Jaciana S. Aguiar

Evaluation of cytotoxic and anti-inflammatory activities of extracts and lectins from Moringa oleifera seeds.

Background The extract from Moringa oleifera seeds is used worldwide, especially in rural areas of developing countries, to treat drinking water. M. oleifera seeds contain the lectins cmol and WSMoL, which are carbohydrate-binding proteins that are able to reduce water turbidity because of their coagulant activity. Studies investigating the ability of natural products to damage normal cells are essential for the safe use of these substances. This study evaluated the cytotoxic and anti-inflammatory properties of the aqueous seed extract, the extract used by population to treat water (named diluted seed extract in this work), and the isolated lectins cmol and WSMoL. Methodology/Principal Findings The data showed that the aqueous seed extract and cmol were potentially cytotoxic to human peripheral blood mononuclear cells, while WSMoL and diluted seed extract were not cytotoxic. The M. oleifera aqueous seed extract and the lectins cmol and WSMoL were weakly/moderately cytotoxic to the NCI-H292, HT-29 and HEp-2 cancer cell lines and were not hemolytic to murine erythrocytes. Evaluation of acute toxicity in mice revealed that the aqueous seed extract (2.000 mg/kg) did not cause systemic toxicity. The aqueous seed extract, cmol and WSMoL (6.25 µg/mL) and diluted seed extract at 50 µg/mL exhibited anti-inflammatory activity on lipopolyssaccharide-stimulated murine macrophages by regulating the production of nitric oxide, TNF-α and IL-1β. The aqueous seed extract reduced leukocyte migration in a mouse model of carrageenan-induced pleurisy; the myeloperoxidase activity and nitric oxide, TNF-α and IL-1β levels were similarly reduced. Histological analysis of the lungs showed that the extract reduced the number of leukocytes. Conclusion/Significance This study shows that the extract prepared according to folk use and WSMoL may be non-toxic to mammalian cells; however, the aqueous seed extract and cmol may be cytotoxic to immune cells which may explain the immunosuppressive potential of the extract.

Cytotoxic effect and apoptosis induction by Bothrops leucurus venom lectin on tumor cell lines

Neoplastic transformation is the abnormal proliferation of cells. These transformations are often related to changes in cell surface glycoconjugates which can be detected by lectins. We evaluated the anti-tumor potential of BlL, a galactoside-binding lectin isolated from Bothrops leucurus venom as well as its cytotoxicity and hemolysis activity. The phosphatidylserine externalization and mitochondrial membrane potential were also determined. BlL exhibited cytotoxic activity against all tumor cell lines tested by induced phosphatidylserine externalization and mitochondrial depolarization, indicating cell death by apoptosis.

Tropane Alkaloids from Erythroxylum caatingaePlowman

Three tropane alkaloids, 1–3, were isolated from Erythroxylum caatingae, i.e., 6β‐benzoyloxy‐3α‐[(4‐hydroxy‐3,5‐dimethoxybenzoyl)oxy]tropane (1), a new tropane alkaloid, along with the known alkaloids 3α,6β‐dibenzoyloxytropane (2) and 6β‐benzoyloxy‐3α‐[(3,4,5‐trimethoxybenzoyl)oxy]tropane (catuabine B; 3). Their structures were determined by 2D‐ (1H and 13C) NMR. By LC/ESI‐MS/MS analysis of the fractions of alkaloids 1–3, it was possible to detect five more alkaloids, 4–8, two of these, 4 and 8, possibly being new natural products. X‐Ray crystallography of the chloride derivate of 1, i.e., 6β‐benzoyloxy‐3α‐(4‐hydroxy‐3,5‐dimethoxybenzoyloxy)tropane hydrochloride (1a) confirmed the structure of 1. Cytotoxicity was tested against the cell lines HEp‐2, NCI‐H292, and KB for the MeOH extract and alkaloid 3, and antitumor activity was tested against Sarcoma 180 only for the MeOH extract.

Antimicrobial and cytotoxicity evaluation of colloidal chitosan – silver nanoparticles – fluoride nanocomposites

The present study aimed to evaluate the antimicrobial activity and cytotoxicity of colloidal chitosan - silver nanoparticle - fluoride nanocomposites (CChAgNpFNc), with different silver nanoparticle shapes and sizes. The syntheses of CChAgNpFNc were performed with silver nitrate added to a chitosan solution, addition of a sodium borohydride solution and solid sodium fluoride. Solution of ascorbic acid was added to synthesize larger silver nanoparticles. CChAgNpFNc obtained: S1- 100% spherical, 8.7±3.1nm; S2- 97% spherical, 15.0±7.9nm and 2.5% triangular, 22.2±9.5nm; S3- 77.3% spherical, 31.8±10.4nm, 15.9% triangular, 27.1±10.1nm and 6.8% elliptical, 33.2±7.8nm; and S4- 75.2% spherical, 43.2±14.3nm; 23.3% triangular 38.2±14.8nm, and 1.5% elliptical 38.4±11.6nm. The CChAgNpFNc showed antimicrobial activity against Staphylococcus aureus, Escherichia coli, Enterococcus faecalis, Pseudomonas aeruginosa and Candida albicans, by microdilution technique. The influence on the growth of microorganisms was evaluated using a fluorescence assay, and showed an increasing lag phase and a decreasing log phase. Cytotoxicity was investigated using Artemia salina and MTT assays. The S3 and S4 samples exhibited low cytotoxicity. The S1 and S2 samples inhibited murine macrophages and revealed lethal dose concentrations above 1000mg/mL that were classified as moderately toxic. Thus, CChAgNpFNc are potential options for the control of multiple-drug-resistant microorganisms and do not represent substantial risks to human health.

Toxic effects of Microgramma vacciniifolia rhizome lectin on Artemia salina, human cells, and the schistosomiasis vector Biomphalaria glabrata

The present study evaluated the toxicity of Microgramma vacciniifolia rhizome lectin (MvRL) to Artemia salina, human tumour cell lines (larynx epidermoid carcinoma Hep-2, NCI-H292 lung mucoepidermoid carcinoma, and chronic myelocytic leukaemia K562), and normal peripheral blood mononuclear cells (PBMCs), as well as to Biomphalaria glabrata embryos and adults. MvRL was toxic to A. salina (LC50=159.9 μg/mL), and exerted cytotoxic effects on NCI-H292 cells (IC50=25.23 μg/mL). The lectin (1-100 μg/mL) did not affect the viability of K562 and Hep-2 tumour cells, as well as of PBMCs. MvRL concentration of 1, 10, and 100 μg/mL promoted malformations (mainly exogastrulation) in 7.8%, 22.5%, and 27.7% of embryos, respectively, as well as delayed embryo development in 42.0%, 69.5%, and 54.7% of embryos, respectively. MvRL at a concentration of 100 μg/mL killed B. glabrata embryos (17.7%) and adults (25%). Further, MvRL damaged B. glabrata reproductive processes, which was evidenced by observations that snails exposed to the lectin (100 μg/mL) deposited fewer eggs than those in the control group, and approximately 40% of the deposited eggs exhibited malformations. Comparison of these results with that from A. salina assay indicates that MvRL is adulticidal at the concentration range which is toxic to environment. In conclusion, the cytotoxicity of MvRL on tumour cell and absence of toxicity to normal cell indicate its potential as chemotherapeutic drug. Also, the study revealed that the lectin is able to promote deleterious effects on B. glabrata embryos at environmentally safe concentrations.

Lectin from Crataeva tapia bark exerts antitumor, anti- inflammtory and analgesic activities

Crataeva tapia bark lectin was evaluated for its antitumor activity against sarcoma 180 in Swiss albino mice. The anti-inflammatory and analgesic properties were investigated in models of inflammation and nociception. The anti-inflammatory assay was induced by carrageenan induced peritonitis and the analgesic activity was induced by acetic acid-induced writhing response. The lectin presents low toxicity with a LD50 of 2,500 mg/kg body weight and significant antitumor activity causing inhibition of tumor growth. The lectin also promoted significant reduction (35.4%) in the number of neutrophil migration induced by carrageenan. Concerning its analgesic property, the lectin inhibits abdominal contractions induced by acetic acid. The current results revealed a lectin with significant antitumoral, anti-inflammatory and antinociceptive activities. Further investigations to unveil the exact mechanisms are needed.

Antimicrobial, Antiproliferative and Proapoptotic Activities of Extract, Fractions and Isolated Compounds from the Stem of Erythroxylum caatingae Plowman

In the study, we have examined the antitumor and antimicrobial activities of the methanol extract, the fractions, a fraction of total alkaloids and two alkaloids isolated from the stem of Erythroxylum caatingae Plowman. All test fractions, except the hexane fractions, showed antimicrobial activity on gram-positive bacteria and fungi. The acetate: methanol (95:5), acetate, chloroform and hexane fractions show the highest cytotoxicity activity against the NCI-H292, HEp-2 and K562 cell lines using MTT. The absence of hemolysis in the erythrocytes of mice was observed in these fractions and 6β-Benzoyloxy-3α-(3,4,5- trimethoxybenzoyloxy) tropane (catuabine B). Staining with Annexin V-FITC and JC-1 was used to verify the mechanism of action of the compounds of E. caatingae that showed cytotoxicity less than 30 μg/mL in leukemic cells. After 48 h of incubation, we observed that the acetate: methanol (95:5), acetate, and chloroform fractions, as well as the catuabine B, increased in the number of cells in early apoptosis, from 53.0 to 74.8%. An analysis of the potential of the mitochondrial membrane by incorporation of JC-1 showed that most cells during incubation of the acetate: methanol (95:5) and acetate fractions (63.85 and 59.2%) were stained, suggesting the involvement of an intrinsic pathway of apoptosis.

Cytotoxic activity of marine algae against cancerous cells

This paper presents an investigation on the cytotoxic activity in human tumor cell from dichloromethane, chloroform, methanol, ethanol, water extracts, and hexane and chloroform fractions from green, brown and red algae collected at Riacho Doce Beach, north coast of Alagoas, Brazil, against the cancer cells K562 (chronic myelocytic leukemia), HEp-2 (laryngeal epidermoid carcinoma) and NCI-H292 (human lung mucoepidermoid carcinoma) through the MTT colorimetric method. The dichloromethane extract and chloroform fraction of Hypnea musciformis showed the best cytotoxic activity against K562 (3.8±0.2 µg.mL-1 and 6.4±0.4 µg.mL-1, respectively). Dichloromethane extracts of Dictyota dichotoma (16.3±0.3 µg.mL-1) and the chloroform fraction of H. musciformis (6.0±0.03 µg.mL-1) and chloroform fraction of P. gymnospora (8.2±0.4) were more active against HEp-2 as well as ethanol extracts of P. gymnospora (15.9±2.8 µg.mL-1) and chloroform fraction of H. musciformis (15.0±1.3 µg.mL-1) against the cell NCI-H292. The constituents with higher anticancer action are present in the extracts of dichloromethane and chloroform and in the chloroform fraction of H. musciformis, Digenea simplex, P. gymnospora, and D.dichotoma. In the case of the seaweed S. vulgare, the anticancer constituents are present in the aqueous extract.

Synthesis and in vitro evaluation of (R), (S) and (R/S)-2-hexyne-1,4-diol, a natural product produced by fungus Clitocybe catinus, and related analogs as potential anticancer agents

The search for natural products and related analogs as potential anticancer agents has seen a significant growth worldwide. Since small sized propargylic diols can be found in nature and chemically synthesized, their evaluation against cancer cells has been of great interest, being a topic of relevance to be investigated. For this purpose, a scalable approach aiming at the synthesis of several propargylic diols and their bioactivity against seven tumor cell lines were evaluated. Interestingly, when the compound 1a, a natural product produced by fungus Clitocybe catinus, was tested in its racemic mixture a more effective activity was observed if compared when enantiopure R-1a or S-1a were tested separately.

N-pentyl-nitrofurantoin induces apoptosis in HL-60 leukemia cell line by upregulating BAX and downregulating BCL-xL gene expression

BACKGROUND Nitrofurantoin is a nitroderivative antibiotic that has bactericidal activity against pathogens causing urinary tract infection. A few studies have reported that nitrofurantoin has cytotoxic activity against cancer cells; however, nitrofurans remain a poorly explored class of compounds with respect to their anticancer potential. The aim of this study was to investigate the anticancer effects of a nitrofurantoin derivative, n-pentyl-nitrofurantoin (NFP), on HL-60 leukemia cells. METHODS Cytotoxicity was assayed by the MTT assay. Cell morphology and phosphatidylserine externalization were visualized after Giemsa-May-Grunwald and annexin V staining, respectively. DNA content and mitochondrial depolarization were measured by flow cytometry. BAX and BCL-xL expression was examined by RT-PCR. RESULTS NFP was 3.8-fold more cytotoxic against HL-60 leukemia cells than against normal cells. NFP reduced the number of viable cells 24h after the treatment with a concomitant increase in the number of apoptotic cells indicated by the externalization of phosphatidylserine, DNA fragmentation, and mitochondrial depolarization. The mRNA levels of BAX increased, whereas the mRNA levels of BCL-xL decreased. CONCLUSION The results indicate that NFP induces apoptosis in HL-60 cells by upregulating BAX and downregulating BCL-xL.