Opposite Effects of Two-Derived Antioxidants from Physalis pubescens L. on Hepatocellular Carcinoma Cell Line Malhavu.

Physalis pubescens L. (P. pubescens) is an edible plant used in folk medicine in China. There is traditional, but not scientific, evidence for the anti-tumour effects of P. pubescens. This study aimed to identify whether, or not, antioxidants rich in phenols and flavonoids from fruits and calyxes of P. pubescens can be the candidates for further development of an anti-hepatoma fraction, and if such biological effects coupled with reactive oxygen species (ROS) changes, can provide a direction for subsequent biological action. The effects of calyx-origin (or fruit-origin) total phenol and flavonoid (CTPF or FTPF) from P. pubescens on Malhavu cell viability were evaluated by using a counting-kit-8 (CCK-8) method. Morphological characterisation of cells was undertaken and the structures were photographed (200 × magnification) using Hoechst 3348 staining after exposure to different concentrations of CTPF or FTPF. Induced-apoptosis activity was determined using flow cytometry (FC) after Annexin VFITC/ PI staining. The corresponding ROS changes in Malhavu cells were observed and quantified by the uploading of 2', 7'-dichlorofluorescin diacetate (DCFH-DA). Anti-oxidation was evaluated by a cellular oxidation-stress model and chemical assessments for DPPH, hydroxyl radial, super-oxide radicals, and reducing power. Result shows that CTPF led to significant anti-proliferation in a time- and dosedependent manner. However, FTPF promoted cell viability at 100-1000 μg/mL with a dose-response manner in 24 h. With the extension of exposure time to 48 h, the cell viability did not increase with the growth of FTPF. Morphological characterisation and FC assay both demonstrated that CTPF, and not FTPF possessed induced-apoptotic activity. CTPF potentially induced cell apoptosis by promoting oxidative stress. FTPF indicated pro-oxidation at a concentration of 10 μg/mL and anti-oxidation capabilities at higher concentrations. ROS scavenging assay by oxidation-stress model indicated that CTPF (10 - 400 μg/mL) had ROS inhibitory capacity (R2 = 0.5156, p < 0.0001). FTPF (10 - 100 μg/mL) boosted the level of ROS (p < 0.0001) and inhibited the generation of ROS at 100-400 μg/mL (R2 = 0.5951, p < 0.0001). CTPF is a potential candidate requiring further exploration for the development of antihepatoma ingredients. The down-regulation of cell viability was related to production and reduction of cellular ROS.