Pharmacological effects of mitraphylline from Uncaria tomentosa in primary human monocytes: Skew toward M2 macrophages.

ETHNOPHARMACOLOGICAL RELEVANCE: Uncaria tomentosa (Willdenow ex Roemer & Schultes) DC. (Rubiaceae) is a Peruvian thorny liana, commonly known as "cat׳s claw", and traditionally used in folk medicine to deal with several inflammatory diseases. Mitraphylline (MTP) is the most abundant pentacyclic oxindolic alkaloid (POA) from U. Tomentosa and has been reported to modify the inflammatory response. Herein, we have sought to identify the mechanisms underlying this modulatory effect of MTP on primary human monocytes and its ability to regulate differentiation processes on human primary monocyte and monocyte-derived macrophages. MATERIAL AND METHODS: In vitro studies with human primary monocytes and monocyte-derived macrophages were performed. Monocytes and M0 macrophages were exposed to MTP (25µM) and LPS (100ng/mL). M0 macrophages were polarized to M1 and M2 phenotypes in the absence or presence of MTP. The activation state of monocytes/macrophages was assessed by flow cytometry, gene expression and protein analysis of different specific markers. RESULTS: In human primary monocytes, the incubation of MTP for 24h reduced the number of classical (CD14(++)CD16(-)) and intermediate (CD14(++)CD16(+)) subsets when compared to untreated or LPS-treated cells. MTP also reduced the chemotactic capacity of human primary monocytes. In addition, MTP promoted the polarization of M0 macrophages toward an anti-inflammatory M2 phenotype, the abrogation of the release of pro-inflammatory cytokines such as TNFα, IL-6 or IL-1ß, as well as the restoration of markers for M2 macrophages in LPS-treated M1 macrophages. CONCLUSIONS: Our results suggest that MTP may be a key modulator for regulating the plasticity of monocytes/macrophages and the attenuation of the inflammatory response.

Long-chain fatty alcohols from evening primrose oil inhibit the inflammatory response in murine peritoneal macrophages.

ETHNOPHARMACOLOGICAL RELEVANCE: Evening primrose (Oenothera biennis L., Onagraceae) is a wild medicinal plant of Central American origin that is now one of the most widely used herbal medicines in different parts of the world. Oil extracted from it seeds is traditionally used in the treatment of eczema, asthma, rheumatoid arthritis, breast problem, premenstrual and menopausal syndrome, all they have an inflammatory component. The present study demonstrates the in vitro anti-inflammatory effect of long-chain fatty alcohols, minor compounds isolated from Evening primrose oil (EPO). MATERIAL AND METHODS: A mixture of long chain fatty alcohols (LCFAs) was isolated from the non-triacylglycerol fraction of the EPO. Hexacosanol (C26OH: 38.65%), tetracosanol (C24OH: 31.59%), docosanol (C22OH: 11.36%) and octocosanol (C28OH: 7.64%), were the major constituents, identified and quantified by GC and GC-MS. LCFA was tested with LPS stimulated murine peritoneal macrophage. This fraction, significantly and dose-dependently decreased nitric oxide production induced by LPS (P<0.001) and the inhibitory effect seems to be consequence of an action at the level of the inducible nitric-oxide synthethase (iNOS) gene enzyme expression rather than to a direct inhibitory action on enzyme activity. The release of PLA2 and TXB2 also was significantly inhibited by LCFAs (P<0.001) although LCFAs did not affect to PGE2 generation, however the western blot assay showed that LCFAs reduced cyclooxygenase-2 enzyme gene expression at all doses assayed. In the same way, the secretion of inflammatory cytokines interleukin 1ß (IL-1ß) and tumour necrosis factor α (TNF-α) from LPS-stimulated murine macrophage, were also significantly reduced (P<0.001). CONCLUSION: These results demonstrates the anti-inflammatory activity of LCFAs, providing an additional value about the role of bioactive minor compounds in the beneficial effect of EPO and supports its traditional uses in inflammatory processes management.

Topical anti-inflammatory effect of tirucallol, a triterpene isolated from Euphorbia lactea latex.

Latex from Euphorbia lactea (Euphorbiaceae), a native Dominican medicinal plant, is claimed to be useful in the treatment of inflammation. Topical application of tirucallol, a tetracyclic triterpene isolated from Euphorbia lacteal latex, suppressed ear edema in the mouse model in a dose-dependent manner, as well as affecting the influx of polymorphonuclear cells in response to topical application of 12-O-tetradecanoylphorbol-acetate (TPA) in the mouse ear. In addition, the effect of tirucallol, on some macrophage functions was analyzed in vitro. Non-toxic concentrations of tirucallol potently inhibited nitrite production in lipopolysaccharide-stimulated macrophages. Western blot analysis showed that nitric oxide reduction was a consequence of the inhibition of inducible nitric oxide synthetase expression although tirucallol slightly affected to prostaglandin E(2) (PGE(2)) generation. The results of the study revealed that tirucallol (0.3%), present in Euphorbia lactea latex, exerts a topical anti-inflammatory effect in vivo, via a mechanism of action related to the neutrophil migration. On the other hand, it can be deduced that the mechanism of the anti-inflammatory activity of this triterpene is related to the control of the production of NO and its effect on the expression of iNOS.