| dc.identifier.citation | Akimanya, Aggrey., Midiwo, Jacob O., Okanga, Francis., Kerubo, Leonidah., Ilias, Muhammad and Walker, Larry. (2015). Two flavonoids and a rearranged clerodane diterpenoid from the leaf exudates of microglossa pyrifolia. The 16th symposium of the natural products reseach network for eastern and central Africa (NAPRECA) 31st August to 3rd September 2015 Arusha, Tanzania | en_US |
| dc.description.abstract | The fresh leaves of
Microglossa pyrifolia
, Asteraceae
(7.5 kg) were extracted by successive
dipping into fresh portions of ethyl acetate for short periods (less than or ca. 15 s) to yield (180 g,
2.4% of dry leaf) of yellow concentrate. The crude extr
act
was found to have IC50 of 8.0
μg/ml
against
P.falciparum
D6 strain and 13.0
μg/ml against W2. A portion of the crude extract (150 g) was subjected to column chromatography on silica gel (1500 g) eluting with mixtures of n
-
hexane/CH
2
Cl
2
and then with CH
2
Cl
2
/MeOH in increasing polarities. A total of seven compounds
(two diterpenoids and five fl
avonoids),whose structures were
determined using NMR (1H, 13C,
COSY, HMQC
, and HMBC) and EIMS as 5,7,4
-
trihydro
xy
-
3,8,3
-
t
rimethoxyflavone (1), 5, 7, 4
-
trihydroxy
-
3,
8, 3, 5
-
tetramethoxyflavone (2), 5,3,4
-
trihydroxy
-
7
-
methoxyflavanone (3), 5,7,3
-
trihydroxy
-
8,4,5
-
trimethoxyflavone (4), 5, 3, 4
-
Trihydroxy
-
3, 7, 8
-
trimethoxyflavone (5) 8
-
acetoxyisochiliolide lactone (6) and 7, 8
-
epoxyisocholiolide lactone (7);
out of the
se 2,4 and 6
were new to literature. Tests with DPPH showed that antioxidant activity was e
xhibited by 1 with
IC50 of 6.2 μg/ml. Compound 6 exhibited modest
in vitro
antileishmanial activity with
IC
50
value
of 13.13 mg/mL
against the growth of Leish
mania d
onovanii promastigotes | en_US |
