José Francisco de Carvalho Gonçalves

Guarana: revisiting a highly caffeinated plant from the Amazon.

ETHNOPHARMACOLOGICAL RELEVANCE Guarana (Paullinia cupana Kunth var. sorbilis (Mart.) Ducke) has been traditionally consumed by indigenous communities of the Amazon region. It is valued mainly for its stimulant property because of its high content of caffeine, which can be up to 6% in the seeds. AIM OF THE REVIEW The purpose of this review is to revisit this typically Brazilian plant, addressing economic considerations, the chemical makeup of the seeds and pharmacological properties so far investigated. RESULTS Guarana is primarily produced in the Brazilian states of Amazonas and Bahia, and approximately 70% of the production is used by the industry of soft and energy drinks. The other 30% becomes guarana powder for direct consumption in capsules or dilution in water, or it serves as a raw material for the pharmaceutical and cosmetics industries. In addition to its stimulant property, guarana has other therapeutic properties, which have aroused the interest of the scientific community. CONCLUSION This review shows that other guarana properties may be explored and how scarce are the studies regarding agronomic, plant pathology, physiology and breeding. So far, caffeine has been the main reason to study guarana and still will lead the researches because the demand for this alkaloid by food and pharmaceutical industry, and a strongly growing market related with beauty products. However, guarana has other components and there is great interest in studies designed to elucidate the effects of guaranas bioactive components and their potential pharmacological applications. Significant part of the guarana production in Brazil still comes from Indians tribes in the Amazon State, and any improvement in this plant, in any aspect, may propitiate a positive economic impact in their lives.

Growth, photosynthesis and stress indicators in young rosewood plants (Aniba rosaeodora Ducke) under different light intensities

Aniba rosaeodora is an Amazonian tree species that belongs to the family Lauraceae. Due to intense exploitation for extraction of essential oils (mainly linalol), A. rosaeodora is now considered an endangered species. On the other hand, there is little information about its ecophysiology which would be useful to support future forest planting programs. Hence, the effect of different light intensities on the growth and photosynthetic characteristics of young plants of A. rosaeodora was studied. Nine-month-old plants were subjected to four light treatments (T1= 10 a 250 µmol.m-2.s-1 / control; T2=500 to 800, T3=700 to 1000 and T4=1300 to 1800 µmol.m-2.s-1 / full sunlight). Allometric variables, gas exchange, contents of pigments and chlorophyll a fluorescence were analysed. As to the relative growth rates, it was found that plants of A. rosaeodora showed higher biomass accumulation when grown under intermediary irradiance conditions (T2). The best photosynthetic performance was achieved under conditions of T3. When growth was correlated with photosynthesis, it was found that plants under treatments T2 and T3 presented better responses in comparison with the lowest (T1) and highest (T4) light extremes. The highest pigment contents were obtained for plants in the shade (T1) and the lowest for those exposed to full sunlight (T4). The photochemical efficiency of photosystem II (Fv/Fm) was found that only plants in the shade treatment (T1) presented no stress from high irradiance. These findings suggest that both treatments (T1 and T4) altered the function of the A. rosaeodora plants, inhibiting photosynthesis and growth. Plants of A. rosaeodora developed photo-protection mechanisms under full sunlight. However, the species presented better photosynthetic response and biomass gain under intermediary irradiance conditions, displaying relative physiological plasticity, during the seedling phase.

Guarana (Paullinia cupana var. sorbilis), an anciently consumed stimulant from the Amazon rain forest: the seeded-fruit transcriptome

Guarana (Paullinia cupana var. sorbilis) is a plant native to the central Amazon basin. Roasted seed extracts have been used as medicinal beverages since pre-Colombian times, due to their reputation as stimulants, aphrodisiacs, tonics, as well as protectors of the gastrointestinal tract. Guarana plants are commercially cultivated exclusively in Brazil to supply the national carbonated soft-drink industry and natural product stores around the world. In this report, we describe and discuss the annotation of 15,387 ESTs from guarana seeded-fruits, highlighting sequences from the flavonoid and purine alkaloid pathways, and those related to biotic stress avoidance. This is the largest set of sequences registered for the Sapindaceae family.

Utilization of the chlorophyll a fluorescence technique as a tool for selecting tolerant species to environments of high irradiance

We examine the hypothesis that the chlorophyll a fluorescence technique can be an efficient tool to support the selection of species adapted to high irradiance and therefore, suitable for use in initial rehabilitation projects of degraded areas. The experiment was conducted at the Pedro de Moura Operational Base, Amazonas, Brazil. The fluorescence transients were obtained using a portable fluorometer for leaves of Bombacopsis macrocalyx (Bm), Eugenia cumini (Ec), Iryanthera macrophyla (Im) and Senna reticulata (Sr), which were subjected to high irradiance between 12:00 am and 1:00 p.m. Using the OJIP test, the following were calculated: performance index (PIABS), density of reaction centres per cross section (RC/CS), maximum efficiency of photosystem II (fPo), and probability of energy excitation (yo) or that an absorbed photon (fEo) moves an electron beyond quinone A. The highest value of PIABS was found in Ec (0.40) while the lowest values were found in Bm (0.08) and Im (0.06). These low values of PIABS in Bm and Im were a result of the low values for RC/CS (121 for Bm; 142 for Im) and fPo (0.50 for Bm; 0.48 for Im) when compared to the values in Ec (RC/CS=303; fPo=0.72) and Sr (RC/CS=326; fPo=0.73). It was also observed that in Sr the decrease in PIABS when compared with Ec resulted from a low value of yo, which was 32 % lower than the value found in Ec. Regarding the PIABS per plant, Ec had the largest number of individuals with high performance while Im and Bm had the largest numbers of individuals with low performance. In conclusion, the chlorophyll a fluorescence technique enabled the evaluation of the photochemical performance of plants in the field, in turn permitting the selection of species most suitable for rehabilitation of degraded areas.

Leaf water potential, gas exchange and chlorophyll a fluorescence in acariquara seedlings (Minquartia guianensis Aubl.) under water stress and recovery

The physiological performance of acariquara (Minquartia guianensis) seedlings submitted to water deficit and the recovery of physiological parameters during rehydration were investigated in a greenhouse experiment. The analyzed parameters were: leaf water potential, gas exchange and chlorophyll a fluorescence. After thirty-five days, non-irrigated plants exhibited a leaf water potential 70 % lower compared to control plants (irrigated daily) and the stomatal conductance reached values close to zero, inducing a severe decrease in gas exchange (photosynthesis and transpiration). Six days after the beginning of the rehydration of drought-stressed plants, the results demonstrated that water stress did not irreversibly affect gas exchange and quantum efficiency of photosystem II (PSII) in M. guianensis seedlings, since four to six days after rehydration the plants exhibited total recovery of the photosynthetic apparatus. We conclude that M. guianensis presented good tolerance to water stress and good capacity to recover the physiological performance related to leaf water status, photosynthesis and photochemical efficiency of PS II under hydric stress, suggesting substantial physiological plasticity during the juvenile phase for this tree species.

Fotossíntese e potencial hídrico foliar de plantas jovens de andiroba submetidas à deficiência hídrica e à reidratação

O objetivo deste trabalho foi investigar o desempenho fotossintetico de plantas jovens de andiroba (Carapa guianensis), submetidas a deficiencia hidrica e a reidratacao. As plantas foram irrigadas diariamente, em casa de vegetacao, durante 15 dias. Apos aclimatacao, as plantas foram separadas em dois tratamentos: plantas irrigadas e nao irrigadas. Quando a resposta fotossintetica das plantas nao irrigadas alcancou valores proximos a zero, as plantas foram reidratadas. A cada sete dias, durante 21 dias, foram realizadas as determinacoes das trocas gasosas e da fluorescencia da clorofila a. O potencial hidrico foliar foi determinado no inicio e no fim do experimento. As taxas de fotossintese liquida, condutância estomatica e transpiracao se reduziram em 88, 89 e 89%, respectivamente, apos 21 dias de supressao da irrigacao. Quanto as variaveis da fluorescencia da clorofila a, observaram-se reducoes de 27 a 58%. O potencial hidrico foliar das plantas foi reduzido em mais de quatro vezes, apos 21 dias de deficiencia hidrica. De quatro a oito dias apos a reidratacao, as plantas recuperaram as caracteristicas fotossinteticas e o potencial hidrico foliar, o que indica que plantas jovens de andiroba apresentaram alta plasticidade fisiologica em relacao ao estresse hidrico.

Chloroplastid pigment contents and chlorophyll a fluorescence in Amazonian tropical three species

ABSTRACT – Plants react to changes in light and hydrological conditions in terms of quantity and compositionof chloroplastidic pigments, which affects the photosynthetic properties and consequently the accumulationof plant biomass. Thus, the chloroplastidic pigment concentration and chlorophyll a fluorescence of threeAmazonian species ( Bertholletia excelsa, Carapa guianensis e Dipteryx odorata ) were investigated in sunand shade leaves form the tree crown collected during two distinct periods of precipitation (dry and rainyseasons). Pigment contents were determined by spectrophotometry and fluorescence variables were determinedusing a portable fluorometer. The results demonstrated that the species showed high concentrations of Chla, Chl b e Chl total during the wet season in relation to the dry season, especially in shade leaves. A higherconcentration of carotenoids was found in B. excelsa , when compared with leaves of C. guianensis and D.odorata . In leaves of B. excelsa and D. odorata

Primary metabolite mobilization during germination in rosewood (Aniba rosaeodora Ducke) seeds

This study aimed to characterize protein, oil, starch and soluble sugar mobilization as well as the activity of α-amylase during rosewood seed germination. Germination test was carried out at 25°C and the following parameters were analyzed: percentage of germination, initial, average, and final germination time. Seed reserve quantification was monitored in quiescent seeds and during different stages of radicle growth. Starch mobilization was studied in function of α-amylase activity. Germination reached 87.5% at the initial, average, and final time of 16, 21 and 30 days, respectively. Oil mobilization showed a negative linear behavior, decreasing 40% between the first and the last stage analyzed, whereas protein levels increased 34.7% during the initial period of germination. Starch content (46.4%) was the highest among those of the metabolites analyzed and starch mobilization occurred inversely to the observed for soluble sugars; α-amylase activity increased until the 15 th day, a period before radicle emission and corresponding to the highest starch mobilization. The high percentage of rosewood seed germination may be related to the controlled condition used in the germination chamber as well as to high seed reserve mobilization, in special oil and starch.

Molecular and biochemical characterization of caffeine synthase and purine alkaloid concentration in guarana fruit

Guarana seeds have the highest caffeine concentration among plants accumulating purine alkaloids, but in contrast with coffee and tea, practically nothing is known about caffeine metabolism in this Amazonian plant. In this study, the levels of purine alkaloids in tissues of five guarana cultivars were determined. Theobromine was the main alkaloid that accumulated in leaves, stems, inflorescences and pericarps of fruit, while caffeine accumulated in the seeds and reached levels from 3.3% to 5.8%. In all tissues analysed, the alkaloid concentration, whether theobromine or caffeine, was higher in young/immature tissues, then decreasing with plant development/maturation. Caffeine synthase activity was highest in seeds of immature fruit. A nucleotide sequence (PcCS) was assembled with sequences retrieved from the EST database REALGENE using sequences of caffeine synthase from coffee and tea, whose expression was also highest in seeds from immature fruit. The PcCS has 1083bp and the protein sequence has greater similarity and identity with the caffeine synthase from cocoa (BTS1) and tea (TCS1). A recombinant PcCS allowed functional characterization of the enzyme as a bifunctional CS, able to catalyse the methylation of 7-methylxanthine to theobromine (3,7-dimethylxanthine), and theobromine to caffeine (1,3,7-trimethylxanthine), respectively. Among several substrates tested, PcCS showed higher affinity for theobromine, differing from all other caffeine synthases described so far, which have higher affinity for paraxanthine. When compared to previous knowledge on the protein structure of coffee caffeine synthase, the unique substrate affinity of PcCS is probably explained by the amino acid residues found in the active site of the predicted protein.

Effects of light and temperature on isoprene emission at different leaf developmental stages of eschweilera coriacea in central Amazon

O isopreno emitido pelas plantas corresponde em cerca de um terco das emissoes globais de compostos orgânicos volateis anualmente. A maior fonte de emissao de isopreno para a atmosfera global e a Bacia Amazonica. Este estudo objetivou identificar e quantificar a emissao de isopreno e fotossintese em diferentes niveis de intensidade de luz e temperatura foliar, em tres fases fenologicas (folha madura recente, folha madura tardia e folha senescente) de Eschweilera coriacea (Matamata verdadeira) - a especie com maior distribuicao na Amazonia central. In situ, as medidas de fotossintese e emissao de isopreno da folha madura recente apresentaram as maiores taxas em todos os niveis de luz e de temperatura. Adicionalmente, a capacidade de emissao de isopreno (ES) mudou consideravelmente entre as diferentes idades foliares, sugerindo que o envelhecimento reduz a atividade fotossintetica e a producao/emissao de isopreno. O algoritmo de Guenther et al. (1999) demonstrou bom ajuste para a emissao de isopreno em diferentes intensidades de luz, entretanto, diferencas na ES entre as idades foliares influenciaram no rendimento quântico estimado pelo modelo. Em relacao a temperatura foliar, a estimativa do algoritmo nao foi satisfatoria para as temperaturas acima de ~40 °C; isto provavelmente ocorreu pelo fato dos dados nao apresentarem temperatura otima ate 45 °C. Nossos resultados sao consistentes com a hipotese do isopreno ter um papel funcional para proteger as plantas de altas temperaturas e apontam a necessidade de incluir os efeitos da fenologia foliar em modelos de emissao de isopreno.