Biological Activities of Extracts from Ageratum fastigiatum: Phytochemical Study and In Silico Target Fishing Approach.

In the present study, the ethanolic extract from aerial parts of Ageratum fastigiatum was evaluated in vitro against epimastigote forms of Trypanosoma cruzi (Y strain), promastigote forms of Leishmania amazonensis (PH8 strain), and L. chagasi (BH400 strain). The extract was also evaluated against Staphylococcus aureus (ATCC 25 923), Escherichia coli (ATCC 11 775), Pseudomonas aeruginosa (ATCC 10 145), and Candida albicans (ATCC 36 802). The phytochemical screening was performed by thin-layer chromatography and high-performance liquid chromatography. The extract was fractionated using flash preparative chromatography. The ethanolic extract showed activity against T. cruzi, L. chagasi, and L. amazonensis and antimicrobial activity against S. aureus, E. coli, P. aeruginosa, and C. albicans. The phytochemical screening revealed coumarins, terpenes/sterols, and flavonoids in the ethanolic extract. In addition, the coumarin identified as ayapin was isolated from this extract. We also performed in silico prediction of potential biological activities and targets for compounds previously found in A. fastigiatum. Several predictions were confirmed both retrospectively and prospectively by experimental results described here or elsewhere. Some activities described in the in silico target fishing approach were validated by the ethnopharmacological use and known biological properties. Some new activities and/or targets were predicted and could guide future studies. These results suggest that A. fastigiatum can be an interesting source of substances with antiparasitic and antimicrobial activities.

Combined In Vitro Studies and in Silico Target Fishing for the Evaluation of the Biological Activities of Diphylleia cymosa and Podophyllum hexandrum.

This paper reports the in silico prediction of biological activities of lignans from Diphylleia cymosa and Podophyllum hexandrum combined with an in vitro bioassays. The extracts from the leaves, roots and rhizomes of both species were evaluated for their antibacterial, anticholinesterasic, antioxidant and cytotoxic activities. A group of 27 lignans was selected for biological activities prediction using the Active-IT system with 1987 ligand-based bioactivity models. The in silico approach was properly validated and several ethnopharmacological uses and known biological activities were confirmed, whilst others should be investigated for new drugs with potential clinical use. The extracts from roots of D. cymosa and from rhizomes and roots of P. hexandrum were very effective against Bacillus cereus and Staphylococcus aureus, while podophyllotoxin inhibited the growth of Staphylococcus aureus and Escherichia coli. D. cymosa leaves and roots showed anticholinesterasic and antioxidant activities, respectively. The evaluated extracts showed to be moderately toxic to THP-1 cells. The chromatographic characterization indicated that podophyllotoxin was the major constituent of P. hexandrum extract while kaempferol and its hexoside were the main constituents of D. cymosa leaves and roots, respectively. These results suggest that the podophyllotoxin could be the major antibacterial lignan, while flavonoids could be responsible for the antioxidant activity.

Aspidosperma species: A review of their chemistry and biological activities.

ETHNOPHARMACOLOGICAL RELEVANCE: Species of Aspidosperma are known popularly as "peroba, guatambu, carapanaúba, pau-pereiro" and "quina". The genus can be found in the Americas, mainly between Mexico and Argentina. Many species of Aspidosperma are used by the population in treating cardiovascular diseases, malaria, fever, diabetes and rheumatism. The phytochemical aspects of the species of the genus Aspidosperma have been studied extensively. The monoterpene indole alkaloids are the main secondary metabolites in Aspidosperma species, and about 250 of them have been isolated showing a considerable structural diversity. Several of them have showed some important pharmacological activities. Aspidosperma subincanum Mart. and Aspidosperma tomentosum Mart. (Apocynaceae) are Brazilian species widely used by the population to treat diabetes mellitus, hypercholesterolemia. The pharmacological activities of both species have been investigated and the biological properties described can be related to their isolated indole alkaloids. However, more pharmacological studies are needed in order to justify the use of these species in folk medicine. In this review, we present reports mainly focused on chemical and biological studies and their relationship with the ethnopharmacological use of both Aspidosperma species. AIM OF THE STUDY: The aim of this review is to present their ethnopharmacological use as correlated to their biological activities as described for the extracts and isolated compounds from Aspidosperma subincanum Mart. and Aspidosperma tomentosum Mart. In addition, some aspects related to the biosynthetic pathways are discussed, also NMR assignments and some synthesis information about indole alkaloids from both Aspidosperma species are included. MATERIAL AND METHODS: The bibliographic search was made in theses and dissertations using some databases such as NDLTD (Networked Digital Library of Theses and Dissertations), OATD (Open Access Theses and Dissertations) and Google Scholar. More data were gathered from books, Brazilian journals and articles available on electronic databases such as, Google Scholar, PubChem, Scifinder, Web of Science, SciELO, PubMed and Science Direct. Additionally, the Google Patents and Espacenet Patent Search (EPO) were also consulted. The keywords Aspidosperma, A. subincanum, A. tomentosum, indole alkaloids were used in the research. The languages were restricted to Portuguese, English and Spanish and references were selected according to their relevance. RESULTS: A. subincanum Mart. and A. tomentosum Mart. (Apocynaceae) are Brazilian species widely used by the population to treat a few diseases. Extracts and isolated compounds of both species have shown antitumor and antimalarial activities. The antitumor activity of isolated compounds has been extensively studied. However, the antiplasmodial activity needs to be investigated further as well as the anti-inflammatory, anti-hyperlipidemic and anorexigenic activities. From A. subincanum twenty-one indole alkaloids were isolated and some of them have been extensively studied. From the leaves and bark of A. tomentosum four alkaloids and one flavonoid were isolated. Furthermore, CG-MS analysis of seeds, branches, leaves and arils identified nine indole alkaloids. Stemmadenine has been proposed as a precursor of indole alkaloids obtained from some species of Aspidosperma. Many of the biosynthetic steps have been characterized at the enzymatic level and appropriate genes have been identified, however, other steps have yet to be investigated and they are still controversial. Some isolated alkaloids from A. subincanum and A. tomentosum were identified only by mass spectrometry. In many cases, their NMR data was either not available or was incomplete. The described meta-analysis of the available NMR data revealed that the chemical shifts belonging to the indole ring might be used to characterize this class of alkaloids within complex matrices such as plant extracts. The biological activities and the structural complexity of these compounds have stimulated the interest of many groups into their synthesis. In this review, some information about the synthesis of indole alkaloids and their derivatives was presented. CONCLUSIONS: A. subincanum and A. tomentosum are used by the population of Brazil to treat many diseases. A few biological activities described for the extracts and isolated compounds of both species are in agreement with the ethnopharmacological use for others species of Aspidosperma, such as, antimalarial, the treatment of diabetes and other illnesses. These species are sources of leading compounds which can be used for developing new drugs. In addition, other biological activities reported and suggested by ethnopharmacological data have yet to be investigated and could be an interesting area in the search for new bioactive compounds.

In vitro antileishmanial activity of leaf and stem extracts of seven Brazilian plant species.

ETHNOPHARMACOLOGICAL RELEVANCE: Leishmaniasis is a parasitic disease that affects people all over the world. The number of cases of leishmaniasis is increasing and the drugs used for its treatment are toxic and not always effective. The recognition of the global nature of this disease and its direct or indirect effects on health economics and actions focuses attention on the development of new therapeutic options. In Brazil, this parasitic disease is endemic in many regions. The plants used by the population against leishmaniasis can be good starting points in the search of new lead compounds for antileishmanial drugs. AIM OF THE STUDY: The aim of the present study was to investigate the antileishmanial activity of extracts from leaves and stems of seven Brazilian plant species used by the population to treat leishmaniasis, and symptoms that might be related to Leishmania infections. MATERIALS AND METHODS: Twenty two extracts from seven plants belonging to five different botanical families were prepared by different methods and evaluated for their effect on the viability of promastigote forms of Leishmania infantum (MHOM/BR/1967/BH46) using the resazurin-based colorimetric assay. The extracts were considered active when they inhibited the growth of promastigotes in a percentage greater than or equal to 50% at 100 and 200 µg/mL. The active samples were further investigated to determine IC50, CC50 and SI values against promastigote forms of L. infantum. The active and non-cytotoxic extracts (SI> 10) were evaluated against amastigote forms of L. infantum. In addition, the active extracts against the amastigote forms were analyzed by TLC and HPLC, while the EtOAc extract of stems from Aspidosperma tomentosum was also evaluated by GC/MS. RESULTS: Among the twenty two extracts evaluated, two were considered active against L. infantum. The EtOH extract of leaves from Dyospiros hispida (IC50 55.48 ±â€¯2.77 µg/mL and IC50 80.63 ±â€¯13.17 µg/mL, respectively) and the EtOAc extract of stems from Aspidosperma tomentosum (IC50 9.70 ±â€¯2.82 µg/mL and IC50 15.88 ±â€¯1.53 µg/mL, respectively) inhibited significantly the growth of promastigote and amastigote forms of L. infantum. Some extracts, although active in the initial screening, were considered toxic since the SI was lower than 10. In TLC and HPLC analysis the leaf extract of Dyospiros hispida showed the presence of anthraquinones, terpenes and saponins, and in the EtOAc extract of stems from Aspidosperma tomentosum alkaloids and flavonoids were detected. In addition, in the latter extract the indole alkaloids uleine and dasycarpidone could be identified by GC/MS. CONCLUSIONS: The ethnopharmacological data of Aspidosperma tomentosum and Dyospiros hispida in part support the results found in the biological models used. Extracts of Aspidosperma tomentosum and Dyospiros hispida presented promising results against L. infantum.

Toxicity and Larvicidal Activity of Podophyllum-Based Lignans Against Aedes aegypti (Diptera: Culicidae).

Aedes aegypti L. (Diptera: Culicidae) is a mosquito species that has adapted to urban environments and is the main vector of dengue viruses. Because of the increasing incidence of dengue, a more environmentally acceptable insecticide needs to be found. Natural products have been and continue to be an important source of leading compounds that can be modified in order to develop new drugs. The lignan family of natural products includes compounds with a diverse spectrum of biological activity. Podophyllotoxin and its related lignans represent an exciting class of natural products that can be targeted at different types of biological activity and are therefore worth exploring further. This study had the aim of evaluating the larvicidal activity of an ethanolic extract from the rhizomes and roots of Podophyllum hexandrum (PM-3) and its isolated lignans, podophyllotoxone (1) and desoxypodophyllotoxin (2), on the larvae of the mosquito vector Ae. aegypti. The PM-3 extract and the compounds (1) and (2) were dissolved in a mixture of acetone and dimethylsulfoxide at final concentrations of 1, 10, 30, 50, 100, and 200 µg/ml. After dilution, the solutions were applied (µg/ml) to the larvae-rearing medium. Overall, the ethanolic extract from the rhizomes and roots of P. hexandrum and the compounds (1) and (2) showed larvicidal activity against the larvae of Ae. aegypti According to the results from this study, it can be concluded that podophyllotoxone (1) and desoxypodophyllotoxin (2) exhibited significant toxicity toward Ae. aegypti larvae.

Screening of Brazilian medicinal plants for antiviral activity against rotavirus.

ETHNOPHARMACOLOGICAL RELEVANCE: Brazilian medicinal plants traditionally used for the treatment of diarrhoea were investigated for their in vitro antiviral activity against the simian rotavirus SA11. MATERIALS AND METHODS: The ethanolic crude extracts of plants collected in the cerrado of Minas Gerais, Brazil were submitted to phytochemical screening. The cytotoxicity of the extracts was inferred by cellular morphologic alterations. Antiviral activity was assessed by the ability of the extracts to inhibit the cytopathic effect (CPE) of rotavirus on the treated cells. RT-PCR was performed to confirm and/or confront antiviral assay data. RESULTS: The maximum non-toxic concentration ranged from 50 to 500 µg/mL. All extracts were toxic at a concentration of 5000 µg/mL but no extract showed cytotoxicity at 50 µg/mL. The species Byrsonima verbascifolia, Myracrodruon urundeuva, Eugenia dysenterica and Hymenaea courbaril exhibited the strongest in vitro activity against rotavirus. Their extracts prevented the formation of CPE, and RT-PCR analysis detected no amplification of genetic material from rotavirus. Tannins, flavonoids, saponins, coumarins and terpenes were the major classes of natural products found in the leaf extracts that showed antiviral activity. CONCLUSION: Among the species studied, Byrsonima verbascifolia, Eugenia dysenterica, Hymenaea courbaril and Myracrodruon urundeuva showed potential activity against rotavirus and are worthy of further study. The present study corroborates ethnopharmacological data as a valuable source in the selection of plants with antiviral activity and to some extent validates their traditional uses.