“…Andrastone A ( 1 ) and 16-epi-citreohybriddione A ( 2 ) are two meroterpenoids biosynthesized from a sesquiterpene and a tetraketide. In fact, compounds possessing the same scaffold are rarely found in nature, including citreohybridones A and B (Kosemura et al, 1991b), Andrastins A–D (Shiomi et al, 1996; Uchida et al, 1996), atlantinones A and B (Wang et al, 2010), citreohybriddiones A–C (Kosemura, 2003), citreohybridones A–G and J–L (Kosemura, 2002), citreohybridonol (Oezkaya et al, 2018), 3-deacetylcitreohybridonol (Gao et al, 2012), 15-deacetylated citreohybridone E (Cheng et al, 2019), isocitreohybridones A–C and H–J (Kosemura, 2002, 2003), and isopenicins A–C (Tang et al, 2019). Among them, 18 possess a lactone moiety at the C-23 position.…”