The endophytic fungus Eupenicillium sp. LG41 was isolated from the roots of Xanthium sibiricum (Asteraceae) collected from Taian, Shandong Province, People's Republic of China. This fungal strain was cultured on PDA medium at 28 ℃ for 1 week. Agar plugs were cut into small pieces, and 40 pieces were selected to inoculate 40 Erlenmeyer flasks (500 mL) each containing 250 mL of PDB. The cultures were incubated at 28 ℃ on a rotary shaker (150 rpm) for 28 days. The endophytic fungus was further fermented in 35 Erlenmeyer flasks (500 mL) each containing 250 mL of PDB supplemented with 15 mg/100 mL of nicotinamide. The cultures were incubated at 28 ℃ on a rotary shaker (150 rpm) for 28 days.