Penicimides A and B, two novel diels–alder [4 + 2] cycloaddition ergosteroids from Penicillium herquei

•Sixteen ergosteroids including five ones were isolated.•Penicimides A and B are novel naturally occurring [4 + 2] Diels–Alder cycloaddition.•3 displayed significant anti-inflammatory activity in LPS-induced RAW264.7 cells.•Plausible biosynthetic pathways of compounds 1–6 were proposed.•The structure–activity relationship of the isolates was summarized.