Five new compounds, including a pair of diphenylcyclopentenone enantiomers (+/-)-phomopsisin A (1), a sesquiterpenoid 15-hydroxylithocarin A (2), a new diketopiperazine alkaloid prenylcyclotryprostatin A (3) and 7hydroxy-cis-L(- )-3,6-dibenzyl-2,5-dioxopiperazine (6), along with five known compounds were isolated from the fungus Phomopsis asparagi. Their structures were elucidated on the basis of spectroscopic analyses (1D and 2D NMR), theoretical electronic circular dichroism (ECD) calculation, modified Mosher's method, and X-ray crystallography. The racemates of (+/-)-phomopsisin A showed inhibition on alpha-glucosidase with IC50 of 30.07 +/- 0.75 mu M (positive control acarbose, 121 +/- 2.7 mu M).