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Mosquito
larvicidal and cytotoxic activities of 3 Annona
species and
isolation of active principles
Joseph J. Magadula*, Ester
Innocent and Joseph N. Otieno
Institute of Traditional Medicine,
Muhimbili University of Health and Allied Sciences,
P.O. Box 65001, Dar es Salaam, Tanzania.
*Corresponding author.
Email:
magadulajanguj@yahoo.com.
Tel. +255 754 568702 OR +255 787 568702. Fax:
+255 22 2150465.
Accepted 31 July, 2009 |
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Cytotoxicity and larvicidal properties of the leaf extracts of 3
Annonaceous plants, Annona muricata L., A. senegalensis
Pers and A. squamosa L. were tested against brine shrimp larva
and the late 3rd instar of Culex quinquefascintus Say.
The larval mortality was observed 24 h post-exposure. Based on the
probit analysis, the LC50 value for crude extracts of A.
muricata, A. senegalensis and A. squamosa were
observed to be 20.87, 0.67 and 0.64 µg/mL respectively for shrimp larvae
and 56.47, 23.42 and 11.01 µg/mL respectively for C. quinquefascintus.
Bioassay-guided fractionation of crude extracts indicated high activity
of the ethyl acetate fractions with mortality of ≥ 90% at 50 µg/mL for
both A. senegalensis and A. squamosa. However, further
bioassay of sub-fraction of the 2 ethyl acetate fractions from the 2
plant species showed close dependent and a decreased activity (p ≥ 0.05)
at the same concentration levels. 2 known aporphine alkaloids, (-)-roemerine
and annonaine were identified as
active principles from the ethyl acetate extracts of A. senegalensis
and A. squamosa respectively. With the larvicidal
properties of A. senegalensis being described here for the first
time, its value together with that of A. squamosa may prove to be
the best natural source of larvicidal agents.
Key
words:
Annona species, cytotoxic and larvicidal activities, isolation,
aporphine alkaloids |
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