Atividades biológicas e identificação dos constituintes químicos isolados das espécies vegetais: Plumeria lancifolia Müll. Arg. (Apocynaceae) e Solanum crinitum Lam. (Solanaceae) e identificação da acetanilida exsudada por Xenohyla truncata (IZECKSOHN, 1998)

Abstract

The analysis of the fractions from the chromatographic fractionation of the extracts from plant species Plumeria lancifolia Müll. Arg. (Apocynaceae) and Solanum crinitum Lam. (Solanaceae) led to the isolation of some chemical constituents belonging to different classes of special metabolites. From the branches and leaves of Plumeria lancifolia Müll. Arg. were obtained the triterpenes: 3-O-acyl-β-amyrin (1), β-amyrin (1a), ursolic acid (3), lupeol (4), 3- O-acyl-lupeol (5) e o 3-O-acyl-β-amirenonol (7), spinasterol (2) and a mixture of aliphatic esters (6, 8 e 9). From the unripe fruits of Solanum crinitum Lam. were isolated three steroids alkaloids glycosides: solamargine (10), epi-solamargine (11) and solasonine (12). The extract from tricomes of unripe fruits of S. crinitum Lam. were isolated cis- and trans-ethylcoumarate (13 e 14); the flavonoids kaempherol (15), benzoic acid (16), cis- and trans-pcoumaric acid (17 e 18); the isoflavone biochanin A in mixture ethyl-1β-O-glucopyranoside (19) and the isoflavone, 7-O-β-D-apiofuranosyl-(1→5)-O-β-D-(1→5)-apiofuranosyl-(1→6)- O-β-D-glucopyranosyl-biochanin A (20). Reactions were used to obtain: ursornic acid (3a), methyl ursolate (3b), methyl 3-O-acetyl-ursolate (3c), methyl 3-oxo-ursolate (3d), 3,7,4 - trimethylkaempherol (15a), 3,5,7,4 -tetramethylkaempherol (15b) and 3,7,4 -trimetoxi-5- acetoxyflavone (15c) besides, the new derivatives, peracetyl-epi-solamargine (11a) and peracetyl-solasonine (12a). From the cutaneous exhalate of anura amphibian Xenohyla truncata (IZECKSOHN, 1998), under stress, only N-phenyl-acetamide (21) was identified. The structures were determined by IR, MS and 1H and 13C NMR spectral analysis, including 2D NMR experiments of the natural substances and of the derivatives. Besides the identification of the steroid spinasterol, and the triterpenes, 3-O-acyl-β-amyrin and 3-O-acyl- β-amirenonol, were identified for the first time in the genera Plumeria; the isoflavone biochanin A triglycoside has not identified before in Solanum genera. Steroidal alkaloids episolamargine and acetyl derivatives epi-solamargine and solasonine, were not found in the literature. Biological tests were carried out: a) molluscicide activities with extracts of Plumeria lancifolia Müll. Arg. and Solanum crinitum Lam. and the pure substances, β-amyrin (1a) and ursolic acid (3); b) antioxidant activities with extracts of Plumeria lancifolia Müll. Arg. and Solanum crinitum Lam.; c) toxicity test with metanolic extract from the leaves of Plumeria lancifolia Müll. Arg. on peritoneum cell of albine mice; d) earedema test with ursolic acid (3), ursonic acid (3a), methyl ursolate (3b), methyl 3-O-acyl-ursolate (3c), methyl 3-oxo-ursolate (3d), epi-solamargine (11), epi-peracetyl-solamargine (11a), kaempherol (15), 3,7,4 -trimethylkaempherol (15a), 3,5,7,4 -tetramethylkaempherol (15b) and 3,7,4 -trimetoxi- 5-acetoxyflavone (15c); e) the metabolic inhibition on promastigotas of Leishmania (Viannia) braziliensis with hexanic extract of aerial part of Solanum crinitum Lam.