Selective polarity- and adsorption-guided extraction/purification ofAnnona sp. Polar acetogenins and biological assay against agricultural pests |
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Authors: | Fontana J D Lanças F M Passos M Cappelaro E Vilegas J Baron M Noseda M Pomiíio A B Vitale A Webber A C Maul A A Peres W A Foerster L A |
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Institution: | (1) LQBB-Biomass Chemio/Biotechnology Lab-UFPR, Federal University of Parana, PO Box-19046, 81531-990 Curitiba-PR, Brazil;(2) CROMA-USP-Sao Carlos, PO Box-19046, 81531-990 Curitiba-PR, Brazil;(3) PROPIAME-UBA/Buenos Aires, PO Box-19046, 81531-990 Curitiba-PR, Brazil;(4) Pharmaceutical Sciences/USP, PO Box-19046, 81531-990 Curitiba-PR, Brazil;(5) Biology/FUAM/Manaus, PO Box-19046, 81531-990 Curitiba-PR, Brazil;(6) Zoology Department, UFPR, PO Box-19046, 81531-990 Curitiba-PR, Brazil |
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Abstract: | Annonaceae acetogenins (AG) comprise a family of natural chemical modifications of long-chain fatty acids (C35_37) bearing one to several hydroxyls (less often oxo), middle-chain tetrahydrofuran rings, and a γ-lactonized, α/β-unsaturated
carboxyl group. Acetogenins’ strong biological activity as larvicides, pesticides, and antitumorals is dependent on these
structural variations. The hydroxylation degree is particularly important for these etfects. Seeds, albeit rich in fats (mostly
triacylglycerols, TAG]), are a nonpredatory source of these drugs as compared to other botanical parts such as roots and
stems. Conventional lipid extractions lead to quantitative lipid recovery and then the unfavorable natural ratio of TAG:AG
in the range >90:<0.1 These extracts thus require, for instance, partitions and extensive sílica gel column chromatographic
steps, in order to enrich or purify the AG fraction(s). Great operational difficulties result from the similar polarity and
mol. wt. range of TAG and AG when carrying out these purification steps. An alternative fast two-step procedure to obtain
polar acetogenin (pAG)-enriched preparations was developed. The extraction procedure forAnnona spp. seeds pAG was carried out with acetonitrile (Eβ = 0.65; log P = - 0.33) as a polar organo-solvent, followed by the adsorption
of the solvent-free extract on activated charcoal, then washed with hexane and/or chloroform (Eβ = 0.0 and 0.40: log P = 3.5
and 2.0) for most of the contaminating TAG removal, and then with acetone (Eβ = 0.56; log P = - 0.23) to the desorption of
an enrichedpAG fraction. An alternative procedure for pAG extraction was supercritical fluid extraction (SFE) at moderate thermopressurization
conditions (65-82βC; 120-130 atm) using CO2, with 10% acetonitrile as the polarity modifier. The pAG fractions’ bioactivity
was evaluated with the brine-shrimp test (BST), and for feed deterrance, growth inhibition, and lethality against the high-impact
agricultural pestsAnticarsia gemmatalis andPseudaletia sequax caterpillars feeding on soya or grass leaves sprayed with a 10% alcohol-stabilized emulsion of pAG. |
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Keywords: | Index Entries" target="_blank">Index Entries Annonaceae polar acetogenins acetonitrile downstream caterpillars |
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