Inflammation has been known to play a crucial role in the development of various human disorders such as atherosclerosis, cancer, asthma, hepatitis, rheumatoid arthritis, and periodontitis. Medicinal plants have been widely used for decades to treat numerous disorders including inflammatory-related diseases and provide an abundant source of natural compounds for medication. One of the medicinal plants traditionally used to cure inflammatory diseases is Plantago lanceolata. In the previous study, we showed that the n-hexane insoluble fraction of Plantago lanceolata leaves (HIFPL) demonstrated a potent anti-inflammatory activity. The purpose of this study was to investigate the active compounds responsible for the antiinflammatory activity of Plantago lanceolata by utilizing a mice experimental model.
The leaves of Plantago lanceolata were dried, powdered and macerated in dichloromethane. The liquid extract was then evaporated in a rotary evaporator instrument until dryness. Dried extract was then partitioned using n-hexane to obtain HIFPL and n-hexane soluble fraction. Both fraction was evaluated for their anti-inflammatory in mice model. The more active fraction (HIFPL) was then separated using a preparative TLC to isolate the major compound. The structure of the isolated compound was determined based on the NMR, IR and LC-MS spectra. The content of the isolated compound in the HIFPL was determined by TLC-densitometry. A thioglycollate-induced leukocytes migration in mice was used as a pharmacological assay to evaluate the inflammatory activity of the fractions and isolated compounds. The level of chemokines (MCP-1 and IL-8), the main cytokine regulating the chemotaxis activity was also evaluated.
We found that ursolic acid, the main compound isolated from HIFPL is responsible for the antiinflammatory activity. It demonstrated antiinflammatory activity by inhibiting the migration of leukocytes, at least partly, by lowering the level of IL-8 and MCP-1. This results provide a scientific evidence regarding the traditional usage of Plantago lanceolata for inflammatory disorders.