Antileishmanial activity of neo-clerodane diterpenes from Croton echioides.

Nowadays, new leishmanicidal drugs are needed and natural products arise as a promising alternative source. Therefore, bioguided fractionation of a hydroethanolic extract from the stem bark of Croton echioides Baill. were conducted based on its antileishmanial activity. Two novel neo-clerodane diterpenoids methyl-15,16-epoxy-3,13(16),14-neo-clerodatrien-17,18-dicarboxylate (1) and dimethyl-3-oxo-15,16-epoxy-13(16),14-neo-clerodadien-17,18-dicarboxylate (2) were isolated, as well as four known compounds (3-6) and lupeol, from the hexane fraction. Their structures were established by NMR analysis. The crude extract, fractions and the compounds (1 and 3-6) were evaluated for their in vitro antileishmanial activity and cytotoxicity against macrophages J774A.1. The selectivity index (SI) were calculated. The most active compound against promastigote forms of L. amazonensis was the clerodane diterpene 4, with IC50 values of 8.3 µM and SI value of 80.9. Our results highlighted stem bark of Croton echioides Baill. as a promising source for the development of a new chemotherapeutic agent to combat leishmaniasis.

Dimeric glycosylated flavan-3-ol and antimicrobial in vitro evaluation of Trichilia catigua extracts.

Trichilia catigua is a tree known as "catuaba", widely distributed in Brazil. Studies carried out with T. catigua barks suggest that plant has antidepressant, antidiabetic, antimicrobial, antioxidant, antiviral, and preventive against brain damage. The aim of this work was to isolate and characterise compounds from the semipurified fraction of T. catigua barks, and to conduct microbiological screening against bacteria and fungi. The crude extract (CE) of "catuaba" was produced by turbo extraction with acetone-water, and later, partitioned to yield ethyl-acetate (EAF) and aqueous (AqF) fractions. From AqF the new catechin-3-O-α-L-rhamnoside-(4α→8)-epicatechin was isolated, identified, and described here for the first time. Regarding antimicrobial activity, the extracts presented impressive results, mainly for Vancomycin Resistant Enterococcus faecium (VREfm) with MIC of 156.5 µg/mL. The results suggest that extract of T. catigua could potentially be used as an adjuvant to treatment and is a promising candidate for the development of new antimicrobial drugs.

Stem bark extract of Poincianella pluviosa incorporated in polymer film: Evaluation of wound healing and anti-staphylococcal activities.

Poincianella pluviosa has already been described as capable of healing skin wounds. In an attempt to prolong contact of the drug with the wound, it was proposed in this study to evaluate wound healing using a crude extract (CE) of P. pluviosa incorporated in carboxymethylcellulose polymer films. The chromatographic profile of the semipurified fraction of P. pluviosa was evaluated by ultra-high performance liquid chromatography (UHPLC), confirming the compounds gallic acid, geraniin, and ellagic acid. The films were evaluated for their physical and mechanical properties, water vapor permeability, moisture absorption capacity, and FTIR spectroscopy. For in vivo experiments, wounds were made on the back of rats and treated daily for 4, 7, 10, or 14 days with film containing CE or control film. At the end of each period, skin permeation analysis and histological analysis were made using re-epithelialisation, cell proliferation, and collagen formation. Statistical significance was determined by GraphPad Prism using t test and Mann-Whitney test. Anti-staphylococcal activity was evaluated with standard strains of Staphylococcus aureus, methicillin-resistant, and coagulase negative. It was demonstrated that the presence of CE in the films increased the capacity to absorb water and decreased resistance and permeability. The CE of the film permeated the skin, reaching the dermis and was able to influence re-epithelisation, cell proliferation, and collagen formation. Satisfactory results were observed against S. aureus strains, particularly coagulase negative. Films with CE of P. pluviosa can be an alternative in the wound healing, protecting against opportunistic infections and giving comfort to the patient.

In vitro evaluation of the protective effects of plant extracts against amyloid-beta peptide-induced toxicity in human neuroblastoma SH-SY5Y cells.

Alzheimer's disease (AD) is the most common form of dementia and has no cure. Therapeutic strategies focusing on the reduction of oxidative stress, modulation of amyloid-beta (Aß) toxicity and inhibition of tau protein hyperphosphorylation are warranted to avoid the development and progression of AD. The aim of this study was to screen the crude extracts (CEs) and ethyl-acetate fractions (EAFs) of Guazuma ulmifolia, Limonium brasiliense, Paullinia cupana, Poincianella pluviosa, Stryphnodendron adstringens and Trichilia catigua using preliminary in vitro bioassays (acetylcholinesterase inhibition, antioxidant activity and total polyphenol content) to select extracts/fractions and assess their protective effects against Aß25-35 toxicity in SH-SY5Y cells. The effect of the EAF of S. adstringens on mitochondrial membrane potential, lipid peroxidation, superoxide production and mRNA expression of 10 genes related to AD was also evaluated and the electropherogram fingerprints of EAFs were established by capillary electrophoresis. Chemometric tools were used to correlate the in vitro activities of the samples with their potential to be evaluated against AD and to divide extracts/fractions into four clusters. Pretreatment with the EAFs grouped in cluster 1 (S. adstringens, P. pluviosa and L. brasiliense) protected SH-SY5Y cells from Aß25-35-induced toxicity. The EAF of S. adstringens at 15.62 µg/mL was able completely to inhibit the mitochondrial depolarization (69%), superoxide production (49%) and Aß25-35-induced lipid peroxidation (35%). With respect to mRNA expression, the EAF of S. adstringens also prevented the MAPT mRNA overexpression (expression ratio of 2.387x) induced by Aß25-35, which may be related to tau protein hyperphosphorylation. This is the first time that the neuroprotective effects of these fractions have been demonstrated and that the electropherogram fingerprints for the EAFs of G. ulmifolia, L. brasiliense, P. cupana, P. pluviosa and S. adstringens have been established. The study expands knowledge of the in vitro protective effects and quality control of the evaluated fractions.

RNAm expression profile of cancer marker genes in HepG2 cells treated with different concentrations of a new indolin-3-one from Pseudomonas aeruginosa.

The present study tested the effects of a newly identified indolin-3-one compound (compound 1), produced by Pseudomonas aeruginosa, on HepG2 cells. The MTT assays demonstrated decreased metabolic activities in HepG2 cells treated with compound 1, with dose- and time-dependent intensifying effect, starting at a concentration of 40 µM. The IC50 after 24, 48, 72, and 96 h treatments were 41.35, 52.7, 92.79 and 66.65 µM of compound 1, respectively. Below 80 µM, no significative damage on erythrocytes membranes was observed by the hemolytic assays. The RT-qPCR revealed that the compound modulated key genes involved in carcinogenesis process, indicating possible indolin-3-one mechanisms of action. The data showed that gene expression alterations promoted by compound 1, in concentrations up to 60 µM after 48 h, led to a decrease in cellular progression and there was no direct cellular damage. In addition, non-cytotoxic concentrations of compound 1 halved the concentration of the chemotherapeutic doxorubicin, maintaining similar therapeutic effect against HepG2 cells. The novelty of the molecule and the biological activities observed in the present study emphasize the potential of the compound 1 in cancer therapy research.

Pheophorbide a, a compound isolated from the leaves of Arrabidaea chica, induces photodynamic inactivation of Trypanosoma cruzi.

BACKGROUND: Approximately 6-7 million people are infected with Trypanosoma cruzi, the etiological agent of Chagas' disease. Only two therapeutic compounds have been found to be useful against this disease: nifurtimox and benznidazole. These drugs have been effective in the acute phase of the disease but less effective in the chronic phase; they also have many side effects. Thus, the search for new compounds with trypanocidal action is necessary. Natural products can be the source of many important substances for the development of drugs to treat this infection. The present study evaluated the biological activity of an extract and fractions of Arrabidaea chica against T. cruzi and observed morphological and ultrastructural characteristics of parasites exposed to the isolated compound pheophorbide a. METHODS: The crude hydroethanolic extract of A. chica was prepared. Fractions were obtained by partition and separated by liquid chromatography. RESULTS: We observed a progressive increase in activity against epimastigote, trypomastigote, and amastigote forms of the parasite over the course of the fractionation process. Interestingly, we isolated a compound known as a photosensitizer that is used in photodynamic therapy. This method of treatment involving a photosensitizer, activation light and molecular oxygen is of great importance due to its selectivity. Pheophorbide a had activity against the protozoan in the presence of light and caused morphological and ultrastructural changes, demonstrating its potential in photodynamic therapy. CONCLUSIONS: Based on the ability of pheophorbide a to eliminate bloodstream forms of T. cruzi, we suggest its use in blood banks for hemoprophylaxis.

Nanoparticles of Waste Material of Propolis and Gelatin as a Novel System for Delivery of L-Ascorbic Acid.

BACKGROUND: The waste material from the preparation of propolis extracts is a potential natural compound for application in pharmaceutical and medicine nanostructured products. Ascorbic acid is an excellent antioxidant and an important cofactor of several physiological and biochemical processes. OBJECTIVE: The aim of this study was to develop and characterize nanoparticles containing L-ascorbic acid prepared with propolis byproduct. METHOD: Nanoparticle's physicochemical characteristics (surface morphology, particle size, zeta potential, and entrapment efficiency), antioxidant activity, in vitro release profile, and in vitro cytotoxicity were evaluated. RESULTS: Nanoparticles showed to be spherical, with agglomeration, mean diameter between 110.93 and 480.59 nm, zeta potential near zero and good entrapment efficiency. Antioxidant activity of L-ascorbic acid increased when nanoencapsulated and the drug release was prolonged, controlled mainly by the phenomenon of relaxation of polymer chains and dependent of propolis residue concentration. The application of technology provided a reduction in the level of cytotoxicity of L-ascorbic acid, and the nanoparticles showed a protective effect on macrophages.

Larvicidal Activity against Aedes aegypti and Chemical Characterization of the Inflorescences of Tagetes patula.

The crude acetone extract (CAE) of defatted inflorescences of Tagetes patula was partitioned into five semipurified fractions: n-hexane (HF), dichloromethane (DF), ethyl acetate (EAF), n-butanol (BF), and aqueous (AQF). BF was fractionated by reversed-phase polyamide column chromatography, obtaining 34 subfractions, which were subjected to HSCCC, where patuletin and patulitrin were isolated. CAE and the fractions BF, EAF, DF, and AQF were analyzed by LC-DAD-MS, and patuletin and patulitrin were determined as the major substances in EAF and BF, respectively. BF was also analyzed by HPLC and capillary electrophoresis (CE), and patulitrin was again determined to be the main substance in this fraction. CAE and the semipurified fractions (750, 500, 300, 100, and 50 mg/L) were assayed for larvicidal activity against Aedes aegypti, with mortality rate expressed as percentage. All fractions except AQF showed insecticidal activity after 24 h exposure of larvae to the highest concentration. However, EAF showed the highest activity with more than 50% reduction in larval population at 50 mg/L. The insecticidal activity observed with EAF might have been due to the higher concentration of patuletin present in this fraction.

In vitro Cytotoxicity and Anti-herpes Simplex Virus Type 1 Activity of Hydroethanolic Extract, Fractions, and Isolated Compounds from Stem Bark of Schinus terebinthifolius Raddi.

BACKGROUND: Herpes simplex virus type 1 (HSV-1) is associated with orofacial infections and is transmitted by direct contact with infected secretions. Several efforts have been expended in the search for drugs to the treatment for herpes. Schinus terebinthifolius is used in several illnesses and among them, for the topical treatment of skin wounds, especially wounds of mucous membranes, whether infected or not. OBJECTIVE: To evaluate the cytotoxicity and anti-HSV-1 activity of the crude hydroethanolic extract (CHE) from the stem bark of S. terebinthifolius, as well as its fractions and isolated compounds. MATERIALS AND METHODS: The CHE was subjected to bioguided fractionation. The anti-HSV-1 activity and the cytotoxicity of the CHE, its fractions, and isolated compounds were evaluated in vitro by SRB method. A preliminar investigation of the action of CHE in the virus-host interaction was conducted by the same assay. RESULTS: CHE presented flavan-3-ols and showed anti-HSV-1 activity, better than its fractions and isolated compounds. The class of substances found in CHE can bind to proteins to form unstable complexes and enveloped viruses, as HSV-1 may be vulnerable to this action. Our results suggest that the CHE interfered with virion envelope structures, masking viral receptors that are necessary for adsorption or entry into host cells. CONCLUSION: The plant investigated exhibited potential for future development treatment against HSV-1, but further tests are necessary, especially to elucidate the mechanism of action of CHE, as well as preclinical and clinical studies to confirm its safety and efficacy. SUMMARY: Crude hydroethanolic extract (CHE) presents promising activity against herpes simplex virus type 1 (HSV 1), with selectivity index (SI) = 22.50CHE has flavan-3-ols in its composition, such as catechin and gallocatechinThe fractions and isolated compounds obtained from CHE by bioguided fractionation are less active than the CHE against HSV-1CHE interferes with viral entry process in the host cell and acts directly on the viral particle. Abbreviations used: HSV: Herpes simplex virus, CHE: Crude hydroethanolic extract, WF: Water fraction, AF: Ethyl-acetate fraction, MPLC: Medium-performance liquid chromatography, TLC: Thin-layer chromatography, NMR: Nuclear magnetic resonance, ESI-MS: Electrospray ionization mass spectrometry, SRB: Sulforhodamine B, CPE: Cytopathic effect, CC50: 50% cytotoxic concentration, EC50: 50% effective concentration, PBS: Phosphate-buffered saline.

Evaluation of the antiproliferative activity of the leaves from Arctium lappa by a bioassay-guided fractionation.

Arctium lappa L. (Asteraceae) is used in folk medicine around the World, and shows several kinds of biological activity, particularly in vitro antitumor activity in different cell lines. This study evaluated the antiproliferative activity of the crude extract, semipurified fractions, and isolated compounds from the leaves of A. lappa, through bioassay-guided testing in Caco-2 cells. The crude extract was obtained with a 50% hydroethanolic extract and then partitioned with hexane, ethyl acetate, and n-butanol. The ethyl-acetate fraction (EAF) showed antiproliferative activity. This fraction was subjected to sequential column chromatography over silica gel to afford onopordopicrin (1), mixtures of 1 with dehydromelitensin-8-(4'-hydroxymethacrylate) (2), a mixture of 2 with dehydromelitensin (3), mixture of 1 with melitensin (4), dehydrovomifoliol (5), and loliolide (6). The compounds were identified by spectroscopic methods (NMR, MS) and comparison with literature data. This is the first description of compounds 2-5 from this species. The compounds tested in Caco-2 cells showed the following CC(50) (µg/mL) values: 1: 19.7 ± 3.4, 1 with 2: 24.6 ± 1.5, 2 with 3: 27 ± 11.7, 1 with 4: 42 ± 13.1, 6 30 ± 6.2; compound 5 showed no activity.

Thiophene derivatives with antileishmanial activity isolated from aerial parts of Porophyllum ruderale (Jacq.) Cass.

Porophyllum ruderale (Jacq.) Cass. is a plant native to Brazil and in the northwest region of the state of Paraná, Brazil, aerial parts of P. ruderale have been used popularly in the treatment of lesions caused by Leishmania sp.. In this study the antileishmanial and cytotoxic activities of the crude extract, fractions, and isolated compounds from aerial parts of P. ruderale was evaluated. The dichloromethane extract was submitted to chromatography to yield compounds active against Leishmania amazonensis. Their structures were established by comparison of their spectroscopic data with literature values. The activities of crude extract against promastigote and axenic amastigote forms of L. amazonensis (IC(50)) were 60.3 and 77.7 µg/mL, respectively. Its cytotoxic activity against macrophage cells (CC(50)) was 500 µg/mL. The thiophene derivatives isolated were: 5-methyl-2,2':5',2"-terthiophene (compound A) and 5'-methyl-[5-(4-acetoxy-1-butynyl)]-2,2'-bithiophene (compound B). The activity of compound A against promastigote and axenic amastigote forms were 7.7 and 19.0 µg/mL and of compound B were 21.3 and 28.7 µg/mL, respectively. The activity of the isolated compounds against promastigote and axenic amastigote forms was better than that of the crude extract and more selective against protozoa than for macrophage cells.