ABSTRACT
Objective: To study the secondary metabolites of Penicillium oxalicum, an endophytic fungus isolated from the medicinal plant Pseudostellariaheterophylla. Methods: The secondary metabolites were isolated by silica gel, Sephadex LH-20 column chromatographies, and prep-TLC methods. Their structures were elucidated by using various spectroscopic techniques including HRESIMS and NMR spectra. Results: A benzofuran compound 5,7-dihydroxy-2-methylbenzofuran-3-carboxylic acid (1), five isocoumarins including (3R,4R)-(-)-4-hydroxymellein (2), O-methylmellein (3), acremonone G (4), decarboxycitrinone (5) and decarboxyhydroxycitrinone (6), four bisabolane-type sesquiterpenoids including (7S,11S)-(+)-12-acetoxysydonic acid (7), (S)-(+)-11-dehydrosydonic acid (8), sydonic acid (9) and 1-hydroxy-boivinianin A (10), as well as two meroterpenoid-type alkaloids decaturin D (11) and decaturinC (12) were isolated. Conclusion: Compound 1 is a new benzofuran compound and named as oxafuranone A, while compounds 2-6 and 10 are characterized from P. oxalicum for the first time.