HPLC-DAD-MS Analysis and Antiviral Activity of Different Extracts and Isolated Constituents from Bituminaria bituminosa

Herpes simplex virus (HSV) is one of the most common viral diseases in humans. Herpes simplex virus 1 (HSV-1) and Herpes simplex virus 2 (HSV-2) have been distinguished by clinical manifestations and biological and serological criteria. Several drugs have proved useful in the treatment of many specific infections, but viral strains resistant to these drugs have been increasingly identified [1]. In order to find less toxic antiviral agents, many researchers have addressed plant products. Indeed, many plant extracts and their secondary metabolites are known in the literature for their antiviral activity [2, 3]. Bituminaria bituminosa L. (syn. Psoralea bituminosa L., Leguminosae) is a perennial herb widespread in the Mediterranean area, known in Italy as “trifoglio bituminoso”; the fresh leaves are used in folk medicine as vulnerary, cicatrizing, and disinfectant agent [4, 5]. Plants of the genus Bituminaria are known as source of furanocoumarins and flavonoids [6, 7]. In our previous phytochemical study [8], three pterocarpans (erybraedin C and the new bitucarpins A and B) together with plicatin B were isolated and identified from B. bituminosa aerial parts. Erybraedin C and bitucarpin A showed cytotoxicity in different cell lines [9], induced apoptosis in colon carcinoma cell lines, and exhibited anti-clastogenic activity in lymphocytes [10, 11]; erybraedin C showed inhibitory activity against human topoisomerase I [12] and significant antioxidant activity [13]. The antiviral activity of the pterocarpan compounds, isolated from different plant sources, has been reported in the literature [14, 15], and some of these derivatives were active against HSV-2 [16]. In the present investigation, the antiviral activity of a few B. bituminosa extracts and their isolates erybraedin C (1), bitucarpin A (2), and plicatin B (3) is reported for the first time. The tested extracts were characterized in their quantitative chemical composition by HPLC-DAD-MS analysis.