The effect of green extraction method, subcritical, water extraction, on selected biological activities in Chaga mushroom

Abstract

Inonotus obliquus, or Chaga, is a medicinal mushroom with a long history of folk medicinal use and growing popularity worldwide. It cannot be cultivated so novel, greener extraction methods are needed to satisfy the market and obtain high-quality supplements. In this study, we evaluated the biological activity (antimicrobial and antioxidant) of Mongolian (IM) and Serbian (IS) Chaga extracts obtained by subcritical water extraction. They were also screened for general chemical composition. Both IM and IS, have high phenolic content. HPLC analysis revealed that extracts are especially rich in chlorogenic acid, followed by catechins, p-coumaric and cinnamic acids. ABTS assay confirmed the remarkable scavenging ability of extracts, reaching 98% when a concentration of 2 mg/mL was tested. The antimicrobial potential was examined by microdilution method using Gram-positive and (Enterococcus faecalis and Staphylococcus aureus), Gram-negative bacteria (Escherichia coli and Actinetobacteria baumannii). According to the obtained minimal inhibitory concentration (MIC) for E. faecalis S. aureus (MIC -1.25 mg / mL), E. coli, and A. baumannii (MIC -2.5 mg / mL) both extracts were shown to have the same effect on the tested bacteria. Hereby, we demonstrated the high biological potential of extracts obtained by subcritical water extraction.