Interaction of fatty acid-containing 9-aminoacridine derivative with surfactants and bio-surfactants: Synthesis and photophysical studies

Preparation and characterization of Gum Arabic Schiff's bases based on 9-aminoacridine with in vitro evaluation of their antimicrobial and antitumor potentiality

The conjugation between drug and biopolymers through an easily hydrolysable bond such as ester linkage, disulfide linkage, or imine-bond have been extensively employed to control the drug release pattern and improve its bioavailability. This work described the conjugation of 9-aminoacridine (9-AA) to Gum Arabic (GA) via Schiff's base, as a pH-responsive bond. First, GA was oxidized to Arabic Gum dialdehyde (AGDA), then a different amount of 9-AA (10, 25, and 50 mg 9-AA) was coupled to defined amount of AGDA, the coupling was confirmed by elemental analysis and different spectroscopic tools. In addition, the physical features of Schiff's base conjugates including surface morphology, thermal stability, and crystalline structure were examined. The thermogravimetric analysis revealed that the incorporation of 9-AA slightly improved the thermal stability. The coupling of 9-AA to AGDA dramatically enhanced its in vitro antimicrobial and antitumor activities. All conjugates exhibited broad-spectrum activity against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, and Candida albicans. Moreover, AGA 25 and AGA 50 demonstrated promising capability to suppress the proliferation of human colon cancer cell line (Caco-2), with IC₅₀ 190.10 and 180.80 μg/mL respectively.

Interaction of alkyl chain containing pyrene derivatives with different micellar media: Synthesis and photophysical study

The present work describes the synthesis and photophysical studies of four newly synthesized alkyl chain containing pyrene derivatives and their applications in micellization process of different types of surfactants e.g. CTAB and SDS. The fluorescent properties of these pyrene derivatives were utilized to understand the micellization process of CTAB and SDS. The length of alkyl chain affects the hydrophobicity of pyrene fluorophore which also affects the sensitivity of fluorophore towards the micellization of CTAB and SDS surfactants. The longest alkyl tail containing, PBBU showed more sensitivity whereas moderate alkyl chain containing, PABU and PBME showed moderate sensitivity and finally PAME contained smallest alkyl tail, showed no sensitivity towards the micellization of CTAB and SDS. The alkyl tail of fluorophore make it more hydrophobic and it could easily bind with the hydrophobic inner core of micelles. In both surfactants, PBBU showed LE emission at ~400 nm and aggregate emission at ~470 nm, whereas, PABU and PBME showed LE emission band at ~400 nm. Before CMC, the aggregates band of PBBU increased with increasing the surfactant concentrations, but after CMC the individual PBBU present into the water medium could binds with the inner core of micelles. Thus PBBU senses the formation of premicellar aggregates of CTAB and SDS. The LE emission of the fluorophore gradually increases while increasing the CTAB and SDS concentrations. The change in fluorescence emission of PABU, PBME and PBBU with increasing concentration of CTAB and SDS were used to calculate the CMC of CTAB and SDS surfactants.

Identification of 15 Phthalate Esters in Commercial Cheese Powder via Cyclodextrin-Promoted Fluorescence Detection

A challenge for detecting phthalates in commercial products such as cheese powders is that the composition of the products is highly complex, and current methods for detection rely on gas chromatography-mass spectrometry, which is not portable and cannot be used by individual consumers at a time and place of their choosing. Herein, we report the development of a new method for phthalate detection in cheese powder using cyclodextrin-promoted fluorescence detection, in which the presence of the phthalate analytes leads to highly analyte-specific changes in the fluorescence emission signal of a fluorophore bound in a cyclodextrin cavity. This method relies on subtle changes in the analyte affinity for the fluorophore and the cyclodextrin cavity and provides for markedly more straightforward sample preparation procedures and an extremely rapid read-out signal, with potential for the development of portable fluorescence sensors. Using this method, we were able to detect 15 phthalate esters with highly analyte-specific responses and at concentrations as low as 0.12 μM, which is well below regulatory levels of concern. Computational investigations strongly support the observed experimental trends.