Investigations of Bioactivity of Acalypha indica (L.), Centella asiatica (L.) and Croton bonplandianus (Baill) against Multidrug Resistant Bacteria and Cancer Cells

Abstract

The rate of infections caused by multidrug resistant (MDR) bacteria has recently increased worldwide. Such infections are prevalent in blood cancer patients increasing the risk of disease complications and mortality. This study aimed to investigate the potential of ethnomedicinal plants to inhibit the growth or survival of MDR bacteria and blood cancer cells. A series of major steps were conducted. First, 190 gram-negative clinical pathogens were collected in central region of Saudi Arabia, of which 89 (46.84%) were identified as extended spectrum of β-lactamase producers and 43 (22.63%) were Carbapenem-resistant. Second, ethanolic fraction and petroleum ether fraction were generated from Acalypha indica (L.), Centella asiatica (L.) and Croton bonplandianus (Baill). Third, antimicrobial analyses revealed that the ethanolic fraction of C. bonplandianus (Baill.) and A. indica (L.) exhibited superior activity against MDR pathogens with minimum inhibitory concentrations (MICs) = 1024–256 μg/mL and 1024–512 μg/mL, respectively. Fourth, cellular viability assay showed that the ethanolic fraction of C. bonplandianus had the highest activity against the survival of blood cancer cells (50% cytotoxic concentration (CC50) of K562 cells = 86.33 ± 10.06 μg/mL and CC50 of Raji cells = 470 ± 35.57 μg/mL). Fifth, flow-cytometric analyses indicated that necrosis was the type of cellular death induced in the malignant cells by C. bonplandianus (necrotic cells = 44%, p = 0.004, n=3). Finally, gas chromatography and tandem mass spectrometry (GC-MS/MS) analyses further supported these findings by identifying phytocompounds with known antibacterial and anticancer properties in the active plant fractions. Overall, the findings indicated a dual activity of C. bonplandianus against MDR bacteria and blood cancer cells.