The structure of zapotin

Isolation Techniques for Flavonoids

“…1966;Markharn et al , 1970;Ohta and Yagishita, 1970;Bhutani et al , 1969a;Cambie and J ames, 1967;Dreyer and Bertelli, 1967). Perhaps the most useful solvent for the extraction of this group of compounds is a 1 : 1 mixture of water and methanol.…”

“…The solvents used for elution were benzene, benzene-ch10roform and chloroform. The fully methylated flavone zapotin (5,6,2'6'-tetramethoxyflavone) was separated on acid washed a1umina (Dreyer and Bertelli, 1967) and the 5-deoxyisoflavones, 6,7,4'-trimethoxyisoflavone and 7-hydroxy-6,4'-dimethoxyflavone have been separated on an alumina (activity IV) column eluted with benzene (Harborne et ai., 1963). Cambie and J ames (1967) have reported the preliminary purification of biflavonoids, containing some of the functional groups mentioned above, on an alumina column.…”

“…Flavonol polyacetates and polymethyl ethers have been successfully chromatographed by Egger (1969) using benzene-acetone (9 : 1) and tolueneacetone (19: 1). Other highly methoxylated flavones and flavonols have been chromatographed with benzene-methanol-n-butyl acetate (20 : 4 : 1) (Govindachari et al , 1965), hexane-acetone-n-butano1 (8 : 1 : 1 and 17 : 2 : 1) (Tatum and Berry, 1972), benzene-acetone (3 : 1), (9 : 1), (49 : 1), (92.8 : 7.2) (Mukerjee et al , 1969;Egger, 1969;Tatum and Berry, 1972), and chloroform-ethyl acetate (1 : 1) (Dreyer and Bertelli, 1967), the degree of solvent polarity depending 1argely upon the extent of methylation in the flavonoids.…”

“…We have found Referencet Dass and Weaver, 1972;Quarmby, 1968;Gupta, 1968b;Neu, 1957. Spiegi, 1969Kirchner, 1967;Beck andKnox, 1971 Dass andWeaver, 1972;Quarmby, 1968;Kirchner, 1967;Hillis and Isoi, 1965Barton, 1965Hörhammer et al, 1964Hörhammer et al, 1964Gupta, 1968bSpiegi, 1969;Silvestri, 1970;Dass and Weaver, 1972Stahl, 1969Cambie and James, 1967Kawano et al, 1964Camp bell et al, 1969Dreyer and Bertelli, 1967 Barton Smith, 1960;J angaard, 1970 Hillis andIsoi, 1965;J angaard, 1970J angaard, Pastuska, 1961…”

“…The adsorption process is favoured with water-alcohol mixtures and as a result retention on the layer is determined largely by the number of isolated (not o-dihydroxy or vicinal) phenolic hydroxyl groups and the number and nature of sugars present. Such solvents are generally unsatisfactory for the separation of aglycones but distinguish different glycosides weIl (Egger, 1964); thus Rf values for flavonol glycosides increase in the order: glucuronide, rhamnoside, glucoside, rhamnoglucoside, diglucoside, 3-galactoside-7-rhamnoside, 3-g1uco-side-7-g1ucoside, 3-rhamnoglucoside-7-g1ucoside, 3-xyloglucoside-7-glucoside (Egger, 1969). However, when lipophilic solvents such as chloroform-methanol-butanone (60: 26 : 14, water saturated) are used, partition processes are also operative.…”