Phytochemical characterization and in vitro assessment of oral-health related pharmacological activities of Salvadora persica leaves

The stems and roots of the ever-green shrub Salvadora persica L. (Salvadoraceae) are important sources of plant-based tooth-cleaning sticks (miswak) commonly used for oral hygiene throughout the Arabian peninsula and the wider Muslim world [1] [2]. Also the leaves of the plant are traditionally eaten as salad and used for medicinal purposes [3], but studied in less detail so far.

Therefore, the aim of this study was the phytochemical and pharmacological investigation of S. persica leaves.

The phytochemical composition of a methanolic S. persica leaf extract was assessed by LC-HRMS analysis. Some of the major compounds were assigned as the glucosinolate glucotropeolin and as a series of kaempferol and isorhamnetin glycosides.

Furthermore, the oral health promoting-effects of the methanolic leaf extract (SPML), of glucotropaeolin (GT) and of benzylisothiocyanate (BT), a glucotropeolin degradation product formed by myrosinase-catalyzed cleavage ([Fig. 1]), were assessed in cell-based assays on anti-inflammatory and anticancer activity.

Only BT was able to inhibit the growth of HNO97 human tongue carcinoma cells. Also LPS/IFN-γ-induced NO production in RAW264.7 cells was only inhibited by BT. However, SPML as well as GT and BT potently inhibited IL-1β, TNF-α and IL-8 production in neutrophils stimulated with LPS. Moreover, SPML and BT strongly inhibited ROS production in this model.

Since primed and hyperactivated neutrophils are known to be involved in inflammatory oral diseases like periodontitis [4], the effects observed for SPML, GT and BT in stimulated neutrophils may substantiate the traditional use of S. persica leaf preparations for oral health purposes.

Fig. 1 Myrosinase- catalyzed degradation of glucotropaeolin to benzylisothiocyanate.

• References

• 1 Aumeeruddy MZ, Zengin G, Mahomoodally MF. A review of the traditional and modern uses of Salvadora persica L. (Miswak): Toothbrush tree of Prophet Muhammad. J Ethnopharmacol 2018; 213: 409-444
• 2 “Salvadora persica” (PDF). Agroforestry Database 4.0.2009. Retrieved 5 April 2019
• 3 Sadhan RI, Almas K. Miswak (chewing Stick): A Cultural And Scientific Heritage”. Saudi Dent J 1999; 11: 80-88
• 4 Granica S, Klebowska A, Kosinski M, Piwowarski JP, Dudek MK, Kazmierski S, Kiss AK. Effects of Geum urbanum L. root extracts and its constituents on polymorphonuclear leucocytes functions. Significance in periodontal diseases. J Ethnopharmacol 2016; 188: 1-12