João B. Fernandes

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.

Toxicity of sesame extracts to the symbiotic fungus of leaf-cutting ants

Extracts of different sesame plant (Sesamum indicum) Linnaeus organs inhibited the in vitro growth of the fungus Leucocoprinus gongylophorus (Moller) (=Rozites gongylophora Moller), which is cultivated by the leaf-cutting ants of the species Atta sexdens rubropilosa Forel (Hymenoptera: Formicidae). The presence of the factor responsible for this inhibition was detected in methanol or chloroform extracts and is constant in the plant.

Trypanocidal activity of Meliaceae and Rutaceae plant extracts.

The in vitro trypanocidal activity of 22 extracts and 43 fractions of plants belonging to the families Meliaceae and Rutaceae was evaluated. The extracts from leaves of Conchocarphus heterophyllus and branches of Trichilia ramalhoi were the most active. The trypanocidal activity seems to be increased by fractionation of the extracts. Fractions from C. heterophyllus and Galipea carinata were the most active and a 100% lysis of the parasites was observed for five fractions. From one of them were isolated two flavonoids: flavone and 7-methoxyflavone, which showed weak trypanocidal activity. The results obtained from the extracts and fractions revealed that the order Rutales is a promising source for the search of new drugs for Chagas disease. Phytochemical studies with the other active fractions are underway in order to isolate compounds, which could be associated with observed activities.

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.

In vitro activity of Rutaceae species against the trypomastigote form of Trypanosoma cruzi.

The activity of crude plant extracts of nine species of Rutaceae against the trypomastigote form of Trypanosoma cruzi was evaluated at 4 mg/ml. Thirty-two crude extracts were tested and eight of them showed significant activity (>80%). The most active extract was obtained from the stems of Pilocarpus spicatus (97.3%). Fractionation of the active crude extracts provided 25 fractions which were tested against the trypomastigote form of T. cruzi at 2 mg/ml. Of these six showed significant activity (>80%). The most active fractions (100%) were obtained from the leaves of Almeidea coerulea (butanol fraction) and Conchocarpus inopinatus (dichloromethane fraction).

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.

Simultaneous quantification of azadirachtin and 3-tigloylazadirachtol in Brazilian seeds and oil of Azadirachta indica: application to quality control and marketing

A rapid, sensitive and selective HPLC-UV method was developed for quantification of azadirachtin (1) and 3-tigloylazadirachtol (2) in Neem kernels and oil, with a good linearity over a range of 5.0–60.0 and 2.5–50.0 μg mL−1 respectively, with r2 > 0.999 for all curves. The limits of detection (LOD) for both limonoids were 25 ng mL−1 for kernels and 0.10 μg mL−1 for oil, and quantification (LOQ) for 1 and 2 were 1.5 μg mL−1 for both matrices. The quantification method was applied to Neem seeds and oil from different areas of Brazil. The low quality of Brazilian oil (concentrations of 1 = 228.5 to 630 mg kg−1 and 2 = 117.1 to 582.9 mg kg−1) could be attributed to mechanical extraction, since the content of azadirachtin and 3-tigloylazadirachtol in seeds was (1 = 2048.8 to 5117.1 mg kg−1, 2 = 224.7 to 1116.5 mg kg−1) similar to values obtained from Indian seeds (1 = 556.9 to 3030.8 mg kg−1, 2 = 43.1 to 590.6 mg kg−1).