Ribwort Plantain (Plantago lanceolata) and Inflammation (general): evidence and sources

Aucubin is an iridoid glycoside that is widely prevalent in traditional medicinal herbs, such as Eucommia ulmoides Oliv., Aucuba japonica Thunb. and Plantago asiatica L. This review aims to provide a comprehensive summary of the source, biological activity, pharmacokinetics and toxicology of aucubin with the ultimate objective of providing a guide for future drug development and potential clinical applications of aucubin. Aucubin is a highly active compound possessing extensive biological effects including antioxidant, anti-aging, anti-inflammatory, anti-fibrotic, anti-cancer, hepatoprotective, neuroprotective and osteoprotective properties. Although aucubin has been shown to have poor oral bioavailability in rats, aucubin is widely distributed in multiple organs including kidney, liver, heart, spleen and lung, and there is a sex difference in the absorption of aucubin. Tolerance of aucubin is good and no serious adverse reactions have been observed to date. In short, aucubin is a compound with abundant potential sources, good safety and numerous beneficial biological activities, which exhibits high potential value for use in health care products and pharmaceuticals. In order to accelerate the development and utilization of aucubin-related products, in-depth studies should be focused on the following questions of interest. First, it is necessary to introduce advanced separation and formulation technologies to improve the yield and stability of aucubin products. Second, studies should focus on the specific pharmacological activities of aucubin to determine the structure-activity relationship so as to improve the efficacy and reduce side effects. Finally, clinical studies are needed to confirm the efficacy of aucubin in specific diseases.

Extracts of the plant species Pinus sylvestris L. and Plantago lanceolata L. have been used in traditional medicine for the treatment of certain respiratory diseases, but little is known about their precise effects and mechanisms of action. In this study, we investigated the effect of these plant extracts on the production of nitric oxide (NO) and prostaglandin E(2), NO synthase (NOS) type II, cyclooxygenase-1 (COX-1) and COX-2 mRNA expression in the murine macrophage cell line J774A.1. We found that Pinus sylvestris and Plantago lanceolata extracts inhibited NO production in a concentration-dependent manner in this cell line, without obvious cytotoxic effects as tested by MTT assay. The Plantago lanceolata extract at all doses used, and the Pinus sylvestris extract at high doses, showed significant scavenging of NO radicals released by the NO donor PAPA-NONOate. Our data also show that pre-treatment with these extracts significantly inhibits inducible NOS (iNOS) mRNA production in this cell line, without affecting COX-1 mRNA expression. COX-2 mRNA levels and PGE(2) levels induced by lipopolysaccharide/interferon-gamma were not modified upon pre-treatment with the extracts. Thus, our results suggest that the anti-inflammatory properties of Pinus sylvestris and Plantago lanceolata extracts may reflect decreased NO production, possibly due to inhibitory effects on iNOS gene expression or to NO-scavenging activity.