Andréa Mendes do Nascimento

Antiparasitic, antineuroinflammatory, and cytotoxic polyketides from the marine sponge Plakortis angulospiculatus collected in Brazil.

Investigation of the bioactive crude extract from the sponge Plakortis angulospiculatus from Brazil led to the isolation of plakortenone ( 1) as a new polyketide, along with five known polyketides ( 2- 6) previously isolated from other Plakortis sponges. The known polyketides were tested in antileishmanial, antitrypanosomal, antineuroinflammatory, and cytotoxicity assays. The results show that plakortide P ( 3) is a potent antiparasitic compound, against both Leishmania chagasi and Trypanosona cruzi, and exhibited antineuroinflammatory activity. The known polyketides 2- 6 were tested for cytotoxicity against four human cancer cell lines, but displayed only moderate cytotoxic activity.

Identification of a bioactive compound isolated from Brazilian propolis type 6.

A prenylated benzophenone, hyperibone A, was isolated from the hexane fraction of Brazilian propolis type 6. Its structure was determined by spectral analysis including 2D NMR. This compound exhibited cytotoxic activity against HeLa tumor cells (IC(50)=0.1756microM), strong antimicrobial activity (MIC range-0.73-6.6microg/mL; MBC range-2.92-106microg/mL) against Streptococcus mutans, Streptococcus sobrinus, Streptococcus oralis, Staphylococcus aureus, and Actinomyces naeslundii, and the results of its cytotoxic and antimicrobial activities were considered good.

Bioassay - guided isolation of proanthocyanidins with antioxidant activity from peanut (Arachis hypogaea) skin by combination of chromatography techniques.

Purification and bioassay-guided fractionation were employed to isolate proanthocyanidins with antioxidant activity from peanut skin (Arachis hypogaea Runner 886). The crude extract was prepared with acetone (60% v/v) and purified using chromatographic methods, including a semipreparative HPLC technique. As a result, two proanthocyanidins were isolated and identified using NMR, epicatechin-(2 β → O → 7, 4 β → 8)-catechin (proanthocyanidin A1) and epicatechin-(β → 2 O → 7, 4 β → 8)-epicatechin (proanthocyanidin A2). Despite the structural similarity, differences were observed in their antioxidant activity. Proanthocyanidin A1 proved to be more active, with EC50 value for DPPH radical scavenging of 18.25 μg/mL and reduction of Fe(3+)-TPTZ complex of 7.59 mmol/g, higher than that of synthetic antioxidant BHT. This compound evaluated by ABTS(+) was similar to that of natural quercetin. Therefore, peanut skin is an important source of bioactive compounds that may be used as a mild antioxidant for food preservation.

Isolamento e atividades biológicas de produtos naturais das esponjas monanchora arbuscula, aplysina sp. petromica ciocalyptoides e topsentia ophiraphidites, da ascídia didemnum ligulum e do octocoral carijoa riisei

The investigation of extracts from six species of marine invertebrates yielded one new and several known natural products. Isoptilocaulin from the sponge Monanchora aff. arbuscula displayed antimicrobial activity at 1.3 mg/mL against an oxacillin-resistant strain of Staphylococcus aureus. Five inactive known dibromotyrosine derivatives, 2 6, were isolated from a new species of marine sponge, Aplysina sp. The sponges Petromica ciocalyptoides and Topsentia ophiraphidites yielded the known halistanol sulfate A (7) as an inhibitor of the antileishmanial target adenosine phosphoribosyl transferase. The ascidian Didemnum ligulum yielded asterubin (10) and the new N,N-dimethyl-O-methylethanolamine (11). The octocoral Carijoa riisei yielded the known 18-acetoxypregna-1,4,20-trien-3-one (12), which displayed cytotoxic activity against the cancer cell lines SF295, MDA-MB435, HCT8 and HL60.The investigation of extracts from six species of marine invertebrates yielded one new and several known natural products. Isoptilocaulin from the sponge Monanchora aff. arbuscula displayed antimicrobial activity at 1.3 mg/mL against an oxacillin-resistant strain of Staphylococcus aureus. Five inactive known dibromotyrosine derivatives, 2 6, were isolated from a new species of marine sponge, Aplysina sp. The sponges Petromica ciocalyptoides and Topsentia ophiraphidites yielded the known halistanol sulfate A (7) as an inhibitor of the antileishmanial target adenosine phosphoribosyl transferase. The ascidian Didemnum ligulum yielded asterubin (10) and the new N,N-dimethyl-O-methylethanolamine (11). The octocoral Carijoa riisei yielded the known 18-acetoxypregna-1,4,20-trien-3-one (12), which displayed cytotoxic activity against the cancer cell lines SF295, MDA-MB435, HCT8 and HL60.

Trypanocidal and antifungal activities of p-hydroxyacetophenone derivatives from Calea uniflora (Heliantheae, Asteraceae).

The dichloromethane extract of underground parts of Calea uniflora (Heliantheae, Asteraceae) exhibited trypanocidal and antifungal activities. Four p‐hydroxyacetophenone derivatives were isolated as the main compounds: 2‐senecioyl‐4‐(hydroxyethyl)‐phenol (1), 2‐senecioyl‐4‐(angeloyloxy‐ethyl)‐phenol (2), and two new derivatives, 2‐senecioyl‐4‐(methoxyethyl)‐phenol (3) and 2‐senecioyl‐4‐(pentadecanoyloxyethyl)‐phenol (4). 1 and 4 were active towards Trypanosoma cruzi trypomastigotes, reducing their number by 70 and 71% at 500 μg mL−1, whereas 2 and 3 were inactive. All the compounds tested showed antifungal activity with minimal inhibitory concentration values between 500 and 1000 μg mL−1 against pathogenic Candida spp. and dermatophytes. The isolation, structure elucidation, NMR spectral assignments and bioactivity results of these compounds are reported.

Kaurene diterpenes and other chemical constituents from Mikania stipulacea (M. Vahl) willd

Phytochemical study of Mikania stipulacea yielded lupeol, a-amyrin, stigmasterol, b-sitosterol, campesterol, b-sitosteryl glucopyranoside, stigmasteryl glucopyranoside, the coumarin isoscopoletin, and vanillic, cinnamoylgrandifloric and ent-kaurenoic acids, besides two new diterpene acids: ent-9a-hydroxy-15b-E-cinnamoyloxy-16-kauren-19-oic and ent-9a-hydroxy-15b-Z-cinnamoyloxy-16-kauren-19-oic. IR, 1H and 13C NMR and MS spectroscopic analyses were used for the identification of these compounds.

Chromanones with leishmanicidal activity from Calea uniflora.

The dichloromethane extract of Calea uniflora afforded a mixture of two novel chromanones, uniflorol-A (1) and uniflorol-B (2), and one known chromanone, 2,2-dimethyl-6- (1-hydroxyethyl)-chroman-4-one (3). The structures of these compounds were determined by spectroscopic methods. Biological activity of the compounds against Leishmania major promastigotes was evaluated. Mixture of the novel chromanones 1 and 2 showed significant growth inhibition of the parasite in the micrograms per milliliter range.

Evaluation of trypanocidal activity from Calea uniflora (Heliantheae-Asteraceae) extracts

Dichloromethane crude extract from xylopodium of Calea uniflora Less (Heliantheae-Asteraceae) showed in vitro trypanocidal activity against trypomastigote forms of Trypanosoma cruzi. The data obtained allow to conclude that the crude extract must be investigate to identify its active compounds.

Screening of Southeastern Brazilian Mikania. Species on Trypanosoma cruzi.

Abstract Southeastern Brazilian Mikania. (Asteraceae) species were evaluated for trypanocidal activity against the trypomastigote forms of Trypanosoma cruzi.at a concentration of 4000 µg/mL. Fourteen extracts were examined for in vitro. trypanocidal properties. Of total extracts, 92.9% (13 extracts) exhibited trypanocidal effects. The dichloromethane extract of Mikania camporum. B. Robinson and the methanol extract of Mikania micrantha. H. B. K. caused 100% lysis of the parasites.