Plantain (Plantago L.) species as modulators of prostaglandin E ₂ and tromboxane A ₂ production in inflammation

Ethnopharmacological relevance: World-wild distributed plantains (genus Plantago L.) are extensively used in the traditional, but some of them are also accepted in the modern medicine. Wide range of usages is mainly connected to the inflammation processes.

Aim of the study: To support usage of renowned P. lanceolata L. and P. major L., underinvestigated P. altissima L., P. argentea Chaix, P. holosteum Scop. and P. media L. methanol extracts, and their typical constituents (aucubin, apigenin, apigenin-7-O-glucoside, luteolin, luteolin-7-O-glucoside, chlorogenic and ursolic acid) in treatment of inflammation disorders, we conducted study on plantain potential to inhibit production of inflammatory mediators, prostaglandin E₂ (PGE₂) and tromboxane A₂ (TXA₂).

Materials and methods: LPS-stimulated monocytes were used as a model-system to examine anti-inflammatory potential of plantains and their constituents. Produced PGE₂ and TXA₂ were quantified by LC-MS/MS; qPCR was applied to examine related gene (PLA₂, COX-1, COX-2, mPGES-1, mPGES-2, cPGES, TXAS) expression; LC-MS/MS and LC-UV/VIS techniques to analyze extracts composition.

Results: In general, examined plantain extracts showed similar inhibition activity of PGE₂ and TXA₂ production as aspirin at low-dose concentration. Underinvestigated P. altissima can be pointed out, since it exerted the strongest effect on both PGE₂ production and related gene expression. Notable suppression of TXA₂ production by P. lanceolata and P. major was observed. But, PCA analysis showed no obvious grouping, implicating that different mechanisms of action are responsible for each sample activity. In most cases, positive correlation was found between content of apigenin and ursolic acid and extracts suppression of PGE₂ and TXA₂ production and related genes expression.

Conclusions: P. altissima can be regarded as promising anti-inflammatory agent, while novel aspect of P. lanceolata and P. major application (anti-aggregation) can be suggested. P. argentea and P. media could be considered as a good source of ursolic acid.

Keywords: Plantago L.; inflammation; prostaglandin E(2); thromboxane A(2).