Phytochemical investigation of ethanol extract of the trunk of Aglaia Lawii (Wight) C. J. Saldanha led to the isolation and identification of 11 triterpenoids (1-11) including a novel tetranortirucallane-type alkaloid aglawic acid (1). Aglawic acid (1) was a novel tetranortirucallane-type alkaloid with an unusual butanoic acid moiety attached to nitrogen atom of the maleimide ring. To the best of our knowledge, compound 1 is the first example of a natural terpenoids with an unusual butanoic acid moiety. 1 possessed potent anti-inflammatory activity against NO production with IC50 values of 9.65 μM compared with the positive control NG-monomethyl-L-arginine (L-NMMA, IC50 = 33.85 μM). In addition, 1 was evaluated for cytotoxicity against five human tumour cell lines (HL-60, A-549, SMMC-7721, MDA-MB-231, and SW480), but was found to be inactive.