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Publikation

Moura, P. H. B.; Brandt, W.; Porzel, A.; Martins, R. C. C.; Leal, I. C. R.; Wessjohann, L. A.; Structural elucidation of an atropisomeric entcassiflavan-(4β→8)-epicatechin isolated from Dalbergia monetaria L.f. based on NMR and ECD calculations in comparison to experimental data Molecules 27, 2512, (2022) DOI: 10.3390/molecules27082512

A rare dihydoxyflavan-epicatechin proanthocyanidin, entcassiflavan-(4β→8)-epicatechin, was isolated from Dalbergia monetaria, a plant widely used by traditional people from the Amazon to treat urinary tract infections. The constitution and relative configuration of the compound were elucidated by HR-MS and detailed 1D- and 2D-NMR measurements. By comparing the experimental electronic circular dichroism (ECD) spectrum with the calculated ECD spectra of all 16 possible isomers, the absolute configuration, the interflavan linkage, and the atropisomers could be determined.
Publikation

de Moura, P. H. B.; de Sousa, A. A.; Porzel, A.; Wessjohann, L. A.; Leal, I. C. R.; Martins, R. C. C.; Characterization of antibacterial proanthocyanidins of Dalbergia monetaria, an amazonian medicinal plant, by UHPLC-HRMS/MS Planta Med. 86, 858– 866, (2020) DOI: 10.1055/a-1170-8016

Dalbergia monetaria is an Amazonian plant whose bark is widely used to treat urinary tract infections. This paper describes a bio-guided study of ethanolic extracts from the bark and leaves of D. monetaria, in a search for metabolites active against human pathogenic bacteria. In vitro assays were performed against 10 bacterial strains, highlighting methicillin-sensitive Staphylococcus aureus and methicillin-resistant Staphylococcus aureus and Pseudomonas aeruginosa. Fractioning of the extracts was performed using instrumental and classical techniques, and samples were characterized by UHPLC-HRMS/MS. Ethyl acetate fractions from bark and leaves showed similar antibacterial activities. EAFB is enriched in isoflavone C-glucosides and EAFL enriched in proanthocyanidins. Subfractions from EAFL presented higher activity and showed a complex profile of proanthocyanidins constructed by (epi)-cassiaflavan and (epi)-catechin units, including dimers, trimers and tetramers. The fragmentation pattern emphasized the neutral loss of cassiaflavan units by quinone-methide fission. Fraction SL7-6, constituted by (ent)-cassiaflavan-(ent)-cassiaflavan-(epi)-catechin isomers, showed the lowest MIC against the S. aureus and P. aeruginosa with values corresponding to 64 and 32 µg/mL, respectively. Cassiaflavan-proanthocyanidins have not been found previously in another botanical genus, except in Cassia, and the traditional medicinal use of D. monetaria might be related to the antibacterial activity of proanthocyanidins characterized in the species.
Publikation

da Silva, I. C. V.; Silva, I. C. V. d.; de Oliveira, P. F.; Oliveira, P. F. d.; Barbosa, G. M.; Wessjohann, L. A.; Cardozo-Filho, L.; Holandino, C.; Muzitano, M. F.; Leal, I. C. R.; Passiflora mucronata leaves extracts obtained from different methodologies: a phytochemical study based on cytotoxic and apoptosis activities of triterpenes and phytosterols constituents Braz. J. Pharm. Sci. 56, e17666, (2020) DOI: 10.1590/s2175-97902019000417666

Cancer is one of the most prevalent diseases worldwide and the natural products could be a source of bioactive compounds. Passiflora mucronata (PM) belongs to a very known vegetal genus, although, there are no studies about cytotoxic activity or isolated compounds. Different extracts from PM were obtained by liquid-liquid partition (P), Soxhlet (Sox) and supercritical fluid (SFE1-5) extraction techniques, being compared concerning their yields, chemical profile and cytotoxicity. The Sox extracts showed the highest yields (6.03%: hexane; 2.51%: dichloromethane) followed by SFE (from 4.34 to 1.63%) and partitions (1.06 and 2.26%). The hexane partition (HP) showed the best cytotoxic activity against K562 cell line (IC50 = 18.72 µg.mL-1). From HP, the following compounds were identified and analysed its cytotoxic activities: β-amyrin (IC50 = 3.92 µg.mL-1), β-sitosterol (IC50 = 3.37 µg.mL-1), stigmasterol (IC50 = 3.31 µg.mL-1) and oleanolic acid. Stigmasterol induced about 75% of K562 total apoptosis. The compounds were tested against MA-104 cell line and the selective index (SI) attributed (SI >10 for all compounds). This indicates good selectivity to K562 cell line at the expense of MA-104. This is the first time, identifying those compounds to PM .
Publikation

da Silva, I. C. V.; Kaluderovic, G.; de Oliveira, P. F.; Guimaraes, D. O.; Quaresma, C. H.; Porzel, A.; Muzitano, M. F.; Wessjohann, L. A.; Leal, I. C. R.; Apoptosis caused by triterpenes and phytosterols and antioxidant activity of an enriched flavonoid extract and from Passiflora mucronata Anti-Cancer Agents Med. Chem. 18, 1405-1416, (2018) DOI: 10.2174/1871520618666180315090949

Background: P. mucronata (Pm) comes from South America, Brazil and is characterized as “Maracujá de Restinga”. It is used in folk medicine for its soothing properties and in treating insomnia. Objective: The present study for the first time analyzed the antioxidant and cytotoxicity of the hydroalcoholic leaves extract and fractions from Pm. Method: The cytotoxicity test will be evaluated by different assays (MTT and CV) against human prostate cancer (PC3) and mouse malignant melanoma (B16F10) cell lines, and the antioxidant test by DPPH method. Results: β-Amyrin, oleanolic acid, β-sitosterol and stigmasterol were isolated of the most active, hexane fraction. These substances were tested against the tumor cell lines: β-sitosterol and stigmasterol showed the most relevant activity to PC3 in CV assay and, oleanolic acid to B16F10 by the MTT assay. In addition, it was possible to indicate that the mode of cell death for stigmasterol, presumably is apoptosis. In terms of antioxidant activity, the hydroalcoholic leaves extract presented higher activity (EC50 133.3 μg/mL) compared to the flower (EC50 152.3 μg/mL) and fruit (EC50 207.9 μg/mL) extracts. By the HPLC-MS, it was possible to identify the presence of flavones in the leaf extract (isoschaftoside, schaftoside, isovitexin, vitexin, isoorientin, orientin). Conclusions: P. mucronata hexane fraction showed promising cytotoxic effect against cancer cell lines, and stigmasterol contributes to this activity, inducing apoptosis of these cells. Furthermore, as other Passiflora species, Pm extract showed antioxidant activity and flavones are its major phenolic compounds.
Publikation

Ruela, H. S.; Leal, I. C. R.; de Almeida, M. R. A.; dos Santos, K. R. N.; Wessjohann, L. A.; Kuster, R. M.; Antibacterial and antioxidant activities and acute toxicity of Bumelia sartorum Mart., Sapotaceae, a Brazilian medicinal plant Rev. Bras. Farmacogn. 21, 86-91, (2011) DOI: 10.1590/S0102-695X2011005000035

In order to validate the Bumelia sartorum Mart., Sapotaceae, traditional use for infection diseases, this study evaluates the antibacterial activity of the stem bark fractions against methicillin-sensitive (MSSA) and methicillin-resistant (MRSA) Staphylococcus aureus strains by using the agar dilution method and reported as MIC (minimal inhibitory concentration). In addition, the DPPH scavenging activity of these fractions was measured and the chemical composition and acute toxicity of the active fraction were also determined. The ethyl acetate (EtOAc) extract was chemically analyzed by LC/MS, direct ionization APCI/MS, 1H NMR and 13C-NMR. All fractions, except butanol extract, presented high antioxidant activity, especially the methanol and the EtOAc extracts, which showed EC50 values (5.67 and 5.30 µg/mL, respectively) considerably lower than the Gingko-standard EGb 761® (38.58 µg/mL). The antibacterial activity against S. aureus strains was observed in EtOAc (MIC 256-512 µg/mL), which showed a very low toxicity. The chemical study of this fraction revealed the abundant presence of polyphenolic compounds. The antibacterial and antioxidant activities reported in this paper for EtOAc extract from B. sartorum and the low toxicity of this fraction opens the possibility that it could be helpful for the developing of new antibacterial agents for treating S. aureus infections.

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