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First report on the termiticidal activity of extracts of Annona squamosa (Annonaceae) seeds and on its active constituent squamocins
2012 - IRG/WP 12-30605
Termites inflict severe damage on wood commodities and impede usage of several forest species. The biological metabolites could potentially replace synthetic termiticidal products which are becoming more restricted to use. Annona squamosa is well known for its edible fruits - tropical custard apple. Annonaceous tetrahydrofuran acetogenins have attracted much interest due to their broad range of biological activities, and seeds containing them are reported to show insecticidal and abortifacient properties. Under the course our exploratory investigation of non food valuable products from less known forest species (here from Benin), the fractions obtained from cake of Annona squamosa with solvents covering a broad range of polarity, revealed a significant termiticidal activity, when applied at 5 - 10 mg/cm² (non-polar solvent) and 1.2 - 5 mg/cm² (case of a more polar solvent). Based on the result (0: no attack) from the standard procedure EN 118, these extracts could be used for preserving wood used hazard class. A derivatization step with Kedde reagents A and B, elemental analysis C,H,O, HPLC/MS and proton NMR showed the presence of squamocin type acetogenins (MW 594 and 622 g/mole: C35H62O7 and C37H66O7) as main components of the most active fraction by no-choice test (FR-13 : 100% mortality within 7 days for a sample applied at 2 mg/cm²). Additional work will be undertaken to confirm the structure of most active compounds in the extracts, and to check whether some Annona squamosa seed extracts (non timber products of sustainable management of native forest) could show even higher activity to protect wood and be alternative active natural products to synthetic compounds.
T S Djenontin, N Amusant, P H Ducrot, D C K Sohounhloué, D Pioch


Seed oil and defatted cake proximate composition of non timber product Annona squamosa (Annonaceae) grown in Benin
2012 - IRG/WP 12-30607
Annona squamosa L. is a small tree which grows wild in many places in the tropical regions, locally called “xwingle” in Benin. Its produces edible fruits, typically globular or heart-shaped which are highly appreciated and the seeds are not used. In the course of work about identifying new oil sources from a large number of oil bearing seeds grown in Benin, we report here on the chemical composition of seed oil (ASSO) and defatted cake (ASDC) of A. squamosa. Fatty acid composition, chemical properties of oil, unsaponifiable fraction, amino acids, lignocellulose and carbohydrates were analyzed by standard analytical procedures. Our objective is to update and to widen available data in order to check and confirm the interest of the seeds as a readily available by-product resulting of the consumption of the fruit pulp for human food. The extracted lipids (33.7%) were examined for fatty acid composition by gas chromatography. Linoleic (25.4%) and oleic (47.4%) acids were the main unsaturated fatty acids, while palmitic acid (12.6%) and stearic acid (11.6%) were the major saturated acids. The iodine value of 92 indicates that the seed oil is of non-drying type. The unsaponifiable matters (1.0wt-%) whose composition was not investigated previously especially for the sterol fraction found to contain -sitosterol (68.7wt-%) and the tocols (143ppm) with - and γ-tocopherol as major components (26.5 and 73.5wt-%). The defatted cake is rich in proteins (25.5g/100g), potassium (0.9%), and fibers (Van Soest; NDL 60.1%, ADF 34.7% and ADL 7.4%).
T S Djenontin, J Dangou, P Lozano, D Pioch, D C K Sohounhloue