Mahesh S. Majik

Bis(indolyl)methane (BIM) alkaloids are an important group of bioactive natural products predominantly found in marine organisms. Thus, compounds like arsindoline A and B, vibrindole A, arundine, and trisindoline are found in marine bacteria, while the related compound, streptindole is obtained from <i>Streptococcus faecium</i> IB 37, found in human feces. In recent years, these molecules, which display a wide range of biological properties (antibacterial, antiviral, anti-oxidant, neurotoxic activity etc.), have attracted the attention of several synthetic and natural product chemists. This review lists selected bis(indolyl)methane analogues reported from different natural sources to date, together with their biological properties and synthesis. 1 Introduction 2 Occurrence, Isolation, Structure Elucidation, and Biological Activity 3 Synthetic Approaches towards Bis(indolyl)methanes 4 Conclusions

On the basis of the potent biological activity of cyclopentenyl-pyrimidines, fluorocyclopentenyl-pyrimidines were designed and synthesized from D-ribose. Among these, the cytosine derivative 5a showed highly potent antigrowth effects in a broad range of tumor cell lines and very potent antitumor activity in a nude mouse tumor xenograft model implanted with A549 human lung cancer cells. However, its 2'-deoxycytidine derivative 5b did not show any antigrowth effects, indicating that 2'-hydroxyl group is essential for the biological activity.

Herein, a sensitive fluorimetric assay for dissolved carbon dioxide (dCO2) was developed by using ion-induced self-assembly of a tetraphenylethylene derivative by taking advantage of its aggregation induced emission property. Chitosan, a commercially available polymer having amine functionality was utilized for the ion induced assay. In the presence of dCO2, the amine groups in the chitosan get protonated to convert neutral chitosan to a positively charged species, triggering negatively charged tetraphenylethene derivative (probe 1) to aggregate with it by electrostatic interaction. The aggregation causes intense blue fluorescence output from the system. The extent of the aggregation is reliant on the charge density of polymer, which is equivalent to dCO2 concentration. A linear relationship from 5 to 50 μM of dCO2, with a limit of detection of 5 × 10(-6) M (0.00127 hPa) was obtained. This is the first report for detecting dCO2 utilizing the AIE property.