Débora Barbosa Vendramini-Costa

Effect of goniothalamin on the development of Ehrlich solid tumor in mice

In this work the antiproliferative activity of goniothalamin (1), both in racemic and in its enantiomeric pure forms, in a solid tumor experimental model using laboratory animals is described. The antiedematogenic activity displayed by racemic 1 in the carrageenan edema model in mice together with the reduction of Ehrlich solid tumor model suggest a relationship between anticancer and antiinflammatory activities with the antiinflammatory activity favoring the antiproliferative activity itself.

Synthesis of methoxylated goniothalamin, aza-goniothalamin and γ-pyrones and their in vitro evaluation against human cancer cells.

The present work describes the preparation of three novel series of compounds based on the structure of goniothalamin, a natural styryl lactone which has been found to display cytotoxic and antiproliferative activities against a variety of cancer cell lines. A focused library of 29 novel goniothalamin analogues was prepared and evaluated against seven human cancer cell lines. While the γ-pyrones and the aza-goniothalamin analogues were less potent than the lead compound, 2,4-dimethoxy analogue 88 has shown to be more potent in vitro than goniothalamin against all cancer cell lines evaluated. Furthermore, it was more potent than doxorubicin against NCI-ADR/RES, OVCAR-03 and HT-29 while being less toxic to human keratinocytes (HaCat). The 3,5-dimethoxy analogue 90 and 2,4,5-trimethoxy analogue 92 also displayed promising antiproliferative activity when compared to goniothalamin (1). These results provide new elements for the design and synthesis of novel representatives of this family of natural compounds.

The antinociceptive activity of harmicine on chemical-induced neurogenic and inflammatory pain models in mice

Harmicine is a β-carboline alkaloid isolated and identified as a major active compound present in many plant species and marine invertebrates. This alkaloid exhibits a wide spectrum of pharmacological activities, including antispasmodic, antipyretic, and anticancer properties. This report described the antinociceptive properties of harmicine by means of chemical experimental models in order to evaluate the use for pain relief. The results demonstrating the potential analgesic properties of harmicine administered intraperitoneally were shown with the writhing test, reducing writhes around 60% (1 mg/kg), and in the formalin test, where harmicine was more effective toward neurogenic (reducing reaction time around 60%, 1 mg/kg) than inflammatory (68% reduction, 10 mg/kg) pain responses. Furthermore, these effects may operate via vanilloid receptors as revealed by the capsaicin test (41% reduction, with 3 mg/kg), as well as via peripheral glutamate receptors as shown by the glutamate test (50% reduction, with 1 mg/kg). Moreover, the opioid antagonist naloxone hydrochloride did not interfere in the antinociceptive properties of harmicine in the writhing test, revealing that this effect may not have a relationship with the opioid systems. Concluding, this report highlights harmicine as a new candidate to be used as analgesic in the future. Therefore, further studies are being undertaken in order to understand the exact mechanisms involved with the antinociceptive properties of harmicine.

Antiproliferative activity of synthetic fatty acid amides from renewable resources

In the work, the in vitro antiproliferative activity of a series of synthetic fatty acid amides were investigated in seven cancer cell lines. The study revealed that most of the compounds showed antiproliferative activity against tested tumor cell lines, mainly on human glioma cells (U251) and human ovarian cancer cells with a multiple drug-resistant phenotype (NCI-ADR/RES). In addition, the fatty methyl benzylamide derived from ricinoleic acid (with the fatty acid obtained from castor oil, a renewable resource) showed a high selectivity with potent growth inhibition and cell death for the glioma cell line-the most aggressive CNS cancer.

Design, synthesis and in vitro evaluation against human cancer cells of 5-methyl-5-styryl-2,5-dihydrofuran-2-ones, a new series of goniothalamin analogues

The present work describes the preparation of a novel series of compounds based on the structure of goniothalamin (1), a natural styryl lactone with known cytotoxic and antiproliferative activities against a variety of cancer cell lines. A focused library of 17 goniothalamin analogues displaying the 5-methyl-2,5-dihydrofuran-2-one motif were prepared, and their cytotoxicity evaluated. While the analogues bearing methoxy and/or hydroxy groups on the aromatic moiety usually were at least three times less potent than the lead compound (1), ortho and para-trifluoromethyl analogues 10 and 11 exhibited levels of cytotoxicity similar to goniothalamin (1) against most cancer cell lines evaluated. One could suggest that the electronic effect of the trifluoromethyl group activates the inhibitors electrophilic site via reduction of the electron density of the α,β-unsaturated ester oxygen atom. These results provide new information on the structure activity relationship of these α,β-unsaturated styryl lactones, thereby further focusing the design of novel candidates.

Antiproliferative activity of three methoxylated flavonoids isolated from Zeyheria montana Mart. (Bignoniaceae) leaves.

The present study isolated three major active flavonoids, two flavones named 4’,5,7‐trimethoxy‐luteolin (1) and 6‐hydroxy‐5,7‐dimethoxyflavone (2) and the flavanone 5‐hydroxy‐6,7‐dimethoxyflavanone (3) from Zeyheria montana dichloromethane leaf extract. Isolation and purification were conducted with the application of column chromatography and structures were assigned by spectral analysis. All compounds were evaluated for cytotoxic activities against human tumor cell lines UACC‐62 (melanoma), MCF‐7 (breast), NCI‐ADR/RES (breast expressing phenotype multiple drug resistance), 786‐0 (renal), NCI‐H460 (lung, non‐small cells), PC‐3 (prostate), OVCAR‐3 (ovarian), HT‐29 (colon) and K562 (leukemia) in vitro. All compounds were active in different degrees on several tumor cell lines and flavanone 3 showed cytotoxicity against almost all cell lines, particularly against human NCI‐ADR/RES and K562 cell lines. In conclusion, three antiproliferative compounds were isolated for the first time from Zeyheria montana and its leaves were characterized as an important source of methoxylated flavones and flavanone as potential antitumor compounds. Copyright

Anticancer and Anti-Inflammatory Activities of a Standardized Dichloromethane Extract from Piper umbellatum L. Leaves.

Despite the advances in anticancer drug discovery field, the worldwide cancer incidence is remarkable, highlighting the need for new therapies focusing on both cancer cell and its microenvironment. The tumor microenvironment offers multiple targets for cancer therapy, including inflammation. Nowadays, almost 75% of the anticancer agents used in chemotherapy are derived from natural products, and plants are an important source of new promising therapies. Continuing our research on Piper umbellatum species, here we describe the anticancer (in vitro antiproliferative activity and in vivo Ehrlich solid tumor model) and anti-inflammatory (carrageenan-induced paw edema and peritonitis models) activities of a standardized dichloromethane extract (SDE) from P. umbellatum leaves, containing 23.9% of 4-nerolidylcatechol. SDE showed in vitro and in vivo antiproliferative activity, reducing Ehrlich solid tumor growth by 38.7 and 52.2% when doses of 200 and 400 mg/kg, respectively, were administered daily by oral route. Daily treatments did not produce signals of toxicity. SDE also reduced paw edema and leukocyte migration on carrageenan-induced inflammation models, suggesting that the anticancer activity of SDE from Piper umbellatum leaves could involve antiproliferative and anti-inflammatory effects. These findings highlight P. umbellatum as a source of compounds against cancer and inflammation.

Gastroprotective effects of goniothalamin against ethanol and indomethacin-induced gastric lesions in rats: Role of prostaglandins, nitric oxide and sulfhydryl compounds

Goniothalamin (GTN), a styryl-lactone, is a secondary metabolite naturally found in its enantiomeric form (R) in plants of the genus Goniothalamus (Annonaceae). The antiproliferative activity against human tumor cell lines reported in several studies suggest that the α,β-unsaturated δ-lactone moiety emerges as a key Michael acceptor for cysteine residues or other nucleophilic biological molecules. Our group reported on the in vivo activity of (R)- and (S)-GTN as well as its racemic form (rac-GTN) in both Ehrlich solid tumor and carrageenan-induced paw edema in mice, without side effects in the effective doses. Despite the rich body of data on the in vitro GTN biological activity, much less is known about its in vivo pharmacological action. Herein we describe the gastroprotective activity of rac-GTN on chemical-induced gastric ulcers models in rats. GTN has a potent gastroprotective effect on ethanol-induced ulcers (effective dose50=18mg/kg) and this activity is dependent on sulfhydryl compounds and prostaglandins generation, but independent of nitric oxide (NO), gastric secretion and mucus production. We hypothesize that goniothalamin may act as a mild irritant, inducing the production of sulfhydryl compounds and prostaglandins, in a process known as adaptive cytoprotection. This hypothesis is supported by the fact that Michael acceptors are the most potent inducers of antioxidant response (as activation of Nrf2 pathway) through generation of mild oxidative stress and that gastroprotective activity of goniothalamin is inhibited after pre-treatment with NEM (N-ethylmaleimide) and NSAID (non-steroidal anti-inflammatory drugs), highlighting the importance of sulfhydryl compounds and prostaglandins on GTN activity.

Expression patterns of sirtuin 1-AMPK-autophagy pathway in chronic colitis and inflammation-associated colon neoplasia in IL-10-deficient mice.

BACKGROUND Interleukin-10-deficient (IL-10 (-/-)) mice spontaneously develop chronic colitis and adenocarcinoma through the dysplasia sequence. Autophagy malfunction is associated to inflammatory bowel disease (IBD) and colorectal cancer (CRC) pathogenesis. Autophagy is regulated by silent information regulator-1 (SIRT1), a NAD+-dependent histone deacetylase. Our aim was to investigate the expression changes of SIRT1-AMPK-autophagy pathway in the progression from chronic colitis to CRC. METHODS We studied C57BL/6-IL-10-deficient mice between 6 and 18weeks of age. Macroscopic and histological analysis, and characterization of inflammatory and tumor biomarkers were performed. RESULTS IL-10-deficient mice developed colitis from the age of 6weeks onward. The severity of inflammation and dysplasia, and the proliferative activity increased gradually with age. IL-10 (-/-) mice were characterized by improved levels of TNF-α and decreased expression of SIRT1. Moreover, our findings show an increase in p-AMPK expression and an activation of the autophagy in IL-10 (-/-) mice from all stages, evidenced by the accumulation of LC3-II protein, the increase in Beclin 1 expression and the reduction in Bcl-2 levels. CONCLUSIONS SIRT1-AMPK-autophagy pathway may be involved in the maintenance of chronic inflammation and dysplasia development in the IL-10-deficient mice model. Modulation of this pathway could be a novel strategy for IBD and CRC treatment.

Anti-inflammatory and antinociceptive effects of racemic goniothalamin, a styryl lactone

AIMS The present study aimed to further investigate the anti-inflammatory activity of goniothalamin (GTN), a styryl lactone, as well as its antinociceptive effects. MAIN METHODS The anti-inflammatory activity was evaluated in models of paw edema induced by different mediators in mice and carrageenan-induced peritonitis. Evaluation of the antinociceptive effect was performed through acetic acid-induced writhing test and formalin test. Activity of GTN on gene expression levels of interleukin-1beta (IL-1β), induced nitric oxidase synthase (iNOS) and cyclooxygenase-2 (COX-2) were evaluated in vitro in lipopolysaccharide (LPS)-stimulated macrophage (RAW 264.7), as well as gene expression and protein levels of tumor necrosis factor-alpha (TNF-α). KEY FINDINGS Pretreatment with GTN (300 mg/kg) significantly reduced paw edema induced by compound 48/80, prostaglandin E2, phospholipase A2 and bradykinin. GTN (10, 30 and 100mg/kg) inhibited leukocyte migration in the peritonitis model and gene expression levels of IL-1β, iNOS and TNF-α, as well as TNF-α protein levels, in LPS-stimulated macrophages, without affecting COX-2 gene expression levels. GTN inhibited nociception induced by acetic acid in the writhing model and in the formalin test, when both neurogenic and inflammatory phases were inhibited. SIGNIFICANCE For the first time the acute anti-inflammatory profile of GTN is characterized and its antinociceptive activity reported. The current study shows that GTN inhibits both vascular and cellular phases of inflammation, with bradykinin and PLA2 induced inflammation being the most affected by GTN. Its anti-inflammatory effects also involved the in vitro inhibition of gene expression of alarm cytokines and mediators as IL-1β, iNOS and TNF-α.