HPTLC Fingerprinting and Cytotoxicity of Secondary Metabolites of Equisetum Diffusum D. Don Extracts
Author(s): Bich-Loan Thi NGUYEN, Claudio PALMIERI, Kim-Thanh Thi NGUYEN, Diep Hong LE, Trang Thi NGO, Chung Kim TRAN, Huy Quang NGUYEN, Hai The PHAM, Marc MULLER, Pierre DUEZ, Amandine NACHTERGAEL
The aerial parts of Equisetum diffusum D.Don (Equisetaceae ED), a Vietnamese folk medicine used for hypertensive, anti-inflammatory, diuretic and hemostatic properties, were collected in Northern Vietnam. The secondary metabolites of the sequential n-hexane, ethyl acetate and methanol extracts were profiled by HPTLC with chromatographic conditions and derivatization reagents characteristic for flavonoids, polyphenols and terpenoids/steroids. All these metabolite classes were present in the methanol extract whereas the ethyl acetate extract comprised some polyphenols and flavonoids; no characteristic compound class could be identified in the n-hexane extract. HPLC allowed to determine the concentration of isoquercitroside, the major flavonoid of the methanol extract (1.60 ± 0.04 mg/g dry weight; n=3). In a preliminary assessment of Equisetum diffusum aerial parts safety, the cytotoxicity of these 3 ED extracts was investigated on the FHs 74 Int human intestinal epithelial cell line, a non-cancerous, non-transformed normal cell line. The ethyl acetate extract was shown to be the most toxic with an IC50 of 8.7 ± 2.3 µg/mL, followed by the n-hexane and methanol extracts, with an IC50 of 46.1 ± 3.6 µg/mL and 124.7 ± 23.0 µg/mL, respectively.