ESTUDO FITOQUÍMICO E BIOLÓGICO DO CACTO – Cereus jamacaru DE CANDOLLE, CACTACEAE

Abstract

Cereus jamacaru De Candolle, Cactaceae, popularly known as mandacaru, is a common columnar cactus in Brazil, mainly in the Semi-Arid Region. Its especially important during the driest months due to its use as cattle food. The stems are used to treat several diseases, but few studies concerning its pharmacological activity were developed. This research is divided in three parts. PART I: Isolation and identification of substances. Two samples were studied, a commercially obtained and a sample supplied by EMBRAPA, which was separated into four parts; only two of them were considered (wood and cortex of the stems). Sodium nitrate was isolated from all the hidroalcoolic extracts, corresponding to 0,18 % of the commercial sample weight, 0,28 % of the wood and 0,32 % of the cortex. The hexane fractions were studied on their steroidal composition using GC and 13C-NMR technologies; β- sitosterol was found to be the main steroid in the species. From the wood 19,3 mg of this substance were isolated. PART II: A HPLC method was developed to quantify the series tyrosine, tyramine and hordenine, and the semi-quantification of N- methyltyramine. It is suggested that the acid hydrolysis is the ideal procedure to release the amines and purify the samples to the HPLC analysis. Tyramine and N- methyltyramine are then suggested as chemical markers. From the samples analysis it was found N-methyltyramine and hordenine for the first time in the species. The commercial sample had 238,1 mg of N-methyltyramine in 100 g of the dried plant; in the wood, tyramine was the main substance, 28,41 mg in 100 g of dried plant. PART III: Biological analysis. The antibacterial activity of the crude extracts was tested using Agar diffusion and MIC methods. The cortex showed the most effective activity against S. epidermidis (MIC= 3,04 mg/mL), S. aureus, P. aeruginosa e E. coli (MIC= 6,09 mg/mL). Tyramine had MIC > 1000 mg/mL. The crude extracts and tyramine showed good allelophatic activity over Lactuca sativa seeds growth, but no effect on their germination. All the crude extracts concentrations were able to inhibit the development of the leaves. The minimal inhibitory concentrations were 0,05 mg of the cortex crude extract over the root, 0,025 mg of wood crude extract over the root and 0,2 mg over the shoot; tyramines best activity was shown with 0,6 mg over the shoot and 0,3 mg over the leaves. The difference between the results shown by the extracts and tyramine in both biological activities suggests that other substances can be responsible for them.

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