Two 3-hydroxyflavone derivatives as two-photon fluorescence turn-on chemosensors for cysteine and homocysteine in living cells

Indole-substituted flavonol-based cysteine fluorescence sensing and subsequent precisely controlled linear CO liberation

“…2 Therefore, it is critically important to detect and visualize Cys rapidly and accurately in vivo for early clinical diagnosis and maintaining normal physiological functions of organisms. Although numerous Cys fluorescent probes have been exploited, [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] their practical applications are restrained due to their poor water solubility and biocompatibility, long response time, low sensitivity and narrow linear concentration range, especially deficient selectivity vs. homocysteine (Hcy) and glutathione (GSH). Therefore, their is still a great demand and challenge to develop water-soluble novel fluorescent probes that can detect and visualize Cys rapidly, selectively and sensitively in a wide linear concentration range in vivo.…”

Cysteine ratiometric fluorescence sensing reaction actuated B-ring naphthalene-substituted flavonol-based PhotoCORM: precisely controlled linear CO liberation

“…As typical ESIPT (excited-state intramolecular proton transfer) fluorophores, flavonoids not only possess special dual-emission characteristics, 54 but also liberate CO by photo-illumination in an aerobic environment, 55 so they can be used as Cys fluorescent probes [8][9][10][11][12][13][14][15][16][17][18][19] and fluorescent photoCORMs. 8,19,[35][36][37][38][39][40][41][42][43][44][45][46][47][48][49][50][51][52][53] Flavonol (3-hydroxyflavone, Fla) is the basic structural moiety of naturally occurring bioactive flavonols (Scheme 1).…”

“…2 Therefore, fast and accurate sensing and visualization of Cys in vivo is crucial for maintaining normal physiological functions and early clinical diagnosis. Although a large number of biothiol fluorescent probes have been reported, 3–23 their practical application is limited by factors such as non-ratiometric nature, long response time, low sensitivity, narrow linear concentration range, small Stokes shift and especially deficient selectivity towards homocysteine (Hcy) and glutathione (GSH). Therefore, developing novel ratiometric fluorescent probes for the rapid, highly selective, and sensitive detection and visualization of Cys in vivo over a wide linear concentration range with large Stokes shifts presents a great challenge.…”

pH dependency of the structural and photophysical properties of the atypical 2′,3-dihydroxyflavone

“…Indeed, they are exploited as uorescent probes in a wide variety of elds such as the chemistry of materials, 22,23 quantitation of biomolecules 24,25 and bioimaging. 26,27 Very little is known however on 2 0 3HF. It has shown potent antiviral properties in vitro and in vivo against inuenza A virus, 28 and it is an inhibitor of HIV-1 proteinase.…”