The effects of seasonal climate changes in the caatinga on tannin levels in Myracrodruon urundeuva (Engl.) Fr. All. and Anadenanthera colubrina (Vell.) Brenan

Abstract

Unitermos: Florestas secas, Folin-Ciocalteau, plantas medicinais, semi-árido. ABSTRACT:The infl uence of seasonal climatic changes on tannin concentrations was examined in two caatinga (semi-arid) plant species (Myracrodruon urundeuva (Engl.) Fr. All. and Anadenanthera colubrina (Vell.) Brenan). The Folin-Ciocalteau method was used to quantify total phenols, and the casein precipitation method was used for tannins. In general, there is a close relationship between tannin levels and rainfall, although species seem to adopt different strategies of tannin compound production in response to periods of drought and rainfall in the caatinga.Keywords: Dry forest, Folin-Ciocalteau, medicinal plant, semi-arid. INTRODUCTIONIt is well documented that some ecological variables can quantitatively and qualitatively affect tannin production in plants (Hatano et al., 1986;Teixeira et al., 1990;Furlan et al., 1999;Simon et al., 1999;Salminen et al., 2001;Paiva et al., 2002). Seasonal changes, for example, alter plant metabolism and, consequently, biosynthetic pathways (Hatano et al., 1986;Salminen et al., 2001). Periods of high temperatures are known to increase the concentration of phenolic compounds in many plants. Species of Lotus, for example, demonstrate seasonal variations in tannin concentration (Gebrehiwot et al., 2002), which have been shown to be signifi cantly higher during the spring and summer. The same response was seen with Alnus rubra Bong (González-Hernández et al., 2000). Comparisons between plants growing in tropical sub-humid and tropical semi-arid regions of Africa have demonstrated that total phenols levels increase in regions with more severe climates and with less available humidity (Makkar; Becker, 1998).In Brazil, only a limited number of studies have examined the infl uence of environmental variables on tannin production, and most of these have focused on plant defenses in areas of cerrado (savannah) and Atlantic Coastal Forest vegetation (Pais;Varanda, 2003;Pansera et al., 2003;Yariwake et al., 2005). Fewer studies have been undertaken in the caatinga yet and it certainly remains the most incompletely studied Brazilian biome. The caatinga is also the least protected region in Brazil, with less than 2 % of its lands included within any type of conservation area. Research programs in this semiarid region are therefore necessary, especially in light of the rapid alteration of this biome, and substitution of the native vegetation even before it can be effectively studied (Fernandes, 2002; Giullieti et al., 2002;Castelletti et al., 2003).In the present work, the tannin levels of two caatinga medicinal plants, Myracrodruon urundeuva (Engl.) Fr. All. and Anadenanthera colubrina (Vell.) Brenan, were quantifi ed and compared with local seasonal rainfall data. Studies which increase our understanding of the behavior of caatinga plants are extremely important at this moment for conservation and sustainable. Management strategies are needed to protect and preserve many semi-arid species threatened with extinction...

QUALIDADE DOS TANINOS DE JUREMA-PRETA (<i>Mimosa tenuiflora</i>) PARA A PRODUÇÃO DE ADESIVO TANINO FORMALDEÍDO

“…Em virtude de sua adstringência, eles impedem o ataque de herbívoros a determinados locais da planta, como frutos, sementes e casca. Segundo Monteiro et al (2006), esses compostos são responsáveis pela adstringência de muitos frutos e produtos vegetais, em virtude da precipitação de glucoproteínas salivares, resultando na perda do poder lubrificante. Graças a sua comprovada atividade antimicrobiana, acredita-se que os taninos atuem na proteção do vegetal contra o ataque de microorganismos patogênicos (VITAL et al, 2001;COLLI et al, 2007).…”

“…Os taninos hidrolisáveis são poliésteres da glicose e classificados, dependendo do ácido formado de sua hidrólise, em taninos gálicos ou taninos elágicos, enquanto os condensados são constituídos por monômeros do tipo catequina e conhecidos por flavonoides (PIZZI, 1993). Monteiro et al (2006) afirmaram que os taninos são compostos fenólicos de grande interesse econômico e ecológico.…”

A dehydrorotenoid produced by callus tissue culture and wild plant roots of Boerhaavia coccinea

“…The absence of this compound or its low presence during a few months may be related with the rainy season, when there is a considerable amount of rain incidence in this Region of Brazil. As described by Monteiro et al (2006), tannins and phenolic compounds decrease in concentration in the rainy season when compared to dry season. As a rule, it is possible to see a relation between high isofl avonoid concentrations in November with the beginning of summer.…”

Bothrops jararacussu venom-induced neuromuscular blockade inhibited by Casearia gossypiosperma Briquet hydroalcoholic extract

“…The chemical composition of plant extracts is very complex and variable as it depends on the climate and/or the soil composition (36). Thus, physicochemical control is indispensable for phytotherapics.…”