The flowers of 20 native taxa of Petunia (Solanaceae) were investigated by
HPLC for the occurrence of anthocyanins, The investigation revealed the pre
sence of at least 24 anthocyanins in their flowers, of which 18 known antho
cyanins isolated from the flowers of P. exserta, P. guarapuavensis, P, inte
grifolia, P. occidentalis, and P. reitzii were fully identified by chemical
and spectral methods to be 3-glucoside of delphinidin; 3-rutinosides of cy
anidin, delphinidin, and petunidin; 3-rutinoside-5-glucosides, 3-trans and
-cis-p-coumaroylrutinoside-5-glucosides, and 3-trans-caffeoylrutinoside-5-g
lucosides of delphinidin, petunidin, and malvidin; and 3-trans-caffeoylgluc
osyl-trans-(caffeoyl or p-coumaroyl) rutinoside-5-glucosides of malvidin, S
ix novel anthocyanins were isolated from the flowers of P, occidentalis, an
d their structures were identified to be 3-glucosyl p-coumaroylrutinoside-5
-glucosides and 3-glucosylcaffeoylrutinosides of petunidin and malvidin, an
d also 3-caffeoylglucosylcaffeoylrutinoside-5-glucoside and 3-caffeoylgluco
syl p-coumaroylrutinoside-5-glucoside of petunidin. Out of the six pigments
, petunidin 3-glucosyl p-coumaroylrutinoside-5-glucoside was unambiguously
determined by spectral methods to be petunidin 3-O-[6-O-(4-O-(4-O-(beta-D-g
lucopyranosyl)-trans-p-coumaroyl)-alpha-L-rhamnopyranosyl)-beta-D-glucopyra
noside]-5-O-[beta-D-glucopyranoside]. The 20 native taxa of Petunia could b
e placed into four groups (A, B, C, and D) with one further into five subgr
oups (D1-D5) regarding their constituents and contents of major anthocyanin
s and also their pigment biosynthesis with respect to the blocks or inhibit
ors of the hydroxylation, glucosylation, and acylation reactions in them. T
he use of anthocyanins as taxonomic markers in the genus Petunia is discuss
ed in relation to the flower colour and possible pollination vectors. (C) 1
999 Elsevier Science Ltd. All rights reserved.