Introduction: Boletus bicolor (B. bicolor) mushrooms are widely consumed as a valuable medicinal and dietary ingredient in China, but the active ingredients of this mushroom and their extraction methods were not extensively studied.Methods: In this paper, we propose an optimized ultrasound-assisted extraction (UAE) method to detect natural antioxidant substances in B. bicolor. The antioxidants were quantitatively and quantitatively determined using UPLC-MS, the polyphenols were evaluated based on response surface methodology (RSM), and density functional theory (DFT) calculations were performed.Results: The results showed that the optimal extraction was obtained under the following conditions: ethanol concentration 42%; solvent to solid ratio 34:1 mL/g; ultrasonic time 41 min; and temperature 40°C. The optimized experimental polyphenol value obtained under these conditions was (13.69 ± 0.13) mg/g, consistent with the predicted value of 13.72 mg/g. Eight phenolic compounds in the extract were identiffed by UPLC-MS: syringic acid, chlorogenic acid, gallic acid, rosmarinic acid, protocatechuic acid, catechin, caffeic acid, and quercetin. Chlorogenic acid exhibits the highest HOMO energy (−0.02744 eV) and the lowest energy difference (−0.23450 eV) among the studied compounds, suggesting that the compound might be the strongest antioxidant molecule. Eight phenolic compounds from the B. bicolor signiffcantly inhibited intracellular reactive oxygen species (ROS) generation, reduced oxidative stress damage in H₂O₂-induced HepG-2 cells.Discussion: Therefore, it was confirmed that the UAE technique is an efficient, rapid, and simple approach for extracting polyphenols with antioxidant activity from B. bicolor.

The essential oil (EO) was extracted from aerial parts with insecticidal and fungicidal activity. Herein, the hydro-distilled essential oils of Seseli mairei H. Wolff roots were determined by GC-MS. A total of 37 components were identified, (E)-beta-caryophyllene (10.49%), β-geranylgeranyl (6.64%), (E)-2-decenal (6.17%) and germacrene-D (4.28%). The essential oil of Seseli mairei H. Wolff had nematicidal toxicity against Bursaphelenchus xylophilus with a LC₅₀ value of 53.45 μg/mL. The subsequent bioassay-guided investigation led to the isolation of three active constituents: falcarinol, (E)-2-decenal, and octanoic acid. The falcarinol demonstrated the strongest toxicity against B. Xylophilus (LC₅₀ = 8.52 μg/mL). The octanoic acid and (E)-2-decenal also exhibited moderate toxicity against B. xylophilus (LC₅₀ = 65.56 and 176.34 μg/mL, respectively). The LC₅₀ of falcarinol for the toxicity of B. xylophilus was 7.7 and 21 times than that of octanoic acid and (E)-2-decenal, respectively. Our findings demonstrate that the essential oil from Seseli mairei H. Wolff roots and their isolates may be developed as a promising natural nematicide.