Nanoparticles of cisplatin augment drug accumulations and inhibit multidrug resistance transporters in human glioblastoma cells.

BACKGROUND: Cisplatin (CSP) is a potent anticancer drug widely used in treating glioblastoma multiforme (GBM). However, CSP's clinical efficacy in GBM contrasted with low therapeutic ratio, toxicity, and multidrug resistance (MDR). Therefore, we have developed a system for the active targeting of cisplatin in GBM via cisplatin loaded polymeric nanoplatforms (CSP-NPs). METHODS: CSP-NPs were prepared by modified double emulsion and nanoprecipitation techniques. The physiochemical characterizations of CSP-NPs were performed using zeta sizer, scanning electron microscopy (SEM), drug release kinetics, and drug content analysis. Cytotoxicity, induction of apoptosis, and cell cycle-specific activity of CSP-NPs in human GBM cell lines were evaluated by MTT assay, fluorescent microscopy, and flow cytometry. Intracellular drug uptake was gauged by fluorescent imaging and flow cytometry. The potential of CSP-NPs to inhibit MDR transporters were assessed by flow cytometry-based drug efflux assays. RESULTS: CSP-NPs have smooth surface properties with discrete particle size with required zeta potential, polydispersity index, drug entrapment efficiency, and drug content. CSP-NPs has demonstrated an 'initial burst effect' followed by sustained drug release properties. CSP-NPs imparted dose and time-dependent cytotoxicity and triggered apoptosis in human GBM cells. Interestingly, CSP-NPs significantly increased uptake, internalization, and accumulations of anticancer drugs. Moreover, CSP-NPs significantly reversed the MDR transporters (ABCB1 and ABCG2) in human GBM cells. CONCLUSION: The nanoparticulate system of cisplatin seems to has a promising potential for active targeting of cisplatin as an effective and specific therapeutic for human GBM, thus eliminating current chemotherapy's limitations.

Protamine-carboxymethyl cellulose magnetic nanocapsules for enhanced delivery of anticancer drugs against drug resistant cancers.

Multidrug resistance is a major therapeutic challenge faced in the conventional chemotherapy. Nanocarriers are beneficial in the transport of chemotherapeutics by their ability to bypass the P-gp efflux in cancers. Most of the P-gp inhibitors under phase II clinical trial are facing failures and hence there is a need to develop a suitable carrier to address P-gp efflux in cancer therapy. Herein, we prepared novel protamine and carboxymethyl cellulose polyelectrolyte multi-layered nanocapsules modified with Fe3O4 nanoparticles for the delivery of doxorubicin against highly drug resistant HeLa cells. The experimental results revealed that improved cellular uptake, enhanced drug intensity profile with greater percentage of apoptotic cells was attained when doxorubicin loaded magnetic nanocapsules were used in the presence of external magnetic field. Hence, we conclude that this magnetic field assisted nanocapsule system can be used for delivery of chemotherapeutics for potential therapeutic efficacy at minimal dose in multidrug resistant cancers. FROM THE CLINICAL EDITOR: Many cancer drugs fail when cancer cells become drug resistant. Indeed, multidrug resistance (MDR) is a major therapeutic challenge. One way that tumor cells attain MDR is by over expression of molecular pumps comprising of P-glycoprotein (P-gp) and multidrug resistant proteins (MRP), which can expel chemotherapeutic drugs out of the cells. In this study, the authors prepared novel protamine and carboxymethyl cellulose polyelectrolyte multi-layered nanocapsules modified with Fe3O4 nanoparticles for the delivery of doxorubicin. The results show that there was better drug delivery and efficacy even against MDR tumor cells.

Development and evaluation of sunscreen cream containing solid lipid nanoparticles of Spinacia oleraceae.

More research is needed to understand the benefits of environmentally safe and human-friendly herbal-based sunscreen agents against ultraviolet (UV) radiation. Because of the toxicity of synthetic chemicals in photoprotective agents, researchers were increasingly focusing on herbal photoprotective formulations. The photoprotective agent's skin retention can be considerably improved by forming solid lipid nanoparticles (SLN). The study's objective is to evaluate the photoprotective potential of sunscreen cream containing spinach (Spinacia oleracea)-loaded SLN. A solvent emulsification technique was used to develop the spinach-loaded SLN. The various characterization techniques of the developed SLN were performed. Out of all the formulations, the optimized one was fitted into cream and estimated for its photoprotective action. The images obtained from scanning electron microscopy (SEM) revealed the morphological characteristics of the prepared SLN. The sunscreen cream's viscosity, spreadability, extrudability, and release rate were within acceptable limits. The formulation's in vitro and in vivo sun protection factor (SPF) was reported to be 15.9 and 14.75, respectively. The results indicated that the prepared formulation possesses good photoprotective action. The accelerated stability tests were carried out with no noticeable changes in the parameters. Our work demonstrated the possibility of using spinach-loaded SLN as a photoprotective agent in cosmetic formulations.

Ameliorative effect of ethoxylated chalcone-based MAO-B inhibitor on behavioural predictors of haloperidol-induced Parkinsonism in mice: evidence of its antioxidative role against Parkinson's diseases.

Parkinson's disease is a progressive neurodegenerative disorder that affects mostly elderly people above the age of 60. Previously, we have reported that the ethoxylated chalcone derivative (E)-1-(4-ethoxyphenyl)-3-(fluorophenyl)prop-2-en-1-one (E7) showed potent, reversible, and competitive MAO-B inhibition with an IC50 value of 0.053 µm. The present study aims to investigate the anti-Parkinson activity of compound E7 in a haloperidol-induced animal model of mice. The disease was induced with haloperidol (1 mg/kg, intraperitoneal route) once daily for 21 days. E7 was given at dose levels of 10, 20, and 30 mg/kg/day for 21 days, consecutively. Behavioural tests were carried out during and at the end of the study. Biochemical analyses such as oxidative stress biomarkers and neurotransmitters were quantified on the brain homogenate at the end of the study. Behavioural results showed that there is a marked improvement in locomotor activity and motor coordination in the treatment group. Oxidative stress biomarkers such as SOD, CAT, and GSH levels were increased dose-dependently with a maximum at 30 mg/kg, whereas the dose-dependent decrease (30 mg/kg) in the MDA and nitrite levels were observed in the treatment groups. Levels of neurotransmitters, such as dopamine, serotonin, and noradrenaline, were increased in the treatment groups while dopamine and noradrenaline levels were more than in the standard treated group. MAO-B level was also decreased dose dependently in the treatment group in comparison with the control group. Based on the findings, it was concluded that the E7 compound exhibited anti-Parkinson activity which was more evident at 30 mg/kg oral dose as evaluated by the haloperidol-induced animal model of mice.

Trimethoxy Crown Chalcones as Multifunctional Class of Monoamine Oxidase Enzyme Inhibitors.

BACKGROUND: Chalcones with methoxy substituent are considered as a promising framework for the inhibition of monoamine oxidase (MAO) enzymes. METHODS: A series of nine trimethoxy substituted chalcones (TMa-TMi) was synthesized and evaluated as a multifunctional class of MAO inhibitors. All the synthesized compounds were investigated for their in vitro MAO inhibition, kinetics, reversibility, blood-brain barrier (BBB) permeation, and cytotoxicity and antioxidant potentials. RESULTS: In the present study, compound (2E)-3-(4-nitrophenyl)-1-(3,4,5-trimethoxyphenyl)prop- 2-en-1-one (TMf) was provided with a MAO-A inhibition constant value equal to 3.47±0.09 µM with a selectivity of 0.008, thus comparable to that of moclobemide, a well known potent hMAOA inhibitor (SI=0.010). Compound (2E)-3-(4-bromophenyl)-1-(3,4,5-trimethoxyphenyl)prop-2- en-1-one (TMh) show good MAO-B inhibition with inhibition constant of 0.46±0.009 µM. The PAMPA assay demonstrated that all the synthesized derivatives can cross the BBB successfully. The cytotoxicity studies revealed that TMf and TMh have 88.22 and 80.18 % cell viability at 25 µM. Compound TMf appeared as the most promising antioxidant molecule with IC50 values, relative to DPPH and H2O2 radical activities equal to 6.02±0.17 and 7.25±0.07 µM. To shed light on the molecular interactions of TMf and TMh towards MAO-A and MAO-B, molecular docking simulations and MM/GBSA calculations have been carried out. CONCLUSION: The lead molecules TMf and TMh with multi-functional nature can be further employed for the treatment of various neurodegenerative disorders and depressive states.

The Dichloromethane Fraction of Vernonia cinerea Impart Pro-Apoptotic, Genotoxic, Cell Cycle Arrest, and Drug Efflux Inhibitory Effects on Human Adenocarcinoma Cells.

BACKGROUND: Vernonia cinerea (VC) is an important medicinal plant used in the indigenous system of therapy. In ethnomedicine, VC has demonstrated anticancer properties. However, the mechanisms of action VC is not known. OBJECTIVE: To establish the anticancer mechanisms of 'bioactive fractions of VC' on human adenocarcinoma cells. METHODS: The IC50 values of characterized VC extract and fractions in human adenocarcinoma and normal epithelial cells were determined using Sulforhodamine B (SRB) assay. Acridine Orange- Ethidium Bromide (AO-EB) assay/Hoechst 33342 assay, Comet assay, and Cell cycle analysis were used to determine apoptosis, genotoxicity, and cell cycle-specific changes in cancer cells, respectively. Rhodamine 123 (Rho-123) efflux assay and Mitoxantrone (MX) efflux assay were used to assess the inhibition of Multidrug Resistance (MDR) transporters. RESULTS: The dichloromethane fraction of VC (VC-DM) imparted dose-dependent cytotoxicity in human adenocarcinoma cells with fewer effects in human normal epithelial cells. This 'sesquiterpenoids' enriched fraction (VC-DM) induced apoptosis, DNA damage, genotoxicity, and G2/M phase arrest in human adenocarcinoma cells. Interestingly, VC-DM significantly inhibited the functional activity of MDR transporters (ABCB1 and ABCG2) and caused 'synergistic cytotoxic effects' with anticancer drugs in human adenocarcinoma cells. CONCLUSION: The bioactivity guided fractionation of VC revealed that the specific 'sesquiterpenoids enriched fraction' (VC-DM) imparted cytotoxicity in human adenocarcinoma cells with fewer effects on normal cells. Mechanistic studies have shown that VC-DM induced apoptosis, DNA damage, genotoxicity, cell cycle arrest (G2/M), inhibited the functional activity of MDR transporters (ABCB1 and ABCG2), and produced 'synergistic cytotoxic effects' (combinatorial treatments with anticancer drugs) in human adenocarcinoma cells. Taken together, the findings of this study emphasize and validates VC-DM as a promising 'anticancer agent' against human adenocarcinomas, including those with a multi-drug resistant phenotype.

A New Potent and Selective Monoamine Oxidase-B Inhibitor with Extended Conjugation in a Chalcone Framework: 1-[4-(Morpholin-4-yl)phenyl]-5-phenylpenta-2,4-dien-1-one.

The general blueprint for the design of monoamine oxidase-B (MAO-B) inhibitors has been based on two phenyl or heteronuclei linked via a spacer of appropriate length. In this study, 1-[4-(morpholin-4-yl)phenyl]-5-phenylpenta-2,4-dien-1-one (MO10) was prepared by the condensation of 4'-morpholinoacetophenone and cinnamaldehyde in basic alcoholic medium. MO10 was assessed for inhibitory activity against two human MAO isoforms, MAO-A and MAO-B. Interestingly, MO10 showed a remarkable inhibition against MAO-B with an IC50 value of 0.044 µM along with a selectivity index of 366.13. The IC50 value was better than that of lazabemide (IC50 value of 0.063 µM), which was used as a reference. Kinetics studies revealed that MO10 acted as a competitive inhibitor of MAO-B, with a Ki value of 0.0080 µM. The observation of recovery of MAO-B inhibition, compared to reference levels showed MO10 to be a reversible inhibitor. MTT assays showed that MO10 was nontoxic to normal VERO cells with an IC50 value of 195.44 µg/mL. SwissADME predicted that MO10 provided advantageous pharmacokinetics profiles for developing agents acting on the central nervous system, that is, high passive human gastrointestinal absorption and blood-brain barrier permeability. Molecular docking simulations showed that MO10 properly entered the aromatic cage formed by Y435, Y398, and FAD of the active site of MAO-B. On the basis of these results, MO10 can be considered a promising starting compound in development of agents for the treatment of various neurodegenerative disorders.

Assessment of the in vitro cytotoxicity and in vivo anti-tumor activity of the alcoholic stem bark extract/fractions of Mimusops elengi Linn.

Various parts of Mimusops elengi Linn. (Sapotaceae) have been used widely in traditional Indian medicine for the treatment of pain, inflammation and wounds. The study was conducted to explore the use of stem bark of M. elengi on pharmacological grounds and to evaluate the scientific basis of cytotoxic and anti-tumor activity. Extract/fractions were prepared and in vitro cytotoxicity was assessed using SRB assay. Most effective fractions were subjected to fluorescence microscopy based acridine orange/ethidium bromide (AO/EB) and Hoechst 33342 staining to determine apoptosis induction and DNA fragmentation assay. Comet and micronuclei assay were performed to assess genotoxicity. Cell cycle analysis was also performed. In vivo anti-tumor potential was evaluated by Ehrlich ascites carcinoma (EAC) model in mice. The alcoholic stem bark extract of M. elengi along with four fractions showed potential in vitro cytotoxicity in SRB assay. Of these, dichloromethane and ethyl acetate fractions were selected for further studies. The fractions revealed apoptosis inducing potential in AO/EB and Hoechst 33342 staining, which was further confirmed by DNA fragmentation assay. Genotoxic potential was revealed by comet and micronuclei assay. Fractions also exhibited specific cell cycle inhibition in G0/G1 phase. In EAC model, ethyl acetate fraction along with the standard (cisplatin) effectively reduced the increase in body weight compared to control and improved mean survival time. Both fractions were able to restore the altered hematological and biochemical parameters. Hence, M. elengi stem bark may be a possible therapeutic candidate having cytotoxic and anti-tumor potential.

The enriched fraction of Elephantopus scaber Triggers apoptosis and inhibits multi-drug resistance transporters in human epithelial cancer cells.

BACKGROUND: Medicinal plants have played an important role in the development of clinically useful anticancer agents. Elephantopus scaber (Asteraceae) (ES) is widely used in Indian traditional system of medicine for the treatment of various ailments including cancer. OBJECTIVE: To investigate anticancer effects of ES in human epithelial cancer cells. MATERIALS AND METHODS: Cytotoxicity of ethanolic extract of ES (ES-ET) and its fractions, such as ES Petroleum ether fraction (ES-PET), ES Dichloromethane fraction (ES DCM), n Butyl alcohol fraction (ES-BT), and ES-Rest (ES-R) were assessed in human epithelial cancer cell lines using sulforhodamine B (SRB) assay. Acridine orange/ethidium bromide assay and Hoechst 33342 assays were used to gauge induction of apoptosis. Cell cycle analysis and micronuclei assay were used to assess cell cycle specific pharmacological effects and drug induced genotoxicty. Further, the ability of ES to inhibit multi drug resistant (MDR) transporters (ABC-B1 and ABC-G2) was determined by Rhodamine (Rho) and Mitoxantrone (MXR) efflux assays. RESULTS: The enriched fraction of ES (ES DCM) possessed dose-dependent potent cytotoxicity in human epithelial cancer cells. Further, treatment of cancer cells (HeLa, A549, MCF-7, and Caco-2) with ES DCM showed hall mark properties of apoptosis (membrane blebbing, nuclear condensation etc.). Similarly, ES DCM caused enhanced sub G0 content and micronuclei formation indicating the induction of apoptosis and drug induced genotoxicity in cancer cells, respectively. Interestingly, ES DCM inhibited MDR transporters (ABC B1 and ABC G2) in cancer cells. CONCLUSION: The enriched fraction of ES imparted cytotoxic effects, triggered apoptosis, induced genotoxicity, and inhibited MDR transporters in human epithelial cancer cells. Thus, ES appears to be potential anticancer agent.

Effects of Withania somnifera and Tinospora cordifolia extracts on the side population phenotype of human epithelial cancer cells: toward targeting multidrug resistance in cancer.

Recent reports suggest the existence of a subpopulation of stem-like cancer cells, termed as cancer stem cells (CSCs), which bear functional and phenotypic resemblance with the adult, tissue-resident stem cells. Side population (SP) assay based on differential efflux of Hoechst 33342 has been effectively used for the isolation of CSCs. The drug resistance properties of SP cells are typically due to the increased expression of ABC transporters leading to drug efflux. Conventionally used chemotherapeutic drugs may often leads to an enrichment of SP, revealing their inability to target the drug-resistant SP and CSCs. Thus, identification of agents that can reduce the SP phenotype is currently in vogue in cancer therapeutics. Withania somnifera (WS) and Tinospora cordifolia (TC) have been used in Ayurveda for treating various diseases, including cancer. In the current study, we have investigated the effects of ethanolic (ET) extracts of WS and TC on the cancer SP phenotype. Interestingly, we found significant decrease in SP on treatment with TC-ET, but not with WS-ET. The SP-inhibitory TC-ET was further fractionated into petroleum ether (TC-PET), dichloromethane (TC-DCM), and n-butyl alcohol (TC-nBT) fractions using bioactivity-guided fractionation. Our data revealed that TC-PET and TC-DCM, but not TC-nBT, significantly inhibited SP in a dose-dependent manner. Furthermore, flow cytometry-based functional assays revealed that TC-PET and TC-DCM significantly inhibited ABC-B1 and ABC-G2 transporters and sensitized cancer cells toward chemotherapeutic drug-mediated cytotoxicity. Thus, the TC-PET and TC-DCM may harbor phytochemicals with the potential to reverse the drug-resistant phenotype, thus improving the efficacy of cancer chemotherapy.

Nanomedicine of anastrozole for breast cancer: Physicochemical evaluation, in vitro cytotoxicity on BT-549 and MCF-7 cell lines and preclinical study on rat model.

AIM: Formulation and evaluation of anastrozole, an anti-cancer drug loaded in different biodegradable polymeric nanoparticles. MATERIALS AND METHODS: Different carrier systems such as poly(lactide-co-glycolide) (PLGA 50:50), poly(lactic-acid) (PLA) and poly(ε-caprolactone) (PCL) are used to prepare nanoparticles by simple emulsion technique. The surfactants polyvinyl alcohol and sodium deoxycholate were studied for their use as stabilizing agents at varying concentrations. The formulations were studied for their particle size, zeta potential, entrapment efficiency and solid state characteristics, and also were tested for their in vitro cytotoxicity and in vivo behavior in rats. KEY FINDINGS: The entrapment ranged from 35 to 85%, depending on the drug-polymer ratio used. Particle size ranged from 100 to 350nm with optimal zeta potential. Accordingly, discrete spherical nanoparticles with smooth surface were obtained as evidence from Field Emission Scanning Electron Microscopy (FESEM) study. The solid state characteristics revealed dispersion of drug at the molecular level in the polymeric matrix of nanoparticles. A non-Fickian transport with initial burst release followed by slow release was observed with nanoparticles. The remarkable decrease in cell viability at various time points was observed for PLGA nanoparticles compared to other polymer matrices. The AUC(0→∞) of PLGA, PLA and PCL nanoparticles were found to be 4.77, 19.31 and 19.81 fold higher than (p<0.05) anastrozole in solution, respectively. Also, pharmacokinetics study revealed the long time circulation of anastrozole loaded polymeric nanoparticles. SIGNIFICANCE: The results suggest that developed nanoparticles could be used successfully for effective management of breast cancer chemotherapy.

The enriched fraction of Vernonia cinerea L. induces apoptosis and inhibits multi-drug resistance transporters in human epithelial cancer cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Vernonia cinerea Less. (VC) of the family Asteraceaes is considered as the sacred plant; 'Dasapushpam' which is ethnopharmacologically significant to the people of Kerala in India. In fact, VC has been used in the traditional system of medicine (Ayurveda) for the treatment of various ailments including cancer. MATERIALS AND METHODS: Cytotoxicity of the ethanolic extract of VC (VC-ET), petroleum ether fraction (VC-PET), dichloromethane fraction (VC-DCM), n-butyl alcohol fraction (VC-BT), and rest fraction (VC-R) was evaluated in cervical carcinoma (HeLa), lung adenocarcinoma (A549), breast cancer (MCF-7), and colon carcinoma (Caco-2) cells using Sulforhodamine B (SRB) assay. The apoptotic effects of VC-DCM were assessed in cancer cells using Annexin V assay. The effects of VC-DCM on multi-drug resistance (MDR) transporters in HeLa, A549, MCF-7, and Caco-2 cells were evaluated using flow cytometry based functional assays. Similarly, drug uptake in cancer cells and sensitization of cancer cells towards chemotherapeutic drugs in the presence of VC-DCM were studied using Daunorubicin (DNR) accumulation assay and SRB assay, respectively. RESULTS: Cytotoxicity assay revealed that the enriched fraction of VC (VC-DCM) possessed dose-dependent cytotoxic effects in human epithelial cancer cells (HeLa, A549, MCF-7, and Caco-2). Further, treatment of cancer cells (HeLa, A549, MCF-7, and Caco-2) with VC-DCM led to a significant increase in both early and late apoptosis, indicating the induction of apoptosis. Interestingly, VC-DCM significantly inhibited functional activity of MDR transporters (ABC-B1 and ABC-G2), enhanced DNR-uptake in cancer cells, and sensitized cancer cells towards chemotherapeutic drug-mediated cytotoxicity, thus indicating the ability of VC-DCM to reverse MDR in cancer and enhance the cytotoxic effects of anticancer drugs. CONCLUSIONS: A methodological investigation on the anti-cancer properties of Vernonia cinerea Less. (VC) revealed that an enriched fraction of VC (VC-DCM) possessed cytotoxic effects, triggered apoptosis, inhibited MDR transporters, enhanced drug uptake, and sensitized cancer cells towards anticancer drug-mediated cytotoxicity in human epithelial cancer cells. Thus, VC appears to be promising for an effective treatment of various drug-resistant human epithelial cancers.

Synthesis, in vitro anticancer and antioxidant activity of thiadiazole substituted thiazolidin-4-ones.

A series of novel 5-alkyl/aryl thiadiazole substituted thiazolidin-4-ones were synthesized by a two-step process. In the first step, 5-alkyl/aryl substituted 2-aminothiadiazoles were synthesized, which on reaction with substituted aromatic aldehydes and thioglycolic acid in the presence of dicyclohexylcarbodiimide afforded thiazolidin- 4-ones. All the compounds were synthesized in fairly good yields and their structures were confirmed by spectral and physical data. The title compounds were screened for in vitro anti-proliferative activity on human breast adenocarcinoma cells (MCF-7) by MTT assay. Most of the derivatives showed an IC50 less than 150 µmol L⁻¹. Among the compounds tested, 2-(2-nitrophenyl)- 3-(5-methyl-1,3,4-thiadiazol-2-yl)-thiazolidin-4-one (3f), 2-(3-fluorophenyl)-3-(5-methyl-1,3,4-thiadiazol-2- -yl)-thiazolidin-4-one (3b), and 2-(4-chlorophenyl)-3- -(5-methyl-1,3,4-thiadiazol-2-yl)-thiazolidin-4-one (3c) were found to be the most active derivatives with IC50 values of 46.34, 66.84, and 60.71 µmol L⁻¹, respectively. Antioxidant studies of all the synthesized compounds were carried out by diphenylpicrylhydrazyl (DPPH) assay. Among the compounds tested, 2-phenyl-3-(5-styryl- -1,3,4-thiadiazol-2-yl)-thiazolidin-4-one (3s) elicited superior antioxidant activity with IC50 of 161.93 µmol L⁻¹.

In vitro anticancer activity of microbial isolates from diverse habitats / In vitro atividade anticancerígena de isolados microbianos de diversos habitats

Extracts from natural products, especially microorganisms, have served as a valuable source of diverse molecules in many drug discovery efforts and led to the discovery of several important drugs. Identification of microbial strains having promising biological activities and purifying the bio-molecules responsible for the activities, have led to the discovery of many bioactive molecules. Extracellular, as well as intracellular, extracts of the metabolites of thirty-six bacterial and twenty-four fungal isolates, grown under unusual conditions such as high temperature, high salt and low sugar concentrations, were in vitro tested for their cytotoxic potential on various cancer cell lines. The extracts were screened on HeLa and MCF-7 cell lines to study the cytotoxic potential. Nuclear staining and flow cytometric studies were carried out to assess the potential of the extracts in arresting the cell cycle. The crude ethylacetate extract of isolate F-21 showed promising results by MTT assay with IC50 as low as 20.37±0.36 µg/mL on HeLa, and 44.75±0.81 µg/mL on MCF-7 cells, comparable with Cisplatin. The isolate F-21 was identified as Aspergillus sp. Promising results were also obtained with B-2C and B-4E strains. Morphological studies, biochemical tests and preliminary chemical investigation of the extracts were also carried out.

Extratos de produtos naturais, especialmente de microrganismos, constituíram-se em fonte valiosa de diversas moléculas em muitas descobertas de fármacos e levaram à descoberta de fármacos importantes. A identificação de espécies microbianas que apresentam atividade biológica e a purificação de biomoléculas responsáveis pelas atividades levou à descoberta de muitas moléculas bioativas. Extratos extracelulares tanto quanto intracelulares de metabólitos de 36 isolados de bactérias e 24 isolados de fungos, que cresceram sob condições não usuais, como alta temperatura, alta concentração de sal e baixa concentração de açúcar, foram testados in vitro quanto ao seu potencial citotóxico em várias linhagens de câncer. Os extratos foram ensaiados em células HeLa e MCF-7 para o estudo do potencial citotóxico. A coloração nuclear e os estudos de citometria de fluxo foram realizados para avaliar o potencial dos extratos em bloquear o ciclo celular. O extrato bruto em acetato de etila do isolado F-21 mostrou resultados promissores no ensaio de MTT, com IC50 de 20,37±0,36 µg/mL em células HeLa e 44,.75±0,81 µg/mL em células MCF-7, comparativamente à cisplatina. O isolado F-21 foi identificado como Aspergillus sp. Resultados promissores foram obtidos com cepas B-2C e B-4E. Realizaram-se, também, estudos morfológicos, testes bioquímicos e investigação química preliminar dos extratos.