Cerli Rocha Gattass

Melissa officinalis L. essential oil: antitumoral and antioxidant activities

Melissa officinalis L (lemon balm) is a traditional herbal medicine used widely as a mild sedative, spasmolytic and antibacterial agent. This paper focuses on the analysis of the chemical composition and the biological activities of M. officinalis essential oil obtained under controlled harvesting and drying conditions. An in‐vitro cytotoxicity assay using MTT indicated that this oil was very effective against a series of human cancer cell lines (A549, MCF‐7, Caco‐2, HL‐60, K562) and a mouse cell line (B16F10). This oil possessed antioxidant activity, as evidenced by reduction of 1,1‐diphenyl‐2‐picryl‐hydrazyl (DPPH). These results pointed to the potential use of M. officinalis essential oil as an antitumoral agent.

Antileishmanial Activity of an Indole Alkaloid from Peschiera australis

ABSTRACT In this study, we show the leishmanicidal effects of a chloroform fraction (CLF) and a purified indole alkaloid obtained from crude stem extract of Peschiera australis againstLeishmania amazonensis, a causative agent of cutaneous leishmaniasis in the New World. In a bioassay-guided chemical fractionation, the leishmanicidal activity in CLF completely and irreversibly inhibited promastigote growth. This fraction was also active against amastigotes in infected murine macrophages. Chemical analysis of CLF identified an iboga-type indole alkaloid coronaridine as one of its major compounds. Coronaridine showed potent antileishmanial activity, inhibiting promastigote and amastigote growth. Promastigotes and amastigotes treated with CLF or coronaridine showed pronounced alterations in their mitochondria as assessed by transmission electron microscopy.

Pentacyclic triterpenes from Chrysobalanaceae species: cytotoxicity on multidrug resistant and sensitive leukemia cell lines.

Plants are known as important source in the search for new anti-cancer agents. Cytotoxicity-guided fractionation of leaves and fruits from Licania tomentosa Bench and leaves from Chrysobalanus icaco L. resulted in the isolation of betulinic, oleanolic and pomolic acids. These triterpenoids inhibited the growth and induced apoptosis of K562, an erythroleukemia cell line. Most importantly, they also inhibited the proliferation of Lucena 1, a vincristine-resistant derivative of K562 that displays several multidrug resistance (MDR) characteristics. Taken together, our findings emphasize the anti-tumor activity of these triterpenes on leukemia cell lines and call attention to their potential as anti MDR agents.

TGF-β Mediates CTLA-4 Suppression of Cellular Immunity in Murine Kalaazar

Recent studies indicate important roles for CTLA-4 engagement in T cells, and for TGF-β production in the immunopathogenesis of murine kalaazar or visceral leishmaniasis, but a functional link between these two pathways in helping intracellular parasite growth is unknown. Here we report that Ag or anti-CD3 activation of splenic CD4+ T cells from visceral leishmaniasis leads to intense CTLA-4-mediated TGF-β1 production, as assessed either by CTLA-4 blockade or by direct CTLA-4 cross-linkage. Production of TGF-β1 accounted for the reciprocal regulation of IFN-γ production by CTLA-4 engagement. Following CD4+ T cell activation, intracellular growth of Leishmania chagasi in cocultured splenic macrophages required both CTLA-4 function and TGF-β1 secretion. Cross-linkage of CTLA-4 markedly increased L. chagasi replication in cocultures of infected macrophages and activated CD4+ T cells, and parasite growth could be completely blocked with neutralizing anti-TGF-β1 Ab. Exogenous addition of rTGF-β1 restored parasite growth in cultures protected from parasitism by CTLA-4 blockade. These results indicate that the negative costimulatory receptor CTLA-4 is critically involved in TGF-β production and in intracellular parasite replication seen in murine kalaazar.

Preliminary results from a phase I/II study of perillyl alcohol intranasal administration in adults with recurrent malignant gliomas

BACKGROUND Activation of the p21-ras signaling pathway from aberrantly expressed receptors promotes the growth of malignant human astrocytomas. Perillyl alcohol has shown to have both chemopreventive and chemotherapeutic activities in preclinical studies. The underlying action mechanism(s) of POH has yet to be delineated but may involve effects on the TGF-beta and/or the Ras signaling pathways. The intranasal delivery allows drugs that do not cross the BBB to enter the CNS; moreover, it eliminates the need for systemic delivery, thereby reducing unwanted systemic side effects. METHODS We are conducting a phase I/II study to evaluate the antitumoral activity of POH intranasal delivery in a 4x daily schedule in patients with recurrent MG. The objective was to determine PFS at 6 months and the safety for POH in adult patients who failed conventional treatment. Assessments were performed every 27 days. Thirty-seven patients with progressive disease after prior surgery, radiotherapy, and at least temozolomide-based chemotherapy were enrolled, 29 of whom had GBM, 5 who had anaplastic astrocytoma, and 3 had AO. RESULTS One patient (3.4%) with GBM and 1 patient (33.3%) with AO achieved partial response; 13 patients (44.8%) with GBM, 3 patients (60%) with AA, and 1 (33.3%) with AO achieved stable disease; 15 (51.7%) patients with GBM, 2 (40%) patients with AA, and 1 (33.3%) with AO showed progressive disease. Progression-free survival (partial response and stable disease) was 48.2% for patients with GBM, 60% for patients with AA, and 66.6% for patients with AO. CONCLUSIONS There were no toxicity events. Perillyl alcohol is well tolerated and regression of tumor size in some patients is suggestive of antitumor activity. This work discusses POH intranasal delivery as a potential adjuvant therapeutic strategy for patients with malignant gliomas.

Oleanolic Acid Initiates Apoptosis in Non-Small Cell Lung Cancer Cell Lines and Reduces Metastasis of a B16F10 Melanoma Model In Vivo

Background Drug resistance, a process mediated by multiple mechanisms, is a critical determinant for treating lung cancer. The aim of this study is to determine if oleanolic acid (OA), a pentacyclic triterpene present in several plants, is able to circumvent the mechanisms of drug resistance present in non-small cell lung cancer (NSCLC) cell lines and to induce their death. Principal Findings OA decreased the cell viability of the NSCLC cell lines A459 and H460 despite the presence of active, multidrug-resistant (MDR) MRP1/ABCC1 proteins and the anti-apoptotic proteins Bcl-2 and survivin. These effects are due to apoptosis, as evidenced by the capacity of OA to induce fragmentation of DNA and activate caspase 3. Induction of NSCLC cell death by OA cannot be explained by inhibition of the MDR proteins, since treatment with triterpene had little or no effect on the activity or expression of MRP1. Moreover, treatment with OA had no effect on the expression of the anti-apoptotic protein Bcl-2, but increased the expression of the pro-apoptotic protein Bax, altering the Bcl-2/Bax balance towards a pro-apoptotic profile. OA also decreased the expression of the anti-apoptotic protein survivin. Furthermore, OA decreased the expression of the angiogenic vascular endothelial growth factor (VEGF) and decreased the development of melanoma-induced lung metastasis. Conclusion Our data provide a significant insight into the antitumoral and antimetastatic activity of OA in NSCLC and suggest that including OA in the NSCLC regimens may help to decrease the number of relapses and reduce the development of metastases.

In Vitro Activities of Iboga Alkaloid Congeners Coronaridine and 18-Methoxycoronaridine against Leishmania amazonensis

ABSTRACT In previous studies, we demonstrated the leishmanicide effect of coronaridine, a natural indole alkaloid isolated from stem bark of Peschiera australis (Delorenzi et al., Antimicrob. Agents Chemother. 45:1349-1354, 2001). In this study we show the leishmanicidal effect of the synthetic coronaridine and its racemic 18-methoxylated analog, 18-methoxycoronaridine. Both alkaloids revealed a potent leishmanicide effect against Leishmania amazonensis, a causative agent of cutaneous and diffuse cutaneous leishmaniasis in the New World. Despite their potent leishmanicide effect, both alkaloids were neither toxic to murine macrophages nor did they modulate their oxidative or cytokine production responses.

Topological Polar Surface Area Defines Substrate Transport by Multidrug Resistance Associated Protein 1 (MRP1/ABCC1)

Multidrug resistance-associated protein 1 (MRP1/ABCC1) is a very promiscuous transporter. Herein we used topological polar surface area (TPSA), a descriptor defined as the sum of surfaces of polar atoms in a molecule, to analyze drug transport by MRP1. We suggested that compounds with high TPSA are transported while those with low TPSA are not. The conjugation to GSH increases TPSA values favoring transport. A strong correlation between TPSA and transport properties (K(m)) was also found.

Trypanosoma cruzi : properties of a clone isolated from CL strain

BALB/c mice injected i.p. with 2×106 metacyclic forms of CL-14, a clone isolated from the CL strain ofTrypanosoma cruzi, did not show parasitemia as evaluated by direct blood microscopy examination, hemoculture and xenodiagnosis. Moreover, new-born mice (1–2 days old) injected with culture-or insect-derived CL-14 trypomastigotes also displayed negative parasitemia. No mortality was observed in either group of animals. However, despite this apparent non-infectivity, mice injected with clone 14 developed high resistance against a lethal challenge with virulent trypomastigotes. All challenged mice survived and the parasitemia was negative. These results indicate that clone 14 is a very good antigen for the study of acquired immunity inT. cruzi infection and, therefore, a potential candidate for the development of a vaccine against this parasite.

Negative tissue parasitism in mice injected with a noninfective clone ofTrypanosoma cruzi

Trypanosoma cruzi is a heterogeneous population of parasites as shown by differences between strains and cloned stock from the same strain. Herein we present evidence of the noninfectivity of CL-14, a clone derived from the CL strain ofT. cruzi. In a previous paper we reported the absence of parasitemia and mortality in mice injected with metacyclic trypomastigotes of this clone. To investigate further this lack of infectivity we did and extensive histopathological analysis in mice at different intervals after i.p. (5 and 15 days as well as 1, 4, and 12 months) or i.v. (5 and 30 days) injection of trypomastigotes. In spite of a systematic search in all tissues and organs of the animals, no parasite or significant pathological change was detected in any of the tissue sections. These data suggest the inability of this clone to mediate infection and/or cause pathological alterations in vivo.