The effects of ethanol concentration (0%–100%, v/v), solid-to-solvent ratio (1:10–1:60, w/v) and extraction time (30–180 min) on the extraction of polyphenols from agarwood (Aquilaria crassna) were examined. Total phenolic content (TPC), total flavonoid content (TFC) and total flavanol (TF) assays and HPLC-DAD were used for the determination and quantification of polyphenols, flavanol gallates (epigallocatechin gallate—EGCG and epicatechin gallate—ECG) and a benzophenone (iriflophenone 3-C-β-glucoside) from the crude polyphenol extract (CPE) of A. crassna. 2,2'-Diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity was used to evaluate the antioxidant capacity of the CPE. Experimental results concluded that ethanol concentration and solid-to-solvent ratio had significant effects (p < 0.05) on the yields of polyphenol and antioxidant capacity. Extraction time had an insignificant influence on the recovery of EGCG, ECG and iriflophenone 3-C-β-glucoside, as well as radical scavenging capacity from the CPE. The extraction parameters that exhibited maximum yields were 40% (v/v) ethanol, 1:60 (w/v) for 30 min where the TPC, TFC, TF, DPPH, EGCG, ECG and iriflophenone 3-C-β-glucoside levels achieved were 183.5 mg GAE/g DW, 249.0 mg QE/g DW, 4.9 mg CE/g DW, 93.7%, 29.1 mg EGCG/g DW, 44.3 mg ECG/g DW and 39.9 mg iriflophenone 3-C-β-glucoside/g DW respectively. The IC₅₀ of the CPE was 24.6 mg/L.

The present study aims to assess the antioxidant activities (AOA) and total phenolic content (TPC) of water extracts of selected edible wild mushrooms: Pleurotus porrigens, Schizophyllum commune, Hygrocybe conica, and Lentinus ciliates. The AOA were evaluated against DPPH radical and ABTS radical cation scavenging ability, ferric-reducing antioxidant power (FRAP) and β-carotene-linoleate bleaching (β-CB) assays, and the Folin-Ciocalteu method for TPC. BHA was used as reference. P. porrigens showed significantly higher (p < 0.05) DPPH· scavenging ability (90.78 ± 0.30%) and FRAP (6.37 ± 0.22 mM FE/100g), while Sch. commune showed significantly higher (p < 0.05) ABTS·+ inhibition activity (94.96 ± 0.70%) and β-CB inhibition activity (94.18 ± 0.17%), respectively. TPC was found in a descending order of P. poriggens > L. ciliatus = Pleurotus ostreatus (cultivated) > H. conica = Sch. commune. Positive correlation was observed between the AOA and TPC. When compared to BHA (2 mM), P. porrigens showed significantly higher (p < 0.05) DPPH· scavenging ability and reducing power, while Sch. commune showed comparable DPPH· scavenging ability and ABTS·+ inhibition activity. All the mushrooms have better ABTS·+ inhibition activity than BHA (1 mM). The β-CB inhibition activity of BHA was significantly higher than those of edible wild mushrooms. The water extracts of edible wild mushrooms showed potent antioxidant activities compared to BHA to a certain extent.

The oxidative stability of sunflower oil supplemented with medicinal split gill mushroom, Schizophyllum commune's crude extract (CE), the formic acid (FA) fraction and semipurified subfractions (SF) II and IV were tested, compared to BHA and α-tocopherol, by measuring their peroxide value, iodine value, p-anisidine value, thiobarbituric acid-reactive substances, and free fatty acid content. Their total phenolic content (TPC), 2,2-diphenyl-1-picryhydrazyl (DPPH) radical scavenging, and ferric reducing/antioxidant power (FRAP) were also evaluated. FA and CE exhibited highest DPPH•scavenging, while FA and SFIV showed the highest FRAP; TPC was found to be highest in CE, FA, and SFIV. BHA and α-tocopherol are more protective in stabilizing the sunflower oil; SFII and SFIV had short-term protective effect in secondary oxidation for 1 year, while CE and FA retarded secondary oxidation and extended the shelf life 11/2 years and 2 years, respectively. HPLC-DAD analysis found (+)-catechin in Sch. commune's extracts. Sch. commune's extracts did not show similar retardation of lipid oxidation in sunflower oil as compared to α-tocopherol and BHA at the 200 ppm level. However, the higher concentration of Sch. commune's extract that provided the protective effect in stabilizing sunflower oil can be further studied.