In vitro structure-toxicity relationship of chalcones in human hepatic stellate cells

Two Important Anticancer Mechanisms of Natural and Synthetic Chalcones

ATP-binding cassette subfamily G and tubulin pharmacological mechanisms decrease the effectiveness of anticancer drugs by modulating drug absorption and by creating tubulin assembly through polymerization. A series of natural and synthetic chalcones have been reported to have very good anticancer activity, with a half-maximal inhibitory concentration lower than 1 µM. By modulation, it is observed in case of the first mechanism that methoxy substituents on the aromatic cycle of acetophenone residue and substitution of phenyl nucleus by a heterocycle and by methoxy or hydroxyl groups have a positive impact. To inhibit tubulin, compounds bind to colchicine binding site. Presence of methoxy groups, amino groups or heterocyclic substituents increase activity.

Melanogenic Inhibition and Toxicity Assessment of Flavokawain A and B on B16/F10 Melanoma Cells and Zebrafish (Danio rerio)

Excessive production of melanin implicates hyperpigmentation disorders. Flavokawain A (FLA) and flavokawain B (FLB) have been reported with anti-melanogenic activity, but their melanogenic inhibition and toxicity effects on the vertebrate model of zebrafish are still unknown. In the present study, cytotoxic as well as melanogenic effects of FLA and FLB on cellular melanin content and tyrosinase activity were evaluated in α-MSH-induced B16/F10 cells. Master regulator of microphthalmia-associated transcription factor (Mitf) and the other downstream melanogenic-related genes were verified via quantitative real time PCR (qPCR). Toxicity assessment and melanogenesis inhibition on zebrafish model was further observed. FLA and FLB significantly reduced the specific cellular melanin content by 4.3-fold and 9.6-fold decrement, respectively in α-MSH-induced B16/F10 cells. Concomitantly, FLA significantly reduced the specific cellular tyrosinase activity by 7-fold whilst FLB by 9-fold. The decrement of melanin production and tyrosinase activity were correlated with the mRNA suppression of Mitf which in turn down-regulate Tyr, Trp-1 and Trp-2. FLA and FLB exhibited non-toxic effects on the zebrafish model at 25 and 6.25 µM, respectively. Further experiments on the zebrafish model demonstrated successful phenotype-based depigmenting activity of FLA and FLB under induced melanogenesis. To sum up, our findings provide an important first key step for both of the chalcone derivatives to be further studied and developed as potent depigmenting agents.

Inhibitory Effects and Kinetic-Docking Studies of Xanthohumol FromHumulus lupulusCones Against Carbonic Anhydrase, Acetylcholinesterase, and Butyrylcholinesterase

Xanthohumol is an essential prenyl flavonoid of Humulus lupulus L. cones, and the taste of beer is due to this compound. Lately, xanthohumol has earned significant interest due to its potential anticancer, antigenotoxic, and adipogenesis effects. In this paper, the inhibitory effects of xanthohumol on human carbonic anhydrase isozymes (hCAI and hCAII), acetylcholinesterase (AChE), and butyrylcholinesterase (BChE) were studied. Also, molecular docking studies were used to investigate ligand interaction diagrams of xanthohumol at the binding cavities of hCAI and II. Xanthohumol was isolated from hop cones by silica gel column chromatography. Carbonic anhydrase enzyme activities were determined spectrophotometrically. In addition, molecular modeling approaches were used for the hCAI and hCAII isoenzymes. Ellman’s method was used for the inhibitor activities of AChE and BChE. The KIvalues of xanthohumol were detected as 0.085 µM for hCAI, 0.049 µM for hCAII, 95.5 nM for AChE, and 124.9 nM for BChE. In conclusion, xanthohumol can pleiotropically exert health promoting effects. It has antiglaucoma, anticonvulsant, antiepileptic, and anticancer activities due to its potent inhibitory effects on hCAI and hCAII. These findings may open new avenues for the design and development of novel hCAI, hCAII, AChE, and BChE inhibitors compared with sulfonamide/sulfamate.

Functionalization of the Chalcone Scaffold for the Discovery of Novel Lead Compounds Targeting Fungal Infections

The occurrence of invasive fungal infections represents a substantial threat to human health that is particularly serious in immunocompromised patients. The limited number of antifungal agents, devoid of unwanted toxic effects, has resulted in an increased demand for new drugs. Herein, the chalcone framework was functionalized to develop new antifungal agents able to interfere with cell growth and with the infection process. Thus, a small library of chalcone-based analogues was evaluated in vitro against C. albicans ATCC 10231 and a number of compounds strongly inhibited yeast growth at non-cytotoxic concentrations. Among these, 5 and 7 interfered with the expression of two key virulence factors in C. albicans pathogenesis, namely, hyphae and biofilm formation, while 28 emerged as a potent and broad spectrum antifungal agent, enabling the inhibition of the tested Candida spp. and non-Candida species. Indeed, these compounds combine two modes of action by selectively interfering with growth and, as an added value, weakening microbial virulence. Overall, these compounds could be regarded as promising antifungal candidates worthy of deeper investigation. They also provide a chemical platform through which to perform an optimization process, addressed at improving potency and correcting liabilities.

Femtosecond electronic relaxation and real-time vibrational dynamics in 2′-hydroxychalcone

Electronic relaxation, proton transfer and instantaneous vibrational frequency change after the impulsive excitation by a deep ultraviolet 9 fs pulse were studied.

In Vitro Osteogenic Differentiation and Antibacterial Potentials of Chalcone Derivatives

Chalcone derivatives have been investigated as therapeutic agents for the anticancer, antioxidant, and anti-inflammatory fields. In this study, we have synthesized four different types of chalcone derivatives and demonstrated in vitro bioactivities. We divided these derivatives into two groups of chalcones on the basis of similar substituents on the aromatic rings, and we tested cell viability and proliferation potentials, which indicated that the methoxy substituent on the A ring could enhance cytotoxicity and antiproliferation potential depending on the chalcone concentration. We also investigated osteogenic differentiation of C2C12 cells by ALP staining, the early marker for osteogenesis, which demonstrated that the chalcones could not only induce activity of BMP-2 but also inhibit the activity of noggin, a BMP antagonist. In addition, chalcone bearing hydroxyl groups at the 2-, 4-, and 6-position on the A ring inhibited treptococcus mutans growth, a major causative agent of dental caries. Therefore, we concluded that the chalcone derivatives synthesized in this research can be good candidates for therapeutic agents promoting bone differentiation, with an expectation of inhibiting S. mutans, in dentistry.

Chalcone Derivatives Enhance ATP-Binding Cassette Transporters A1 in Human THP-1 Macrophages

Atherosclerosis is a process of imbalanced lipid metabolism in the vascular walls. The underlying pathology mainly involves the deposition of oxidized lipids in the endothelium and the accumulation of cholesterol in macrophages. Macrophages export excessive cholesterol (cholesterol efflux) through ATP-binding cassette transporter A1 (ABCA1) to counter the progression of atherosclerosis. We synthesized novel chalcone derivatives and assessed their effects and the underlying mechanisms on ABCA1 expression in macrophages. Human THP-1 macrophages were treated with synthetic chalcone derivatives for 24 h. In Western blot and flow cytometry analyses, a chalcone derivative, (E)-1-(3,4-diisopropoxyphenyl)-3-(4-isopropoxy-3-methoxyphenyl)prop- 2-en-1-one (1m), was observed to significantly enhance ABCA1 protein expression in THP-1 cells (10 µM, 24 h). Levels of mRNA of ABCA1 and liver X receptor alpha (LXRα) were quantified using a real-time quantitative polymerase chain reaction technique and were found to be significantly increased after treatment with the novel chalcone derivative 1m. Several microRNAs, including miR155, miR758, miR10b, miR145, miR33, and miR106b, which functionally inhibit ABCA1 expression were suppressed after treatment with 1m. Collectively, 1m increases ABCA1 expression in human THP-1 macrophages. The mechanisms involve the activation of the LXRα-ABCA1 pathway and suppression of certain microRNAs that regulate ABCA1 expression.

Halogenated naphthochalcones and structurally related naphthopyrazolines with antitumor activity

Three 3-(3-halo-4,5-dimethoxyphenyl)-1-(2-naphthyl)prop-2-en-1-ones 1 and three structurally related 2-pyrazolines 2 were prepared and assessed in vitro for anticancer activity. The chalcones 1 were antiproliferative with low double-digit micromolar IC₅₀ values against six tumor cell lines whereas the pyrazolines 2 showed low single-digit micromolar IC₅₀ values against this panel. The pyrazolines inhibited ATP-binding cassette efflux transporters of types P-gp and BCRP while the chalcones inhibited selectively BCRP. All test compounds induced an accumulation of HT-29 colon carcinoma cells in the G2/M phase of the cell cycle and they interfered with the microtubule and F-actin dynamics, but only the chalcones induced apoptosis in 518A2 melanoma cells after 24h.