Studies on the syntheses, structural characterization, antimicrobial-, and DPPH radical scavenging activity of the cocrystals caffeine:cinnamic acid and caffeine:eosin dihydrate

Antioxidant synergistic effects of Osmanthus fragrans flowers with green tea and their major contributed antioxidant compounds

The antioxidant synergistic effects of Osmanthus fragrans flowers with green tea were evaluated, and their major antioxidant compounds contributed to the total amount of synergy were determined. The antioxidant compounds in O. fragrans flowers with green tea were identified by LC-MS and quantified by UPLC-PDA. The synergistic antioxidant interactions between O. fragrans flowers with green tea and their antioxidant compounds were tested using the Prieto’s model after the simulated digestion. The main antioxidant compounds in O. fragrans flowers were acteoside and salideroside, whereas the main antioxidant compounds in green tea were caffeine, gallic acid, and L-epicatechin. The significant synergistic effect between O. fragrans flowers and green tea was observed and among nearly all of the combinations of their antioxidant compounds. Among the combinations, acteoside and gallic acid contributed most to the antioxidant synergy between O. fragrans flowers and green tea. However, the simulated digestion decreased this antioxidant synergy because it reduced the contents and the antioxidant capacities of their compounds, as well as the antioxidant synergy among the compounds.

Molecular structure investigation of organic cocrystals of 1,10-phenanthroline-5,6-dione with aryloxyacetic acid: a combined experimental and theoretical study

Two organic cocrystals namely, 1,10-phenanthroline-5,6-dione:2-naphthoxyacetic acid [(phendione)(2-naa)] (1) and 1,10-phenanthroline-5,6-dione:2-formylphenoxyacetic acid [(phendione)(2-fpaa)] (2) were synthesized and studied by single crystal XRD, FT-IR, NMR, thermogravimetric, and powder X-ray diffraction analysis. The molecular properties of cocrystals were studied using density functional theory (DFT), basis set B3LYP/6-31G(d,p). Both cocrystals are stabilized through intermolecular hydrogen bonding (OH⋯N). The total electron density and molecular electrostatic potential surfaces of the cocrystals were constructed by NBO analysis using B3LYP/6-31G(d,p) method to display the electrostatic potential (electron+nuclei) distribution. The energy gap between HOMO and LUMO was measured for both cocrystals.

In situ Bronsted-Lowry acid catalyzed syntheses, characterization, single crystal XRD, electronic spectral-, DPPH radical scavenging-, and DNA protection studies of aryl-3,3'-bis(indolyl)methanes

A series of novel aryl-3,3'-bis(indolyl)methanes (BIMs) were synthesized using indole and formylphenoxyaliphatic acid(s) in water in the absence of any catalyst. The formylphenoxyaliphatic acid behaves as an in situ Bronsted-Lowry acid catalyst in water. UV-Visible and fluorescence spectra of the compounds were recorded in selected solvents. The gas phase geometry optimization of the compounds were achieved using DFT calculations at B3LYP/3-21G((*)) level of theory. The electronic properties, such as HOMO-LUMO energies were calculated using the above method based on the optimized structure. Compounds have better DPPH radical scavenging activity and reduction of oxidative damage of DNA.

Chemical composition and biological activities of Gerbera anandria

Gerbera anandria (Compositae) was extracted with 75% ethanol and the residue was fractionated using light petroleum, chloroform and ethyl acetate. The constituents of the extracts were separated by column chromatography employing solvents of different polarity. Column chromatography of the light petroleum fraction resulted in the isolation of methyl hexadecanoate, while the chloroform fraction afforded xanthotoxin, 2-hydroxy-6-methylbenzoic acid, 7-hydroxy-1(3H)-isobenzofuranone, a mixture of β-sitosterol and stigmasterol, and 8-methoxysmyrindiol and the ethyl acetate fraction gave gerberinside, apigenin-7-O-β-d-glucopyranoside and quercetin. A new coumarin, 8-methoxysmyrindiol, was found. The chemical structures of the isolated compounds were established by MS and NMR (HSQC, HMBC). Free radical scavenging and cytotoxic activities of crude extracts and 8-methoxysmyrindiol were further investigated. The ethyl acetate phase exerted the strongest DPPH free radical scavenging activity in comparison to the other fractions. The coumarin 8-methoxysmyrindiol demonstrated cytotoxicity against multiple human cancer cell lines, with the highest potency in HepG2 cells.