Osteoclastogenesis inhibitory phenolic derivatives produced by the Beibu Gulf coral-associated fungus Acremonium sclerotigenum GXIMD 02501

Three new chlorinated orsellinic aldehyde derivatives, orsaldechlorins A - C (1-3) and a naturally new brominated orsellinic acid (7), along with ten known biosynthetically related phenolic (4-6, 8-13) and cyclohexanone (14) derivatives, were identified from the Beibu Gulf coral-derived fungus Acremonium sclerotigenum GXIMD 02501. Their structures were determined by spectroscopic data interpretation and comparison with those reported in the literature. Several of them showed inhibition of lipopolysaccharide (LPS)-induced NF-κB activation in RAW 264.7 macrophages at 20 μM. Moreover, the two new potent inhibitors (1 and 2) suppressed RANKL-induced osteoclast differentiation without cytotoxicity in bone marrow macrophages cells (BMMs). Our findings reveal that the phenolic compounds could be potential candidates for the prevention and treatment of osteolytic bone diseases.