M. Fátima das G. F. da Silva

Limonoids from andiroba oil and Cedrela fissilis and their insecticidal activity

Nine limonoids were isolated from Carapa guianensis and Cedrela fissilis. Among them, 1,2-dihydro-3b-hydroxy-7-deacetoxy-7-oxogedunin is a new compound. Moreover, the assignments of some chemical shifts of xyloccensin k have been corrected and 1H NMR data of 7-deacetylgedunin have been assigned for the first time. These isolated limonoids were assayed on Atta sexdens rubropilosa workers showing moderate insecticidal activities.

Evolution of limonoids in the meliaceae

Abstract The structural types of limonoids or meliacins can be characterized in terms of complexity by their position along biosynthetic routes on a biogenetic map, as well as by their basic skeletal specialization and state of oxidation. Genera of the Melioidease, one major subfamily of the Meliaceae, contain meliacins formed along several biosynthetic routes and characterized by relatively low skeletal specializations and oxidation states. Genera of the Swietenioideas, the other major subfamily of the Meliceae, contain meliacins formed along only one biosynthetic route and characterized by relatively high skeletal specializations and oxidation states. Evolutionary trends of meliacin chemistry thus correspond to the morphological division of the Meliaceae.

Chemogeographical evolution of quassinoids in simaroubaceae

Abstract The presence of canthinones and β-carbolines suggests the derivation of the Simaroubaceae from protorutaceous stock. The evolutionary trend towards the substitution of such anthranilate-derived alkaloids by limonoids in Rutaceae is paralleled by their substitution by quassinoids in Simaroubaceae. Specialization of quassinoid skeletons is accompanied by a West to East spacial radiation of the simaroubaceous lineage. The structural analysis of the most numerous and widespread derivatives of the quassin skeleton itself confirms this finding. Indeed, the transition from the American and West African genera (belonging mainly to the tribe Simaroubeae) to the East African and Asian genera (belonging mainly to Picrasmeae and Soulameae) is accompanied by diversification of oxygenation and unsaturation patterns, as well as by increase in oxidation level of the quassinoids.

Norlimonoids from seeds of Toona ciliata

Abstract Further examination of the seeds of Toona ciliata led to the isolation of two new norlimonoids which were identified on the basis of spectroscopic analysis as 5α,6β,8α-trihydroxy-28-norisotoonafolin and 5α,6β,8α,12α-tetrahydroxy-28-norisotoonafolin. In addition, the known limonoids cedrelone and toonacilin and the sterols sitosterol, stigmasterol, campesterol and 3β-O-β- d -glucopyranosylsitosterol were also isolated and characterised. These results show that Toona has a less pronounced relationship to the Swietenioideae.

Limonoids from leaves of Khaya senegalensis

Abstract The leaves of Khaya senegalensis yielded two new limonoids. These compounds were identified on the basis of spectroscopic analysis as methyl 1α-acetoxy-3β,6,8α-trihydroxy-2α-methoxy-2β,14β-epoxy-[4.2.1 10,30 .1 1,4 ]-tricyclomeliac-7-oate and methyl 1α-acetoxy-6,8α,14β,30β-tetrahydroxy-3-oxo [3.3.1 10,2 .1 1,4 ]-tricyclomeliac-7-oate. Scopoletin, β-quercitrin and rutin were also isolated.

Sesquiterpenes, triterpenoids, limonoids and flavonoids of Cedrela odorata graft and speculations on the induced resistance against Hypsipyla grandella

Abstract From the stem of Cedrela odorata grafted on Toona ciliata var. australis were isolated calamenene, cycloeucalenol, sitosterol, stigmasterol, campesterol, gedunin, 7-deacetylgedunin, 7-deacetoxy-7-oxogedunin, methylangolensate, febrifugin, azadiradione, 20,21,22,23-tetrahydro-23-oxoazadirone, 3β-deacetylfissinolide and, catechin, together with the new limonoid 1α-methoxy-1,2-dihydrogedunin and the new cycloartane 3β-O-β- d - glucopyranosylcycloeucalenol . The limonoids were of little value to clarify the basis of the induced resistance in the graft against Hypsipyla grandella. The cycloartanes and catechin could have been translocated from Toona stock to the Cedrela graft.

Biological Activity of Quinoline Alkaloids from Raulinoa echinata and X-ray Structure of Flindersiamine

Phytochemical survey of stems and leaves extracts of the South Brazilian endemic plant Raulinoa echinata Cowan, Rutaceae, led to the isolation of known furoquinoline alkaloids: the widespread skimmianine; kokusaginine, maculine, flindersiamine, and also quinolone derivatives: 1-methyl-2-n-nonyl-4-quinolone, 2-n-nonyl-4-quinolone and 1-methyl-2-phenyl-4-quinolone. These alkaloids showed antifungal activity against Leucoagaricus gongylophorus; the symbiotic fungus of leaf-cutting ants (Atta sexdens). They were inactive or displayed weak inhibitory activity when assayed in vitro against trypomastigote forms of Trypanosoma cruzi. In this paper, the isolation, structure elucidation and bioactivity results of these compounds are reported together with the X-ray structure of flindersiamine.

Rearranged limonoids from Khaya senegalensis

Abstract The stems of Khaya senegalensis yielded three limonoids which appear to be novel. These compounds were identified on the basis of spectroscopic analysis as methyl 1α,6,8α,14β,30β-pentahydroxy-3-oxo-[3.3.1 10,2 .1 1,4 ]-tricyclomeliac-7-oate; methyl 1α,2β,3α,6,8α,14β-hexahydroxy-[4.2.1 10,30 .1 1,4 ]-tricyclomeliac-7-oate and methyl 1α-acetoxy-2β,3α,6,8α,14β-pentahydroxy-[4.2.1 10,30 .1 1,4 ]-tricyclomeliac-7-oate. The two latter ones represent a novel group of methyl tricyclomeliac-7-oates. Scopoletin, scoparon, sitosterol, stigmasterol, Campesterol and 3β-O-β- d -glucopyranosylsitosterol were also isolated.

Chemical Characterization of Citrus sinensis Grafted on C. limonia and the Effect of Some Isolated Compounds on the Growth of Xylella fastidiosa

Citrus sinensis grafted on C. limonia produces a considerable number of compounds that are not common in both plants developed from germination of seeds. The chemical profile of scion and rootstock differ notably for absence in the form of flavonoids and coumarins containing C5 prenyl groups attached to the carbon atoms of aromatic and heterocyclic systems or to oxygen. Only linear pyranocoumarins xanthyletin and xanthoxyletin were found in scion. This observation indicates that the prenylated compounds once biosynthesized in the roots could have been translocated to other organs. Xylella fastidiosa colonizes the xylem of plants causing diseases on several economically important crops such as citrus variegated chlorosis (CVC). A number of flavonoids, coumarins, alkaloids, dihydrocinnamic acid derivative, anacardic acid, triterpenes, and limonoids were tested for in vitro activity on the growth of Xylella fastidiosa. Azadirachtin A was the most active. Hesperidin, which occurs in great amounts in cells of the mesophyll of the affected leaves with CVC, showed a moderate activity suggesting that it can act as a good barrier for small-size colonies from X. fastidiosa.

Strategies for the isolation and identification of trypanocidal compounds from the Rutales

Crude extracts of Rutales species were tested in vitro against the trypomastigote form of Trypanosoma cruzi at 4 mg/mL, and 20% of them showed significant activity (80%). Their inhibitory activity against the glycolytic enzyme GAPDH from T. cruzi has also been evaluated at the concentrations of 100 and 200 mg/mL. Additionally, the inhibitory activity of 13 purified coumarins were also assayed against T. cruzi-GAPDH. Chalepin was the most active substance with IC50 = 64 mM. The 3D structure of the complex chalepin-enzyme was elucidated by X-ray crystallography, revealing the architecture of the interactions between the inhibitor and the enzyme active site.