Coumarin bioactivities

Coumarins are known to have pronounced bioactivity. A rather new procedure for the synthesis of pyrrolo[3,2-c]coumarins uses a domino process in which an amine oxide rearrangement [61] is involved (Scheme 7.37) [62]. Reaction of the cou-... 

Even P, Chaubet F, Letoumeur D, Viriot ML, Carre MC (2003) Coumarin-like fluorescent molecular rotors for bioactive polymers probing. Biorheology 40(l) 261-263... 

Kofmas, C. et al., Flavonoids and bioactive coumarins of Tordylium apulum, Phytochemistry, 48, 637, 1998. 

To design a supercritical fluid extraction process for the separation of bioactive substances from natural products, a quantitative knowledge of phase equilibria between target biosolutes and solvent is necessary. The solubility of bioactive coumarin and its various derivatives (i.e., hydroxy-, methyl-, and methoxy-derivatives) in SCCO2 were measured at 308.15-328.15 K and 10-30 MPa. Also, the pure physical properties such as normal boiling point, critical constants, acentric factor, molar volume, and standard vapor pressure for coumarin and its derivatives were estimated. By this estimated information, the measured solubilities were quantitatively correlated by an approximate lattice equation of state (Yoo et al., 1997). 

The major types of bioactive constituents reported from Broussonetia papyrifera are the prenylated flavonoids, which include compounds of the diphenylpropane, chalcone, flavan, flavanone, flavone, flavonol, and aurone classes (Table 2), Fig. (7). An early study on B. papyrifera resulted in the isolation of two diphenylpropanes, broussonins A (29) and B (30), and a coumarin, marmesin (52), with antifungal activity [39]. Also, a diprenylated diphenylpropane derivative, kazinol F (31) [40], was reported as an antioxidant and tyrosinase inhibitory constituent [34]. 

Chapter 5). Separation of a mixture of BODIPY and fluorescein was achieved in less than 20 s (see Figure 6.23). Five bioactive peptides (papain inhibitors, proctobin, opioid fragment 90-95, ileangiotensin HI, and angiotensin III) were also separated in this manner [639]. A similar method has been used to separate two coumarin dyes or to separate Alexafluor-labeled angiotensin from the excess dye [587,640]. CEC separation of four FITC-labeled synthetic peptides was... 

Furthermore, eight 3-(thiazol-4-yl)-4-hydroxychromen-2-one derivatives were prepared in good yields in the reaction of 3-(2-bromoacetyl)-4-hydroxychromen-2-one with thioureas, thioacetamide, thiobenzamide and ammonium dithiocarbamate. The obtained coumarin derivatives can be used as potentially bioactive compounds and as precursors in the synthesis of medications. 

From different species of this genus triterpenoid saponins have been isolated, together with other compounds such as lignans, coumarins, flavonoids and polyacetylenes. The saikosaponins from Bupleurum L. are considered as the major bioactive components mainly used for their antiinflammatory and antihepatotoxic actmties. 

The third chapter, Quantitative Structure-Cytotoxicity Relationship of Bioactive Heterocycles by the Semi-empirical Molecular Orbital Method with the Concept of Absolute Hardness by Mariko Ishihara, Hiroshi Sakagami, Masami Kawase, and Noboru Motohashi, presents the relationship between the cytotoxicity (defined as 50% cytotoxic concentration) of heterocycles such as phenoxazine, 5-trifluoromethyloxazoles, O-heterocycles such as 3-formylchromone and coumarins, and vitamin K2 derivatives against some tumor cell lines and 15 chemical descriptors. The results suggest the importance of selecting the most appropriate descriptors for each cell type and compound. The review is of interest as it represents the relationship of the molecular structures with the cytotoxic activity of these heterocycles. 

Abstract Construction of chemical libraries is a useful approach to the discovery of better fluorescent materials, and several types, such as styryl dyes and cyanine dyes, have been reported. In this chapter, we focus on construction of a library of chemicals having a coumarin skeleton as the core structure. Coumarin and its derivatives are key structures in various bioactive or fluorescent molecules, and their fluorescence properties are dependent on the precise structure, including the positions of substituents. 

Furanocoumarin 8-methoxypsoralen (8-MOP) (1-100 pg/ml) in the dark showed a protective affect against hypotonic hemolysis of the erythrocyte membrane. However, the effect against heat-induced hemolysis was dependent on the concentration of 8-MOP lower concentrations of 8-MOP showed an inhibiting effect, whereas higher concentrations caused acceleration of hemolysis. The erythrocytes reacted with 8-MOP in the dark were shrunk and had altered shapes. It can be deduced that modification of erythrocyte membrane by 8-MOP is via the reaction with membrane lipids and proteins [295]. From these results, it could be concluded that the effect on the cell membrane by coumarins could have an important role in their bioactivity. 

The focus of this review was to look at the position of natural products in antifungal research and role of coumarins in this respect. In addition, we tried to consider other aspects of coumarin compoimds with major bioactivities as well. Natural products have served as an important source of drug for centuries, as about half of the pharmaceuticals in today s market are derived from natural products [322] In addition, they have had a significant role in identifying new biomedical cellular/molecular targets and act as biochemical probes, therefore, more attention should be paid to this field of research by scientists and pharmaceutical companies. In this article, we tried to present potentials of coumarins for such attentions. Moreover, Mother Nature has provided us with many new ideas in drug discovery itself. Combinatorial chemistry, wherein a molecular scaffold is substituted with a variety of substituents, was initiated as a close mimic of synthesis of different antibodies by the immune system [323]. 

Coumarins, The Bioactive Structures with Antifungal Property... 

Citrus fruits provide a diverse range of flavonoids [35] naringenin, a flavonone, has been shown to posses cholesterol-lowering and anticancer properties [36]. The naringin content of lime juice has been estimated to be -100 pg/g [37], and the lime is also a source of limonene, a biologically active terpene (see above). Other bioactive substances in lime (Table 4) include coumarins that possess anticoagulatory and anti-inflammatory properties. 

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