Nídia F. Roque

Diterpene from Baccharis trimera with a relaxant effect on rat vascular smooth muscle

A bioassay monitored fractionation of a chloroform extract from the aerial parts of Baccharis trimera yielded a mixture that blocked the Ca2+-induced contractions of KCl- depolarized rat portal vein preparations. Pharmacological tests of two pure compounds isolated from the mixture revealed the dilactonic clerodane diterpene as the active compound.

Antifungal polysulphides from Petiveria alliacea L.

Bioactivity-directed fractionation of the CH(2)Cl(2)/MeOH (2:1, v/v) extract of the roots of Petiveria alliacea, using mutant yeast strains of Saccharomyces cerevisiae and fungi Cladosporium cladosporioides and C. sphaerospermum led to the isolation of dipropyl disulphide (1), dibenzyl sulphide (2), dibenzyl disulphide (3), dibenzyl trisulphide (4), dibenzyl tetrasulphide (5), benzylhydroxymethyl sulphide (6) and di(benzyltrithio) methane (7). Of these, 5-7 are new compounds and this is the first report of the natural occurrence of 2 and 3.

Antifungal aromadendrane sesquiterpenoids from the leaves of Xylopia brasiliensis

Um novo sesquiterpeno, aromadendrano-4b,10a,15-triol, foi isolado das folhas de Xylopia brasiliensis Spreng (Annonaceae), juntamente com quatro derivados de esqueleto aromadendrano e tres esteroides. As estruturas dos metabolitos foram definidas por meio da analise dos respectivos espectros de RMN, incluindo experimentos bidimensionais, alem de espectrometria de massas. Os sesquiterpenos aromadendranos diidroxilados apresentaram atividade antifungica frente a Cladosporium cladosporioides.

Cycloartane derivatives from Guarea trichilioides

Abstract Investigation of the leaves of Guarea trichilioides afforded nine cycloartane derivatives including the following seven novel ones: cycloart-24-en-

Amides and lignanamides from Porcelia macrocarpa

Abstract Two new lignanamides, 1,2-dihydro-6,8-dimethoxy-7-hydroxy-1-(3,5-dimethoxy-4-hydroxyphenyl)- N 1 , N 2 -bis-[2-(4-hydroxyphenyl)ethyl]-2,3-naphthalene dicarboxamide and 1,2-dihydro-6,8-dimethoxy-7-hydroxy-1-(3,4-dihydroxyphenyl)- N 1 - N 2 -bis-[2-(4-hydroxyphenyl)ethyl]-2,3-naphthalene dicarboxamide, together with N - trans -feruloyltyramine, N - trans -caffeoyltyramine and the new N - trans -sinapoyltyramine were isolate from the branches of Porcelia macrocarpa . This is the first report of lignanamides from an Annonaceae species.

Isocoumarin from Paepalanthus bromelioides

Abstract The new isocoumarin, 9,10-dihydroxy-5, 7-dimethoxy-1H-naphtho(2,3 c )pyran-1-one, was isolated from the capitula of Paepalanthus bromelioides . The structure was established by means of the spectral data of the natural product and its derivatives. The natural isocoumarin isolated has strong antibiotic activity.

Terpenes from leaves of Guarea macrophylla (Meliaceae)

The dichloromethane extract from the leaves of Guarea macrophylla (Meliaceae) was submitted to adsorption chromatography. Guai-6-en-10beta-ol, isopimara-7,15-dien-2alpha-ol and cycloarta-23,25-dien-3-one were isolated and identified by spectroscopic data, mainly by 1H and 13C NMR analyses; eight other known terpenoids were also isolated.

Aldingenin A, new brominated sesquiterpene from red algae Laurencia aldingensis

Abstract A new brominated bisabolene derivative, aldingenin A, was isolated from red alga Laurencia aldingensis Saito et Womersley (Ceramiales, Rodophyta). Its structure was determined by analysis of spectroscopic data ( 1 H and 13 C NMR, IR, MS), including bidimensional NMR ( 1 H– 1 H COSY, HMQC, HMBC and NOESY) and biogenetic considerations.

Limonoids from Trichilia elegans ssp. elegans

Abstract From the seeds of Trichilia elegans ssp. elegans , six new limonoids, four of which possess the uncommon seco -A, B and D carbocyclic rings, have been isolated, together with two known limonoids-kihadanin A and B and 3-O-β- d -glucopyranosyl-sitosterol . The structures of these compounds have been established on the basis of 1D and 2D NMR spectroscopic techniques.

Diterpenes from the fruits of Xylopia aromatica

Abstract Fruits of Xylopia aromatica contain atisane, labdane, kaurane and trachylobane diterpenes besides three new nor -diterpenes characterized as degraded products. The ent -labdan-13,16-diol-8(17),14-dien-18-oic acid, ent -trachyloban-3β-ol, ent -atisan-16α,18-diol and ent -atisan-16α-ol-18-oic acid are novel natural products. The monoacetate and the methyl ester respectively of the two last compounds are known as trachylobane degradation products.