Pyridine Alkaloids from Senna multijuga As Acetylcholinesterase Inhibitors

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Further monoterpene chromane esters from Peperomia obtusifolia: VCD determination of the absolute configuration of a new diastereomeric mixture

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Xylarenones C-E from an Endophytic Fungus Isolated from Alibertia macrophylla

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

An Unprecedented Neolignan Skeleton from Chimarrhis turbinata

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antiprotozoal Sesquiterpene Pyridine Alkaloids from Maytenus ilicifolia

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cytotoxic Guanidine Alkaloids from Pterogyne nitens

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Cytotoxic Clerodane Diterpenoids from Casearia obliqua

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Anticholinesterasic, Nematostatic and Anthelmintic Activities of Pyridinic and Pyrazinic Compounds

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Structure Elucidation and Absolute Stereochemistry of Isomeric Monoterpene Chromane Esters

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Acetylcholinesterase Inhibitory Pyridine Alkaloids of the Leaves of Senna multijuga

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Antibacterial activity of labdane diterpenoids from Stemodia foliosa

As part of a continuing interest in exploring the chemistry of Brazilian medicinal plants, three new labdane diterpenoids, 6 alpha-acetoxymanoyl oxide (1), 6 alpha-malonyloxymanoyl oxide (2), and 6 alpha-malonyloxy-n-butyl ester manoyl oxide (3), together with the known betulinic acid, lupeol, sitosterol, and stigmasterol, were isolated from the aerial parts of Stemodia foliosa. The structures of 1-3 were established on the basis of interpretation of spectroscopic data, including HRESIMS, and 1D and 2D NMR techniques. All compounds were tested against a bacteria panel consisting of Staphylococcus aureus, Bacillus cereus, B. subtilis, B. anthracis, Micrococcus luteus, Mycobacterium smegmatis, and M. phlei. Compound 2 showed, moderate activity against these strains, with MIC values in the range 7-20 mu g/mL.

Cytotoxic Clerodane Diterpenes from Casearia rupestris

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Biomimetic synthesis of xuxuarines E alpha and E beta: Structure revision of Rzedowskia bistriterpenoids

Reaction of pristimerin with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) resulted in a biomimetic-type coupling leading to xuxuarines E alpha and E beta and not the previously reported Rzedowskia bistriterpenoids I and II suggesting that the structures proposed for these natural products need revision. A product obtained in this reaction by an unusual Diels-Alder addition followed by retro-Diels-Alder-type elimination was characterized as pristimerin dicyanophenalenedione. Complete H-1, and C-13 NMR spectral assignments of xuxuarines Ea and Eb have been made by the application of 1D and 2D NMR techniques. (c) 2007 Elsevier Ltd. All rights reserved.

HPLC-ESIMSn Profiling, Isolation, Structural Elucidation, and Evaluation of the Antioxidant Potential of Phenolics from Paepalanthus geniculatus

The methanol extract of the flowers of Paepalanthus geniculatus Kunth. showed radical-scavenging activity in the TEAC assay. An analytical approach based on HPLC:ESIMSn was applied to obtain the metabolite profile of this extract and led to the rapid identification of 19 polyphenolic compounds comprising flavonoids and naphthopyranones. The new naphthopyranone (10, 16), quercetagetin (1, 5, 7, 13), and galetine derivatives (9, 11, 17, 19), and a flavonol glucoside cyclodimer in the truxillate form (12), were identified. Compounds 2, 6, and 7 showed the highest antioxidant capacity and ability to affect the levels of intracellular ROS in human prostate cancer cells (PC3).

Antinociceptive profile of 2,3,6-trisubstituted piperidine alkaloids: 3-O-acetyl-spectaline and semi-synthetic derivatives of (-)-spectaline

In early studies, we have reported the antinociceptive profile of (-)-spectaline, a piperidine alkaloid from Cassia spectabilis. The present study describes the synthesis, the antinociceptive and anti-inflammatory activities of a series of 2,3,6-trialkyl-piperidine alkaloids: the natural (-)-3-O-acetyl-spectaline (LASSBio-755) and ten semi-synthetic spectaline derivatives. Structure-activity relationship (SARs) studies were performed. The structures of all synthesized derivatives were confirmed by means of nuclear magnetic resonance. Compounds were evaluated for their analgesic (acetic acid-induced mouse abdominal constrictions, hot-plate test, formalin-induced pain test) and some of them for the anti-inflammatory activities (carrageenan-induced rat paw edema test). The pharmacological results showed that several of the new compounds given orally at a dose of 100 mu mol/kg significantly inhibited the acetic acid-induced abdominal constrictions, but they were less active than (-)-spectaline. LASSBio-755 and LASSBio-776 were the most actives with 37% and 31.7% of inhibition. In the formalin-induced pain only LASSBio-776 was able to inhibit by 34.4% the paw licking response of the inflammatory phase, (-)-spectaline and LASSBio-755 did show any activity. In the carrageenan-induced rat paw edema, only (-)-spectaline exhibited an anti-inflammatory profile, showing an ED(50) value of 56.6 mu mol/kg. Our results suggest different mechanisms of action for the analgesic activity observed for LASSBio-776 (3-O-Bocspectaline), LASSBio-755 (3-O-acetyl-spectaline) and (-)-spectaline (LASSBio-754). The antinociceptive profile of some of the semi-synthetic spectaline derivatives extends our research concerning the chemical and pharmacological optimization of isolated natural products in the search of new drug candidates from brazilian biodiversity.