| dc.description.abstract | The family Leguminosae, with some 18,000 species and 650
genera, is the second largest family of dicotyledons. It is
divided
into three
subfamilies;
namely Mimosoideae,
Caesalpinoideae and Papilionoideae. The family is known for
elaborating a wide
range of
flavonoids including
isoflavonoids, the latter being more or less restricted to the
subfamily Papilionoideae. Isoflavonoids are known to possess
a wide range of biological activities, the most prominent of
which being insecticidal and antimicrobial properties. The
insecticidal activities are associated with rotenoids which
are mainly found in the tribe Tephroseae (including the genus
Millettia) , while the antimicrobial activities
with
pterocarpans and flavanones which are found in the tribe
Phaseoleae (including the genus Erythrina). In this study two
Millettia and two Erythrina species have been investigated for
compounds with potential insecticidal and antimicrobial
activities.
..-~'" -
Chemical investigation of th& seeds, seed pods and stem
bark of two Millettia species (M. dura and M. usaramensis
subspecies
usaramensis) resulted In the
isolation and
characterization of isoflavones, rotenoids and chalcones. M.
dura produced five novel isoflavones (durallone (1), 6demethyldurallone
(2), predurallone (3), isoerythrin-A 4'-(3methylbut-2-enyl)
ether
(4)
and
6-methoxycalopogonium
xix
isoflavone-A (5)), known isoflavones (formononetin (6),
ferrugone (7), jamaicin (8), durmillone (13), calopogonium
isoflavone A (14), maximaisoflavone D (15) and
maximaisoflavone H (16) ) These isoflavones have lost
oxygenation at C-5 and in most cases additional oxygenation
occur at C-6, C-8 and/or C-3'. Such oxygenation pattern
reflects the taxonomic affinity of M. dura to M. ferruginea.
The rotenoids millettone (9), millettosin (10), deguelin (11)
and tephrosin (12) have also been isolated from this plant.
The second Millettia species investigated, M. usaramensis
subsp. usaramensis, produced four new rotenoids wi th trans-B/C
ring junction (12a-epimillettosin (17), usararotenoid-A (18),
12-dihydrousararotenoid-A (19), and usararotenoid-B (20))
These compounds represent the first natural rotenoids with
6aR,6aS B/C- ring junction. This plant also elaborated a new
QI-hydroxydihydrochalcone (4' -geranyloxY-Ql,4,2'trihydroxydihydrochalcone
(21) , a new isoflavone
(norisojamaicin (22)) and a new cinnamyl derivative (4-0geranylc
innamyl acetate (23)) .::~-T"Woknown chalcones (4'-0geranylisoliquiritigenin
(24) and· isoliquiritigenin (25)),
four known isoflavones (barbigerone (26), jamaicin (8),
maximaisoflavone G (27) and toxicarolisoflavone (29)) and a
triterpene (lupeol (28)) were also isolated from this plant.
The bark of two Erythrina species (E. burttii and E.
sacleuxii) were also investigated resulting in the isolation
and characterization of several flavonoids. From the stem bark
XlX
isoflavone-A
(5) ) , known isoflavones (formononetin
(6) ,
ferrugone (7), jamaicin (8), durmillone (13), calopogonium
isoflavone
A
(14) ,
(16) )
maximaisoflavone D
(15)
and
maximaisoflavone H
These isoflavones have lost
oxygenation at 'C-5 and in most cases additional oxygenation
occur at C-6, C-8 and/or C-3'. Such oxygenation pattern
reflects the taxonomic affinity of M. dura to M. ferruginea.
The rotenoids millettone (9), millettosin (10), deguelin (11)
and tephrosin (12) have also been isol~ted from this plant.
The second Millettia species investigated, M. usaramensis
subsp. usaramensis, produced four new rotenoids with trans-B/C
ring junction (12a-epimillettosin (17), usararotenoid-A (18),
12-dihydrousararotenoid-A (19), and usararotenoid-B (20))
These compounds represent the first natural rotenoids with
6aR,6aS B/C- ring junction. This plant also elaborated a new
a-hydroxydihydrochalcone
(4' -geranyloxy-a, 4,2'trihydroxydihydrochalcone
(21)
,
a new isoflavone
(norisojamaicin (22)) and a new cinnamyl derivative (4-0-
.•.--- -
geranylcinnamyl acetate (23)) Two known chalcones (4'-0geranylisoliquiritigenin
(24) and i·soliquiritigenin (25)),
four known isoflavones (barbigerone (26), jamaicin (8),
maximaisoflavone G (27) and toxicarolisoflavone (29)) and a
triterpene (lupeol (28)) were also isolated from this plant.
The bark of two Erythrina species (E. burttii and E.
sacleuxii) were also investigated resulting in the isolation
and characterization of several flavonoids. From the stem bark
xx
of Erythrina burttii two new flavanones (abyssinone V-4'methyl
ether (30) and burttinone (32)) were characterized. In
addition known fl~vanones (abyssinone V (31) and sigmoidin B-
4' -methyl ether (33)), pterocarpans (calopocarpin (34) and
neorautenol (35»), an isoflavanone (bidwillon A (36)), a
chalcone
(isobavachalcone
(37) )
and a
cinnamyl
ester
(erythrinasinate (38)) were isolated.
In the same way, from the stem bark of E. sacleuxii a new
isoflavanone (saclenone-A (39)) and four new isoflavones (7-
demethylrobustigenin (40),3'- (3-methylbut-2-enyl)biochanin A
(41) ,
5'-(3-methylbut-2-enyl)pratensien
(42)
and
5' -
formylpratensein (43)) were isolated and characterized.
Some of the isolated compounds and their derivatives were
tested for
larvicidal, anti-feedant,
antibacterial,
anti fungal, anti -brine shrimp, cell growth inhibitory and
antimalarial activities. Potent larvicidal activities against
the larvae of Aedes aegypti were observed for deguelin and
tephrosin. Anti -feedant acti vi ties against the 5th instar
--- -
nymphs of Locus ta migra t.oxi-e were observed for deguelin,
tephrosin and
calopocarpin ~ .
Antibacterial
(against
Staphylococcus aureus and Bacillus subtilis) and antifungal
activities
(against
Saccharomyces
cerevi siae,
Candida
albicans, Trichophyton mentagrophyte and Microsporum gypsum)
were
observed
with a,4,2'-trihydroxy-4'-O-geranyldihydrochalcone,
calopocarpin, neorautenol, sigmoidin B-4'methyl
ether and bidwillon A.
Cell growth inhibitory | en |
