Folk medicinal applications, phytochemical composition and biological activities of some Lebanese endemic plants

The Lebanese flora is known for its biodiversity and high rate of endemism. The data found in the literature between January 2010 and October 2021, about the extracts and essential oils of Origanum ehrenbergii Boiss., Origanum syriacum L., Stachys nivea Labill., Stachys ehrenbergii Boiss., Cousinia libanotica DC., Salvia fruticosa Miller and Berberis libanotica C.K. Schneider, were gathered. These plants are considered to be endemic in many countries of the Levantine area. The aim of the present review is to investigate the therapeutic actions, biological activities (in vitro and in vivo) and phytochemical composition of the seven plants. The scientific content and accurate information of this review have been gathered from accessible journals available in many databases such as Medline/Pubmed, Scopus, Sci-finder and Science Direct. The search terms being the scientific name of each plant, around sixty articles were investigated. The chemical profile of the plants revealed the presence of phenolic acids, tannins, vitamins, flavonoids, fatty acids, alkaloids, triterpenes, phytosterols, diterpenes, phenylpropanoid glucosides, acetophenones, phenylethanoid glucosides and polysaccharides. The majority of the plant species are used in folk medicine to treat rheumatism with the exception of S. ehrenbergii and S. nivea. Moreover, they have several pharmacological applications. The O. ehrenbergii dichloromethane extract exhibited a significant antibacterial activity against Listeria monocytogenes (MIC=4 μg/mL). The ethanol extract of O. syriacum showed a high cytotoxic activity against the MCF-7 cell line (IC₅₀=6.4 μg/mL). The S. nivea-dichloromethane extract inhibited the growth of the THP-1 cell line and presented an IC₅₀ of 15.7 μg/mL. Interestingly, the B. libanotica-MeOH extract induced a noticeable discoloration of ß-carotene (IC₅₀=3.1 μg/mL). The S. fruticosa-water extract registered a very interesting anti-hyperglycemic activity (IC₅₀ =167.4 μg/mL). It is important to highlight that some chemical compounds were detected for the first time in plants extracts, which underlines the originality of these plant materials.