Cytotoxicity and bacterial membrane destabilization induced by Annona squamosa L. extracts.

This study aimed to further investigate the cytotoxicity against tumor cell lines and several bacterial strains of Annona squamosa and its mode of action. Methanol extracts of A. squamosa leaves (ASL) and seeds (ASS) were used. ASL showed significant antibacterial activity against S. aureus, K. pneumoniae and E. faecalis with MIC values of 78, 78 and 39 µg/mL respectively. Moreover, ASL exhibited significant biofilm disruption, rapid time dependent kinetics of bacterial killing, increased membrane permeability and significantly reduced the cell numbers and viability. Regarding the cytotoxicity against tumor cell lines, ASS was more active against Jurkat and MCF-7 cells, with CI50 1.1 and 2.1 µg/mL, respectively. ASL showed promising activity against Jurkat and HL60, with CI50 4.2 and 6.4 µg/mL, respectively. Both extracts showed lower activity against VERO cells and reduced the clonogenic survival at higher concentrations (IC90) to MCF-7 and HCT-116 lineages. The alkaloids anonaine, asimilobine, corypalmine, liriodenine nornuciferine and reticuline were identified in extracts by UPLC-ESI-MS/MS analysis. This study reinforced that A. squamosa presents a remarkable phytomedicinal potential and revealed that its antimicrobial mechanism of action is related to bacterial membrane destabilization.

Cytotoxicity and bacterial membrane destabilization induced by Annona squamosa L. extracts

ABSTRACT This study aimed to further investigate the cytotoxicity against tumor cell lines and several bacterial strains of Annona squamosa and its mode of action. Methanol extracts of A. squamosa leaves (ASL) and seeds (ASS) were used. ASL showed significant antibacterial activity against S. aureus, K. pneumoniae and E. faecalis with MIC values of 78, 78 and 39 µg/mL respectively. Moreover, ASL exhibited significant biofilm disruption, rapid time dependent kinetics of bacterial killing, increased membrane permeability and significantly reduced the cell numbers and viability. Regarding the cytotoxicity against tumor cell lines, ASS was more active against Jurkat and MCF-7 cells, with CI50 1.1 and 2.1 µg/mL, respectively. ASL showed promising activity against Jurkat and HL60, with CI50 4.2 and 6.4 µg/mL, respectively. Both extracts showed lower activity against VERO cells and reduced the clonogenic survival at higher concentrations (IC90) to MCF-7 and HCT-116 lineages. The alkaloids anonaine, asimilobine, corypalmine, liriodenine nornuciferine and reticuline were identified in extracts by UPLC-ESI-MS/MS analysis. This study reinforced that A. squamosa presents a remarkable phytomedicinal potential and revealed that its antimicrobial mechanism of action is related to bacterial membrane destabilization.

Bismuth(III) complexes with 2-acetylpyridine- and 2-benzoylpyridine-derived hydrazones: Antimicrobial and cytotoxic activities and effects on the clonogenic survival of human solid tumor cells.

Complexes [Bi(2AcPh)Cl2]·0.5H2O (1), [Bi(2AcpClPh)Cl2] (2), [Bi(2AcpNO2Ph)Cl2] (3), [Bi(2AcpOHPh)Cl2]·2H2O (4), [Bi(H2BzPh)Cl3]·2H2O (5), [Bi(H2BzpClPh)Cl3] (6), [Bi(2BzpNO2Ph)Cl2]·2H2O (7) and [Bi(H2BzpOHPh)Cl3]·2H2O (8) were obtained with 2-acetylpyridine phenylhydrazone (H2AcPh), its -para-chloro-phenyl- (H2AcpClPh), -para-nitro-phenyl (H2AcpNO2Ph) and -para-hydroxy-phenyl (H2AcpOHPh) derivatives, as well as with the 2-benzoylpyridine phenylhydrazone analogues (H2BzPh, H2BzpClPh, H2BzpNO2Ph, H2BzpOHPh). Upon coordination to bismuth(III) antibacterial activity against Gram-positive and Gram-negative bacterial strains significantly improved except for complex (4). The cytotoxic effects of the compounds under study were evaluated on HL-60, Jurkat and THP-1 leukemia, and on MCF-7 and HCT-116 solid tumor cells, as well as on non-malignant Vero cells. In general, 2-acetylpyridine-derived hydrazones proved to be more potent and more selective as cytotoxic agents than the corresponding 2-benzoylpyridine-derived counterparts. Exposure of HCT-116 cells to H2AcpClPh, H2AcpNO2Ph and complex (3) led to 99% decrease of the clonogenic survival. The IC50 values of these compounds were three-fold smaller when cells were cultured in soft-agar (3D) than when cells were cultured in monolayer (2D), suggesting that they constitute interesting scaffolds, which should be considered in further studies aiming to develop new drug candidates for the treatment of colon cancer.