CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / A Caatinga possui uma vegetaÃÃo heterogÃnea cuja biodiversidade taxonÃmica conta com mais de 2.000 espÃcies de plantas. Dentre essas, cerca de 220 pertencem à famÃlia das leguminosas com 80 espÃcies endÃmicas, Ãnicas desse bioma. Muitas sÃo usadas para diversas finalidades de forma indiscriminada, reduzindo consideravelmente a diversidade e o nÃmero de espÃcies antes mesmo do conhecimento de suas potencialidades. Estudos que possam agregar valor econÃmico e viabilizar o uso racional, sustentÃvel e a conservaÃÃo das mesmas, aliada à constante busca por novas fontes de proteÃnas vegetais para atender à demanda crescente da populaÃÃo, bem como a grande necessidade de descoberta de compostos naturais que auxiliem no combate aos patÃgenos humanos e de plantas, sÃo de extrema relevÃncia. Assim, o presente estudo objetivou avaliar o potencial nutricional e bioativo de sementes de dez espÃcies vegetais da Caatinga destacando a espÃcie mais promissora. Para tanto, dez espÃcies de leguminosas selvagens da Caatinga foram analisadas quanto a sua composiÃÃo nutricional, apresentando elevado percentual de proteÃna bruta (10,9  0,4 a 50,0  3,4 %), fibras (0,8  0,0 a 52,3 Â1,0 %) e energia (1.000 a 1.804 kJ/100g), com perfil de aminoÃcidos comparÃveis aos da soja, com maiores teores de lisina (1088 a 456 mg/gN) e histidina (199 a 918 mg/gN) e bom perfil de minerais por apreentar boas quantidades de (mg/100g de farinha) de todos eles, em especial, de ferro (3,8 a 20,2), cÃlcio (31 a 268), magnÃsio (102 a 244) e potÃssio (366 a 1.581). As sementes apresentaram baixas quantidades de lectinas (80 a 2.560 e 160 a 2.560 UH/gF, quando nÃo tratadas e tratadas com enzimas, respectivamente), inibidores de tripsina (4,1  0,4 a 27,4  0,2 gTI/mgF ), ureases (465  13 a 47.178  3.351 U/KgF) e atividade tÃxica, em apenas trÃs espÃcies, com DL50 variando de 0,72  0,03 a 1,12  0,04 g/Kg peso. Foi determinado um Ãndice de qualidade nutricional para todas as espÃcies, o qual apontou a espÃcie Piptadenia moniliformis Benth. (Catanduva) como detentora de melhor qualidade nutricional, sendo assim destacada e avaliada in vivo a qualidade das proteÃnas de suas sementes. Os processamentos tÃrmicos (fervura, cozimento em micro-ondas e autoclavagen) e o processo de extraÃÃo de -galactosÃdios nas sementes dessas espÃcies nÃo proporcionaram bom desempenho dos animais, tendo em vista a perda de peso apresentada. Melhoria nos parÃmetros nutricionais, como NPU e VB foi verificada apÃs a retirada de -galactosÃdios dessas sementes, sugerindo que a anÃlise de outros processamentos para o aproveitamento das proteÃnas de suas sementes, pode tornÃ-las uma fonte promissora. AlÃm do alto potencial nutricional, as dez espÃcies apresentam tambÃm potencial bioativo devido à presenÃa de metabÃlitos secundÃrios como alcalÃides, catequinas, calchonas, auronas, flavonÃis, fenÃis flavonas, xantonas, flavononÃis, saponinas e triterpenÃides. Possuem proteÃnas bioativas como proteases, quitinases (0,23  0,02 a 2,0  0,33 nKat/mgP), β-1,3-glucanases (0,01  0,0 a 0,8  0,01 nKat/mgP), alÃm de proteÃnas ativas contra microorganismos que tambÃm sÃo consideradas antinutricionais (lectinas, inibidores de tripsina, ureases e toxinas). A avaliaÃÃo dos extratos brutos (EB) das espÃcies mostrou que todas sÃo ativas contra larvas de Aedes aegipty com percentual de mortalidade variando de 13,33  0,54 a 100,00  0,00 %, exceto o EB de Caesalpinea bracteosa que foi ativo contra a cepa Bacillus subtilis e contra o fungo Fusarium oxysporum, juntamente como o EB de Dioclea megacarpa. A espÃcie Senna rugosa inibiu o crescimento das cepas Bacillus subtilis e Staphylococcus aureus. Os fungos fitopatogÃnicos Aspergilus niger e Colletotrichum truncatum foram inibidos pelos EBs de Piptadenia moniliformis e Enterolobium contortisiliquum, que alÃm destes, foi ativo frente a Neurospora sp. e Trichoderma viridae. A espÃcie P. moniliformis destacou-se por sua elevada atividade quitinÃsica (1,12  0,0 nKat/mgP) em adiÃÃo à atuaÃÃo contra modelos biolÃgicos susceptÃveis a essa enzima, tendo sido escolhida para sua purificaÃÃo. A fraÃÃo proteica purificada de P. moniliformis (PmFP) contÃm elevada atividade de quitinases e causou pequena reduÃÃo no crescimento das leveduras Saccharomyces cerevisiae e Candida tropicalis, bem como da bactÃria B. subtilis. Inibiu ainda, a eclosÃo de ovos de A. aegypti com CI50 de 204, 42  2,19 ÂgP/ml e alterou a estrutura dos ovos e morfologia das larvas de primeiro estÃdio. A investigaÃÃo do potencial nutricional e bioativo das espÃcies mostrou boa composiÃÃo de nutrientes, em especial de proteÃnas e confirmou a presenÃa de compostos bioativos de natureza proteica e de metabÃlitos secundÃrios, tornando-as promissoras fontes de nutrientes e compostos antimicrobianos e anti-inseticidas que podem ser utilizados biotecnologicamente para fins agrÃcolas e industriais / The Caatinga Biome shows an heterogeneous vegetation with a taxonomic biodiversity of over 2,000 species of plants. Among these, approximately 220 belong to the Leguminosae family with 80 endemic species, unique to that biome. Many are used for various purposes in an indiscriminate manner, greatly reducing the variety and number of species even before the knowledge of their potential uses. Studies that can add economic value and enable the rational, sustainable use of these species, coupled with the constant search for new sources of plant protein to meet the ever increasing demand of the population are extremely important. Similarly important is the search for natural compounds which may help to combat human and plant pathogens. Thus, this study aimed to assess the nutritional and bioactive value of the seeds of ten plant species from Caatinga, highlighting the most promising ones. For this, the seeds were analyzed for nutritional composition, showing a high percentage of crude protein (10.9  0.4 to 50.0  3.4%), dietary fiber (0.8  0 , 0 to 52.3  1.0%) and energy (1,000 kJ/100g a1.804), with amino acid profile similar to that of soybeans, with higher amounts of lysine (1088-456 mg/gN) and histidine (199-918 mg/gN) and good mineral profile, with good content (mg/100 g flour) for all of them, especially, iron (3.8 to 20.2), calcium (31 to 268), magnesium (102-244) and potassium ( 366-1581). The seeds showed low amounts of lectins (80-2560 and 160-2560 UH / gF, when untreated and treated with enzymes, respectively), trypsin inhibitor (4.1  0.4 to 27.4  0.2 GTI / mgF), urease (465  13 to 47,178  3,351 U / KGF) and toxic activity in only three species, with LD50 ranging from 0.72  0.03 to 1.12  0.04 g / kg body weight . Was given an index of nutritional quality for all species, which pointed to Piptadenia moniliformis Benth. species (Catanduva) as the most promising one and because of that the seeds of this species was had the quality of its proteins evaluated in vivo. The thermal processing (boiling, microwave cooking and autoclaving) as well as the removal of α-galactosides did not improve animals performance. The nutritional parameters NPU and BV were improved when the animals were fed the seeds diet after removal of the α-galactosides. This may indicate that the search for apropriate processing methods may turn these seeds a promising source of proteins. Besides the high nutritional potential, the seeds of the ten studied species also have bioactive potential due to the presence of secondary metabolites such as alkaloids, catechins, calchonas, Auron, flavonols, flavones phenols, xanthones, flavononols, saponins and triterpenoids. These seeds also have bioactive proteins such as proteases, chitinases (0.23  0.02 to 2.0  0.33 nkat / mg P), β-1,3-glucanase (0.01  0.0 to 0.8  0, 01 nkat / mg P), and proteins active against microorganisms that are also considered antinutritional factors (lectins, trypsin inhibitors, urease and toxins). The evaluation of the crude extracts (CE) of the seeds showed that all species are active against the larvae of Aedes aegipti with mortality rates ranging from 13.33  0.54 to 100.00  0.00%, except that of Caesalpinea bracteosa which similarly to the CE of Dioclea megacarpa, was active against the bacterium Bacillus subtilis and against the fungus Fusarium oxysporum. Seeds extract of Senna rugosa species was able to inhibit the growth of Bacillus subtilis and Staphylococcus aureus. The pathogenic fungi Aspergillus niger and Colletotrichum truncatum were inhibited by the CE of Piptadenia moniliformis and Enterolobium contortisiliquum. The latter was also active against Neurospora sp. and Trichoderma viridae. The species P. moniliformis was distinguished for its high chitinase activity (1.12  0.0 nkat / mg P) in addition to its activity against biological models susceptible to this enzyme. For these reasons attempts were made for its purification. The purified protein fraction of P. moniliformis (PmFP) contains high activity of chitinases and caused a small reduction in the growth of the yeasts Saccharomyces cerevisiae and Candida tropicalis, and of the the bacterium B. subtilis. This protein fraction also inhibits the hatching of A. aegypti eggs with IC50 of 204. 42  2.19 μgP / ml. It causes changes in the eggs structure and in the morphology of first stage larvae. Thus, investigation of bioactive and nutritional potential of the species showed good composition of nutrients, especially of proteins, and confirmed the presence of bioactive compounds from protein nature and secondary metabolites, making them promising sources of nutrients, antimicrobial and insecticides that can biotechnologically be used for agricultural and industrial purposes.