Lúcia Pinheiro Santos Pimenta

Antibacterial activity of eight Brazilian annonaceae plants

Sixteen extracts, obtained from eight Brazilian plants of Annonaceae family, were screened for their antibacterial activity: Xylopia frutescens, X. aromatica, X. amazonica, X. benthamii, Annona ambotay, A. crassiflora, A. muricata and A. cherimolia. Amongst the investigated extracts, six showed antibacterial activity against at least one of the tested organisms at the concentration of 100 µg/mL. The most active extracts were those prepared from X. frutescens, X. amazonica, and A. ambotay. A phytochemical screening showed the presence of anonaceus acetogenins in some active extracts. Eleven diterpenoids were also tested for comparison purposes. Six were natural products, previously isolated from Xylopia sp. (kaurenoic, frutoic, xylopic, 15β-hydroxy-kaurenoic and trachylobanic acids plus kaurenol) and five were derivatives of such compounds, obtained by esterification or reduction reactions. Trachylobanic acid showed antibacterial activity against B. subtilis and S. aureus.

Acetogeninas de anonáceas isoladas de folhas de Rollinia laurifolia

Phytochemical investigation of hexanic extract of leaves of Rollinia laurifolia afforded three known acetogenins, uvariamicin-I (1), solamin(2) and gonionenin(3), for the first time isolated from Rollinia genus. The structures of 1, 2 and 3 were elucidated by spectroscopic methods.

In vivo antimalarial efficacy of acetogenins, alkaloids and flavonoids enriched fractions from Annona crassiflora Mart.

Annona crassiflora and Annonaceae plants are known to be used to treat malaria by traditional healers. In this work, the antimalarial efficacy of different fractions of A. crassiflora, particularly acetogenin, alkaloids and flavonoid-rich fractions, was determined in vivo using Plasmodium berghei-infected mice model and toxicity was accessed by brine shrimp assay. The A. crassiflora fractions were administered at doses of 12.5 mg/kg/day in a 4-day test protocol. The results showed that some fractions from woods were rich in acetogenins, alkaloids and terpenes, and other fractions from leaves were rich in alkaloids and flavonoids. The parasitaemia was significantly (p < 0.05, p < 0.001) reduced (57–75%) with flavonoid and alkaloid-rich leaf fractions, which also increased mean survival time of mice after treatment. Our results confirm the usage of this plant in folk medicine as an antimalarial remedy.

The first report on flavonoid isolation from Annona crassiflora Mart

Annona crassiflora, a native tree from Brazilian Cerrado, is reported to possess several ethnomedical uses. Here, we report the isolation and unambiguous characterisation of the flavonoids quercetin-3-O-β-D-glucopyranosil(1 → 6)-O-α-L-arabinoside (1), known as peltatoside, kaempferol-3-O-β-D-galactopyranoside (2), quercetin-3-O-β-D-galactopyranoside (3), quercetin-3-O-β-L-arabinopiranoside (4) and the ( − )-epicatechin (5) from the hydroalcoholic portion of the leaf ethanolic extract. Their structures were elucidated by using 1D and 2D NMR, ESI-MS, UV/Vis spectroscopy, optical rotation analysis and literature data comparison. The leaf ethanolic extract and its isolated compounds were evaluated by using antimicrobial, antioxidant and larvicidal assays, expressing antimicrobial and antioxidant activities. This is the first report on flavonoid isolation from A. crassiflora.

In vitro antifungal activity of fatty acid methyl esters of the seeds of Annona cornifolia A.St.-Hil. (Annonaceae) against pathogenic fungus Paracoccidioides brasiliensis

INTRODUCTION Fatty acids are abundant in vegetable oils. They are known to have antibacterial and antifungal properties. METHODS Antifungal susceptibility was evaluated by broth microdilution assay following CLSI (formerly the NCCLS) guidelines against 16 fungal strains of clinical interest. RESULTS In this work, fatty acid methyl esters (FAME) was able to inhibit 12 clinical strains of the pathogenic fungus Paracoccidioides brasiliensis and were also active in the bioautographic assay against Cladosporium sphaerospermum. CONCLUSIONS FAME was a more potent antifungal than trimethoprim-sulfamethoxazole against P. brasiliensis under the experimental conditions tested.

Effects of kaurane diterpene derivatives on germination and growth of Lactuca sativa seedlings.

Kaurenoic and grandiflorenic acid, isolated from Wedelia paludosa (Asteraceae), some derivatives from these acids (alcohols, esters, amides, lactones, oximes) and other naturally occurring kaurane diterpenes were tested for their action on the growth of radical and shoot of Lactuca sativa. Gibberellic acid, GA3, a commercially available phytohormone, belonging to the same class of diterpenes, was also tested. Some of the tested substances showed a remarkable activity either in the inhibition or in stimulation of L. sativa growth. The activity, in some cases, was even higher than that of GA3.

Evaluation of antimicrobial activity and toxic potential of extracts and triterpenes isolated from Maytenus imbricata

The phytochemical study of hexane/ethyl ether (1:1) extract of the roots of M. imbricata, Celastraceae, resulted in the isolation and characterization of six known triterpenes: 11α-hydroxylup-20(29)-en-3-one, previously isolated from this species besides, 3β,11α-di-hydroxylup-20(29)-ene, 3,7-dioxofriedelane, 3-oxo-29-hydroxyfriedelane, tingenone and 6-oxo-tingenol. The chemical structures of these triterpenes were established by spectrometric data (IR, 1H and 13C NMR) and through comparison with literature data. The hexane/ethyl ether (1:1), ethyl acetate and methanol extracts, and 11α-hydroxylup-20(29)-en-3-one, tingenone and 6-oxo-tingenol, showed antimicrobial properties on in vitro assays. All extracts and triterpenes, except 3β,11α-di-hydroxylup-20(29)-ene, presented toxicity demonstrated by the larvicidal effect test using Artemia salina.

Two new adjacent bis-tetrahydrofuran annonaceous acetogenins from seeds of Annona cornifolia.

Two new adjacent bis-THF annonaceous acetogenins, 9-hydroxyfolianin (1) and folianin B (2), together with two known acetogenins, asimicin (3) and bullatacin (4), significantly bioactives in brine shrimp lethality test, were isolated from seeds of Annona cornifolia A. St. Hil (Annonaceae). Their structures were elucidated by NMR and ESI-MS analysis, and relative configurations were established. The absolute configuration around the THF rings of 1 was defined by Mosher esters methodology and circular dichroism.

Laurifolin, a novel acetogenin from Rollinia laurifolia leaves

Abstract Laurifolin ( 1 ), a novel mono-tetrahydrofuran acetogenin, has been isolated from Rollinia laurifolia leaves. The structure of 1 was elucidated by spectroscopic methods.

Quantitative analysis of trigonelline in some Annona species by proton NMR spectroscopy

A quantitative 1H NMR method (qHNMR) was used to measure the trigonelline content in the leaves of six species of the Annona genus. The methodology employed compared the intensities of the signals at δ 9.14 (H-2) and δ 0.00, the internal standard TSP-d4. This measuring method was able to establish the concentration of trigonelline in the range from 0.67 to 10.04 mg·g−1 depending on the investigated extract.