Anti-inflammatory effects of a methanol extract from Montanoa grandiflora DC. (Asteraceae) leaves on in vitro and in vivo models

Montanoa grandiflora, a plant species native from Mexico to Central America, locally known as “Teresita” in Yucatán, México, is used to alleviate anxiety, rheumatism, and stomach issues. This study aims to investigate the anti-inflammatory properties of the methanol extract of Montanoa grandiflora leaves (MMG) in experimental models of inflammation.

Gas chromatography-mass spectroscopy was used to characterize the MMG; cytotoxicity was assessed by MTT assay on murine macrophages and hemolysis assay. The in vitro anti-inflammatory activity was evaluated on LPS-stimulated murine macrophages by measuring of pro- and anti-inflammatory cytokines, NO and H₂O₂ release. The in vivo anti-inflammatory activity was evaluated using carrageenan-induced mouse paw edema, 12-O-tetradecanoylphorbol 13-acetate induced-ear edema, and 1-fluoro-2,4-dinitrobenzene induced-delayed-type hypersensitivity. In addition, the serum levels of prostaglandins and leukotrienes were assessed.

The main compounds found in MMG were terpenes (i.e., β-caryophyllene, (-)-α-cubebene, alloaromadendrene, ( +)-δ-cadinene, β-eudesmol), alkaloid (( ±)-nor-β-hydrastine), cyclic polyol (quinic acid), carbohydrates and their derivatives, and fatty acids (octadecatrienoic acid and octadecanoic acid). MMG did not exhibit cytotoxic or hemolytic activity. However, it demonstrated in vitro anti-inflammatory effects by increasing the production of IL-10, decreasing the levels of TNF-α, IL-1β, IL-6, NO and H₂O₂. MMG significantly reduced carrageenan-induced paw edema, TPA-induced ear edema, and DNFB-induced delayed-type hypersensitivity in mice with effects comparable to those of standard drugs, as well as serum levels of prostaglandins and leukotrienes.

The anti-inflammatory activity of MMG is associated with increased IL-10 levels and inhibiting inflammatory cell migration mechanisms, without causing cytotoxic or hemolytic damage in both in vitro and in vivo assays.