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most diverse family and nearly 80% are
endemic, distributed in almost all ecosys-
tems, with more abundance in arid and
semi-arid regions of central and northern
states. Of the nearly 1500 species grouped
in the family, very few have been studied on
a chemical level. According to the data
accumulated in the literature, the family is
rich in triterpenes, alkaloids, phenolic com-
pounds, betalains and sterols (Bravo-Hollis,
1978; Anderson, 2001).
As we noted, the history of sterol chem-
istry from Cactaceae has been linked closely
with ecdysteroids and some related com-
pounds were isolated early. Knight
et al
.
(1966) mentioned that they had found vipe-
ridinone (
11
), the first molecule of vegetal
origin with a structure similar to that of
ecdysone, in the cactus
Peniocereus viperi-
nus
(before
Wilcoxia viperina
). Viperidinone
is 5a-cholest-7-en-6-one- 3b, a9, 14a-triol,
with a
cis
A/B ring junction and without the
characteristic hydroxylation pattern of ecdys-
one. The other compounds that were isolated,
viperidone (
12
) and deoxyviperidone (
13
),
both analogues of viperidinone, have one and
two hydroxyl groups fewer, respectively.
Moreover, some sterols related to the
structure of ecdysteroids have been isolated
from Cactaceae (Figs 11.6 and 11.7). The ster-
ols lophenol (
20
), schottenol (
21
), 24-methyl-
enelophenol (
22
), lathosterol (
23
),
5a-campest-7-en-3b-ol (
24
), spinasterol (
25
),
all of them with a double bond at C-7,
together with locereol (
26
) and 5a-cholesta-
8,14-dien-3b-ol (
27
), were isolated from
Lophocereus schotii
(Djerassi
et al
., 1958;
Campbell and Kircher, 1980). The 3b, 6a-
dihydroxysterols peniocerol (
28
) and mac-
dougallin (
29
), together with small amounts of
lophenol, campesterol, b-sitosterol and chol-
esterol, were obtained from both
Peniocereus
fosterianus
and
Peniocereus macdougallii
(Djerassi
et al
., 1961, 1963, 1965). Lophenol
and macdougallin are very peculiar because
they have an extra a-methyl group on the
cholesterol core, the former at C-4 and
the latter at C-14.
HH
HH
HO
HO
H
Lophenol (
20
)
Schottenol (
21
)
H
HH
H
H
HO
HO
H
H
24-methylenelophenol (
22
)
Lathosterol (
23
)
HH
HH
HO
HO
H
H
Spinasterol (
25
)
5
α
-campest-7-en-3
β
-ol (
24
)
Fig. 11.6.
Chemical structures of delta-7 sterols isolated from Cactaceae.
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