No abstract

Release of a payload in a spatiotemporal fashion has a substantial impact on increasing therapeutic efficacy. In this work, a novel monolayer of gold nanoparticles (AuNPs) featuring light-responsive ligands was investigated as a potential drug carrier whose drug release can be triggered by UV light. Hydrophobic molecules were noncovalently entrapped in the compartments of its monolayers. Once irradiated with UV light, the dinitrobenzyl linker was cleaved, leading to release of the entrapped agent. AuNPs were characterized using UV spectrophotometry, TEM, and a zetasizer. A naturally occurring compound extracted from Goniothalamus elegans Ast was chosen as a hydrophobic model drug. Entrapment and release of dye were monitored using fluorimetry. The percent encapsulation of dye was of 13.53%. Entrapped dye can be released upon UV irradiation and can be regulated by changing irradiation time. Up to 83.95 ± 2.2% entrapped dye can be released after irradiation for 20 minutes. In the absence of UV light, dye release was only 19.75%. For comparison purposes, AuNPs having no dinitrobenzyl groups showed a minimal release of 12.23% and 11.69% with and without UV light, respectively. This demonstrated an alternative strategy to encapsulate drugs using a noncovalent approach followed by their controlled release upon UV irradiation.

A new (naphthalenyl)methyl acetate, (1,4,5-trimethoxynaphthalen-2-yl)methyl acetate ( 1) and (±)-4,5-dihydroxy-2-methyltetralone (2) were isolated together with five lupane triterpenes (3-7), naphthoquinone derivatives (8-13), coumarins (14 and 15) and a vanillic acid ( 16) from the stems of Diospyros ehretioides. Their structures were established through spectroscopic analysis, IR, 1D and 2D NMR. Both 1 and 2 displayed significant cytotoxicity against three cancer cell lines including HeLa, HCT116 and MCF-7, with IC 50 values in the range of 5.05-15.90 µg/mL, while 16 exhibited moderate cytotoxicity against HeLa and HCT116 cell lines and was not toxic to Vero cells.

Key indicators: single-crystal X-ray study; T = 293 K; mean (C-C) = 0.002 Å; Hatom completeness 92%; disorder in solvent or counterion; R factor = 0.043; wR factor = 0.127; data-to-parameter ratio = 21.6.In the crystal structure of the title compound, [Ni(N 3 ) 2 -(C 12 H 12 N 2 ) 2 ]ÁH 2 O, the Ni II atom is situated on a twofold axis and adopts a distorted octahedral geometry with the two 5,5 0 -dimethyl-2,2 0 -bipyridyl (dmbpy) and the two azide ligands in a cis arrangement. The water solvent molecule is disordered over two positions in a 1:1 ratio. Related literatureFor general background to 2,2 0 -bipyridine and its derivatives, see: Blau (1888)

A new plumbagin derivative, 3-(5-oxohexyl)plumbagin (1), together with six known benzoquinone derivatives (2-7), four known triterpenoids (8-11) and coniferyl aldehyde (12) were isolated from Diospyros undulata roots. Their structures were elucidated by intensive spectroscopy including 1D and 2D NMR, UV, IR and MS spectrometric analysis. Compound 1 exhibited strong cytotoxicity against three cancer cell lines as lung cancer (NCI-H187), breast cancer (MCF-7), and oral cancer (KB) with IC 50 values of 7.16, 12.85 and 28.67 µM, respectively. Moreover, it did not showed cytotoxicity to Vero cells. In addition, the antimicrobial activity of compound 1 was moderate that kill only S. aureus with MBC of 250 µg/mL while other compounds especially compound 4 showed a broader activity that kill all tested bacteria.