Phytochemical and biological research on Herniaria hirsuta

Urinary stone disease is considered as an important healthcare problem which affects 10 – 15% of the population. In the absence of prophylactic therapies, recurrence rates are as high as 50% within 10 years. An aqueous extract of the aerial parts of Herniaria hirsuta (Caryophyllaceae) is a widely used herbal medicine. Despite its proven activity against urolithiasis, little is known about the active compounds and the mechanism of action. (1,2) Previous phytochemical research on Herniaria species revealed a limited amount of compounds including saponins, flavonoids and coumarins. (2)

As a first step in the quest for the active constituents, phytochemical research on the aerial parts of the dried herb was performed, using a comprehensive extraction. (3) An aliquot was analysed with ultra-high performance liquid chromatography-photodiode array-high resolution mass spectrometry (UHPLC-PDA-HRMS). Multiple flavonoids and saponins were (tentatively) identified with analytical standards or based on spectral and chromatographic data. Besides the known saponins, 7 new saponins were tentatively identified as glycosides of acetylated medicagenic acid, zanhic acid and medicagenic acid.

It is suggested that gastro-intestinal and/or hepatic metabolites of phytochemicals present in H. hirsuta (most likely saponin metabolites) are responsible for the beneficial effects. (2) An in vitro gastro-intestinal model will be used to simulate the biotransformation of the extracts in the stomach, small intestine and colon, to avoid extensive in-vivo studies. The well-characterized metabolised extract will be evaluated in vitro for its activity against urinary stones.

[1] Atmani F, Slimani Y, et al. J Ethnopharmacol. 2004;95:87 – 93.

[2] van Dooren I, Foubert K, et al. Planta Med. 2016;82:1576 – 83.

[3] Bijttebier S, Van der Auwera A, et al. chimica acta. 2016;935:136 – 50.