Sesquiterpenoids from Carpesium abrotanoides and their anti-inflammatory activity both in vitro and in vivo

Twenty-nine sesquiterpenoids, including pseudoguaiane-type ( 1 – 11 ), eudesmane-type ( 12 – 23 ), and carabrane-type ( 24 – 29 ), have been identified from the plant Carpesium abrotanoides . Of them, compounds 1 – 4 , 12 – 15 , and 24 – 27 , namely carpabrotins A–L, are twelve previously undescribed ones. Compound 3 possessed a pseudoguaiane backbone with a rearrangement modification at C-11, C-12 and C-13, while compound 4 suffered a carbon bond break between the C-4 and C-5 to form a rare 4,5- seco -pseudoguaiane lactone. Compounds 1 – 3 , 5 , 13 – 16 and 25 – 27 exhibited anti-inflammatory activity by inhibiting NO production in LPS-induced RAW264.7 macrophages with IC 50 values less than 40 μM, while compounds 1 , 2 , 5 , 13 , 14 , 16 , and 25 – 27 showed significant inhibitory activity comparable to that of dexamethasone. The anti-atopic dermatitis (AD) effects of compounds 5 and 16 were tested according to 2,4-dinitrochlorobenzene (DNCB)-induced AD-like skin lesions in KM mice, and the results revealed that the major products 5 and 16 improved the histological features of AD-like skin lesions and mast cell infiltration in mice. This study suggested that sesquiterpenoids in C. abrotanoides should play a key role in its anti-inflammatory use.