Astréa M. Giesbrecht

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.

Benzoyl esters and amides, styrylpyrones and neolignans from the fruits of Aniba riparia

Abstract The fruits of Aniba riparia contain a series of benzyl esters and phenylethyl amides of benzoic acids, accompanied by styrylpyrones and neolignans. This is the first report on the co-occurrence of representatives of the two latter classes of natural products in the same species.

The neolignans of Licaria canella

Abstract The trunk wood of Licaria canella contains, besides dillapiol and elemicin, the neolignans canellin-A, -B and -C, for which the respective structures of 1-allyl-4,8-dihydroxy-3,5-dimethoxy-7-methyl-6-piperonylbicyclo-[3,2,1]octane; 3a-allyl-4,5-dimethoxy-3-methyl-2-piperonyl-2,3,3a,6,7,7a-hexahydro-6-oxobenzofuran and 1-allyl-4,8-dihydroxy-5-methoxy-7-methyl-6-piperonyl-3-oxobicyclo-[3,2,1] octane are proposed.

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.

Ocotea Quixos, American Cinnamon

Among the three South American Lauraceae with cinnamon odours, Ocotea quixos Lam. is distinguished with the richest historical legacy. Cinnamaldehyde, its odoriferous principle, occurs besides o-methoxycinnamaldehyde, cinnamic acid and methyl cinnamate in the fruit calyx. In contradistinction, 1-nitro-2-phenylethane is responsible for the cinnamon odour of bark and leaves of Aniba canelilla (H..B.K.) Mez and Ocotea pretiosa (Nees) Mez.

Neolignans from Urbanodendron verrucosum

Abstract Branch wood of the shrub Urbanodendron verrucosum from the Atlantic forest of southern Brazil contains the benzofuranoid neolignans licarin-A, licarin-D, porosin and the novel porosin-B, as well as the tetrahydrofurane neolignans austrobailignan-7, calopiptin and the novel verrucosin. The acid-catalysed rearrangement of the porosins yields the corresponding dihydrofutoenones.

1,3-diaryl-propanes and propan-2-ols from Virola species☆

Abstract The trunk woods of two Amazonian Myristicaceae, Virola minutiflora and V. elongata, contain respectively 1-(2-hydroxy-4-methoxyphenyl)-3-(3,4-m

Canthinones from Simaba cuspidata.

Abstract Two new alkaloids, 8-methoxycanthin-6-one and 3-methoxycanthin-2,6-dione, were isolated from the EtOH extract of the bark of Simaba cuspidata Spruce ex Engl. Elucidation of the structure of the latter compound included 13 C NMR spectral comparison with 2-methoxypyridine- N -oxide and N -methoxy-2-pyridone.

Bicyclo[3,2,1]octanoid, neolignans from Aniba simulans

Abstract Six bicyclo[3,2,1]octanoid neolignans, isolated from the benzene extract of Aniba simulans Allen (Lauraceae) trunk wood, are shown to derive from two basic structures: 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-3-oxobicyclo[3,2,1]octane, substituted by 4-hydroxy, 4-hydroxy-5-methoxy, 4-methoxy or 4,5-dimethoxy groups; and 1-allyl-8-hydroxy-6-(3′-methoxy-4′,5′-methylenedioxyphenyl)-7-methyl-4-oxobicyclo[3,2,1]oct-2-ene, substituted by 3-hydroxy or 3-hydroxy-5-methoxy groups. The structural proposals are based on spectral data, interconversions synthesis of a derivative from the known (2 R ,3 S ,3a S )-3a-allyl-5-methoxy-2-(3′-methoxy,4′,5′-methylenedioxyphenyl)-3-methyl-2,3,3a,6-tetrahydro-6-oxobenzofuran.

Benzofuranoid neolignans from Aniba simulans

Abstract Forteen neolignans, isolated from the benzene extract of Aniba simulans (Lauraceae) trunk wood, included the hitherto undescribed (2 S , 3 S , 5 R )-5-allyl-5,7-dimethoxy-2-(3′,4′,5′-trimethoxyphenyl)-3-methyl-2,3,5,6-tetra-hydro-6-oxobenzofuran, (2 R ,3 S ,5 R ) -5-allyl-5-methoxy-2-(3′-methoxy-4′,5′-methylenedioxyphenyl)-3-methy1-2,3,5, 6-tetrahydro-6-oxobenzofuran, (2 S ,3 S )-6- O -allyl -5-methoxy-2-(3′-methoxy-4′-5′-methylenedioxyphenyl)-3-methyl-2,3-dihydrobenzofuran, (2 R ,3 S )-6- O -allyl-5-methoxy-2- (3′-methoxy-4′,5′-methylenedioxyphenyl)-3-methyl-2,3-dihydrobenzofuran and 7-allyl-6-hydroxy-5-methoxy-2-(3′-methoxy-4,5′ -methylenedioxyphenyl)-3-methylbenzofuran.