The cytotoxic effect and glucose uptake modulation of Baeckea frutescens on breast cancer cells

Abstract

Background Baeckea frutescens ( B. frutescens ) of the family Myrtaceae is a plant that has been used in traditional medicine. It is known to have antibacterial, antipyretic and cytoprotective properties. The objective of this study is to explore the mechanism of B. frutescens leaves extracts in eliminating breast cancer cells. Method B. frutescens leaves extracts were prepared using Soxhlet apparatus with solvents of different polarity. The selective cytotoxicity of these extracts at various concentrations (20 to 160 μg/ml) were tested using cell viability assay after 24, 48 and 72 h of treatment. The IC 50 value in human breast cancer (MCF-7 and MDA-MB-231) and mammary breast (MCF10A) cell lines were determined. Apoptotic study using AO/PI double staining was performed using fluorescent microscope. The glucose uptake was measured using 2-NBDG, a fluorescent glucose analogue. The phytochemical screening was performed for alkaloids, flavonoids, tannins, triterpenoids, and phenols. Results B. frutescens leaves extracts showed IC 50 value ranging from 10 -127μg/ml in MCF-7 cells after 72 h of treatment. Hexane extract had the lowest IC 50 value (10μg/ml), indicating its potent selective cytotoxic activity. Morphology of MCF-7 cells after treatment with B. frutescens extracts exhibited evidence of apoptosis that included membrane blebbing and chromatin condensation. In the glucose uptake assay, B. frutescens extracts suppressed glucose uptake in cancer cells as early as 24 h upon treatment. The inhibition was significantly lower compared to the positive control WZB117 at their respective IC 50 value after 72 h incubation. It was also shown that the glucose inhibition is selective towards cancer cells compared to normal cells. The phytochemical analysis of the extract using hexane as the solvent in particular gave similar quantities of tannin, triterpenoids, flavonoid and phenols. Presumably, these metabolites have a synergistic effect in the in vitro testing, producing the potent IC 50 value and subsequently cell death. Conclusion This study reports the potent selective cytotoxic effect of B. frutescens leaves hexane extract against MCF-7 cancer cells. B. frutescens extracts selectively suppressed cancer cells glucose uptake and subsequently induced cancer cell death. These findings suggest a new role of B. frutescens in cancer cell metabolism. Electronic supplementary material The online version of this article (10.1186/s12906-019-2628-z) contains supplementary material, which is available to authorized users.

The cytotoxic effect of Baeckea frustescens extracts in eliminating hypoxic breast cancer cells

“…Previously, we have measured the cytotoxic activity of hexane, water and ethanolic B. frutescens extracts (0-160 μg/ml) from leaves against MCF-7 cells for 24, 48 and 72 h in normoxic condition. It was noted that hexane extract of B. frutescens leaves possess selective cytotoxic activity and modulate glucose uptake in breast cancer cells [21,22]. To our knowledge, this is the first report describing the cytotoxic activity of B. frutescens extracts against MCF-7 cells in hypoxic condition.…”

“…The leaves and branches of B. frutescens were air-dried under shade for 7 days and were pulverized into coarse powder. The coarse powder was extracted using hexane, ethanol, and water as previously described by Shahruzaman et al [21]. Briefly, for ethanol extracts, 111 g, 142 g, and 200 g of coarse powder were weighed and extracted in 5 l of ethanol to obtain 90, 70, and 50, respectively.…”

“…The MTT assay was conducted as previously described [21]. Briefly, 30 μl of MTT/Phosphate buffered saline (PBS) (Amresco, USA) solution was added into each well and incubated for 4 hours in dark.…”

“…Our lab has previously explored the cytotoxicity of B. frutescens leaves [21] and branch [22] extracts on human breast cancer cells (MCF-7). The extracts showed selective cytotoxicity with IC 50 of less than 50 μg/mL and inhibited glucose consumption as early as 24 hours after treatment.…”

Chemical Composition of a Supercritical Fluid (Sfe-CO2) Extract from Baeckea frutescens L. Leaves and Its Bioactivity Against Two Pathogenic Fungi Isolated from the Tea Plant (Camellia sinensis (L.) O. Kuntze)

“…Baeckea frutescens L. is an important medicinal plant belonging to the Myrtaceae family [ 1 ] and is found in Peninsular Malaysia and Sumatra and distributed along coastal areas of southeastern China and Australia [ 2 ]. B. frutescens has various bioactive properties, such as antibacterial [ 1 , 3 ], antioxidant [ 2 ], anticancer [ 4 ], anti-inflammatory [ 5 ] and insecticidal activities [ 1 ]. The leaves of B. frutescens are rich in various volatile constituents such as terpenoids, sesquiterpenes and phenylpropanoids, which are secondary metabolites associated with numerous bioactivities [ 1 , 5 , 6 ].…”