Three new cytochalasan alkaloids, cytochrysins A-C (1-3), and a new cyclobutane dimer, cytospodimer A (4), along with three known compounds (5-7), were isolated from the solid culture of Cytospora chrysosperma, an endophytic fungus isolated from Hippophae rhamnoides. Their structures were determined by a combination of spectroscopy and single-crystal X-ray crystallography. Compound 1 showed significant antibacterial activity against multi-drug resistant Enterococcus faecium with an MIC value of 25 mu g/mL, and compound 3 against methicillin-resistant Staphylococcus aureus with an MIC value of 25 mu g/mL. (C) 2021 Elsevier Ltd. All rights reserved.