TY - BOOK
T1 - Distribution and Biosynthesis of Iridoid Glucosides in the
Loasaceae Family
AU - Rodriguez-Lopez, Veronica
PY - 2000
Y1 - 2000
N2 - In order to make a more precise inventory of iridoid glucosides
from Loasaceae family 13 species belonging to 7 genera (Eucnide
bartonioides, E. grandiflora, Gronovia scandens, Fuertesia
domingensis, Loasa parviflora, L. tricolor, L. urens, L. speciosa,
Klaphrotia mentzeloides, Cajophora cernua, C. lateritia,
Blumenbachia hieronymi) were investigated. Six new compounds were
isolated and fully characterized. From E. bartonioides, a novel
iridoid named 5-hydroxyloganin, was isolated and characterized by
NMR. While a novel pair of secoiridoids,
6alpha/beta-hydroxysweroside, were obtained from Gronovia
scandens. A new oleoside-type secoiridoid, named
10-hydroxyoleoside 7-methyl ester was isolated from Cajophora
cernua. Finally, two new secoiridoids were found in C. lateritia,
namely 10-acetoxyoleoside 7-methyl ester and 10-acetoxyoleoside
11-methyl ester. The phytochemical work for the rest of the
species investigated revealed only known compounds. - In order to
elucidate the biosynthesis of secoiridoids found in the Loasaceae
family, the synthesis of four possible 2H labelled precursors
([6,7,8,10-2H4]-deoxyloganic acid, [6,10-2H2]-ketologanin,
[6,10-2H2]-ketologanic acid, and [6,10-2H2]-7-epi-loganic
acid)were performed. additionally, one 13C labelled precursor
(13C-stanside) was synthesized. - The introductory administrations
of 2H labelled precursors to E. bartonioides, E. grandiflora and
C. lateritia demonstrated that deoxyloganic acid is significantly
incorporated into several sweroside-morroniside type secoiridoids
present in these species. - Deoxyloganic acid and loganin were
shown to be incorporated into morroniside in E. bartonioides and
E. grandiflora. Ketologanin was also incorporated into morroniside
in E. bartonioides. The incorporations obtained in Eucnide
supports a biosynthetic route from deoxyloganic acid through
loganin and ketologanin, which is suggested to be the precursor
that undergoes ring cleavage to morroniside.- In C. lateritia
loganin also proved to be a precursor of 10-acetoxyoleoside
11-methyl ester whereas 7-epi-loganic acid was not incorporated at
all. The incorporations obtained in C. lateritia support a
different biosynthetic route for oleoside-type iridoids in the
Loasaceae family in comparison with Oleaceae family. - Finally,
the implications of the biosynthetic and the phytochemical studies
on the taxonomic placement and phylogenetic relationships of
Loasacae are discussed. It is difficult to establish phylogenetic
relationships within the Loasacae family using the iridoid
distribution pattern known until now. The iridoids and
secoiridoids present derive from the biosynthetic route I, which
is shared by Cornales, Gentianales and Loasales. The presence of
10-decarboxylated iridoids is common for the genus Mentzelia
(Loasaceae) and the family Hydrangeaceae (Cornales). And finally,
the presence of oleoside-type secoiridoids in Loasaceae, which is
shared by the family Oleaceae (Gentianales), confirm a common
ancestry for Cornales, Gentianales and Loasales. However, the
presence of the oleoside-type iridoids in Loasaceae and the
differences of the biosynthetic pathways between Oleaceae and
Loasaceae justify the placement of Loasaceae in its own order near
to Cornales and Gentianales as suggested by Dahlgren.
AB - In order to make a more precise inventory of iridoid glucosides
from Loasaceae family 13 species belonging to 7 genera (Eucnide
bartonioides, E. grandiflora, Gronovia scandens, Fuertesia
domingensis, Loasa parviflora, L. tricolor, L. urens, L. speciosa,
Klaphrotia mentzeloides, Cajophora cernua, C. lateritia,
Blumenbachia hieronymi) were investigated. Six new compounds were
isolated and fully characterized. From E. bartonioides, a novel
iridoid named 5-hydroxyloganin, was isolated and characterized by
NMR. While a novel pair of secoiridoids,
6alpha/beta-hydroxysweroside, were obtained from Gronovia
scandens. A new oleoside-type secoiridoid, named
10-hydroxyoleoside 7-methyl ester was isolated from Cajophora
cernua. Finally, two new secoiridoids were found in C. lateritia,
namely 10-acetoxyoleoside 7-methyl ester and 10-acetoxyoleoside
11-methyl ester. The phytochemical work for the rest of the
species investigated revealed only known compounds. - In order to
elucidate the biosynthesis of secoiridoids found in the Loasaceae
family, the synthesis of four possible 2H labelled precursors
([6,7,8,10-2H4]-deoxyloganic acid, [6,10-2H2]-ketologanin,
[6,10-2H2]-ketologanic acid, and [6,10-2H2]-7-epi-loganic
acid)were performed. additionally, one 13C labelled precursor
(13C-stanside) was synthesized. - The introductory administrations
of 2H labelled precursors to E. bartonioides, E. grandiflora and
C. lateritia demonstrated that deoxyloganic acid is significantly
incorporated into several sweroside-morroniside type secoiridoids
present in these species. - Deoxyloganic acid and loganin were
shown to be incorporated into morroniside in E. bartonioides and
E. grandiflora. Ketologanin was also incorporated into morroniside
in E. bartonioides. The incorporations obtained in Eucnide
supports a biosynthetic route from deoxyloganic acid through
loganin and ketologanin, which is suggested to be the precursor
that undergoes ring cleavage to morroniside.- In C. lateritia
loganin also proved to be a precursor of 10-acetoxyoleoside
11-methyl ester whereas 7-epi-loganic acid was not incorporated at
all. The incorporations obtained in C. lateritia support a
different biosynthetic route for oleoside-type iridoids in the
Loasaceae family in comparison with Oleaceae family. - Finally,
the implications of the biosynthetic and the phytochemical studies
on the taxonomic placement and phylogenetic relationships of
Loasacae are discussed. It is difficult to establish phylogenetic
relationships within the Loasacae family using the iridoid
distribution pattern known until now. The iridoids and
secoiridoids present derive from the biosynthetic route I, which
is shared by Cornales, Gentianales and Loasales. The presence of
10-decarboxylated iridoids is common for the genus Mentzelia
(Loasaceae) and the family Hydrangeaceae (Cornales). And finally,
the presence of oleoside-type secoiridoids in Loasaceae, which is
shared by the family Oleaceae (Gentianales), confirm a common
ancestry for Cornales, Gentianales and Loasales. However, the
presence of the oleoside-type iridoids in Loasaceae and the
differences of the biosynthetic pathways between Oleaceae and
Loasaceae justify the placement of Loasaceae in its own order near
to Cornales and Gentianales as suggested by Dahlgren.
M3 - Book
BT - Distribution and Biosynthesis of Iridoid Glucosides in the
Loasaceae Family
PB - Dept. Organic Chemistry, DTU
CY - Lyngby
ER -