The molluscicidal activity of plants used in Brazilian folk medicine

Biomphalaria embryotoxicity test (BET): 60 years of research crossing boundaries for developing standard protocols

Snail's embryotoxicity test is a suitable approach for toxicity assay of traditional and emerging pollutants, environmental risk assessment, as well as screening and development of new molluscicides. Among the snail species, Biomphalaria spp. has been indicated as a promising model system for developing standardized test protocols for assessing the chemical toxicity using early developmental stages. Thus, the current study aimed to review the data available in the scientific literature concerning the experimental approach, type of chemicals and the response of multiple biomarkers (survival, hatching rate, development delays, morphological and behavior changes) in snail embryos applied in toxicity tests. Revised data showed that the use of Biomphalaria embryos to assess chemical toxicity began in 1962. Snail's embryotoxicity test was applied mainly for analyzing the toxicity and development of new molluscicides, while its use in ecotoxicological studies is emerging. Biomphalaria glabrata was the main species analyzed. Embryos exposed to chemicals showed bioaccumulation, mortality, hatching inhibition, development delays, and morphological malformations, which were classified into four categories (hydropic, shell, cephalic and unspecified malformations). Besides, research gaps and recommendations for future research are indicated. Overall, the results showed that the Biomphalaria embryotoxicity test (BET) is a suitable tool for toxicity and health risk assessment.

Anti-Infective and Anti-Cancer Properties of the Annona Species: Their Ethnomedicinal Uses, Alkaloid Diversity, and Pharmacological Activities

Annona species have been a valuable source of anti-infective and anticancer agents. However, only limited evaluations of their alkaloids have been carried out. This review collates and evaluates the biological data from extracts and purified isolates for their anti-infective and anti-cancer activities. An isoquinoline backbone is a major structural alkaloid moiety of the Annona genus, and more than 83 alkaloids have been isolated from this genus alone. Crude extracts of Annona genus are reported with moderate activities against Plasmodium falciparum showing larvicidal activities. However, no pure compounds from the Annona genus were tested against the parasite. The methanol extract of Annona muricata showed apparent antimicrobial activities. The isolated alkaloids from this genus including liriodenine, anonaine, asimilobine showed sensitivity against Staphylococcus epidermidis. Other alkaloids such as (+)-Xylopine and isocoreximine indicated significant anti-cancer activity against A549 and K-562 cell lines, respectively. This review revealed that the alkaloids from Annona genus are rich in structural diversity and pharmacological activities. Further exploration of this genus and their alkaloids has potential for developing novel anti-infective and anticancer drugs.

Potential therapeutic applications of the genus Annona: Local and traditional uses and pharmacology

ETHNO-PHARMACOLOGICAL RELEVANCE

Annona species (Annonaceae) have long been used as traditional herbal medicines by native peoples in tropical areas. In different countries they are used against a large variety of illnesses, such as parasitic and infectious diseases, cancer, diabetes, peptic ulcers, and mental disorders.

AIM OF THE STUDY

This review aims to achieve a comprehensive understanding of the research conducted so far on the local and traditional uses, pharmacological activities, mechanism of actions of active compounds, toxicity, and possible interactions with other drugs of the Annona species. Through analysis of these findings, evidences supporting their applications in ethno-medicines are described. We discuss the possible research opportunities and stand out the weak points in our knowledge that deserves further investigation.

MATERIAL AND METHODS

Information on ethno-medicinal uses and pharmacological activities of the Annona genus was collected. The main scientific biomedical literature databases (Cochrane, PubMed, Scopus, Lilacs, SeCiMed, Elsevier, SpringerLink, Google Scholar, SciFinder) were consulted. The search covered all the literature available until September 2017. National and regional databases of Herbal Medicine and Complementary and Alternative Medicine were also revised in order to explore further data. For a better understanding of the therapeutic importance of these species, we have classified the pharmacological activities within each group of disorders. The International Classification of Diseases (ICD), used from WHO Member States, was chosen as the reference classification.

RESULTS

From among the 27 species revised, four species are highlighted for their important pharmacological activities in most of the groups of illnesses: A. muricata, A. squamosa, A. senegalensis, and A. cherimola. Many investigations have been performed with extracts from the leaves, bark, fruit and seeds and have shown a wide range of pharmacological activities, such as antiprotozoal, antitumoural, antidiabetic, hepato-protective, anti-inflammatory and anxiolytic activities. The chemistry on the annonaceous acetogenins (ACGs) has been extensively investigated due to their potent antitumoural activity. Many of the assays were carried out with the isolated acetogenins in different lines of tumour culture cells and were found effective at very low doses even in multidrug-resistant tumours, and hence constitute promising compounds in the treatment of different types of cancers. No studies were found with extracts rich in acetogenins in the clinical field.

CONCLUSIONS

The experimental results from the pharmacological research enable the validation of their traditional uses in several of the groups of diseases in the countries of origin and reveal these plants to be a valuable source for therapeutic molecules. However, more toxicity assays and clinical trials would be necessary to establish optimal and safe doses of consumption on the application of these medicinal plants.

Contents of constituents and antioxidant activity of seed and pulp extracts of Annona coriacea and Annona sylvatica

AbstractThe antioxidant potential of fruit pulp and seeds of extracts of the Annona coriacea, and A. sylvatica(Annonaceae) were investigated, as well contents total phenolics, flavonoids, condensed tannins and ascorbic acid. Was used to determine the antioxidant activity the 1,1-diphenyl-1-picrylhydrazyl free radical (DPPH), β-carotene bleaching and ABTS radical cation method. The total phenol, total flavonoid, condensed tannin, and ascorbic acid contents were measured spectrophotometrically. In this study, the pulp and seeds of the fruits were extracted using methanol/water (8:2) for maceration. The seed extracts of A. coriacea demonstrated a moderate antioxidant effect with free radical scavenging activity of 31.53%, by the DPPH test, 51.59% by the β-carotene bleaching test and 159.50 µM trolx/g of extract in the ABTS assay. We found that the hydromethanolic seed extract of A. coriacea had high total phenol (147.08 ± 4.20 mg of GAE/g of extract) and flavonoid (131.18 ± 2.31 mg of QE/g of extract) content. This indicated that the antioxidant activity of the extracts was related to the contents of these constituents.

In vitro biological screening of the anticholinesterase and antiproliferative activities of medicinal plants belonging to Annonaceae

The aim of this research was to investigate the antiproliferative and anticholinesterase activities of 11 extracts from 5 Annonaceae species in vitro. Antiproliferative activity was assessed using 10 human cancer cell lines. Thin-layer chromatography and a microplate assay were used to screen the extracts for acetylcholinesterase (AchE) inhibitors using Ellman's reagent. The chemical compositions of the active extracts were investigated using high performance liquid chromatography. Eleven extracts obtained from five Annonaceae plant species were active and were particularly effective against the UA251, NCI-470 lung, HT-29, NCI/ADR, and K-562 cell lines with growth inhibition (GI₅₀) values of 0.04-0.06, 0.02-0.50, 0.01-0.12, 0.10-0.27, and 0.02-0.04 µg/mL, respectively. In addition, the Annona crassiflora and A. coriacea seed extracts were the most active among the tested extracts and the most effective against the tumor cell lines, with GI₅₀ values below 8.90 µg/mL. The A. cacans extract displayed the lowest activity. Based on the microplate assay, the percent AchE inhibition of the extracts ranged from 12 to 52%, and the A. coriacea seed extract resulted in the greatest inhibition (52%). Caffeic acid, sinapic acid, and rutin were present at higher concentrations in the A. crassiflora seed samples. The A. coriacea seeds contained ferulic and sinapic acid. Overall, the results indicated that A. crassiflora and A. coriacea extracts have antiproliferative and anticholinesterase properties, which opens up new possibilities for alternative pharmacotherapy drugs.

Antimicrobial and cytotoxic activities of medicinal plants of the Brazilian cerrado, using Brazilian cachaça as extractor liquid

ETHNOPHARMACOLOGICAL IMPORTANCE

Many species of plants in the Brazilian cerrado (savanna) are widely used in ethnomedicine. However, the safety and effectiveness of medicinal plants used in communities with little or no access to manufactured drugs should be evaluated.

AIM OF THE STUDY

Evaluate the antimicrobial and cytotoxic activities of extracts from eight plant species, obtained using Brazilian cachaça as the extractor liquid.

MATERIALS AND METHODS

The extracts were tested against Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans, Candida parapsilosis, promastigote forms of Leishmania amazonensis, and poliovirus. In addition, cytotoxic activity was assayed in Vero cells and in human erythrocytes.

RESULTS

The plant species Curatella americana, Sclerolobium aureum, and Plathymenia reticulata showed the best activity against yeasts, especially the crude extract of C. americana and its ethyl-acetate fraction. Kielmeyera lathrophyton showed a minimum inhibitory concentration of 250 μg/ml against S. aureus, and was inactive against gram-negative bacteria. The extract obtained from Annona coriacea showed the best activity against the promastigote forms of Leishmania amazonensis (IC(50)=175 μg/ml). Only C. americana showed potential for antipoliovirus activity. The concentrations of the crude extracts that showed toxicity to VERO cells had CC(50) between 31 and 470 μg/ml, and the lyophilized Brazilian cachaça showed a CC(50) of 307 μg/ml. None of the extracts showed toxicity against human erythrocytes.

CONCLUSIONS

Among the plant species studied, C. americana proved to be effective against microorganisms, especially as an antifungal. The results will help in the search for alternative drugs to be used in pharmacotherapy, and will contribute to establish safe and effective use of phytomedicines in the treatment of infectious diseases.

Jatropha toxicity--a review

Jatropha is a nonedible oil seed plant belonging to Euphorbiaceae family. Global awareness of sustainable and alternative energy resources has propelled research on Jatropha oil as a feedstock for biodiesel production. During the past two decades, several cultivation projects were undertaken to produce Jatropha oil. In future, the increased cultivation of toxic Jatropha plants and utilization of its agro-industrial by-products may raise the frequency of contact with humans, animals, and other organisms. An attempt was thus made to present known information on toxicity of Jatropha plants. The toxicity of Jatropha plant extracts from fruit, seed, oil, roots, latex, bark, and leaf to a number of species, from microorganisms to higher animals, is well established. Broadly, these extracts possess moluscicidal, piscicidal, insecticidal, rodenticidal, antimicrobial, and cytotoxic properties, and exert adverse effects on animals including rats, poultry, and ruminants. The toxicity attributed to these seeds due to their accidental consumption by children is also well documented. An attempt was also made to identify areas that need further study. The information provided in this review may aid in enhancing awareness in agroindustries involved in the cultivation, harvesting, and utilization of Jatropha plants and its products with respect to the potential toxicity of Jatropha, and consequently in application and enforcement of occupational safety measures. Data on the wide range of bioactivities of Jatropha and its products were collated and it is hoped will create new avenues for exploiting these chemicals by the phamaceutical industry to develop chemotherapeutic agents.

8,15-epoxylabdane and norlabdane diterpenoids from Eragrostis viscosa

Four labdanes with a 8alpha,15-epoxy ring (8alpha,15-epoxylabdan-16beta-oic acid; 8alpha,15-epoxy-16-norlabdan-13-one; 8alpha,15-epoxy-16-norlabdane; and 16-acetoxy-8alpha,15-epoxylabdane) and the known compound ambreinolide were isolated from the hexane extract of the aerial parts of the grass Eragrostis viscosa. The structures of all compounds were established based on spectroscopic data and the X-ray analysis of 8alpha,15-epoxy-16-norlabdan-13-one. The hexane extract presented moderate activity against the snail Biomphalaria glabrata. 8alpha,15-Epoxylabdan-16beta-oic acid showed no mutagenic activity for doses up to 1000 microg/plate and no significant clastogenic activity for doses up to 100 microg/ml.

Antiprotozoal activity of Brazilian plant extracts from isoquinoline alkaloid-producing families

Leishmaniasis and Chagas disease afflict the poorest countries in the world. The Brazilian flora represents a rich source for the screening of potential antiparasitic compounds. In this work, we tested the total alkaloid and ethanol extracts of nine different plants from Brazilian families which produce isoquinoline alkaloids, to determine their in vitro antiparasitic effect against L. chagasi and T. cruzi parasites. Promastigotes of L. chagasi were shown to be susceptible only to the total alkaloid extracts of A. crassiflora (EC50 value = 24.89 microg/ml), A. coriacea (EC50 value = 41.60 microg/ml), C. ovalifolia (EC50 value = 63.88 microg/ml) and G. australis (EC50 value = 37.88 microg/ml). Except for the G. australis total alkaloids, all the three extracts presented a considerable activity when tested against intracellular amastigotes. The most effective alkaloid extracts were those from A. crassiflora and C. ovalifolia, which reduced the number of infected macrophages at 25 microg/ml by 86.1% and 89.8%, respectively. Among the 18 tested extracts, 16 showed anti-Trypanosoma activity. Eight extracts (A. crassiflora, A. coriacea, C. ovalifolia, D. furfuracea, D. lanceolata, S. guianensis, X. emarginata and G. australis) were the most effective against the trypomastigotes, killing approximately 100% of the parasites at the maximal concentration of 100 microg/ml. Cytotoxicity against mammalian cells was evaluated for all extracts, but potential ones showed little or no cytotoxicity and a considerable antiparasitic effect, including D. furfuracea, D. lanceolata, G. australis, S. guianensis and X. emarginata. Plants are a rich source of natural compounds, and a powerful tool for the development of new arsenals for the therapy of protozoan diseases.

Synthesis and evaluation of the molluscicidal activity of the 5,6-dimethyl-dihydro-pyran-2,4-dione and 6-substituted analogous

Five dihydro-piran-2,4-diones, including 5,6-dimethyl-dihydro-piran-2,4-dione one of the intermediates of the synthesis of caloverticilic acid, were synthesized and submitted to molluscicidal bioassay. The compound's yields varied from moderate to good (42%- 80%) and were achieved through the preparation of the dianion of ethyl acetoacetate, reaction with and aldehyde followed by hydrolysis of the ester (NaOH, H(2)O, 2 h, T.A.) and lactonization in acidic medium (HCl, 0 degrees C). The 5,6-dimethyl-dihydro-piran-2,4-dione and three analogous dihydro-piran-2,4-diones 6-substituted,-phenyl, (4-methoxy-phenyl), and -propenyl, showed significant activities against the Biomphalaria glabrata egg masses, while the analogous 6-(3,4-dimethoxy-phenyl) was inactive as molluscicide. This activity is reported for the first time, extending the range of biological activities of this group.

Molluscicidal properties of some species of Annona

In search for plant molluscicides for the vector control of schistosomiasis, ethanolic extracts from different parts of six species of the Annonaceae family were evaluated against adult forms and egg masses of Biomphalaria glabrata. Results from accurate experiments indicate that the majority of analyzed extracts possess properties lethal to Biomphalaria glabrata, some of them with significant LD90 values (< 20 ppm), as showed for Annona crassiflora M: [pulp and seed (LD50 = 13.21), steem (2.34), root bark (3.79)], Annona glabra L. [seed (17.02)], Annona muricata [leaf (8.75)]. Emphasis is held mainly into Annona muricata L. (leaf) and Annona squamosa Veil. (root) for presenting additional toxicity toward snail egg masses.