Zanthoxylum Rhoifolium Research Articles

How to access viability of Zanthoxylum rhoifolium seeds? A protocol of tetrazolium test as an alternative to evaluate a dormant seed

A tetrazolium test method is proposed for evaluating seed quality of Zanthoxylum rhoifolium Lam. We used seeds from two lots, which we immersed in distilled water for 8 hours and subjected to two preparations: A - lateral incision into the seed, parallel to the hilum, to expose the endosperm, and B - extraction of the embryos. We then exposed the seeds of both preparations to the tetrazolium solution at two concentrations (0.1% and 0.05%) for two periods (24 hours and 48 hours) at a temperature of 25 ºC, then the seeds were evaluated in a 2 × 8 factorial scheme (lots × treatments) and classified in viable and non-viable. We found that the best preparation for the tetrazolium assay in Zanthoxylum rhoifolium was to remove part of the seed coat, this allowed the solution to penetrate the internal tissues without damaging the embryo. There were no significant differences between concentrations of 0.1% at 24 hours and 0.05% for 48 hours. We concluded that immersion of seeds in water for 8 hours, followed by a lateral cut parallel to the hilum exposing the endosperm at a concentration of 0.1% tetrazolium for 24 hours or 0.05% for 48 hours is an efficient method for quality assessment of Zanthoxylum rhoifolium seeds.

Neuroprotective and antioxidant activities of Colombian plants against paraquat and C2-ceramide exposure in SH-SY5Y cells

Abnormal production of reactive oxygen species (ROS) has been implicated in the physiopathology of neuronal cell death. Increased ROS levels are associated with exacerbated peptide aggregation, inflammation, and mitochondrial dysfunction, which facilitate the triggering of specific cell death pathways. Antioxidant molecules are potentially useful in the amelioration of neurodegeneration. In this regard, natural products are an invaluable source of antioxidants. Therefore, we investigate the antioxidant and neuroprotective activities of four Colombian angiosperm extracts. Antioxidant activity was evaluated by phytochemical assays using TLC techniques with Dragendorff reagent, ninhydrin, and chloranil in dioxane, NH3, Fast Blue, and FeCl3, together with bioautography using DPPH and β-carotene. In vitro neuroprotective activity, cell death, and ROS accumulation were evaluated by MTT and flow cytometry in the SH-SY5Y cell line exposed to paraquat and C2-ceramide. We found that Zanthoxylum rhoifolium Lam, Zanthoxylum martinicense, Nectandra membranacea, and Nectandra reticulata extracts have antioxidant activity higher than quercetin under a β-carotene bleaching assay and protect SH-SY5Y cells against paraquat and C2-ceramide associated with a reduction in ROS. In conclusion, these extracts have a strong neuroprotective potential, and the precise mechanism requires more evaluation.

Cytotoxicity and Genotoxicity Evaluation of Zanthoxylum rhoifolium Lam and In Silico Studies of Its Alkaloids.

The alkaloids isolated from Zanthoxylum rhoifolium have demonstrated great pharmacological potential; however, the toxic profiles of these extracts and fractions are still not well elucidated. This study evaluated the toxicity of the ethanol extract (EEZR) and neutral (FNZR) and alkaloid (FAZR) fractions. Chemical characterization was performed by chromatographic methods: thin-layer chromatography (TLC) and high-performance liquid chromatography coupled with diode array detection (HPLC-DAD). The cytotoxicity of the samples was evaluated in human hepatocellular carcinoma (HepG2) cells using the cell viability method (MTT) and mutagenicity by the Allium cepa assay (ACA). Alkaloids isolated from the species were selected for toxicity prediction using preADMET and PROTOX. The molecular docking of the topoisomerase II protein (TOPOII) was used to investigate the mechanism of cell damage. In the EEZR, FNZR, and FAZR, the presence of alkaloids was detected in TCL and HPLC-DAD analyses. These samples showed a 50% inhibitory concentration (IC50) greater than 400 μg/mL in HepG2 cells. In ACA, time- and concentration-dependent changes were observed, with a significant reduction in the mitotic index and an increase in chromosomal aberrations for all samples. Nuclear sprouts and a micronucleus of the positive control (PC) were observed at 10 µg/mL and in the FAZR at 30 µg/mL; a chromosomal bridge in FNZR was observed at 105 µg/mL, CP at a concentration of 40 µg/mL, and nuclear bud and mitotic abnormalities in the EEZR were observed at 170 µg/mL. The alkaloids with a benzophenanthridine were selected for the in silico study, as structural alterations demonstrated certain toxic effects. Molecular docking with topo II demonstrated that all alkaloids bind to the protein. In summary, the fractionation of Z. rhoifolium did not interfere with toxicity; it seems that alkaloids with a benzophenanthridine nucleus may be involved in this toxicity.

Avaliação da sobrevivência e modelagem do desenvolvimento inicial de árvores para restauração da Mata Atlântica

ABSTRACT: Ecological restoration has become an important complementary practice to protect natural resources and preserve biodiversity. However, native species may be used in restoration programs in ways that do not optimize their performance. This research evaluated the survival and to model the initial growth of 15 native tree species planted in “filling” and “diversity” lines in the post-planting phase of a restoration experiment in the subtropics of the Brazilian Atlantic Forest. We measured survival rate (%) one year after planting and collar diameter (mm), total height (m), crown projection area (m²) and crown volume (m³) in the first 48 months after planting. Growth modeling for each variable and species was based on the non-linear mathematical Logistic, Gompertz, and Chapman-Richards models. Model selection for each variable/species was supported by the Akaike Information Criterion, standard error of the estimate, and coefficient of determination. The highest survival rates were reported for Cordia americana, Gochnatia polymorpha, Inga uruguensis, Peltophorum dubium, Prunus sellowii e Zanthoxylum rhoifolium (91.7%) and for Solanum mauritianum (90.3%). The species with faster growth were, by increasing order, Mimosa scabrella, Trema micrantha, Solanum mauritianum and Croton urucurana. With a better understanding of the initial developmental potential of tree species, it is possible to increase the species and functional diversity of the filling group. There was no single model capable of describing the variables analyzed and different models were needed to describe different characteristics and species.

DIRECT SEEDING FOR FOREST RESTORATION IN SOUTHERN BRAZIL: INFLUENCE OF SOIL CONDITIONS AND SUBTROPICAL CLIMATE

In this study, we evaluated the direct seeding of tree Atlantic Forest species for ecological restoration under subtropical climate. We aimed to answer: Are the seedling survival and development influenced by the low temperatures in the winter or soil conditions? Which species have the best development and are most suitable for restoration projects in the subtropical region? The study was carried out in a degraded riparian forest in the center of the Rio Grande do Sul state, southern Brazil. The seeded species were Schinus terebinthifolia Raddi, Psidium cattleyanum Sabine, Eugenia uniflora L., Cupania vernalis Cambess., Prunus myrtifolia L. (Urb.), Zanthoxylum rhoifolium Lam. Evaluations were performed monthly for 12 months. Generalized linear models (GLM) were evaluated using emergence, survival and seedling height as response variables, also species and time as explanatory variables with the Gamma distribution. The species that germinated were P. cattleyanum, E. uniflora and C. vernalis. Eugenia uniflora presented a higher germination rate (83.33%) and survival (80.00%) at 360 days after sowing. The species did not differ in height growth. We noted differences in height development over time caused by winter conditions. Cupania vernalis and E. uniflora may be considered as potential species for direct seeding in their natural occurrence areas in southern Brazil. Our study highlights the importance of enhancing ecological aspects of direct seeding.

What is the cause of low seed germination of Zanthoxylum rhoifolium Lam.?

This study aimed to determine the main causes of low germination of Zanthoxylum rhoifolium Lam. (Rutaceae) seeds. Initially, the physical and physiological qualities were evaluated in seeds from four areas (lots) (Step I). Then, tests were performed (Step II) to determine physical dormancy (imbibition in water and methylene blue), physiological (germination test with scarification) and morphological (analysis of the embryo), in addition to histochemical analysis and (Step III) bioassay in aqueous and hydroalcoholic extracts. In Step I, a low germination was observed in all evaluated lots (≤ 1.0%); however, in the tetrazolium test, a high viability was verified for the Dois Vizinhos lot (88%). The lots showed differences in their physical aspects, with the predominance of seeds with damage. In Stage II, developed embryos were verified and there has no germination without the tegument. The methylene blue and histochemical test indicated the presence of an impermeable and thick tegmen. The bioessays with hydroalcoholic extracts indicated the presence of germination inhibitor(s). The main causes associated with low germination of Z. rhoifolium seeds are attributed to the combined dormancy due to an impermeable tegmen and some non-specific physiological dormancy, as well as the presence of damaged seeds. The seeds also contain germination inhibitors.

Characterization of Zanthoxylum rhoifolium (Sapindales: Rutaceae) Essential Oil Nanospheres and Insecticidal Effects to Bemisia tabaci (Sternorrhyncha: Aleyrodidae).

Encapsulation via nanotechnology offers a potential method to overcome limited thermal and photo-stability of botanical pesticides. In this study, nanospheres of essential oils (NSEO) derived from Zanthoxylum rhoifolium Lam. fruit were characterized and evaluated for their photostability and insecticidal activity against Bemisia tabaci. Three major compounds of Z. rhoifolium fruits were detected by CG-MS: β-phellandrene (76.8%), β-myrcene (9.6%), and germacrene D (8.3%). The nanoprecipitation method was used to obtain homogeneous spherical NSEO, with ≥98% encapsulation efficiency. Tests with UV/Vis spectrophotometry showed significantly reduced photodegradation from exposed NSEO samples when compared with essential oil (EO) controls. Whitefly screenhouses bioassays with bean plants treated with 0.25, 0.5, 1 and 1.5% suspensions showed EO treatments in both free and nanoencapsulated forms reduced adult whitefly oviposition by up to 71%. In further tests, applications at 1.5% caused ≥64% mortality of second instar nymphs. When the test was conducted under high temperature and light radiation conditions, the insecticidal effect of NSEO treatments was improved (i.e., 84.3% mortality) when compared to the free form (64.8%). Our results indicate the insecticidal potential of EO-derived from Z. rhoifolium fruits with further formulation as nanospheres providing greater photostability and enhanced insecticidal activity against B. tabaci under adverse environmental conditions.

Analgesic and neuromotor effects of two extracts of Zanthoxylum rhoifolium (Rutaceae) in the Swiss albino mouse (Mus musculus)

BACKGROUND: Colombia has a high diversity of medicinal plants, including Tachuelo (Zanthoxylum rhoifolium), a tree belonging to the family Rutaceae, which has been attributed an analgesic use by communities of the Colombian southwest. Nevertheless, this species has been scarce studied in Colombia. The studies have been limited to the isolation of compounds with antifungal and insecticide activity, using the leaves, branches, and bark of the plant in aqueous, and organic extracts. Neither pharmacological tests have been carried out, nor the analgesic and neuromotor activity have been tested from preparations with this plant’s fruits. OBJECTIVES: To evaluate the analgesic and neuromotor effect of the aqueous and hexane extract of the fruits of Z. rhoifolium. METHODS: As there were no preliminary reports of this study, the first observation was made through Irwin’s test. The formalin and the rotarod test were performed to determine the analgesic and motor coordination effects, respectively. RESULTS: All the evaluated treatments demonstrated to generate analgesia, anesthesia, passivity, reduction in the alarm reaction, and have antinociceptive activity in the formalin test; while only the high dose of the nonpolar extract generated a deficit in the motor performance of the rodents in the rotarod test. CONCLUSIONS: the antinociceptive effect of the aqueous and hexane extracts of this species’ fruits was demonstrated. The hexane extract generated a neuromotor effect, which validates the ethnobotanical reports on Z. rhoifolium fruits.

Unsuitability of indigenous South American Rutaceae as potential hosts of Diaphorina citri.

'Candidatus Liberibacter asiaticus' is transmitted by Diaphorina citri, an insect with a wide range of hosts in Rutaceae. Species related to Citrus occur in Brazilian forests where they may serve as hosts for psyllids and infested citrus orchards. The suitability of plants as hosts of D. citri was classified into four groups. Group I (high suitability): Citrus × aurantium 'Valencia', 'Citrus limonia', Murraya paniculata (syn. Murraya exotica L.) (Aurantioideae: Aurantieae) and Bergera koenigii (Aurantioideae: Clauseneae). Group II (intermediate to low suitability): Citrus (Poncirus) trifoliata 'Pomeroy', Citrus wintersii, Swinglea glutinosa (Aurantieae) and Clausena lansium (Clauseneae). Group III (not suitable): Aegle marmelos, Atalantia buxifolia, Citrus ('Microcitrus') sp. (Aurantieae) and Helietta apiculata (Amyridoideae). Group IV (non-hosts): Glycosmis pentaphylla (Clauseneae), Balfourodendron riedelianum, Casimiroa edulis, Esenbeckia febrifuga, Esenbeckia leiocarpa, Metrodorea stipularis, Zanthoxylum rhoifolium (Amyridoideae) and Dictyoloma vandellianum (Cneoroideae). Insects survived longer on newly differentiated leaves compared with fully expanded soft leaves. Psyllids either did not develop or did not survive for long on most Group IV species, all of which, with the exception of G. pentaphylla, occur naturally in Brazilian forests. Citrus relatives occurring in forests near citrus orchards are not suitable hosts of D. citri and, therefore, do not contribute to huanglongbing spread. © 2018 Society of Chemical Industry.

Interference of Noxious Shrubs on Grazing Behavior by Bovines

ABSTRACT: The grazing behavior practice by bovines can be positive or negatively influenced by the pasture structure where the animal is inserted. Several factors determine the pasture structure and the presence of weeds is considered one of the most important. This study aimed to assess the effect of species with and without stiff structures over the grazing behavior of bovines in pasture areas. The experimental design was a split block design with four replications, in which treatments were arranged in a 4 x 3 factorial design: four weed species (Zanthoxylum rhoifolium, Cnidoscolus urens, Dasyphyllum brasiliensis, and Luehea divaricata) associated with three proximity strips of weeds: 0-50, 50-100, and 100-150 cm in relation to the main stem of the studied weed. Forage intake by animals was measured by determining the real forage offers at 0, 3, 6, 9, and 15 days after the beginning of animal grazing (DAP). The presence of noxious shrubs influenced bovine grazing behavior. The influence on the intake is most evident in the presence of plants that promote animal discomfort. The species Z. rhoifolium, C. urens, and D. brasiliensis were the weeds with the greatest influence on feed access among the species that have stiff structures. The negative influence on grazing behavior is higher in the proximity strip closest to the plant, i.e. 0-50 cm from the main stem of the weed.

Vasorelaxant activity and acute toxicity of the ethanolic extract of Zanthoxylum rhoifolium Lam leaves

The study evaluated the vasorelaxant effect induced by the ethanolic extract of the leaves of Zanthoxylum rhoifolium Lam (EEtOH-Zr/leaves). Wistar rats were treated with the leaf extract containing a single dose of 2,000 mg / kg, v.o. After 14 days, the animals were anesthetized for blood collection and subsequent analysis of the biochemical parameters; they were then euthanized (sodium pentobarbital-100 mg/kg, i.p.) for the removal and morphological analysis of the heart, lung, liver and kidney. The vasorelaxation activity the and vascular reactivity of EEtOH-Zr/leaves were evaluated on artery mesenteric rings isolated from rats. The extract showed no signs of toxicity and no significant difference in the values of the biochemical parameters between the control group and the group of treated animals. In the evaluation of pharmacological activity in the smooth muscle, the EEtOH-Zr/leaves caused vasorelaxant effect on the tonic contraction induced by phenylephrine in mesenteric artery preparations in the presence (pD2=2.17±0.05 µg/mL; Emax=99.8±5.2%) and absence (pD2=2.14±0.05 µg/mL; Emax=95.3±6.4%) of the vascular endothelium. Oral administration of EEtOH-Zr/leaves reduced the contraction induced by the cumulative addition of PHE. It is concluded that the EEtOH-Zr/leaves promote vasorelaxation and reduce vascular reactivity of adrenergic alpha-1 agonist in the mesenteric artery. The results did not show toxic effects of the extract.

COMPOSIÇÃO FLORÍSTICA E POTENCIAL DE REGENERAÇÃO DA MATA CILIAR REMANESCENTE DE UM TRIBUTÁRIO DO VACACAÍ-MIRIM, SANTA MARIA - RS

O presente trabalho teve como objetivo avaliar a composição florística da mata ciliar remanescente da Sanga Lagoão do Ouro, procurando obter informações acerca de sua degradação, analisando a distribuição das espécies nos diferentes estratos florísticos, a regeneração natural e a presença de espécies exóticas. O estudo foi realizado na mata ciliar da Sanga Lagoão do Ouro, tributário de 3ª ordem do Vacacaí-mirim. Sua nascente localiza-se em área urbana, percorrendo várias vilas, o Campus da UFSM, além de uma extensa área rural. Os solos predominantes classificam-se como: Argissolos Bruno-Acinzentados, Vermelho-Amarelos e Vermelhos, além de Planossolos Háplicos, sendo estes de baixa fertilidade natural e bastante suscetíveis à erosão hídrica. O levantamento florístico ocorreu em 12 parcelas de 300 m2 cada, demarcadas ao longo da margem da Sanga Lagoão do Ouro, em que foram avaliados os estratos: plântulas, regeneração natural e arbóreo. O levantamento florístico mostrou haver degradação da mata ciliar, evidenciada pelo baixo número de espécies nativas, pela má distribuição das espécies nos diferentes estratos e pela grande presença de espécies exóticas. Possuem maior potencial de regeneração natural nas espécies que apresentaram maior frequência e que aparecem nos três estratos florísticos levantados, tais como: Eugenia uniflora, Allophylus edulis (A.St.-Hil., Cambess. & A. Juss.) Radlk, Psidium guajava L., Cestrum strigilatum Ruiz & Pav., Prunus myrtifolia (L.) Urb., Zanthoxylum rhoifolium Lam., Casearia sylvestris Sw., Cupania vernalis Cambess. e Schinus terebinthifolius Raddi.

Savanna trees do not have thicker outer bark than forest trees of two tropical species

Although the outer bark is important for protecting the inner tissues of stems of woody plants, especially from fire, the variation of outer bark in environments with different water availability, wind intensities, and solar radiation is little understood. Here, we examined the outer bark structure of Moquiniastrum polymorphum (Asteraceae) and Zanthoxylum rhoifolium (Rutaceae), co-occurring species in cerrado sensu stricto, cerradão, semi-deciduous seasonal forest and rainforest. Cerrado sensu stricto is a savanna with relatively intense solar radiation and winds. Cerradão, semi-deciduous seasonal forest and rainforest are progressively more closed and humid. We tested if trees in cerrado sensu stricto have relatively thicker outer and total bark than trees in the other three environments. For individuals of each species from each habitat, we described the morphological and anatomical features of the outer bark, including the origin of the first periderm. We compared the relative thickness of outer and total bark among habitats by means of ANOVA. In both species, we observed no qualitative differences in the morphological and anatomical features of the outer bark; therefore, these features are diagnostic for each species. For all habitats, the deep-seated origin of the first periderm and formation of a rhytidome in M. polymorphum produce a grooved bark with a loose appearance, whereas the subepidermal origin and formation of a single periderm in Z. rhoifolium produce a more uniform and smooth-appearing bark. Zanthoxylum rhoifolium trees in cerrado sensu stricto and cerradão have a thinner periderm, whereas M. polymorphum trees do not vary in rhytidome thickness among the habitats. In summary, trees from cerrado sensu stricto did not have relatively thicker outer bark and total bark than trees in cerradão, semi-deciduous seasonal forest and rainforest, suggesting that seasonal drought, intense solar radiation and winds do not seem to affect the total thickness of the outer bark.

Growth, Survival and Spore Formation of the Pathogenic Aquatic Oomycete Aphanomyces astaci and Fungus Fusarium avenaceum Are Inhibited by Zanthoxylum rhoifolium Bark Extracts In Vitro

This study aimed to evaluate the in vitro activity of Zanthoxylum rhoifolium bark (Zr-b) extracts against pathogenic aquatic oomycete/fungal isolates that cause different diseases in native European crayfish resulting in an elevated mortality rate and severe economic repercussions. n-hexane, chloroform, chloroform–methanol (9:1) and methanol extracts of Zr-b were used to evaluate the antifungal activity against the strain UEF88662 of Aphanomyces astaci (oomycete) and the strain SMM2 of Fusarium avenaceum (fungus). The anti-oomycete and antifungal activity was quantitatively evaluated by growth, survival and sporulation microbiological assays. The extracts tested demonstrated a dose-dependent inhibitory effect on oomycete and fungal growth and survival, as well as on the production of oomycete and fungal spores. This work presents alternatives for the treatment and prevention of the spreading of Aphanomyces astaci and Fusarium avenaceum, the etiological agents of the diseases crayfish plague and brown spot disease, respectively. The antifungal properties of Zanthoxylum rhoifolium bark extracts warrant further research on their use in the prevention and treatment of both oomycete and fungal diseases. The antifungal properties of Zanthoxylum rhoifolium bark extracts, shown in vitro, indicate the possibility of their use in new therapeutic and prophylactic strategies, providing perspectives for the design of in vivo studies.

Essential oil repellent action of plants of the genus Zanthoxylum against Bemisia tabaci biotype B (Homoptera: Aleyrodidae)

Several insects cause harm to agricultural production, increasing its cost. An insect of great interest is Bemisia tabaci, considered a major pest of tomatoes and other crops. Essential oils are alternative products for the control of agricultural pests. In this context, the objective of this work was to carry out chemical analyses of the essential oils of the fruits of Zanthoxylum rhoifolium and Zanthoxylum riedelianum and to evaluate their repellent activity against B. tabaci. The average yields of Z. rhoifolium and Z. riedelianum fruit were 0.44 and 0.21% (v/v), respectively. The major compounds in the essential oil of Z. rhoifolium were sabinene (55.9%), germacrene-D (17.1%) and β-myrcene (8.03%); the major compounds in the essential oil Z. riedelianum were γ-elemene (21.2%), D-germacrene (14.2%), sabinene (11.9%) and limonene (11.3%). Six (0.1; 0.2; 0.5; 1.0; 1.5 and 2.0%) and five (0.1; 0.2; 0.5; 1.0 and 1.5%) concentrations of essential oils of Z. rhoifolium and Z. riedelianum, respectively, were evaluated under no-choice and choice bioassay conditions. The best results obtained in the bioassays were achieved at concentrations ranging from 1.0 to 2.0% for both essential oils, with a reduced efficiency of egg laying between 85 and 98%. This is the first time that the chemical compositions of the essential oil from the fruits of Z. riedelianum have been described. The repellency tests suggest that these essential oils are promising for the management of B. tabaci.

DINÂMICA DE POPULAÇÕES DE ESPÉCIES ARBÓREAS EM UM FRAGMENTO DE FLORESTA OMBRÓFILA MISTA MONTANA EM LAGES, SANTA CATARINA

O presente estudo teve como principal objetivo avaliar a dinâmica de populações de espécies arbóreas, em um fragmento de Floresta Ombrófila Mista Montana, no Município de Lages, Santa Catarina - SC, ao longo de um período de quatro anos (2008-2012). Para isto, em todas as espécies amostradas em 50 parcelas permanentes de 10 x 20 m, foram determinadas as guildas de regeneração [Pioneiras (P), Climácicas Exigentes em Luz (CEL) e Climácicas Tolerantes ao Sombreamento (CTS)] e as taxas de dinâmica (mortalidade, recrutamento, ganho e perda em área basal, mudança líquida em abundância e área basal). A existência de associação significativa entre as guildas de regeneração e os padrões de dinâmica foi verificada por meio de testes de qui-quadrado, aplicados a tabelas de contingência. Mudanças das participações relativas das guildas de regeneração entre os anos foram analisadas por meio de testes de proporção. No ano 2008 foram verificadas 87 espécies (P: 9, CEL: 64, CTS: 11 e não classificadas: 3), 1.841 ind.ha-1 e 36,17m2.ha-1. Em 2012, verificaram-se 86 espécies (P: 9, CEL: 63, CTS: 11, não classificadas: 3), 1.882 ind.ha-1 e 39,17m2.ha-1. A maior parte das espécies apresentou ganho em abundância e área basal. Dentre as mais abundantes, as maiores taxas de recrutamento e ganho em área basal foram observadas para Banara tomentosa Clos, com, respectivamente, 5,43%.ano-1 e 6,08%.ano-1, e as maiores taxas de mortalidade e perda em área basal ocorreram para Zanthoxylum rhoifolium Lam., com, respectivamente, 7,75%.ano-1 e 4,74%.ano-1. Não foi verificada associação significativa entre os padrões de dinâmica observados e guildas de regeneração, cujas participações relativas na comunidade no período avaliado, permaneceram constantes. Desta forma, conclui-se que o fragmento florestal se encontra em fase de instabilidade estrutural, indicada pelo incremento no número de indivíduos e área basal, e estabilidade florística sucessional, em função da baixa substituição florística e manutenção da importância relativa das guildas de regeneração ao longo do tempo avaliado.

FIRE EFECT ON THE SEASONAL FOREST STRUCTURE IN THE CERRADO BIOME

There are few studies on the effects of fire on the seasonal semideciduous forest of the Cerrado region. This study aimed to assess the effect of fire on Semideciduous forest fragments located in the Altamiro Moura Pacheco State Park (AMPSP). The study area is located in the central state of Goias. A total of 10 plots (50 x 20 m; 1,000 m 2 ) were drawn in the remaining forests seeking to portray two areas: area which underwent forest fire (burned area; B) and unburned area (unburned; UB). A total of 771 individuals with DBH (≥ 5 cm) were identified. A total of 303 individuals were recorded in the burned area (B), comprising 28 families, 41 genera and 47 species, while the unburned area (UB) had 468 individuals comprising 25 families, 43 genera and 50 species. The species Anadenanthera colubrina (Vell.) Brenan, Emmotum nitens (Benth.), Zanthoxylum rhoifolium Lam, Tapirira guianensis Aubl., Myracrodruon urundeuva Allemao and Luehea candicans Mart. had the highest Importance Value Index (IVI) values and occur in both areas. The percentage of dead trees differed between the areas, where the burned area had a mortality of 12.69% and the unburned area of 7.29% in regards to the number of individuals. Density per plot was the only parameter that differed between the areas, where the burned area (B) had the lowest values. The fire affected all diameter classes, demonstrating the fragility of this vegetation type in regards to fire. The fire had a greater effect on trees in the smaller diameter classes, reducing the frequency of individuals in the burned area and changing height distribution, which may have favored the establishment of lianas and invasive species.

Inhibitory effects of Zanthoxylum rhoifolium Lam. (Rutaceae) against the infection and infectivity of macrophages by Leishmania amazonensis.

Zanthoxylum rhoifolium Lam. (Rutaceae) has been traditionally used in the treatment of microbial infections and parasitic diseases. In the present study, the antileishmanial effect induced by the ethanol extract of stem barks from Z. rhoifolium (ZR-EEtOH) and its n-hexane fraction (ZR-FHEX) on infection and infectivity of murine macrophages by promastigote forms of Leishmania amazonensis were investigated. In different set of experiments, macrophages or promastigotes were pretreated with ZR-EEtOH or ZR-FHEX at non-lethal concentrations for 24 hours, and then macrophages were submitted to infection by promastigotes. Moreover, their effects on activation of macrophages, as well as on the DNA content, size and number of promastigotes by flow cytometry were also evaluated. The infection rate and the number of internalized amastigote forms were markedly decreased after pretreatment of macrophages or promastigotes when compared with non-treated cells. The increase in phagocytic capability and nitrite content was also observed. Furthermore, the decrease of DNA content, size and number of promastigotes was also observed. In conclusion, ZR-EEtOH and ZR-FHEX promoted a markedly significant antileishmanial effect and reduction of infection of macrophages, probably underlying defense mechanisms activation in macrophages. These findings reinforce the potential application of Z. rhoifolium in the treatment of leishmaniasis.

Toxicity of plant extracts from Bahia, Brazil, to Atta sexdens sexdens workers (Hymenoptera: Formicidae)

The aim of this study was to evaluate the toxicity of extracts of Aspidosperma spruceanum Benth ex. Mull Arg. (leaf and bark), Casearia arborea (Rich.) Urb. (leaf and branch), Casearia sylvestris Sw. (leaf and bark), Erythroxylum affine A.St.-Hil. (leaf and branch), Esenbeckia grandiflora Mart. (leaf and bark), Ocotea brasiliensis Coe-Teix (bark and branch), Simarouba amara Aubl. (bark), Tabernaemontana bracteolaris Mart. ex Müll.Arg. (leaf, bark and branch) and Zanthoxylum rhoifolium Lam. (leaf and branch) plant species, collected in the state of Bahia, Brazil, to workers of Atta sexdens L. cutting-ants. The toxicity of extracts was assessed through tests of ingestion and contact, with topical application on thorax of ants and through addition of extracts in diet, respectively. Data of topical application were submitted to analysis of variance and to the Tukey test while data from ingestion were compared by survival curves using the statistical test ¨log rank¨. Through contact, the extracts of leaf and branch of Z. rhoifolium and of bark of S. amara were the most toxic ones. Through ingestion, four extracts were toxic and were characterized as of delayed action, with the extract of Z. rhoifolium branch presenting the slowest action (S50= 10 days). This characteristic is crucial to its possible use in toxic baits. The extracts of leaf and branch of Z. rhoifolium were the only ones that presented toxicity through contact and ingestion.

Cytotoxic potential of selected medicinal plants in northeast Brazil.

BackgroundGreat biodiversity is a highlight of Brazilian flora. In contrast, the therapeutic potentialities of most species used in folk medicine remain unknown. Several of these species are commonly used to treat cancer. In this study, we investigated the cytotoxic activity of 18 plants from 16 families that are found in the northeast region of Brazil.MethodsThe following species were studied: Byrsonima sericea DC. (Malpighiaceae), Cupania impressinervia Acev. Rodr. var. (revoluta) Radlk (Sapindaceae), Duranta repens Linn. (Verbenaceae), Helicostylis tomentosa (Poepp. & Endl) Rusby (Moraceae), Himatanthus bracteatus (A.DC.) Woodson (Apocynaceae), Ipomoea purga (Wender.) Hayne (Convolvulaceae), Ixora coccinea Linn. (Rubiaceae), Mabea piriri Aubl. (Euphorbiaceae), Miconia minutiflora (Melastomataceae), Momordica charantia L. (Cucurbitaceae), Ocotea glomerata (Nees) Mez (Lauraceae), Ocotea longifolia Kunth (Oreodaphne opifera Mart. Nees) (Lauraceae), Pavonia fruticosa (Mill.) Fawc. & Rendle (Malvaceae), Psychotria capitata Ruiz & Pav. (Rubiaceae), Schefflera morototoni (Aubl.) Maguire, Steyerm. & Frodin (Araliaceae), Solanum paludosum Moric. (Solanaceae), Xylopia frutescens Aubl. (Annonaceae) and Zanthoxylum rhoifolium Lam. (Rutaceae). Their dried leaves, stems, flowers or fruits were submitted to different solvent extractions, resulting in 55 extracts. After incubating for 72 h, the cytotoxicity of each extract was tested against tumor cell lines using the alamar blue assay.ResultsThe B. sericea, D. repens, H. bracteatus, I. purga, I. coccinea, M. piriri, O. longifolia and P. capitata extracts demonstrated the most potent cytotoxic activity. The chloroform soluble fractions of D. repens flowers and the hexane extract of I. coccinea flowers led to the isolation of quercetin and a mixture of α- and β-amyrin, respectively, and quercetin showed moderate cytotoxic activity.ConclusionThe B. sericea, D. repens, H. bracteatus, I. purga, I. coccinea, M. piriri, O. longifolia and P. capitata plants were identified as having potent cytotoxic effects. Further investigations are required to determine the mechanisms of cytotoxicity exhibited and their in vivo activities. This work reinforces the need to understand the therapeutics potentialities of Brazilian medicinal plants.