In Vivo Bioinsecticidal Activity toward Ceratitis capitata (Fruit Fly) and Callosobruchus maculatus (Cowpea Weevil) and in Vitro Bioinsecticidal Activity toward Different Orders of Insect Pests of a Trypsin Inhibitor Purified from Tamarind Tree (Tamarindus indica) Seeds

A proteinaceous inhibitor with high activity against trypsin-like serine proteinases was purified from seeds of the tamarind tree (Tamarindus indica) by gel filtration on Shephacryl S-200 followed by a reverse-phase HPLC Vidac C18 TP. The inhibitor, called the tamarind trypsin inhibitor (TTI), showed a M r of 21.42 kDa by mass spectrometry analysis. TTI was a noncompetitive inhibitor with a K i value of 1.7 x 10 -9 M. In vitro bioinsecticidal activity against insect digestive enzymes from different orders showed that TTI had remarkable activity against enzymes from coleopteran, Anthonomus grandis (29.6%), Zabrotes subfasciatus (51.6%), Callosobruchus maculatus (86.7%), Rhyzopertha dominica (88.2%), and lepidopteron, Plodia interpuncptella (26.7%), Alabama argillacea (53.8%), and Spodoptera frugiperda (75.5%). Also, digestive enzymes from Diptera, Ceratitis capitata (fruit fly), were inhibited (52.9%). In vivo bioinsecticidal assays toward C. capitata and C. maculatus larvae were developed. The concentration of TTI (w/w) in the artificial seed necessary to cause 50% mortality (LD 50 ) of larvae was 3.6%, and that to reduce mass larvae by 50.0% (ED 50 ) was 3.2%. Furthermore, the mass C. capitata larvae were affected at 53.2% and produced ∼34% mortality at a level of 4.0% (w/w) of TTI incorporated in artificial diets.