Anti-dermatophyte activity of Leguminosae plants from Southern Brazil with emphasis on Mimosa pigra (Leguminosae).

BACKGROUND: Intensive prophylactic use of antifungals leads to the increase of drug resistance and the need for new and more effective treatments are real. Plants from Leguminosae family are rich in flavonoids, for which numerous biological activities have been described, including antifungal effects. PURPOSE: To screen methanolic extracts from Leguminosae species looking for alternative sources for antifungal agents (anti-dermatophyte and anti-Candida) and their innocuity. METHODS: Antifungal activity was evaluated using the strains Candida albicans, C. krusei, C. glabrata, C. tropicalis, C. parapsilosis, Epidermophyton floccosum, Trichophyton mentagrophytes, T. rubrum and, Microsporum gypseum in the broth microdilution method. Later, the minimum inhibitory concentration (MIC) for Mimosa pigra, Eriosema heterophyllum, and Chamaecrista nictitans was determined. The most promising extract was fractionated and cytotoxicity and genotoxicity of the most active fraction were also assayed. RESULTS: Fungicide and/or fungistatic activity against dermatophyte strains were presented by 60% of the methanolic extracts assayed. M. pigra, E. heterophyllum, and C. nictitans methanolic extracts could inhibit dermatophyte strains at concentrations ranging from 1.9 to 1000µg/mL. M. pigra showed the lowest MIC values for a dichloromethane fraction (1.9µg/mL) without DNA damage at 10 and 50µg/mL and 100% of cell viability of human leukocytes. CONCLUSION: Our results indicate that methanolic extracts from Leguminosae plants are potential sources of antifungal compounds, mainly the extract and fractions from M. pigra. The dichloromethane fraction from M. pigra did not showed in vitro toxicity according to the applied assays.

Monoamine levels in rat striatum after acute intraperitoneal injection of strictosidinic acid isolated from Psychotria myriantha Mull. Arg. (Rubiaceae).

Strictosidinic acid 10mg/kg, isolated from Psychotria myriantha leaves, were administered intraperitoneally to Wistar male rats (n=5-6). After 60 minutes, striatum was dissected, homogenized and injected onto HPLC-ED chromatographic system. It was observed a 28.7% reduction in the 5-HT levels followed up by an increase of 5-HIAA levels (29.4%). Furthermore there was a decrease of 8.0% in DA levels and an increase in the levels of metabolites DOPAC (21.5%) and HVA (52.5%). The results indicate that strictosidinic acid has a promising effect in the central nervous system, justifying more studies about the central actions of Psychotria compounds.

Effect of isoquinoline alkaloids from two Hippeastrum species on in vitro acetylcholinesterase activity.

The treatment of neurological disorders and neurodegenerative diseases is related to the levels of acetylcholine (ACh) through the inhibition of acetylcholinesterase (AChE). Galanthamine, an important alkaloid isolated from the Amaryllidaceae family, is approved for the pharmacological treatment of Alzheimer's disease (AD) and acts by inhibiting the acetylcholinesterase (AChE) activity. In the present study, Ellman's method was used to verify the inhibition of AChE activity of some isoquinolines alkaloids such as galanthamine, montanine, hippeastrine and pretazettine. At the concentrations 1mM, 500 microm and 100 microm, galanthamine presented an AChE inhibition higher than 90%. Montanine inhibited, in a dose-dependent manner, more than 50% of the enzyme at 1mM concentration. With the concentrations 500 microm and 100 microm, 30-45% of AChE activity inhibition was detected. The alkaloids hippeastrine and pretazettine presented no significant inhibition of the AChE activity. The results demonstrate that montanine significantly inhibits AChE activity at the tested concentrations, suggesting the necessity of further investigations on this alkaloid use in treating neurological disorders.

Screening for cytotoxic activity of extracts and isolated alkaloids from bulbs of Hippeastrum vittatum.

The dichloromethane and n-butanol extracts obtained from fresh bulbs of Hippeastrum vittatum (Amaryllidaceae), collected in Southern Brazil, were evaluated for their cytotoxic activity in vitro against five human cell lines (HT29 colon adenocarcinoma, H460 non-small cell lung carcinoma, RXF393 renal cell carcinoma, MCF7 breast cancer, and OVCAR3 epithelial ovarian cancer), using the sulphorhodamine B assay. Both extracts showed potential antiproliferative activity. From CH(2)Cl(2) fraction, three alkaloids were isolated: lycorine, vittatine and montanine. The two last compounds were submitted to the antiproliferative assay and the highest level of cytotoxicity was found for the alkaloid montanine.

Avaliação da atividade antiviral e determinação do perfil cromatográfico de Hippeastrum glaucescens (Martius) Herbert (Amaryllidaceae) / Evaluation of antiviral activity and determination of the chromatographic profile of Hippeastrum glaucescens (Martius) Herbert (Amaryllidaceae)

Plantas da família Amaryllidaceae são caracterizadas pela presença de alcalóides isoquinolínicos. Desde o primeiro estudo envolvendo alcalóides desta família em 1877, um grande número destas plantas tem sido analisado quimicamente. Estes compostos apresentam uma ampla variedade de atividades biológicas, tais como: antiviral, citotóxica, antitumoral e analgésica. Neste trabalho, foram avaliados o perfil cromatográfico e a potencial atividade antiviral das frações diclorometano A e B, isoladas dos diferentes órgãos vegetais (bulbos, raízes, folhas e flores) de Hippeastrum glaucescens (Martius) Herbert, assim como dos alcalóides licorina, tazetina e pretazetina, previamente isolados desta planta. A extração dos alcalóides de H. glaucescens foi realizada por métodos clássicos, a partir de bulbos, raízes, folhas e flores fornecendo rendimentos totais em alcalóides de 0,53 por cento; 0,81 por cento; 0,29 por cento e 0,12 por cento, respectivamente. Empregando-se cromatografia em camada delgada, verificou-se que os bulbos e as raízes apresentam perfis cromatográficos semelhantes e que os alcalóides licorina, tazetina e pretazetina estão presentes em todas as partes testadas do vegetal. As frações diclorometano A e B, de cada órgão vegetal, e os alcalóides isolados (licorina, tazetina e pretazetina) não inibiram a replicação do herpesvírus simples humano tipo 1 (HSV-1) cepa KOS, quando avaliados através do método de inibição do efeito citopático viral.

Plants of Amaryllidaceae are characterized by isoquinoline alkaloids. Since the first study with Amaryllidaceae alkaloids in 1877, a large number of these plants have been chemically investigated. These compounds have shown a wide range of biological activities such as: antiviral, cytotoxic, antitumoral and analgesic. In this work, the dichloromethane (CH2Cl2) extracts obtained from different parts of the Hippeastrum glaucescens (Martius) Herbert (bulbs, roots, leaves and flowers) and the isolated alkaloids lycorine, tazettine and pretazettine were analyzed by a chromatographic method (TLC) and tested for antiviral activity. The extraction of alkaloids from bulbs, roots, leaves and flowers of H. glaucescens was performed by classic methods and yields 0.53 percent, 0.81 percent, 0.29 percent and 0.12 percent, respectively. Through TLC, bulbs and roots revealed similar chromatographic profiles and lycorine, tazettine and pretazettine were found in all the parts analyzed. The CH2Cl2-A and CH2Cl2-B extracts from each part of the plant and the isolated alkaloids (lycorine, tazettine and pretazettine) did not inhibit the HSV-1 strain KOS replication, when evaluated through the inhibition of cytophatic viral effect.

Alkaloids of Erythroxylum (Erythroxylaceae) species from Southern Brazil.

A new alkaloid identified as 3beta,6beta-ditigloyloxynortropane as 3beta,7beta-ditigloyloxynortropane, 4-hydroxyhygrinic acid, methylecgonidine and tropacocaine have been isolated from the leaves of Erythroxylum argentinum. The new structure was established by means of spectroscopic techniques. Four other species E. deciduum, E. microphyllum, E. pelleterianum and E. cuneifolium collected in the state of Rio Grande do Sul were screened for methylecgonidine and tropacocaine by CG/MS. Two of these plants contain tropacocaine and two contain methylecgonidine. GC/MS analysis of all 5 species for cocaine proved fruitless. The chemotaxonomic significance of these results is discussed.