In vitro evaluation of cytotoxic potential of essential oil extracted from leaves of Croton heliotropiifolius Kunth in human tumor cells.

Croton heliotropiifolius Kunth, popularly known as "velame," is a shrub that resides in northeastern Brazil. The essential oil of C. heliotropiifolius contains high concentrations of volatile compounds in the leaves and is widely used in folk medicine for many purposes as an antiseptic, analgesic, sedative, and anti-inflammatory agent. Due to the apparent limited amount of information, the aim of this study was to determine the cytotoxic potential of essential oil extracted from leaves of C. heliotropiifolius, utilizing different human cancer cell lines (HL-60, leukemia; HCT-116, colon; MDA-MB435, melanoma; SF295, glioblastoma) and comparison to murine fibroblast L929 cell line. The chemical characterization of the essential oil revealed the presence of large amounts of monoterpenes and sesquiterpenes, the majority of which were aristolene (22.43%), germacrene D (11.38%), ɣ-terpinene (10.85%), and limonene (10.21%). The essential oil exerted significant cytotoxicity on all cancer cells, with low activity on murine L929 fibroblasts, independent of disruption of cell membranes evidenced by absence of hemolytic activity. The cytotoxicity identified was associated with oxidative stress, which culminated in mitochondrial respiration dysfunction and direct or indirect DNA damage (strand breaks and oxidative damage), triggering cell death via apoptosis. Our findings suggest that extracts of essential oil of C. Heliotropiifolius may be considered as agents to be used therapeutically in treatment of certain cancers.

Diterpenoids from Leaves of Cultivated Plectranthus ornatus.

Two new diterpenoid derivatives 7α,12ß,17-triacetoxy-6ß,19-dihydroxy-13ß,16-spirocicloabiet-8-ene-11,14-dione ( 1: ) and 6ß-acetoxy-3ß,7α,12α-trihydroxy-13ß,16-spirocicloabiet-8-ene-11,14-dione ( 2: ) along with 11 ( 3: - 13: ) miscellaneous compounds were isolated from the leaves of Plectranthus ornatus Codd. Their structures were elucidated by spectroscopic analysis and gauge independent atomic orbitals 13C NMR calculations. The isolated compounds were screened for their effects on intestinal motility using guinea-pig ileum and duodenum and by their cytotoxicity against 4 human cancer cell lines (HCT-116, SF-295, PC-3, and HL-60). Compounds 6: and 9: were moderately cytotoxic against HL-60, whereas 6: and 13: were more active on SF-295 and HCT-116.

Behavioral effects induced by antitumor cleronade diterpenes from Casearia sylvestris and in silico interactions with neuron receptors.

ETHNOPHARMACOLOGICAL RELEVANCE: Casearia sylvestris is a medicinal plant traditionally used to treat snakebites, wounds, inflammation and gastric ulcers and scientific supports for have demonstrated its antitumor, antihyperlipidemic and antiparasitic properties. AIM OF THE STUDY: To assess the effects of a fraction with casearins (FC) on adult mice using classical experimental models of animal behavior and theoretical calculations to verify the interaction of Casearin X (Cas X) with neuron receptors. MATERIALS AND METHODS: Animals divided in 6 groups (n=9/group) were intraperitoneally treated with vehicle (DMSO 4%), FC (2.5, 5, 10 and 25mg/kg/day) and diazepam (2mg/kg) for 7 days. Thirty minutes after the last dose of treatment, acute toxicity and behavioral experiments were performed. RESULTS: The highest dose of FC (25mg/kg/day) caused diarrhea, weight loss and death of one animal. Elevated plus maze test showed that lower doses [2.5mg/kg/day (36.4±5.1s) and 5mg/kg/day (43.9±6.2s)] increased the time spent in open arms (TSOA). Open field test revealed reduction in the number of crossings (54.9%, 51.1%, 48% and 67.7% for 2.5, 5, 10 and 25mg/kg/day, respectively) in all doses of FC studied and decrease of rearings at 25mg/kg/day (p<0.05). Computational calculations showed that the inhibition constant (Ki) for the Cas X-D1 complex is up to 1000-fold more favourable than the Cas X-GABAA complex. All ∆G° values obtained for Cas X-D1 complexes were more negative than those seen with Cas X-GABAA complexes. CONCLUSIONS: Findings indicate a probable anxiolytic action of the FC since it reduces the number of crossings and rearings and prolonged the time spent in open arms, without sedative and myorelaxant effects, probably due to the interaction of Cas X with dopaminergic system.

Endophytic Actinobacteria from the Brazilian Medicinal Plant Lychnophora ericoides Mart. and the Biological Potential of Their Secondary Metabolites.

Endophytic actinobacteria from the Brazilian medicinal plant Lychnophora ericoides were isolated for the first time, and the biological potential of their secondary metabolites was evaluated. A phylogenic analysis of isolated actinobacteria was accomplished with 16S rRNA gene sequencing, and the predominance of the genus Streptomyces was observed. All strains were cultured on solid rice medium, and ethanol extracts were evaluated with antimicrobial and cytotoxic assays against cancer cell lines. As a result, 92% of the extracts showed a high or moderate activity against at least one pathogenic microbial strain or cancer cell line. Based on the biological and chemical analyses of crude extracts, three endophytic strains were selected for further investigation of their chemical profiles. Sixteen compounds were isolated, and 3-hydroxy-4-methoxybenzamide (9) and 2,3-dihydro-2,2-dimethyl-4(1H)-quinazolinone (15) are reported as natural products for the first time in this study. The biological activity of the pure compounds was also assessed. Compound 15 displayed potent cytotoxic activity against all four tested cancer cell lines. Nocardamine (2) was only moderately active against two cancer cell lines but showed strong activity against Trypanosoma cruzi. Our results show that endophytic actinobacteria from L. ericoides are a promising source of bioactive compounds.

Inhibition of metastatic potential of B16-F10 melanoma cell line in vivo and in vitro by biflorin.

AIM: The aim of this study was to determine the antimetastatic potential of biflorin using in vivo and in vitro approaches. MAIN METHODS: Biflorin was isolated from Capraria biflora collected in Fortaleza, Ceará, Brazil. Adhesion, migration and invasion assays were performed to avail of the antimetastatic potential of this quinone. Experimental metastasis was performed to avail of the antimetastatic potential of bilflorin using in vivo assay. KEY FINDINGS: Treatment with biflorin (25 and 50mg/kg/day) was shown to be effective in reducing B16-F10 melanoma metastasis in C57BL/6 mice. The administration of biflorin at 25mg/kg/day intraperitoneally inhibited the formation of metastases by about 57% compared to untreated control animals. When the animals were treated with 50mg/kg/day intraperitoneally, there was a 71% decrease in the number of lung metastases. Morphological assays showed the presence of hemosiderin and erythrocytes in the lung parenchyma, indicating the occurrence of hemorrhage, probably a side effect of biflorin. Biflorin at non-toxic concentrations (0.5, 1.0 and 1.5g/mL) was tested directly on B16-F10 cells in vitro, and it inhibited cell adhesion to type I collagen and cell motility using the wound-healing assay. SIGNIFICANCE: These data suggest that biflorin has a promising antimetastatic potential, as shown by its anti-adhesion, anti-migration and anti-invasion properties against a metastatic melanoma cell line. However, further studies are essential to elucidate its mechanism of action.

Vasorelaxant and antihypertensive effects of methanolic fraction of the essential oil of Alpinia zerumbet.

Alpinia zerumbet is used in folk medicine in Brazil to treat hypertension. However, several pathways involved in the mechanism of vasorelaxation are still unclear. This study was designed to verify the antihypertensive effect of the methanolic fraction of the essential oil of A. zerumbet (MFEOAz) and to characterize its mechanism of action. The thoracic aortic rings from the Wistar rats were perfused in the organ chambers filled with Kreb's solution, where the tension of each ring was measured. The antihypertensive effect of MFEOAz was assessed in rats submitted to chronic hypertension by inhibition of nitric oxide synthesis by indirect measurement of blood pressure with indirect tail cuff method. MFEOAz relaxed phenylephrine and KCl-induced contraction of either endothelium-intact or endothelium-denuded rat aortic rings in a concentration-dependent manner. Pre-incubation with MFEOAz (100 and 300 µg/mL) in Ca(2+)-free Krebs solution attenuated phenylephrine- or caffeine-induced contraction. Pre-incubation with L-NAME, ODQ, wortmannin, atropine, indomethacin, catalase, SOD, TEA, 4-aminopyridine, glibenclamide, apamin, charybdotoxin, or iberiotoxin did not affect MFEOAz-induced relaxation. The intragastric administration of MFEOAz induced an antihypertensive effect. MFEOAz it seems inhibited the calcium influx via voltage-operated calcium channels and receptor-operated calcium channels, as well as inhibition of calcium mobilization from intracellular stores.

Inhibition of ketamine-induced hyperlocomotion in mice by the essential oil of Alpinia zerumbet: possible involvement of an antioxidant effect.

OBJECTIVES: The antipsychotic, hypnotic, myorelaxant and antioxidant effects of the essential oil of Alpinia zerumbet (EOAZ) were studied. METHODS: EOAZ (50, 100 and 200 mg/kg i.p.) was administered once to mice for the determination of antipsychotic activity (evaluated by ketamine-induced hyperlocomotion), hypnotic activity (induced by sodium pentobarbital, 40 mg/kg i.p.), motor coordination (rotarod test), antioxidant effects (determination of lipid peroxidation and GSH levels), as well as alterations in nitric oxide levels (determination of nitrite content). KEY FINDINGS: EOAZ at doses of 100 and 200 mg/kg prevented ketamine hyperlocomotion, as did haloperidol (0.2 mg/kg i.p). EOAZ at a dose of 200 mg/kg decreased sleep latency, while all doses increased sleeping time. There was no effect on motor coordination. The in-vitro antioxidant capacity of the oil caused a decrease in lipid peroxidation and increase in GSH levels. EOAZ also prevented the decrease in nitrite content caused by oxidative stress. CONCLUSIONS: The results suggest antipsychotic and antioxidant effects for the EOAZ that may have promising efficacy for the treatment of schizophrenia.

Genetic biomonitoring of inhabitants exposed to uranium in the north region of Brazil.

Aiming to assess the susceptibility of populations in the Brazilian Amazon region to ionizing radiation emitted from uranium, mutations frequencies in the DNA repair genes XRCC1 and XRCC3 and in the metabolic gene GSTM1 were evaluated. The XRCC1 allele frequencies for the 194Trp polymorphism in the municipalities of Monte Alegre, Prainha and Alenquer were, respectively, 0.12, 0.13 and 0.07, and for 399Gln polymorphism they were, respectively, 0.28, 0.30 and 0.32. Frequencies for GSTM1 gene deletion homozygotes were, respectively, 0.36, 0.31 and 0.40 for all municipalities. These frequencies are comparable to those described for Brazilian individuals from other regions of the country. Also, allele frequencies of XRCC3 241Met polymorphism of the Monte Alegre and Alenquer populations were 0.28 and 0.33, respectively. In conclusion, frequencies of important polymorphic features of cellular DNA repair and metabolic apparatus in the populations studied do not differ from those of populations in other regions of Brazil.

Cytogenetic biomonitoring of inhabitants of a large uranium mineralization area: the municipalities of Monte Alegre, Prainha, and Alenquer, in the State of Pará, Brazil.

Uranium is a natural radioactive metallic element; its effect on the organism is cumulative, and chronic exposure to this element can induce carcinogenesis. Three cities of the Amazon region-Monte Alegre, Prainha, and Alenquer-in North Brazil, are located in one of the largest uranium mineralization areas of the world. Radon is a radioactive gas, part of uranium decay series and readily diffuses through rock. In Monte Alegre, most of the houses are built of rocks removed from the Earth's crust in the forest, where the uranium reserves lie. The objective of the present work is to determine the presence or absence of genotoxicity and risk of carcinogenesis induced by natural exposure to uranium and radon in the populations of these three cities. The frequency of micronuclei (MN) and chromosomal aberrations (CA) showed no statistically significant differences between the control population and the three study populations (P > 0.05). MN was also analyzed using the fluorescence in situ hybridization (FISH) technique, with a centromere-specific probe. No clastogenic and/or aneugenic effects were found in the populations. Using FISH analysis, other carcinogenesis biomarkers were analyzed, but neither the presence of the IGH/BCL2 translocation nor an amplification of the MYC gene and 22q21 region was detected. Clastogenicity and DNA damage were also not found in the populations analyzed using the alkaline comet assay. The mitotic index showed no cytotoxicity in the analyzed individuals' lymphocytes. Once we do not have data concerning radiation doses from other sources, such as cosmic rays, potassium, thorium, or anthropogenic sources, it is hard to determine if uranium emissions in this geographic region where our study population lives are too low to cause significant DNA damage. Regardless, genetic analyses suggest that the radiation in our study area is not high enough to induce DNA alterations or to interfere with mitotic apparatus formation. It is also possible that damages caused by radiation doses undergo cellular repair.

Evaluation of native and exotic Brazilian plants for anticancer activity.

Native and exotic Brazilian plants collected in the State of Minas Gerais were evaluated for their anticancer potential. Methanol extracts from leaves of 51 plant species were tested for cytotoxicity against four tumor cell lines: B16 (murine skin), HL-60 (human leukemia), MCF-7 (human breast), and HCT-8 (human colon). Plant extracts that exhibited IC(50) values less than 30 microg/ml against any tumor cell line were tested on sea urchin egg development and mouse erythrocytes. In addition, all extracts were evaluated for their general toxicity using the brine shrimp lethality assay. The most active extracts against the tumor cells were those obtained from Lantana fucata, Copaifera langsdorffii, and Momordica charantia. These three extracts inhibited sea urchin development from the first cleavage, but those from C. langsdorffii and M. charantia were very active against mouse erythrocytes. Only the L. fucata extract presented no hemolytic activity. Consequently, although the extracts of L. fucata, M. charantia, and C. langsdorffii could be useful in the development of new anticancer products, the first of these extracts is the most promising since it did not present unspecific toxicity, as suggested by negative results obtained with brine shrimp lethality and mouse erythrocytes assays.

Central nervous system effects of the essential oil of the leaves of Alpinia zerumbet in mice.

OBJECTIVES: Alpinia zerumbet, known in Brazil as colônia, is popularly used as a diuretic, antihypertensive, anti-ulcerogenic and sedative. Based on this, we have investigated the central effects of the essential oil isolated from A. zerumbet leaves. METHODS: Mice were treated once with 50 or 100 mg/kg of the essential oil, intraperitoneally, 30 min before being submitted to behavioural models of: locomotor activity (open-field), catalepsy, anxiety (elevated plus maze), depression (forced swimming test and tail suspension tests) as well as apomorphine-induced stereotypy. KEY FINDINGS: Results showed a dose-related decrease on locomotor activity and apomorphine-induced stereotypy. There was a decrease to the order of 55% of the grooming behaviour with both doses studied. The essential oil 100 mg/kg increased cataleptic activity (167%) and the immobility time in the forced swimming and tail suspension tests. Pretreatment with haloperidol (0.2 mg/kg, i.p.) alone also decreased locomotion, increased cataleptic activity and immobility time in the tail suspension test. No alterations in the elevated plus maze test were registered. CONCLUSIONS: The essential oil of A. zerumbet leaves had depressant and possible antipsychotic activity, since it could reverse the stereotypy induced by apomorphine, presenting effects comparable with those obtained with haloperidol treatment.

Cytotoxic activity of Brazilian Cerrado plants used in traditional medicine against cancer cell lines.

UNLABELLED: The search for new anti-cancer drugs is one of the most prominent research areas of natural products. Numerous active compounds isolated from Brazilian Cerrado plant species have been studied with promising results. AIM OF THE STUDY: To investigate the cytotoxic potential of 412 extracts from Brazilian Cerrado plants used in traditional medicine belonging to 21 families against tumor cell lines in culture. MATERIAL AND METHOD: Maceration of 50 plant species resulted in 412 hexane, dichloromethane, ethanol and hydroalcohol extracts. The cytotoxicity of the extracts was tested against human colon carcinoma (HCT-8), melanoma (MDA-MB-435), and brain (SF-295) tumor cell lines, using the thiazolyl blue test (MTT) assay. Bioassay-guided fractionation was performed for one active extract. RESULTS AND CONCLUSIONS: Twenty-eight of the 412 tested extracts demonstrated a substantial antiproliferative effect, at least 85% inhibition of cell proliferation at 50 microg/mL against one or more cell lines. Those extracts are obtained from different parts of Anacardiaceae, Annonaceae, Apocynaceae, Clusiaceae, Flacourtiaceae, Sapindaceae, Sapotaceae, Simaroubaceae and Zingiberaceae. Complete dose-response curves were generated and IC(50) values were calculated for these active extracts against four cell lines HCT-8, MDA-MB-435, SF-295 and HL-60 (leukemia), and their direct cytotoxic effects were determined. In summary, 14 extracts of 13 species showed toxicity in all tested tumor cell lines, with IC(50) values ranging from 0.1 to 19.1 microg/mL. The strongest cytotoxic activity was found for the hexane extract of Casearia sylvestris var. lingua stem bark, with an IC(50) of 0.1 microg/mL for HCT-8, 0.9 microg/mL for SF-295, 1.2 microg/mL for MDA-MB-435, and 1.3 microg/mL for HL-60, and Simarouba versicolor root bark, with an IC(50) of 0.5 microg/mL for HCT-8, 0.7 microg/mL for SF-295, 1.5 microg/mL for MDA-MB-435, 1.1 microg/mL for HL-60. Bioassay-guided fractionation of the last extract led to the isolation of glaucarubinone, which showed pronounced activity against the four cell lines studied. Further studies of the active extracts are necessary for chemical characterization of the active compounds and more extensive biological evaluations.

Neuroprotective effects of chalcones from Myracrodruon urundeuva on 6-hydroxydopamine-induced cytotoxicity in rat mesencephalic cells.

In the present work, we showed that a chalcone-enriched fraction (CEF) isolated from the stem bark of a Brazilian medicinal plant, Myracrodruon urundeuva, presents neuroprotective actions on 6-hydroxydopamine (6-OHDA)-induced neuronal cell death, in rat mesencephalic cells. In the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium] assay, which is an index of cell viability, CEF (1-100 microg/ml) reversed in a concentration-dependent manner the 6-OHDA-induced cell death. While cells exposed to 6-OHDA (40 microM) showed an increased concentration of thiobarbituric acid reactive substances (TBARS), the pretreatment with CEF (10-100 microg/ml) significantly decreased the 6-OHDA-induced TBARS formation, indicative of a neuroprotection against lipoperoxidation. Furthermore, the drastic increase of nitrite levels induced by 6-OHDA, indicative of nitric oxide formation and free radicals production, was prevented by CEF. Double staining with acridine orange/ethidium bromide showed that cultures exposed to 6-OHDA (40 and 200 microM) presented an increase of apoptotic and necrotic cell numbers in a concentration-dependent manner. CEF (100 microg/ml) protected cells from apoptosis and necrosis and increased number of cells presenting a normal morphology. The immunohistochemical analysis for tyrosine hydroxylase (TH) positive neurons indicated that 6-OHDA (40 and 200 microM) caused a concentration-dependent loss of TH+ and TH- neurons. CEF protected both cells types from 6-OHDA-induced cell death. All together, our results demonstrated neuroprotective effects of chalcones, which are able to reduce oxidative stress and apoptotic injury caused by 6-OHDA. Our findings suggest that chalcones could provide benefits, along with other therapies, in neurodegenerative injuries, such as Parkinson's disease.

In vivo growth-inhibition of Sarcoma 180 by an alpha-(1-->4)-glucan-beta-(1-->6)-glucan-protein complex polysaccharide obtained from Agaricus blazei Murill.

Agaricus blazei Murrill, a native mushroom of Brazil, has been widely consumed in different parts of the world due to its anticancer potential. This effect is generally attributed to its polysaccharides; however, the precise structure of these has not been fully characterized. To better understand the relationship between polysaccharide structures and antitumor activity, we investigated the effect of the intraperitoneally (i.p.) or orally (p.o.) administered alpha-(1-->4)-glucan-beta-(1-->6)-glucan-protein complex polysaccharide from A. blazei alone or in association with 5-fluorouracil (5-FU) in tumor growth using Sarcoma 180 transplanted mice. Hematological, biochemical, and histopathological analyses were performed in order to evaluate the toxicological aspects of the polysaccharide treatment. The polysaccharide had no direct cytotoxic action on tumor cells in vitro. However, the polysaccharide showed strong in vivo antitumor effect. Thus, the tumor growth-inhibitory effect of the polysaccharide is apparently due to host-mediated mechanisms. The histopathological analysis suggests that the liver and the kidney were not affected by polysaccharide treatment. Neither enzymatic activity of transaminases (AST and ALT) nor urea levels were significantly altered. In hematological analysis, leucopeny was observed after 5-FU treatment, but this effect was prevented when the treatment was associated with the polysaccharide. In conclusion, this polysaccharide probably could explain the ethnopharmacological use of this mushroom in the treatment of cancer.

New antimalarial and cytotoxic 4-nerolidylcatechol derivatives.

4-Nerolidylcatechol (1) was isolated from cultivated Pothomorphe peltata root on a multigram scale using straight-forward solvent extraction-column chromatography. New semi-synthetic derivatives of 1 were prepared and tested in vitro against multidrug-resistant Plasmodium falciparum K1 strain. Mono-O-methyl, mono-O-benzyl, O,O-dibenzyl and O,O-dibenzoyl derivatives 2-8 exhibited IC(50) in the 0.67-22.52 microM range. Mono-O-methyl ethers 6 and 7 inhibited the in vitro growth of human tumor cell lines HCT-8 (colon carcinoma), SF-295 (central nervous system), LH-60 (human myeloblastic leukemia) and MDA/MB-435 (melanoma). In general, derivatives 2-8 are more stable to light, air and pH at ambient temperatures than their labile, natural precursor 1. These derivatives provide leads for the development of a novel class of antimalarial drugs with enhanced chemical and pharmacological properties.

Antitumor activity of pisosterol in mice bearing with S180 tumor.

It has been reported that pisosterol was active against cancer cells but lacked activity on the development of sea urchin eggs. Recently, it was reported that pisosterol induces differentiation in leukemia cell line. The present study evaluated the in vivo antitumor activity of pisosterol a triterpene isolated from Pisolithus tinctorius. Histopathological and morphological analyses of the tumor and the organs, including liver, spleen and kidney, were performed in order to evaluate toxicological aspects associated with pisosterol treatments. Antitumor activity of pisosterol (50 or 100 mg/m2) was confirmed in mice bearing Sarcoma 180 tumor cells. The tumor growth inhibition ratios were 43.0% and 38.7% for mice treated with pisosterol at 50 and 100 mg/m2, respectively. Histopathological analysis of liver, kidney and spleen was also evaluated. Liver and kidney were the major affected organs by pisosterol, although the observed alterations can be considered reversible.

Antiproliferative activity of pristimerin isolated from Maytenus ilicifolia (Celastraceae) in human HL-60 cells.

Pristimerin has been shown to be cytotoxic to several cancer cell lines. In the present work, the cytotoxicity of pristimerin was evaluated in human tumor cell lines and in human peripheral blood mononuclear cells (PBMC). This work also examined the effects of pristimerin (0.4; 0.8 and 1.7 microM) in HL-60 cells, after 6, 12 and 24h of exposure. Pristimerin reduced the number of viable cells and increased number of non-viable cells in a concentration-dependent manner by tripan blue test showing morphological changes consistent with apoptosis. Nevertheless, pristimerin was not selective to cancer cells, since it inhibited PBMC proliferation with an IC50 of 0.88 microM. DNA synthesis inhibition assessed by 5-bromo-2'-deoxyuridine (BrdU) incorporation in HL-60 cells was 70% and 83% for the concentrations of 0.4 and 0.8 microM, respectively. Pristimerin (10 and 20 microM) was not able to inhibit topoisomerase I. In AO/EB (acridine orange/ethidium bromide) staining, all tested concentrations reduced the number of HL-60 viable cells, with the occurrence of necrosis and apoptosis in a concentration-dependent manner, results in agreement with trypan blue exclusion findings. The analysis of membrane integrity and internucleosomal DNA fragmentation by flow cytometry in the presence of pristimerin indicated that treated cells underwent apoptosis. The present data point to the importance of pristimerin as representative of an emerging class of potential anticancer chemicals, exhibiting an antiproliferative effect by inhibiting DNA synthesis and triggering apoptosis.

Studies on the cytotoxicity of miscellaneous compounds from Eupatorium betonicaeforme (D.C.) Baker (Asteraceae).

A detailed study on the cytotoxic effects of five known constituents isolated from the flowers and roots of Eupatorium betonicaeforme is reported, including 2,2-dimethyl-6-vinylchroman-4-one (1), 2-senecioyl-4-vinylphenol (2), 6-acetyl-2,2-dimethylchroman-4-one (3), (4E)-8beta-angeloyloxy-9beta,10beta-dihydroxy-1-oxogermacra-4,11(13)-dien-12,6alpha-olide (4), and 3beta-hydroxyicosan-1,5beta-olide (5). The sesquiterpene lactone 4 exhibited the highest cytotoxicity, with IC50 values ranging from 3.9 to 9.9 microM, showing some degree of cell selectivity. The antiproliferative activity of 4 was examined towards HL-60 cells, and found to diminish cell viability in a dose-dependent manner. Moreover, at all concentrations tested, there was a decrease in the number of cells capable of incorporating 5-bromo-2'-deoxyuridine (BrdU), indicating disruption of DNA synthesis. The morphological changes induced by 4 were compatible with apoptotic cell death. This work, thus, corroborates the anticancer potential of Eupatorium secondary metabolites.

Bioassay-guided fractionation of pterocarpans from roots of Harpalyce brasiliana Benth.

Pterocarpans, a special kind of isoflavonoids possessing two contiguous benzofuran and benzopyran rings, have been reported as possessing several biological activities. In order to isolate and identify the active principles possibly responsible for the stronger activity of the EtOH extract from roots of Harpalyce brasiliana on the antimitotic assay using sea urchin egg development, a bioassay-guided fractionation was performed. Six bioactive pterocarpan derivatives: 4'-dehydroxycabenegrin A-I, leiocarpin, medicarpin, cabenegrins A-I and A-II, and maackiain were isolated from the chloroform fraction of H. brasiliana extract. Leiocarpin was the most active on the sea urchin egg assay with IC(50) values ranging from 0.1 to 1.2 microg/mL, followed by 4'-dehydroxycabenegrin A-I. The isolated compounds were also tested for cytotoxicity against tumor cell lines in cultures, where 4'-dehydroxycabenegrin A-I was the most active, followed by leiocarpin. Additionally, some studies on the structure-activity relationship of these pterocarpans are suggested.

In-vitro and in-vivo antitumour activity of physalins B and D from Physalis angulata.

We have evaluated the in-vitro and in-vivo antitumour activity of physalin B and physalin D isolated from the aerial parts of Physalis angulata. In-vitro, both compounds displayed considerable cytotoxicity against several cancer cell lines, showing IC50 values in the range of 0.58 to 15.18 microg mL(-1) for physalin B, and 0.28 to 2.43 microg mL(-1) for physalin D. The antitumour activity of both compounds was confirmed in-vivo using mice bearing sarcoma 180 tumour cells. The in-vivo antitumour activity was related to the inhibition of tumour proliferation, as observed by the reduction of Ki67 staining in tumours of treated animals. Histopathological examination of the kidney and liver showed that both organs were affected by physalin treatment, but in a reversible manner. These compounds were probably responsible for the previously described antitumour activity of ethanol extracts of P. angulata, and their identification and characterization presented here could explain the ethnopharmacological use of this species in the treatment of cancer.