Bioassay-Guided Isolation of 2-[p-(2-Carboxyhydrazino)phenoxy]-6-(hydroxymethyl)tetrahydro-2H-pyran-3,4,5-triol from Oroxylum indicum and the Investigation of Its Molecular Mechanism Action of Apoptosis Induction.

The leaf crude extract of Oroxylum indicum (L.) Kurz induces genomic DNA fragmentation, comet formation, and the inhibition of cell proliferation in the prostate cancer cell line PC3, as assessed by agarose gel electrophoresis, comet assay and MTT assay, respectively. The bioactive compound was purified through bioassay-guided fractionation using preparative HPLC and MTT assay. The light brown and water-soluble compound was characterized using 1H and 13C nuclear magnetic resonance (NMR), Fourier transform infrared (FT-IR), and electrospray ionization (ESI) mass spectrometry. The compound was identified as a glycosylated hydroquinone derivative, 2-[p-(2-Carboxyhydrazino)phenoxy]-6-(hydroxymethyl) tetrahy-dro-2H-pyran-3,4,5-triol (molecular formula, C13H18N2O8; molecular mass = 330). The identified phytocompound has not been reported earlier elsewhere. Therefore, the common name of the novel anticancer phytocompound isolated from Oroxylum indicum in this current study is oroxyquinone. The half-maximal inhibitory concentration (IC50) of oroxyquinone on PC3 cells was 58.9 µM (95% CI = 54.5 to 63.7 µM). Treatment of PC3 cells with oroxyquinone induced genomic DNA fragmentation and chromatin condensation, increased in the annexin-V positive cells, arrested the cell cycle at S phases, and inhibited the cell migration; as assessed by comet assay, DAPI staining, flow cytometry and a wound healing assay, respectively. On the investigation of the molecular mechanism of the induction of apoptosis, the results indicated that oroxyquinone induced caspase-3 and PARP independent apoptosis but through the p38 pathway and the localization of AIF into the nucleus. The present study identifies a novel anticancer molecule and provides scientific evidence supporting the therapeutic potency of Oroxylum indicum for ethnomedicinal uses.

Synthesis of Green/Blue Light Emitting Quinolines by Aza-D-A Reaction Using InCl3 Catalyst.

An efficient InCl3-catalyzed sequential reaction of aromatic amines, aromatic aldehydes and functionalized alkynes leading to the formation of new quinoline derivatives exhibiting significant fluorescence activities is described. The photophysical investigations of quinolines were carried out by absorption and photoluminescence measurements. One particular compound 4 h having maximum intensity, emitting green colour (Φ = 0.78) with average life time of 6.20 ns was the best amongst the tested compounds. The presence of the amino group at the 4-aryl substituent of the quinoline backbone played an important role in executing the Povarov cyclization successfully and enhancing the flourescence properties of the newly synthesized quinolines.

Recent Progress in Biological Activities of Indole and Indole Alkaloids.

The indole scaffold is found in a wide range of bioactive heterocycles and natural products. Moreover, the indole moiety is considered as the active principle in several alkaloids such as mitomycin C and reserpine. Thus, over the past decade, chemists are increasingly attracted towards the studies on the pharmacological and therapeutic activities of indole containing compounds. Furthermore, the molecular structures of well-known drugs such as sumatriptan, tadalafil, fluvastatin and rizatriptan are based on indole frameworks. This mini-review covers some of the significant and recent achievements of indole derivatives with respect to their biological activities up to 2015.

Indium/TFA-catalyzed synthesis of tetracyclic [6,5,5,6] indole ring, via a tandem cycloannulation of ß-oxodithioester with tryptamine.

The cycloannulation of ß-oxodithioesters and tryptamine in dichloromethane in the presence of a catalytic amount of InCl3 and TFA gave the novel 5-aryl/heteroaryl 2a(1),9b-dihydro-1H-2a,5a-diaza-cyclopenta[jk]fluorene-3(2H)-thiones in moderate to good yields. The reaction was proposed to involve a tandem transformation of thioamide, protonation, and dehydrative cyclization. KMnO4-oxidation of these newly prepared compounds yielded oxidative desulfurization products in good yields.

Novel 3-alkanoyl/aroyl/heteroaroyl-2H-chromene-2-thiones: synthesis and evaluation of their antioxidant activities.

A facile, convenient and high yielding synthesis of a combinatorial library of 3-alkanoyl/aroyl/heteroaroyl-2H-chromene-2-thiones has been developed by the condensation of easily accessible beta-oxodithioesters and salicylaldehyde/substituted 2-hydroxybenzaldehydes under solvent-free conditions. The assessment of radical scavenging capacity of the compounds towards the stable free radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) was measured and these compounds were found to scavenge DPPH free radical efficiently. Five selected compounds were able to protect curcumin from the attack of sulfur free radical generated by radiolysis of glutathione (GSH). The newly synthesized compounds exhibited profound antioxidant activities. Five of them rendered comparatively high antioxidant capacity.

Application of beta-oxodithioesters in domino and multicomponent reactions: facile route to dihydropyrimidines and coumarins.

A facile route to hitherto unknown 5-methylmercaptothiocarbonyl-4-aryl-3,4-dihydropyrimidin-2(1H)-ones and substituted 2H-chromene-2-thiones has been developed. SnCl(2)-catalyzed cyclocondensation of beta-oxodithioesters with a variety of readily accessible aldehydes and urea affords the dihydropyrimidinones. The methodology involves the three-component Biginelli reaction. On the other hand, substituted salicylaldehyde and beta-oxodithioesters reacted under the same condition to afford the substituted 2H-chromene-2-thiones in high yields.

Synthesis and in vitro evaluation of the antifungal activities of dihydropyrimidinones.

Copper (II) chloride in the absence of any solvent, efficiently catalyses the synthesis of dihydropyrimidinones (80-96% yields) by the Biginelli reaction. Six compounds were selected and examined their antifungal activities against the radial growth of three fungal species viz., Trichoderma hammatum, Trichoderma koningii and Aspergillus niger.