Characterization of Eight New Secondary Metabolites from the Mutant Strain G‐444 of Tubercularia sp. TF5

Abstract

AbstractEight new metabolites, including five new sesquiterpenoids, 10,11‐epoxyguaian‐10‐ol (1), 10,11‐epoxyguaian‐13‐ol (2), a new backbone sesquiterpene rearranged from guaiane (3), two 1,5 : 1,10‐disecoguaianes, 4 and 5, two new dihydroisocoumarins, 7‐chloromellein‐4‐ol (6) and 7‐chloromellein‐5‐ol (7), and one new tetralone, 7‐chloroscytalone (8), were isolated from the mutant strain G‐444 of Tubercularia sp. TF5, an endophytic fungus of Taxus mairei, along with ten known compounds, 3,4‐dihydro‐4,8‐dihydroxy‐2H‐naphthalen‐1‐one (9), (3R,4S)‐4‐hydroxymellein (10), 5‐formylmellein (11), 5‐carboxymellein (12), sporogen‐AO1 (13), tuberculariols A (14) and B (15), hymatoxin E (16), 4‐oxo‐4H‐pyran‐3‐acetic acid (17), and penicillic acid (18). Their structures were elucidated by spectroscopic analyses including HR‐ESI‐MS, 1D‐ and 2D‐NMR (HMQC, HMBC, 1H,1H‐COSY and NOESY). The antimicrobial activities of 1–8 were evaluated, but none showed any substantial effect.