EVALUATION OF IN VITRO AND IN VIVO EFFECTS OF SEMIPURIFIED PROTEINASE INHIBITORS FROM T HEOBROMA SEEDS ON MIDGUT PROTEASE ACTIVITY OF L EPIDOPTERAN PEST INSECTS

We have characterized in vitro and in vivo effects of trypsin inhibitors from T heobroma seeds on the activity of trypsin‐ and chymotrypsin‐like proteins from L epidopteran pest insects. The action of semipurified trypsin inhibitors from T heobroma was evaluated by the inhibition of bovine trypsin and chymotrypsin activities determined by the hydrolysis of N ‐Benzoyl‐ DL ‐Arginine‐p‐Nitroanilide ( BAPA ) and N‐Succinyl‐Ala‐Ala‐Pho‐Phe p‐Nitroanilide (S ‐ (Ala)2ProPhe ‐ pNA). Proteinase inhibitor activities from T heobroma cacao and T . obovatum seeds were the most effective in inhibiting trypsin‐like proteins, whereas those from T . obovatum and T . sylvestre were the most efficient against chymotrypsin‐like proteins. All larvae midgut extracts showed trypsin‐like proteolytic activities, and the putative trypsin inhibitors from T heobroma seeds significantly inhibited purified bovine trypsin. With respect to the influence of T heobroma trypsin inhibitors on intact insects, the inclusion of T . cacao extracts in artificial diets of velvet bean caterpillars ( A nticarsia gemmatalis) and sugarcane borer ( D iatraea saccharalis) produced a significant increase in the percentage of adult deformation, which is directly related to both the survival rate of the insects and oviposition .