Assessment of chalcones as cancer chemopreventive agents

Chemoprevention is based upon the use of natural or synthetic products to eliminate or minimize the development of cancer1. Many cancers are thought to occur due to processes such as oxidative stress and lipid peroxidation causing DNA damage. Chemopreventive compounds may prevent such damage from occurring. Chalcones belong to the flavonoid based group of compounds and have been reported to possess cancer chemopreventive properties2,3. In this study, we investigated the ability of novel synthetic chalcones to act as chemopreventive agents. The aim was to assess the ability of the chalcones to switch on the transcription factor Nrf2 thus inducing many cell defence genes. This was achieved using the AREc32 reporter cell line that contains the luciferase gene linked to the antioxidant response element (ARE), which is a sequence found within the promoters of cell defence genes to which the Nrf2 transcription factor binds4. The luciferase reporter AREc32 cell line was exposed to varying concentrations of synthetic chalcones to determine a suitable non-toxic concentration to use (MTT assay). The AREc32 cells were then exposed to this non-toxic concentration of chalcones for 24 h after which the amount of luciferase activity (Nrf2 activity) was quantified. Of the 30 chalcones tested, 12 chalcones were found to activate the luciferase reporter gene by 2-fold or more (relative to untreated control) with the greatest induction being 16-fold. Further investigations are now in progress to delineate the common structural features of the chalcones that give the greatest induction in addition to the ability of these chalcones to prevent cellular cytotoxicity

Cytotoxic stilbenes and canthinone alkaloids from Brucea antidysenterica (Simaroubaceae)

Phytochemical study of the root and bark of Brucea antidysenterica J. F. Mill. (Simaroubaceae) afforded three new compounds including a stilbene glycoside bruceanoside A (1), and two canthinone alkaloids bruceacanthinones A (3) and B (4), as well as ten known secondary metabolites, rhaponticin (2), 1,11-dimethoxycanthin-6-one (5), canthin-6-one (6), 1-methoxycanthin-6-one (7), 2-methoxycanthin-6-one (8), 2-hydroxy-1,11-dimethoxycanthin-6-one (9), β-carboline-1-propionic acid (10), cleomiscosin C (11), cleomiscosin A (12) and hydnocarpin (13). The structures of all the compounds were determined using spectrometric and spectroscopic methods including 1D and 2D NMR, and HRSEIMS. The identity of the known compounds was further confirmed by comparison of their data with those reported in the literature. The root and bark methanolic extracts, the dichloromethane and ethyl acetate soluble fractions, as well as the isolated compounds (3–13), were assessed for their cytotoxicity against the cancer cell lines A-549, MCF-7 and PC-3. The results suggested that compounds in the extracts might possess a synergic action in their cytotoxicity

Beilschglabrines A and B: Two new bioactive phenanthrene alkaloids from the stem bark of Beilschmiedia glabra

Two new phenanthrene alkaloids, beilschglabrines A (1) and B (2) were isolated from the stem bark of Beilschmiedia glabra, together with lupeol, taraxerol, and 24-methylenelanosta-7,9-diene-3β-15α-diol. The structures of the isolated compounds were elucidated by extensive spectroscopic data analysis and comparison with respective literature data. The compounds were tested for DPPH radical scavenging, acetylcholinesterase and lipoxygenase inhibitory activities. Compound 1 displayed considerable activity in the acetylcholinesterase (IC50 50.4 μM), the DPPH radical scavenging (IC50 115.9 μM) and the lipoxygenase (IC50 32.8 μM) assays. © 2016 Phytochemical Society of Europe. Published by Elsevier B.V. All rights reserved

Chemical Composition, and Antibacterial (Against Staphylococcus aureus) and Free-Radical-Scavenging Activities of the Essential Oil of Scrophularia amplexicaulis Benth.

Chemical composition of the essential oil obtained from the aerial parts of Scrophularia amplexicaulis Benth. was analyzed, for the first time, by the gas chromatography/mass spectrometry (GC-MS) and gas chromatography/flame ionization detection (GC-FID). A total yield of 3 mg of essential oil per100 g of plant dry mass was obtained, and 27 compounds were identified, representing 97. 7 % of total oil. The essential oil were characterized by a high content of oxygenated monoterpenes and phenolic derivatives. The main constituents were eugenol (53.8%), eugenol acetate (24.5%), b -caryophyllene (5.7%), caryophyllene oxide (6.4%) and aromadendrene oxide II (2.1%). The antimicrobial activity of the essential oil was tested against Staphylococcus aureus using the well diffusion method, and t he free-radical-scavenging activity was assessed by the 2,2-diphenyl-picryl-hydrazyl (DPPH) assay