Inonotus obliquus is a white rot fungus commonly known as “chaga” habiting as parasitism on birch trees in the cold latitudes of North America, Canada, Europe, Japan, China and Korea. Chaga has been recognized as a folk medicine since the sixteenth century for the treatment of gastrointestinal cancer, cardiovascular disease, and diabetes. Phenolic compounds are some of the main bioactive components in inonotus obliquus. In this study, response surface methodology (RSM) was used to optimize the extraction conditions to obtain an extract with high phenolic content and antioxidant activity from inonotus obliquus using accelerated solvent extraction (ASE). The total phenolic content TPC, antioxidant activity AA, and individual phenolic acid IPA of inonotus obliquus extracts at optimized conditions using ASE were compared with conventional extraction methods (reflux and maceration). The TPC and TAA in ASE extracts were higher than the other conventional extracts. The phenolic profile was quantitatively analyzed using high-performance liquid chromatography-diode array detection (HPLC–DAD). Analysis of optimized condition revealed five phenolic acids (3,4-dihydroxybenzoic acid, 3,4-dihydroxybenaldehyde, vanillic acid, caffeic acid, and syringic acid). A face-centered central composite design (FCCCD) by Design Expert Version 6.0.10 (Stat-Ease, USA) was employed for experimental design to obtain the optimized combination of extraction temperature (X1: 160-200 °C), and solvent (X2: EtOH, 70-90 %) based on the response of total phenolic content (TPC, mg gallic acid/g) value. The experimental data obtained from a thirteen-sample set were fitted to a second-order polynomial equation using multiple regression analysis. The corresponding response surface model was highly statistically significant (P &lt; 0.0001) and sufficient to describe and predict phenolic content value (R2 of 0.98). The optimum extraction conditions for phenolic extraction were temperature: 200°C, and solvent: 90% EtOH. Under these conditions, the predicted TPC of the extract was 56.5 mg gallic acid /g. Close agreement between experimental and the value predicted by the model was found.

Optimization by response surface methodology of phenolic compounds extraction from chaga (inonotus obliquus) using accelerated solvent extraction

256th National Meeting (2018)

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