Purpose

Phellinus fastuosus (Lév.) S. (Hymenochaetaceae, Hymenochaetales, Agaricomycetes, Basidiomycota) is a member of wood-rotting polyporoid fungi that contains numerous metabolites reported with many medicinal properties and has been used in traditional medicine for the treatment of various diseases. Inspired by the medicinal properties of this polypore the present study on the antioxidant and antiproliferative potential of methanolic extract of Phellinus fastuosus using various in vitro assays was proposed.

Methods

The extraction of the basidiocarp of Ph. fastuosus was done sequentially in hot water (Pfaq), methanol (Pfme) and ethyl acetate (Pfea) to obtain the respective extracts. The antioxidant potential of different extracts was examined with 2,2-Diphenyl-1-picrylhydrazyl (DPPH) assay, Ferric ion reducing antioxidant power and Phosphomolybdate assay. The cytotoxicity activity was determined by using MTT assay in human epidermoid carcinoma cells (A431), human cervical cancer (HeLa cells), human osteosarcoma (MG-63) and normal epidermoid cells (L929). For the assessment of changes in cell morphology, and apoptotic induction in A431 cell line was further investigated using phase-contrast microscopy, Hoechst 33342 staining and AO/EtBr dual staining. Flow cytometry was used for the estimation of production of reactive oxygen species (ROS) andmitochondrial membrane potential (MMP).

Results

Among all, Pfme extract showed effective free radical scavenging potential in DPPH assay, as compared to the other extracts. Therefore the Pmfe extract was further evaluated for the antiproliferative activity in A431, HeLa and MG-63 cell lines. This extract was very effective in A431 with GI₅₀ (growth inhibitory dose 50%) value of 81.39 compared to its effect in HeLa and MG-63 cells with GI₅₀ values of 173.47 and 191.53 μg/ml respectively. The Pfme extract was further investigated to explore its role in apoptosis induction in A431 cell line. Phase-contrast and fluorescence microscopic studies exhibited all the characteristics indicative of apoptosis, viz., shape change, cell shrinkage, cell rounding-off and nuclear condensation. To understand the cause of effectiveness of Pfme extract, HPLC analysis was carried out which showed the presence of different polyphenols.

Conclusions

A critical examination of results highlighted that the Pmfe extract induced apoptosis in A431 cells via ROS-mediated apoptotic pathway which may be ascribed to the presence of polyphenols in it.

Graphical Abstract