human skin fibroblasts (BJ) using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide test, cell cycle analysis and real-time monitoring of cell viability. We detected caffeic, p-coumaric, ferulic and gentisic acids among the PhAs. Although the extracts obtained demonstrated low total phenolic content and did not show significant antioxidative properties, the nonhydrolyzed PhA fraction exhibited cytotoxic activity against a human melanoma cancer cell line, without affecting normal fibroblasts. Both acidic and alkaline hydrolysis abolished this activity, indicating that the esterified forms of phenolic compounds caused the observed cytotoxic effects. Further investigation of these compounds may facilitate the development of novel drugs for cancer treatment.