99 resultados para Bioma caatinga
Resumo:
The genus Hemidactylus Oken, 1817 has cosmopolite distribution, with three species occurring in Brazil, two of them native, H. brasilianus and H. agrius, and one exotic, H. mabouia. Considering the studies about ecology of lizards conducted in the Ecological Station of the Seridó, from 2001 to 2011, this study aimed (1) to re-evaluate the occurrence of the species of Hemidactylus in this ESEC; (2) to analyze ecological and biological aspects of the H. agrius population; and (3) to investigate the current and potential distribution of the native species of the genus in northeastern Brazil, analyzing the suitability of ESEC to this taxon. For the first two objectives, a sampling area consisting of five transects of 200 x 20 m, was inspected in alternating daily shifts for three consecutive days, from August 2012 to August 2013. For the latter objective, occurrence points of H. agrius and H. brasilianus from literature and from the database of Herpetological Collections of the UFRN and the UNICAMP were consulted to build predictive maps via the Maximum Entropy algorithm (MaxEnt). In ESEC Seridó, 62 H. agrius individuals were collected (25 females, 18 males and 19 juveniles), and two neonates were obtained from a communal nest incubated in the laboratory. No record was made for the other two species of the genus. Hemidactylus agrius demonstrated to be a nocturnal species specialized in habitats with rocky outcrops; but this species is generalist regarding microhabitat use. In the population studied, females had an average body length greater than males, and showed higher frequencies of caudal autotomy. Regarding diet, H. agrius is a moderately generalist species that consumes arthropods, especially insect larvae, Isoptera and Araneae; and vertebrates, with a case of cannibalism registered in the population. With respect to seasonal differences, only the number of food items ingested differed between seasons. The diet was similar between sexes, but ontogenetic differences were recorded for the total volume and maximum length of the food items. Significant relationships were found between lizard body/head size measurements and the maximum length of prey consumed. Cases of polydactyly and tail bifurcation were recorded in the population, with frequencies of 1.6% and 3.1%, respectively. In relation xv to the occurrence points of the native species, 27 were identified, 14 for H. agrius and 13 for H. brasilianus. The first species presented restricted distribution, while the second showed a wide distribution. In both models generated, the ESEC Seridó area showed medium to high suitability. The results of this study confirm the absence of H. brasilianus and H. mabouia this ESEC, and reveal H. agrius as a dietary opportunist and cannibal species. Further, the results confirm the distribution patterns shown by native species of Hemidactylus, and point ESEC Seridó as an area of probable occurrence for the species of the genus, the establishing of H. brasilianus and H. mabouia are probably limited by biotic factors, a fact yet little understood
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Environmental degradation is a global problem that particularly affects areas subject to seasonal climatic variations, such as the brazilian semiarid region, namely the Caatinga Domain. Combined with other negative factors, such as natural resource misuse and disorderly land occupation, the consequences of Environmental Degradation have challenged science in the quest for addressing the resulting social and environmental problems. Accordingly, Environmental Perception methodology, by analyzing the concepts, attitudes and values, (especially those pertaining to environmental conservation) represent an important tool in studies that address the relationship between the environment and human actions. Sustainability Indicators are also relevant tools to assess the possible causes and consequences of environmental problems. Among several Sustainability Indicators available, the PressuresState-Impact-Response (PSIR) method is an analytical tool that permits the grouping of factors affecting sustainability as well as their consequences for nature and human health, and thus indicate mitigating actions for society and the public authorities. From this perspective, three areas of Caatinga were studied in Rio Grande do Norte state: Seridó Ecological Station (ESEC), Municipality of Serra Negra do Norte; Private Natural Reserve Stoessel de Brito (PNRSB), Municipality of Jucurutu; and part of the Serra de Santana, Municipality of Tenente Laurentino Cruz. The areas are both legally protected and unprotected and subject to diferent management protocols, though their share the common characteristic of human misuse of natural resources. In this scenario, this thesis´ main goal was to introduce the rural communities into the conservation process, using the results of Environmental Perception of such communities, combined with the analysis of the sustainability of municipalities through PSIR. Information on Environmental Perception was obtained from primary and secondary data from previous studies carried out in the ESEC Seridó and PRNP Stoessel de Brito. Additional data was obtained through direct observation and interview forms applied to rural communities in the Municipality of Tenente Laurentino Cruz. The results showed that respondents possessed a broad knowledge regarding environmental degradation, its causes and consequences for the caatinga biome. PEIR analysis showed that environmental degradation was smaller in countries with protected areas, as compared to those without. The population´s knowledge about environmental degradation and their acceptance of conservation units, as showed by Environmental Perception Analysis, coupled with the results of PEIR, suggest that those attitudes may foster actions aimed at reduction of environmental degradation in the Caatinga domain
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Dengue fever, currently the most important arbovirus, is transmitted by the bite of the Aedes aegypti mosquito. Given the absence of a prophylactic vaccine, the disease can only be controlled by combating the vector insect. However, increasing reports of resistance and environmental damage caused by insecticides have led to the urgent search for new safer alternatives. Twenty - um plant s eed extracts from the Caatinga were prepared , tested and characterized . Sodium phosphate ( 50 mM pH 8.0) was used as extractor. All extracts showed larvicidal and ovipositional deterrence activity . Extracts of D. grandiflora, E. contortisiliquum, A. cearenses , C. ferrea and C. retusa were able to attract females for posture when in low co ncentration . In the attractive concentrations, the CE of E. contortisiliquum and A. cearenses were able to kill 52% and 100% of the larvae respectively . The extracts of A. cearenses , P. viridiflora, E. velutina, M. urundeuva and S. brasiliensis were also pupicides, while extracts of P. viridiflora, E. velutina, E. contortisiliquum , A. cearenses, A. colubrina, D. grandiflora , B. cheilantha , S. spectabilis, C. pyramidalis, M. regnelli e G. americana displayed adulticidal activity. All extracts were toxic to C. dubia zooplankton . The EB of E. velutina and E. contortisiliquum did not affect the viability of fibroblasts . In all extracts were identified at least two potential insecticidal proteins such as enzyme inhibitors, lectins and chitin - binding proteins and components of secondary metabolism . Considering all bioassays , the extracts from A. cearenses, P. viridiflora, E. contortisiliquum , S. brasiliensis, E. velutina and M. urundeuva were considered the most promising . The E. contortisiliquum extracts was the only one who did not show pupicida activity, indicating that its mechanism of action larvicide and adulticidal is related only to the ingesti on of toxic compounds by insect , so it was selected to be fragmenting. As observed for the CE , th e protein fractions of E. contortisiliquum also showed larvicidal activity, highlighting that F2 showed higher larvicidal activity and lower en vironmental toxicity than the CE source. The reduction in the proteolytic activity of larvae fed with crude extra ct and fractions of E. contortisiliquum suggest ed that the trypsin inhibitors ( ITEc) would be resp onsible for larvicidal activity . However the increase in the purification of this inhibitor resulted in loss of larvicidal activity , but the absence of trypsin inhibitor reduced the effectiveness of the fractions , indicating that the ITEC contributes to the larvicidal activity of this extract. Not been observed larvicidal activity and adulticide in rich fraction vicilin, nor evidence of the contribution o f this molecule for the larvicidal activity of the extract. The results show the potential of seeds from plant extracts of Caatinga as a source of active molecules against insects A. aegypti at different stages of its development cycle, since they are comp osed of different active compounds, including protein nature, which act on different mechanisms should result in the death of insec
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The trophic ecology studies issues related to the diet of individuals within a community .The relation between the body size of the predator and the prey size, individual specialization and niche breadth are some of the issues that can be discussed by it .I collected the lizards using pitfall trap, glue and active collecting traps in a fragment of Caatinga. The most common species in this community were Tropidurus hispidus, T. semitaeniatus and Cnemidophorus ocellifer. The visits to the farm also relied on collecting invertebrates at each season to understand how the nutritional resources of lizards were presented in each one of them. I tried to answer some questions : 1) If there was a positive relation between body size of the predator and the size of prey of the community ; 2) If in different seasons the relation of body size of the predator and the maximum and/or minimum size of the prey would be positive ; 3) If species with different foraging strategies have positive relation on the size of the predatorprey relation; 4) If the seasonality would influence on the individual expertise of lizards community and more common species; 5) If the breadth of the niche would be influenced by seasonality ; 6) If more individuals with different morphology between them would present less similar diet. I found that there was indeed a positive relationship between size of prey and predator, but nonexistent related to the minimum size of prey; Among the seasons relative size of predators and prey was different for the maximum and minimum size, but was positively related only to the size of the maximum prey. And comparisons between different foraging strategies had the maximum and minimum line inclination greater than zero and different from each other; individual specialization was not influenced by seasonality and the niche breadth was wider in the dry season only to T. semitaeniatus. At last I didn't find a significant negative relationship between morphological dissimilarity and similarity of diet.
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Nanoemulsions are emulsified systems, characterized for reduced droplet size (50- 500nm), which the main characteristic are kinect stability and thermodynamic instability. These are promising systems on cosmetic area due to their droplet size that provide different advantages when compared to conventional systems, among others, larger surface area and better permeability. The Opuntia ficus-indica (L.) Mill is a plant cultivated on Caatinga Brazilian biome, which has great socioeconomic importance to region. This plant shows carbohydrates utilized for cosmetic industry as moisturizing active in their chemical composition. The aim of study was to develop, characterize, evaluate stability and moisturizing efficacy of cosmetic nanoemulsions added to Opuntia ficus-indica (L.) Mill extract. Nanoemulsions preparation was made using a low energy method. Different nanoemulsions were formulated varying the ratio of oil, water and surfactant phases beyond xanthan gum (0.5% e 1%) and Opuntia ficus-indica (L.) Mill hydroglycolic extract addition on 1% and 3%. Obtained nanoemulsions were submitted to preliminary and accelerated stability tests. The evaluated parameters monitored were: macroscopic aspect, pH value, droplet size, zeta potential and polydispersion index, during 60 days on different temperatures. Stable formulations were submitted to moisturizing efficacy assessment by capacitance and transepidermal water loss methodologies during 5 hours. Stable samples were white and showed homogeneous and fluid aspect, pH value was inside ideal range (4,5-6,0) to topical application and droplet size under 200nm characterizing these system as nanoemulsions. Developed nanoemulsions did not decrease transepidermal water loss, however increased the water content on stratum corneum, highlighting the nanoemulsions containing 0.5% of xanthan gum and 1% of hydroglycolic extract. This work presents cosmetic moisturizing nanoemulsions composed to vegetal raw material from Brazilian Caatinga with potential to be used on cosmetic area.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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O estudo dos efeitos que a diversidade de espécies pode causar nos processos ecossistêmicos tem crescido vertiginosamente nas últimas duas décadas. Diversos trabalhos experimentais realizados no mundo todo têm demonstrado que uma maior diversidade de plantas contribui para o aumento da produtividade de ecossistemas terrestres. Além disso, esse efeito pode influenciar processos em diversos níveis tróficos, contribuindo assim para a estabilidade dos processos ecossistêmicos a longo prazo. Paralelamente com os estudos do efeito da diversidade, muita atenção tem sido dada para desvendar o papel das características funcionais das espécies no funcionamento dos ecossistemas. Isto porque as características funcionais das espécies têm se mostrado importantes "peças" no entendimento dos efeitos que espécies individuais podem exercer nos ecossistemas e suas respostas ao ambiente. Nesta tese de doutorado eu explorei algumas lacunas de conhecimento dentro dessa área em crescente desenvolvimento conhecida na literatura ecológica como "biodiversidade e funcionamento dos ecossistemas". No primeiro capítulo, eu busquei evidências para mecanismos que podem explicar a relação positiva entre diversidade e funcionamento com foco em cinco mecanismos relacionados às interações entre plantas, tendo como parâmetro de funcionamento a produtividade primária. No segundo capítulo, eu utilizei técnicas para a estimativa de padrões de diversidade em escalas biogeográficas e bases de dados de satélites com longa duração para desvendar se a biodiversidade em escalas macroecológicas promove a estabilidade da produtividade dos ambientes terrestres no semiárido brasileiro. Por fim, o objetivo do terceiro capítulo foi entender como a perda da cobertura vegetal originária do uso da terra por comunidades tradicionais no semiárido brasileiro influenciaria os processos de interações entre plantas e o papel das características funcionais das espécies nessas interações. Acredito que a contribuição individual de cada capítulo preenche lacunas de conhecimento importantes dessa área da Ecologia que ainda se encontra em expansão.
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While the carnivores are considered regulators and structuring of natural communities are also extremely threatened by human activities. Endangered little-spotted-cat (Leopardus tigrinus) is one of the lesser known species from the Neotropical cats. In this work we investigate the occupancy and the activity pattern of L. tigrinus in Caatinga of Rio Grande do Norte testing: 1) how environmental and anthropogenic factors influence their occupation and 2) how biotic and abiotic factors influence their activity pattern. For this we raised occurrence data of species in 10 priority areas for conservation. We built hierarchical models of occupancy based on maximum likelihood to represent biological hypotheses which were ranked using the Akaike Information Criterion (AIC). According to the results the feline occupancy is more likely away from rural settlements and in areas with a higher proportion of woody vegetation. The opportunistic killing of L. tigrinus and in retaliation for poultry predation close to residential areas can explain this result; as well as more complex vegetation structure can better serve as refuge and ensure more food. Analyzing the records of the species through circular statistics we conclude that the activity pattern is mostly nocturnal, although considerable crepuscular and a small diurnal activity. L. tigrinus activity was directly affected by the availability of small terrestrial mammals, which are essentially nocturnal. In addition, the temperatures recorded in the environment directly and indirectly affect the activity of the little-spotted-cat, as also influence the activity of their potential prey. Generally, the cats were more active when possible prey were active, and this happened at night when lower temperatures are recorded. Moreover, the different lunar phases did not affect the activity pattern. The results improve the understanding of an endangered feline inhabiting the Caatinga biome, and thus can help develop conservation and management strategies, as well as in planning future research in this semi-arid ecosystem.
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Despite the importance of the study of roots, little is known about the negative effects of soil compaction in the development of the Caatinga forest species. In this sense, the objective was to evaluate the initial growth of Mimosa caesalpiniifolia, Tabebuia caraiba and Erythina velutina in soil under varying levels of compression. The experiment was conducted in a greenhouse located at the Academic Unit Specialized in Agricultural Sciences, UFRN. To perform the experiment, was used Oxisoil of sandy loam texture, from forest trial Area Agricultural School of Jundiaí (EAJ) of the municipality of Macaíba-RN, in an experimental unit consisting of three overlapping PVC rings, 10 cm in diameter and 25 cm in height, with a central ring which has undergone compression. The experimental design was a randomized block with six replications, being tested four levels of soil compaction (1.35; 1.45; 1.60 and 1.80 kg.dm-³), evaluating the following variables: diameter, height, number of leaves, dry weight of shoot and root system in each layer of the vessels. Overall, the species M. caesalpiniifolia, T. caraiba and E. velutina had initial growth favored by treatment consists of uncompressed soil. The M. caesalpiniifolia and T. caraiba species proved relatively resistant to compaction of the soil does not undergo any significant reduction in root growth density equal to or less than 1.60 kg.dm-³, whereas E. velutina proved susceptible effects of soil compaction, with significant changes in root growth under soil densities equal to or greater than 1.45 kg.dm-³. Increased soil compaction caused the impediment to the expansion of taproot inside the experimental units, promoting the accumulation of roots in the upper layers of the soil for the studied species. The subsoil physical impediment changed the initial aerial growth of M. caesalpiniifolia and E. velutina, but did not influence the growth of air T. caraiba seedlings the tested compression levels.
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Cervídeo Mazama gouazoubira é a espécie de veado que possui maior distribuição dentre as espécies sul americanas. Aspectos da vegetação, predação, competição, caça e perda de habitat são fatores importantes para compreender a distribuição espacial de herbívoros na paisagem. Dessa forma, considerando a falta de estudos de mamíferos de médio e grande porte na Caatinga, objetivamos compreender quais os fatores ambientais e antrópicos que influenciam a ocupação do veado-catingueiro (M. gouazoubira) na região semiárida do estado do Rio Grande do Norte, Brasil. O estudo foi realizado em 10 áreas amostrais e utilizamos armadilhas fotográficas para amostragem e modelos de ocupação foram construídos representando nossas hipóteses biológicas. Os modelos foram ranqueados através dos valores obtidos do AIC. As variáveis cobertura vegetal de caatinga e densidade da vegetação mostraram maior efeito, já a caatinga arbórea mostrou um efeito menor, sugerindo que a espécie é altamente dependente da vegetação para ocorrer, possuindo menor dependência de caatinga arbórea. Esperamos que nossos resultados possam ser utilizados como suporte para planos de manejo e criação de novas unidades de conservação no estado.
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The microorganisms play very important roles in maintaining ecosystems, which explains the enormous interest in understanding the relationship between these organisms as well as between them and the environment. It is estimated that the total number of prokaryotic cells on Earth is between 4 and 6 x 1030, constituting an enormous biological and genetic pool to be explored. Although currently only 1% of all this wealth can be cultivated by standard laboratory techniques, metagenomic tools allow access to the genomic potential of environmental samples in a independent culture manner, and in combination with third generation sequencing technologies, the samples coverage become even greater. Soils, in particular, are the major reservoirs of this diversity, and many important environments around us, as the Brazilian biomes Caatinga and Atlantic Forest, are poorly studied. Thus, the genetic material from environmental soil samples of Caatinga and Atlantic Forest biomes were extracted by direct techniques, pyrosequenced, and the sequences generated were analyzed by bioinformatics programs (MEGAN MG-RAST and WEBCarma). Taxonomic comparative profiles of the samples showed that the phyla Proteobacteria, Actinobacteria, Acidobacteria and Planctomycetes were the most representative. In addition, fungi of the phylum Ascomycota were identified predominantly in the soil sample from the Atlantic Forest. Metabolic profiles showed that despite the existence of environmental differences, sequences from both samples were similarly placed in the various functional subsystems, indicating no specific habitat functions. This work, a pioneer in taxonomic and metabolic comparative analysis of soil samples from Brazilian biomes, contributes to the knowledge of these complex environmental systems, so far little explored
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Dengue, amongst the virus illnesses one can get by vectorial transmission, is the one that causes more impact in the morbidity and mortality of world s population. The resistance to the insecticides has caused difficulties to control of vector insect (Aedes aegypti) and has stimulated a search for vegetables with larvicidal activity. The biodiversity of Caatinga is barely known and it is potential of use even less. Some plants of this biome are commercialized in free fairs northeast of Brazil, because of its phytotherapics properties. The vegetables in this study had been selected by means of a questionnaire applied between grass salesmen and natives of the Serido region from Rio Grande do Norte state; culicids eggs had been acquired with traps and placed in container with water for the larva birth. Thirty larvae had been used in each group (a group control and five experimental groups), with four repetitions four times. The vegetables had been submitted to the processes of decoction, infusion and maceration in the standard concentration of 100g of the vegetable of study in 1l of H2O and analyzed after ½, 1, 2, 4, 8, 12, 24 and 48 hours for verification of the average lethal dose (LD50) from the groups with thirty larva. The LD50 was analyzed in different concentrations (50g/l, 100g/l, 150g/l, 200g/l e 300g/l) of Aspidosperma pyrifolium Mart. 48 extracts of rind, leaf and stem of the seven vegetal species: Aspidosperma pyrifolium Mart., Mimosa verrucosa Benth, Mimosa hostilis (Mart.) Benth., Myracrodruon urundeuva Allemão, Ximenia americana L, Bumelia sartorum Mart Zizyphus joazeiro Mart, had been analyzed. The extracts proceeding from the three methods were submitted to the freezedrying, to evaluate and to quantify substances extracted in each process. The results had shown that Aspidosperma pyrifolium Mart. and Myracrodruon urundeuva Allemão are the species that are more distinguished as larvicidal after 24 hours of experiment, in all used processes of extraction in the assays. The Zizyphus joazeiro Mart species has not shown larvicidal activity in none of the assays. In relation to the extraction method, the decoction was the most efficient method in the mortality tax of the A. aegypti larvae
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The composition of termite assemblages was analyzed at three Caatinga sites of the Seridó Ecological Station, located in the municipality of Serra Negra do Norte, in the state of Rio Grande do Norte, Brazil. These sites have been subjected to selective logging, and cleared for pasture and farming. A standardized sampling protocol for termite assemblages (30h/person/site) was conducted between September 2007 and February 2009. At each site we measured environmental variables, such as soil granulometry, pH and organic matter, necromass stock, vegetation height, tree density, stem diameter at ankle height (DAH) and the largest and the smallest crown width. Ten species of termites, belonging to eight genera and three families, were found at the three experimental sites. Four feeding-groups were sampled: wood-feeders, soil-feeders, wood-soil interface feeders and leaf-feeders. The wood-feeders were dominant in number of species and number of encounters at all sites. In general, the sites were not significantly different in relation to the environmental variables measured. The same pattern was observed for termite assemblages, where no significant differences in species richness, relative abundance and taxonomic and functional composition were observed between the three sites. The agreement between the composition of assemblages and environmental variables reinforces the potential of termites as biological indicators of habitat quality
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A taxonomic survey of representatives of the genus Geastrum took place during the rainy season from 2006 to 2009 in four districts in the state of Rio Grande do Norte: Parque Estadual Dunas do Natal (Atlantic Forest), Mata do Jiqui EMPARN (Atlantic Forest) and Estação Ecológica do Seridó (Caatinga). Fourteen species were recorded: G. entomophilum, G. fimbriatum, G. hirsutum, G. javanicum, G. lageniforme, G. lloydianum, G. minimum, G. morganii, G. ovalisporum, G. pectinatum, G. saccatum, G. schweinitzii, G. setiferum and G. triplex. Of these species, eleven occurred in the Atlantic Forest and six in the Caatinga. A new species has been recorded to science, G. entomophilum, other as a first record for Brazil, G. morganii, six new records for the Northeast, and ten new records for Rio Grande do Norte. The material was tumbled in the Herbarium UFRN. Additionally, a survey of the species of the genus deposited in the Herbarium UFRN was accomplished, resulting in 244 herbarium specimens belonging to thirty-three species. Of these ones, twenty-three were collected in Brazil and ten are from Czech Republic, Europe, as donation from the VZ Herbarium
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The species of the genus Marsdenia, Apocynaceae, are widely used in folk medicine of several countries. In Brazil is found several species belonging to this genus. The in vitro antioxidant, anticoagulant and antiproliferative activities were evaluated to aqueous extracts of stalk, leaf and root of Marsdenia megalantha. In the total antioxidant capacity assay (expressed as ascorbic acid equivalents) the stalk extract showed 76.0 mg/g, while leaf and root extracts 141.3 mg/g and 57.0 mg/g, respectively. The stalk and leaf extracts showed chelating activity around 40% at 1.5 mg/mL, while root extract, at the same concentration showed, 17%. Only the leaf extract showed a significant ability in superoxide scavenging (80% at 0.8 mg/mL). Any extract was able in scavenge hydroxyl, as well anticoagulant activity. The antiproliferative activity of the extracts was evaluated against HeLa tumor cell line. The extracts inhibited in a dose-dependent manner the cell growth. However, the leaf extract showed 80% of inhibition at 1.0 mg/mL, while stalk and root extracts inhibited 63% and 30%, respectively. To assess the mechanism of cell death caused by the leaf extract in HeLa, was performed flow cytometry and western blot. The results show that leaf extract induces cell death by apoptosis through an activation caspase-independent pathway. These data indicate that stalk and leaf extracts obtained have potential to be used as antioxidants and anticancer drugs