Terpenoid Compounds From Montanoa tomentosa Cerv. With Anti-inflammatory Potential

Montanoa tomentosa has been used in Mexican traditional medicine as a labor inducer and contraceptive, as well as for the treatment of pain after childbirth. In this sense, M. tomentosa is an important source of metabolites with potent anti-inflammatory activity. The objective of this work was to evaluate the anti-inflammatory activity of extracts: n-hexane (MtHex), ethyl acetate (MtAc), and methanol (MtMe), and compounds isolated from leaves of M. tomentosa. The anti-inflammatory effect was evaluated in the 12-O-tetradecanoylphorbol-13-acetate (TPA)-induced ear edema model in mice. The compounds were structurally characterized using one- and two-dimensional nuclear magnetic resonance spectroscopy. The MtHex (1 mg/ear) reduced edema (61.16 ± 3.8%), showing a similar effect to indomethacin (70.02 ± 1.24%). From the MtHex extract, the following compounds were isolated and identified: β-sitosterol (1), stigmasterol (2), kaurenoic acid (3), grandiflorenic acid (4), taraxasterol (5), and 15-cinnamoylkaurenic acid (6). Compounds 5, 6, and the mixture of 3 and 4 were evaluated; compound 6 showed the most significant effect in the TPA model (79.05 ± 3.07%). These exploratory results demonstrate that M. tomentosa could be an important source of terpene-type metabolites such as kaurenoic acid derivatives and sterols with potential anti-inflammatory effects.