5-methyl kaempferol

Rhododendron mucronatum G. Don Bai Du Juan Hua (white azalea) (flower) Essential oil, germacrone, farreol, grayanotoxin, gossypetin, azaleatin, 5-methyl kaempferol, 5-methyl myricetin, syringic acid, dihydroquercetin, coumarins, phenolic acid, p-hydroxybenzoic acid, protocatechuic acid, vanillic acid.48 Treat cough, asthma, headache, respiratory infection. 

Additional information on chemical variation within this species came from studies of exudate and internal (vacuolar) pigments based on broader collections of the fern (Star et al., 1975a, b). Exudate flavonoids, identified from specimens representing the range of the species, were identified as ceroptene [221], the C-methylflavonol pityrogrammin [222], and two derivatives of kaempferol, the 4 -methyl ether [223] and the 7,4 -dimethyl ether [224] (see Fig. 2.69 for stmctures 221-224). 

The plant is known elaborate a series of quite unusual phenanthrene alkaloid derivatives, of which aristoliukine-C, aristofolin A and E, aristolochic acid-la methyl ester, and aristolochic acid. Other chemical constituents found in this plant are flavonoid glycosides such as kaempferol-3-O-rutinoside and quercetin kaempferol-3-O-rutinoside (3,4). Exposure to Aristolochiaceae family is associated with the development of cancer in humans. A significant advance is the toxicological effects of aristolochic acid has been provided by the work of Pezzuto et al. They showed that aristolochic acid is a mutagen... 

Compounds 1 = 4-hydroxycoumarin 2 = umbelliferon 3 = 4-methyl-esculetin 4 = isopimpinellin 5 = esculin 6 = flavone 7 = a-naphtoflavone 8 = kaempferol 9 = quercetin 10 = isoquercitrin 11 = robinetin 12 = robinin 13 = myricetin 14 = luteolin 7-O-glucoside 15 = rutin 16 = hes-peretin 17 = hespiridin 18 = naringin 19 = pelargonin chloride 20 = polargonin chloride 21 = malvin chloride. 

The retention behaviour of flavonoids has also been extensively studied on silica stationary phases using heptane, benzene or dichloromethane as weaker components of the binary mobile phase and ethyl acetate and methyl ethyl ketone as modifier. Flavones (3-hydroxy, 5-hydroxy and 7-hydroxyflavone, tectochrysin, chrysin, apigenin, genkwanin, baicalein), flavonols (galangin, pilloin, kaempferol, rhamnetin, quercetin, robinetin,... 

Flavonoid sulphates such as quercetin 3,7-di-O-methyl 3-sulphate and kaempferol 7-0-methyl 3-sulphate, which inhihited the growth of Mycobacterium tuberculosis and Klebsiella pneumoniae, were isolated from the -hutanol fraction of 80% methanol extract of Argyreia speciosa (Burm. f) Boj. (Convolvulaceae), while flavonoids with mti-Helicobacter pylori activity, such as quercetin 3-methyl ether (isorhamnetin) (Fig. 3), were isolated from Cistus laurifolius L. (Cistaceae). ... 

Species of the genus Vellozia have been extensively studied for their flavonoid complement in relation to chemosystematics. In addition to a series of C-methylflavonols and two C-prenylated flavonols, derivatives of vellokaempferol and velloquercetin are accumulated in whole plants, leaves, and leaf exudates. The basic structure of these compounds is characterized by 7,6-isopropenylfurano substitution, based upon kaempferol, quercetin, and their 0-methyl ethers. In addition, 8-C-methyl derivatives of these compounds were also identified from leaves of V. stipitata " So far, species of this genus are the only reported sources of these compounds, which in parts have been proved to be accumulated externally. ° Structures are exemplified by Figure 12.10. 

C-Sulfate Kaempferol 3-methyl ether Phyllanthus virgatus whole plant Euphorbiaceae 165... 

Glucuronide Kaempferol 7-methyl ether (rhamnocitrin) Centaurea bracteata aerial parts Compositae 275... 

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