New γ-lactams from Paraphoma sp. AC-G1 isolated from Artemisia argyi

Phomalactones A ( 1 ) and B ( 2 ), two new γ -lactam derivatives, and one known compound, namely, phaeosphaeride A ( 3 ), were isolated from Paraphoma sp. AC-G1, an endophytic fungus isolated from Artemisia argyi . Their structures were determined using 1D and 2D NMR spectra, HRESIMS, and optical rotation measurements. Compounds 1–3 were assessed for their antimicrobial activities on Ralstonia solanacearum , Fusarium oxysporum , and Alternaria alternata . The results showed that compounds 1 and 3 exhibited significant inhibition on F. oxysporum . • Two new γ -lactam derivatives ( 1 and 2 ) were isolated from Paraphoma sp. AC-G1. • Chemical structures of compounds were determined by comprehensive spectroscopic data. • Compounds 1 and 3 exhibited significant inhibition on Fusarium oxysporum .