Production of Childinan SF-2 as Bioactive Compound from Daldinia childiae: A Survey on Antioxidant, Antibacterial and Antitumor Properties.

Background: Fungal extracts have received increased attention due to their great medicinal applications including antitumor, immune-modulating, antioxidant, radical scavenging, antiviral, antibacterial, antifungal and detoxificating properties.

Objectives: This study is the first report on a novel bioactive compound, namely Childinan SF-2 which was isolated from soil ascomycete fungus. The significant antibacterial, antioxidant and cytotoxic properties of the extract may lead to development of novel, safe and useful substances.

Materials and methods: The isolate was identified on the basis of molecular approach. Spore suspension was inoculated in the culture medium and the bioactive compound was isolated from the viscous fermented broth via ethanol precipitation of the extracellular compound. The basic chemical composition of the extract including protein, carbohydrate, sulfate radical and uronic acid content were measured. FTIR (Fourier-transform infrared spectroscopy) and GC-MS (Gas chromatography-mass spectrometry) analysis were used for further structural characterization. The extract was utilized for treatment of AGS and MDA cell lines to assess the cell cycle and apoptosis. The antioxidant activity was examined using DPPH, hydroxyl radicals scavenging, β-carotene bleaching inhibition and ferric reducing power assay methods. The extract was tested for evaluation of antibacterial activity using different Gram-positive and Gram-negative bacterial strains.

Results: The fungal isolate was identified as the new strain Daldinia childiae SF-2. Initial biochemical characterization of the extract showed that the fungal biopolymer was composed of total sugars, protein, uronic acids and sulfated groups with values of 91.6%, 2.15%, 2.25% and 1.05% (w/w), respectively. FTIR and GC-MS analysis revealed that Childinan SF-2 might be mainly constructed from D-glucose, D-mannitol and D-galactofuranose. The in vitro experiments revealed that Childinan SF-2 enhanced the percentage of necrosis and apoptosis of cancer cells and blocked the cell cycle progression as shown by flowcytometry. Childinan SF-2 represented a considerable antioxidant and antibacterial activity.

Conclusions: These results indicated that Childinan SF-2 can serve as a potential source in medicinal applications. Keywords Exopolysaccharides; Fungal Biopolymers; Mycelial Secretions; Natural Pharmaceuticals; Xylariaceae.