Synthesis of nigranoic acid and manwuweizic acid derivatives as HDAC inhibitors and anti-inflammatory agents

As a successful anti-tumor drug target, the family of histone deacetylases (HDACs) is also a critical player in immune response, making the research of anti-inflammatory HDAC inhibitors an attractive new focus. In this report, triterpenoids nigranoic acid (NA) and manwuweizic acid (MA) were identified as HDAC inhibitors through docking-based virtual screening and enzymatic activity assay. A series of derivatives of NA and MA were synthesized and assessed for their biological effects. As a result, hydroxamic acid derivatives of NA and MA showed moderately increased activity for HDAC1/2/4/6 inhibition (the lowest IC50 against HDAC1 is 1.14 ?M), with no activity against HDAC8. In J774A.1 macrophage, compound 1?3, 13 and 17?19 demonstrated inhibitory activity against lactate dehydrogenase (LDH) and IL-113 production, without affecting cell viability. Compound 19 increased the histone acetylation level in J774A.1 cells, as well as inhibited IL-113 maturation and caspase-1 cleavage. These results indicated that compound 19 blocks the activation of NLRP3 inflammasome, probably related to HDAC inhibition. This work provided a natural scaffold for developing low-cytotoxic and antiinflammatory HDAC inhibitors, as well as a class of tool molecules for studying the relationship between HDACs and NLRP3 activation.

Automated summary

This study identified hydroxamic acid derivatives of nigranoic acid and manwuweizic acid as potential HDAC inhibitors with anti-inflammatory properties. These compounds showed promising activity in inhibiting HDACs and impacting immune response pathways, providing a natural scaffold for developing new anti-inflammatory drugs.