Estudo fitoquímico de piperaceas do norte e nordeste brasileiro: Piper lateripilosum Yuncker, Piper montealegreanum Yuncker, Piper mollicomum Kunth

Abstract

The genus Piper is the largest in the family Piperaceae, with at least 1,000 species distributed particularly in the Neotropical region, where about two thirds of the described species can be found. It is a genus commercially important and with many medical applications. The phytochemical investigation of species of this genus which is so rich in metabolites and has widespread use in folk medicine, besides its various biological activities reported in the literature, can open exciting perspectives for the chemistry, pharmacology and chemotaxonomy. This work reports the phytochemical study of three species of Piper, aiming at the isolation and identification of their chemical constituents as well as the pharmacological evaluation of extracts, fractions and isolated compounds. Through usual chromatographic methods and spectroscopic techniques such as IR and one- and two-dimensional 1H and 13C NMR techniques and comparison with literature data it was possible to isolate and identify five amides and two steroids from the aerial parts of Piper lateripilosum collected in Amapá, all of them isolated for the first time in this species. From Piper mollicomum collected in Paraíba were isolated a new amide and a coumarin of the hexane and chloroform phases of the crude ethanol extract of the leaves, respectively, and a benzoic acid derivative and a aristolactam of the chloroform phase obtained from the crude ethanol extract of the stem of this species. The amide is first reported in the literature, the coumarin for the first time in the genus and the benzoic acid derivative and the aristolactam for the first time in this species. From Piper montealegreanum collected in Belém-PA it was possible to isolate a new chalcone, 3 -methoxy,3,4 ,6 -trihydroxy, 2 ,5 -dimethylchalcone, and reisolate the flavonoids 8-formyl-3 ',5-dihydroxy-7-methoxy-6-methylflavanone; 3 '-formyl-3, 4', 6'-trihydroxy-2- methoxy-5-methylchalcone and (2'-methoxy-3'-formyl-4', 6'-dihydroxy-5'-methyl phenyl) - [3''-(dimethylbut-6''-enyl)- 7- phenyl-(3-hydroxy) -cyclohex-2''-enyl]-methyl-9-one. The extracts, some phases and substances isolated from the species studied were submitted to investigation of antimicrobial and hemolytic activities, and modulator of resistance to antibacterial drugs.