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jueves, junio 02, 2011

Flavonoides en Eucryphia

Después de la nota sobre la ultima patente de Gloria Montenegro y su equipo de la PUC, me dio por mirar más sobre flavonoides y Ulmo, caía en un lindo paper del 2000, "Variation in flavonoid exudates in Eucryphia species from Australia and South America" E. Wollenweber et al. / Biochemical Systematics and Ecology 28 (2000) 111 - 118.

Bien cagónes los latinos ... mejor aplicar la patente de Gloria en las mieles de Downunder!

Leaf and bud exudate #avonoids were analysed for all Eucryphia species, and 28 compounds
were identi"ed. Cladistic analyses of phytochemical data indicate that the two Tasmanian
species, E. lucida and E. milliganii are sister taxa, which is consistent with morphological
studies. Cluster analysis and ordination would suggest that the species E. wilkiei from north
eastern Queensland is relatively isolated from other Australian and South American
taxa. ( 2000 Elsevier Science Ltd. All rights reserved.

The family placement of Eucryphia is uncertain. Cronquist (1981) placed it in its
own family, Eucryphiaceae, based on a number of floral characters including the 4}14
(18), multi-ovulate, carpels and large solitary flowers, with prominent petals. Several
morphological characters e.g. interpetiolar stipules and pollen, however strongly
support its inclusion in Cunoniaceae (Hu!ord and Dickison, 1992; Hideux and
Ferguson, 1976). Phytochemical characters (Jay, 1968; Bate-Smith et al., 1977) have
also been interpreted by Hu!ord and Dickison (1992) as supporting its inclusion in

A correlation between tissue flavonoid chemistry and plant geography among
Eucryphia species was recognised by Bate-Smith et al. (1967). The authors studied the
five species E. cordifolia, E. glutinosa, E. lucida, E. milliganii and E. moorei, as neither
E. jinksii or E. wilkiei were known at that time. They reported seven flavonol
glycosides and one dihydroflavonol glycoside, along with two flavanol methyl ethers
that were found as aglycones from these five species.

In this study the flavonoids in leaf and bud exudates were recovered from all
Eucryphia species. The two Tasmanian species, E. lucida and E. milliganii, exhibit
conspicuous sticky exudates which cover the young buds (Forster and Hyland, 1997).
Eucryphia glutinosa is named after the sticky exudate that occurs on young foliage
and buds. These exudates are probably derived from colleters, that are present in all
species, and occur on the inner surface of the stipules that protect the developing buds
(Dickison, 1978; Rutishauser and Dickison, 1989).

3. Results and discussion
Twenty-eight flavonoids were identified from the seven Eucryphia species (Table 1).
The South American species E. glutinosa exhibits two flavones, apigenin-7, 4@-
dimethyl ether and luteolin-7,3@-dimethyl ether, which it shares with two Australian
and one Tasmanian species. The other South American species, E. cordifolia, contains
only apigenin-7,4@-dimethyl ether as a trace constituent. Both South American species
lack 3-hydroxylation, i.e. flavonols are missing. The two Tasmanian species, E. lucida
and E. milliganii, with their conspicuous bud exudates, are rich in flavone and flavonol
methyl ethers. These two species share 8 flavonoids (apigenin-7-methyl ether,
luteolin-7,3@,4@-trimethyl ether, kaempferol-3-methyl ether, kaempferol-3,7,4@-
trimethyl ether, quercetin-3-methyl ether, quercetin-3,7,4@-trimethyl ether, quercetin-
3,3@,4@-trimethyl ether and quercetin-3,7,3@,4@-tetramethyl ether) which are not
recorded from any other taxon. Four flavonoids (luteolin-3@-methyl ether, kaempferol-
3,7-dimethyl ether, kaempferol-3,4@dimethyl ether and quercetin-3-methyl ether)
are only produced by Eucryphia lucida, two others (luteolin-7,4@-dimethyl ether,
quercetin-3,4@-dimethyl ether) are only produced by E. milliganii. The southern
Australian mainland species (E. jinksii and E. moorei) also have a diverse range
of flavonoids. Four flavonoids, i.e. isoscutellarein-8,4@-dimethyl ether isoscutellarein-
7,8,4@-trimethyl ether, kaempferol-4@-Methyl ether, and quercetin-3,7,4@-trimethyl
ether, were identified from E. jinksii only. We want to stress that E. jinksii is the
only species capable of hydroxylating the 8-position. Another flavone, 6-OH-luteolin-
6,7-dimethyl ether, was also found to be present in only one species, E. moorei.
The S. Australian and the Tasmanian species are able to methylate the same hydroxyls.
E. wilkiei from north eastern Queensland is the only species where flavonoid
glycosides have been found as exudate constituents. Further, Eucryphia wilkiei,
E. jinksii and E. lucida. share a flavonoid aglycone whose identity remains to be established.

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