A norterpenoid and tripenoids from Commiphora mukul: isolation and biological activity

Bio-guided fractionation of the guggul gum resin of Commiphora mukulHOOK using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay for the breast cancer cell line MDA-MB-231 led to the isolation of a new C17 norditerpene named myrrhanone C (1) along with two known polypodane-type triterpenes, namely, myrrhanone B (2) and myrrhanol B (3). The structures of the isolated compounds were elucidated by means of 1D (1H and 13C) and 2D (correlation spectroscopy, heteronuclear single-quantum coherence, heteronuclear multiple-bond correlation, and nuclear Overhauser effect spectroscopy) NMR spectroscopy as well as mass (electrospray ionization-mass spectroscopy) spectral analyses. Interestingly myrrhanone C (1) was able to induce a substantial decline in cell proliferation. It reduced the viability of cancer cells by almost 81% and 87% at concentrations of 50 and 100 μg mL−1, respectively. Myrrhanone B (2) and myrrhanol B (3) showed a concentration-dependent growth inhibitory effect on cancer cells, with the latter being slightly more cytotoxic than the former at both the concentrations tested. Furthermore, myrrhanone C (1) and myrrhanone B (2) showed good α-glucosidase and urease inhibition.