Cláudia Pessoa

In vivo growth-inhibition of Sarcoma 180 by piplartine and piperine, two alkaloid amides from Piper

Piplartine {5,6-dihydro-1-[1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propenyl]-2(1H)pyridinone} and piperine {1-5-(1,3)-benzodioxol-5-yl)-1-oxo-2,4-pentadienyl]piperidine} are alkaloid amides isolated from Piper. Both have been reported to show cytotoxic activity towards several tumor cell lines. In the present study, the in vivo antitumor activity of these compounds was evaluated in 60 female Swiss mice (N = 10 per group) transplanted with Sarcoma 180. Histopathological and morphological analyses of the tumor and the organs, including liver, spleen, and kidney, were performed in order to evaluate the toxicological aspects of the treatment with these amides. Administration of piplartine or piperine (50 or 100 mg kg(-1) day(-1) intraperitoneally for 7 days starting 1 day after inoculation) inhibited solid tumor development in mice transplanted with Sarcoma 180 cells. The inhibition rates were 28.7 and 52.3% for piplartine and 55.1 and 56.8% for piperine, after 7 days of treatment, at the lower and higher doses, respectively. The antitumor activity of piplartine was related to inhibition of the tumor proliferation rate, as observed by reduction of Ki67 staining, a nuclear antigen associated with G1, S, G2, and M cell cycle phases, in tumors from treated animals. However, piperine did not inhibit cell proliferation as observed in Ki67 immunohistochemical analysis. Histopathological analysis of liver and kidney showed that both organs were reversibly affected by piplartine and piperine treatment, but in a different way. Piperine was more toxic to the liver, leading to ballooning degeneration of hepatocytes, accompanied by microvesicular steatosis in some areas, than piplartine which, in turn, was more toxic to the kidney, leading to discrete hydropic changes of the proximal tubular and glomerular epithelium and tubular hemorrhage in treated animals.

The cytotoxic and embryotoxic effects of kaurenoic acid, a diterpene isolated from Copaifera langsdorffii oleo-resin.

In this work, we studied the effects of kaurenoic acid, a diterpene isolated from the oleo-resin of Copaifera langsdorffii in developing sea urchin (Lytechinus variegatus) embryos, on tumor cell growth in microculture tetrazolium (MTT) test and on mouse and human erythrocytes in hemolysis assay. Continuous exposure of embryos to kaurenoic acid starting immediately after fertilization inhibited the first cleavage (IC(50): 84.2 microM) and progressively induced embryo destruction (IC(50): 44.7 microM and < 10 microM for blastulae and larvae stages, respectively). In MTT assay, kaurenoic acid at a concentration of 78 microM produced growth inhibition of CEM leukemic cells by 95%, MCF-7 breast and HCT-8 colon cancer cells by 45% each. Further, kaurenoic acid induced a dose-dependent hemolysis of mouse and human erythrocytes with an EC(50) of 74.0 and 56.4 microM, respectively. The destruction of sea urchin embryos, the inhibition of tumor cell growth and the hemolysis of mouse and human erythrocytes indicate the potential cytotoxicity of kaurenoic acid.

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.

Overview of the therapeutic potential of piplartine (piperlongumine).

Piplartine (piperlongumine, 5,6-dihydro-1-[(2E)-1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propenyl]-2(1H)-pyridinone) is a biologically active alkaloid/amide from peppers, as from long pepper (Piper longum L. - Piperaceae). Long pepper is one of the most widely used in Ayurvedic medicine, which is used to treat many diseases, including tumors. The purpose of the current paper is to address to the chemical structure establishment and to systematically survey the published articles and highlight recent advances in the knowledge of the therapeutic potential of piplartine, establishing new goals for future research. The reported pharmacological activities of piplartine include cytotoxic, genotoxic, antitumor, antiangiogenic, antimetastatic, antiplatelet aggregation, antinociceptive, anxiolytic, antidepressant, anti-atherosclerotic, antidiabetic, antibacterial, antifungal, leishmanicidal, trypanocidal, and schistosomicidal activities. Among the multiple pharmacological effects of piplartine, its anticancer property is the most promising. Therefore, the preclinical anticancer potential of piplartine has been extensively investigated, which recently resulted in one patent. This compound is selectively cytotoxic against cancer cells by induction of oxidative stress, induces genotoxicity, as an alternative strategy to killing tumor cells, has excellent oral bioavailability in mice, inhibits tumor growth in mice, and presents only weak systemic toxicity. In summary, we conclude that piplartine is effective for use in cancer therapy and its safety using chronic toxicological studies should be addressed to support the viability of clinical trials.

Antitumor properties of a sulfated polysaccharide from the red seaweed Champia feldmannii (Diaz‐Pifferer)

In recent years, much attention has been focused on polysaccharides isolated from natural sources. The aim of this study was to investigate the in vitro and in vivo antitumor properties of a sulfated polysaccharide isolated from the seaweed C. feldmannii (Cf‐PLS). Hematological, biochemical and histopathological analyses were performed in order to evaluate the toxicological aspects related to Cf‐PLS treatment. Its effects on the immunological system were also investigated. The Cf‐PLS did not show any significant in vitro cytotoxicity at the experimental exposure levels that were used, but showed in vivo antitumor effect. The inhibition rates of sarcoma 180 tumor development were 48.62 and 48.16% at the doses of 10 and 25 mg kg−1, respectively. In addition, Cf‐PLS was also able to increase the response elicited by 5‐fluorouracil (5‐FU) from 48.66 to 68.32%. The histopathological analysis of liver and kidney showed that both organs were moderately affected by Cf‐PLS‐treatment. Neither enzymatic activity of alanine aminotransferase nor urea or creatinine 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 Cf‐PLS. It was also demonstrated that Cf‐PLS acts as an immunomodulatory agent, raising the production of specific antibodies, and increasing the production of OVA‐specific antibodies. It also induced a discreet hyperplasia of lymphoid folicules of the white pulp in the spleen of treated mice. In conclusion, Cf‐PLS has some interesting anticancer activity that could be associated with its immunostimulating properties. Copyright

Folk uses and pharmacological properties of Casearia sylvestris: a medicinal review

Folk uses and scientific investigations have highlighted the importance of Casearia sylvestris extracts and their relevant bioactive potential. The aim of this work was to review the pharmacological properties of C. sylvestris, emphasizing its anti-ulcer, anti-inflammatory, anti-ophidian and antitumor potentialities. Ethanolic extracts and essential oil of their leaves have antiulcerogenic activity and reduce gastric volume without altering the stomach pH, which corroborates their consumption on gastrointestinal disorders. Leaf water extracts show phospholipase A(2) inhibitory activity that prevents damage effects on the muscular tissue after toxin inoculation. This antiphospholipasic action is probably related to the use as an anti-inflammatory, proposing a pharmacological blockage similar to that obtained with non-steroidal anti-inflammatory drugs on arachidonic acid and cyclooxygenase pathways. Bioguided-assay fractionations lead to the identification of secondary metabolites, especially the clerodane diterpenes casearins (A-X) and casearvestrins (A-C), compounds with a remarkable cytotoxic and antitumor action. Therefore, the C. sylvestris shrub holds a known worldwide pharmacological arsenal by its extensive folk utilization, exciting searches for new molecules and a better comprehension about biological properties.

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 μg mL−1 for physalin B, and 0.28 to 2.43 μg 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.

3-Arylamino and 3-Alkoxy-nor-β-lapachone Derivatives: Synthesis and Cytotoxicity against Cancer Cell Lines

Several 3-arylamino and 3-alkoxy-nor-beta-lapachone derivatives were synthesized in moderate to high yields and found to be highly potent against cancer cells SF295 (central nervous system), HCT8 (colon), MDA-MB435 (melanoma), and HL60 (leukemia), with IC(50) below 2 microM. The arylamino para-nitro and the 2,4-dimethoxy substituted naphthoquinones showed the best cytoxicity profile, while the ortho-nitro and the 2,4-dimethoxy substituted ones were more selective than doxorubicin and similar to the precursor lapachones, thus emerging as promising new lead compounds in anticancer drug development.

Cytotoxic, Trypanocidal Activities and Physicochemical Parameters of nor-β-Lapachone-based 1,2,3-Triazoles

The cytotoxicities of five nor-²-lapachone-based 1,2,3-triazoles and the precursor azidonaphthoquinone were assayed against six neoplasic cancer cell lines: SF-295 (central nervous system), HCT-8 (colon), MDAMB-435 (melanoma), HL-60 (leukaemia), PC-3 (prostate) and B-16 (murine melanoma). IC50 values ranging from 0.43 to 9.48 µM were obtained. 3-(4-(1-hydroxycyclohexyl)-1H-1,2,3-triazol-1yl)-2,2-dimethylnaphtho[1,2-b]furan-4,5-dione proved highly cytotoxic to MDAMB-435, with IC50 even lower than the one from doxorubicin (positive control). In an attempt to correlate physicochemical parameters (reduction potentials and calculated log P) with cytotoxic activity, electrochemical studies were conducted in acetate buffer, pH 4.5, using a vitreous carbon electrode and calculated log P values were obtained. Despite the absence of a structural conjugative interaction between the two systems (quinone and triazole), the heterocyclic group was found to influence the voltammetric behaviour, as indicated by anodic shifts in the reduction potentials. No correlation was found between EpIc and cytotoxicity. In contrast, a comparison of EpIc with previously reported trypanocidal activities reconfirmed the trend for higher activity coupled with better quinone electrophilicity (> EpIc).A leading term in the correlation of cytoxicity, despite the absence of a linear correlation, was the calculated log P: the lower the lipophilicity, the lower the cytoxicity (> IC50).

Casearin X, Its Degradation Product and Other Clerodane Diterpenes from Leaves of Casearia sylvestris: Evaluation of Cytotoxicity against Normal and Tumor Human Cells

An EtOH extract of the leaves of Casearia sylvestris afforded new clerodane diterpene, casearin X, together with the known compounds casearins B, D, L, and O, and caseargrewiin F. Casearin X degraded to the corresponding dialdehyde when stored in CDCl3. The diterpenes isolated were cytotoxic to human cancer cell lines, with caseargrewiin F being the most active and the new clerodane, casearin X, the second active compound with IC50 values comparable to the positive control doxorubicin. All isolated diterpenes showed lower activities against normal human cells than against cancer cell lines, which might indicate a possible selective action on cancer cells. Casearin X dialdehyde was not cytotoxic to cancer cells indicating that the occurrence of these CO groups at C(18) and C(19) is incompatible with the cytotoxic activity.