RESUMEN
This work presents a new procedure to synthesize ruthenium-phthalocyanine complexes and uses diverse spectroscopic techniques to characterize trans-[RuCl(Pc)DMSO] (I) (Pc = phthalocyanine) and trans-[Ru(Pc)(4-ampy)2] (II) (4-ampy = 4-aminopyridine). The triplet excited-state lifetimes of (I) measured by nanosecond transient absorption showed that two processes occurred, one around 15 ns and the other around 3.8 µs. Axial ligands seemed to affect the singlet oxygen quantum yield. Yields of 0.62 and 0.14 were achieved for (I) and (II), respectively. The lower value obtained for (II) probably resulted from secondary reactions of singlet oxygen in the presence of the ruthenium complex. We also investigate how axial ligands in the ruthenium-phthalocyanine complexes affect their photo-bioactivity in B16F10 murine melanoma cells. In the case of (I) at 1 µmol/L, photosensitization with 5.95 J/cm2 provided B16F10 cell viability of 6%, showing that (I) was more active than (II) at the same concentration. Furthermore, (II) was detected intracellularly in B16F10 cell extracts. The behavior of the evaluated ruthenium-phthalocyanine complexes point to the potential use of (I) as a metal-based drug in clinical therapy. Changes in axial ligands can modulate the photosensitizer activity of the ruthenium phthalocyanine complexes.
RESUMEN
Abstract Lichens have exhibited numerous biological activities, including growth inhibition of tumor cells. This study evaluated the antiproliferative activity of hypostictic and salazinic acids against tumor cell lines (B16-F10, PC-03, MCF7, HT-29, HEP-G2, K562 and 786-0) by the SRB assay in vitro and antitumor activity in experimental murine melanoma in vivo. Activation of caspase-3 was quantified by flow cytometry. The murine experimental melanoma model B16-F10 was used in BALB/c mice for evaluation of antitumor activity. Hypostictic acid showed significant antiproliferative activity in K562 cells (GI50 2.20 µM), B16-F10 (GI50 13.78 µM) and 786-0 (GI50 14.24 µM), whereas salazinic acid was more active against K562 cells (GI50 64.36 µM), HT-29 (GI50 67.91 µM) and B16-F10 (GI5078.64 µM). Quantification of capase-3 revealed that the test compounds did not increase the expression of that enzyme. In the in vivo antitumor evaluation in B16-F10 melanoma, the isolated compounds inhibited tumor growth in relation to weight and volume. Hypostictic acid (16.7 mg/kg) inhibited 72% and salazinic acid 88% of tumor volume (p < 0.05). The results indicated that, both in the in vitro and in vivo models, the compounds evaluated showed antiproliferative and antitumor activities.
RESUMEN
The current study aims to extract bromelain from different parts (stem, crown, peels, pulp and leaves) of Ananas comosus var. comosus AGB 772; to determine of optimum pH and temperature; to test bromelain stability in disodium EDTA and sodium benzoate, and to investigate its pharmacological activity on B16F10 murine melanoma cells in vitro. The highest enzymatic activity was found in bromelain extracted from the pulp and peel. The optimum bromelain pH among all studied pineapple parts was 6.0. The optimum temperature was above 50 °C in all bromelain extracts. The fluorescence analysis confirmed the stability of bromelain in the presence of EDTA and sodium benzoate. Bromelain was pharmacologically active against B16F10 melanoma cells and it was possible verifying approximately 100% inhibition of tumor cell proliferation in vitro. Since bromelain activity was found in different parts of pineapple plants, pineapple residues from the food industry may be used for bromelain extraction.