Calysolins X–XIII, Resin Glycosides from <i>Calystegia soldanella</i>, and Their Antiviral Activity toward Herpes Simplex Virus

Abstract

Four new resin glycosides having macrolactone structures (jalapins), named calysolins X (1)-XIII (4), were isolated from the leaves, stems, and roots of Calystegia soldanella ROEM. et SCHULT. (Convolvulaceae). Their structures were determined on the basis of spectroscopic data as well as chemical evidence. The sugar moieties of 1-4 were partially acylated by some organic acids, including tiglic acid, 2S-methylbutyric acid, and 2S,3S-nilic acid. Additionally, the antiviral activity of 1-4 toward herpes simplex virus type 1 was evaluated. All the compounds showed antiviral activity.Key words resin glycoside; jalapin; Calystegia soldanella; Convolvulaceae; calysolin; anti-herpes simplex virus activityis commonly found on the sandy beaches of seas and lakes located the temperate regions of the world. The roots of this plant are used in the treatment of arthritis.1) In our previous paper, we reported the isolation and structural elucidation of four new glycosidic acids, calysolic acids A-D, which were obtained along with the known glycosidic acid, soldanellic acid B, and three organic acids, 2S-methylbutyric, tiglic, and 2S,3S-nilic acids, upon alkaline hydrolysis of the crude resin glycoside fraction of the leaves, stems, and roots of C. soldanella.2) Further, we isolated nine genuine resin glycosides namely calysolins I-IX, all of which possessed characteristic macrolactone structures similar to those of the already known jalapins, 3) along with one known jalapin, soldanelline B, and their antiviral activities toward herpes simplex virus type 1 (HSV-1) were evaluated. 4,5) As a part of an ongoing study of the resin glycosides from this plant, the current study deals with the isolation and structural elucidation of four new resin glycosides named calysolins X (1)-XIII (4). Additionally, the antiviral activity of 1-4 toward HSV-1 is described herein.The fresh leaves, stems, and roots of C. soldanella were extracted using methanol (MeOH). This extract was suspended in H 2 O and then extracted successively using ethyl acetate (EtOAc) and n-butanol (BuOH). The EtOAc-soluble fraction was subjected to silica gel column chromatography and HPLC on octadecyl silica (ODS) and silica gel to yield 1-4.Calysolin X (1) was obtained as an amorphous powder. The negative-ion FAB-MS and positive-ion FAB-MS of 1 exhibited an [M-H] -ion peak at m/z 1051 and an [M+ Na] + ion peak at m/z 1075, respectively, indicating its molecular weight to be 1052. The molecular formula of 1 was found to be C 50 H 84 O 23 using high-resolution (HR)-positive-ion FAB-MS. Upon alkaline hydrolysis, 1 yielded a glycosidic acid and an organic acid fraction. The gas chromatography (GC) analysis of the organic acid fraction revealed the presence of tiglic and nilic acids. The glycosidic acid was identified as soldanelic acid B (5) by comparing with an authentic sample 2) using 1 H-NMR spectroscopy. The 1 H-NMR spectrum of 1 exhibited signals due to one H-2 of the niloyl residue, one H-3 of the tigloyl residue, and four anomeric protons. The 13 C-NMR spectrum...

Chemistry and biological activity of resin glycosides from Convolvulaceae species

“…Ono's group has isolated a series of antiviral resin glycosides from Calystegia soldanella . Among them, Calysolins I and X ( 48 and 49 ) possess the soldanelic acid B as oligosaccharide core 64,65 . They both possessed the macrolactone with the acylated site located at C‐2 of the glucose unit, and a 2 S ,3 S ‐Nla group acylated at the C‐2 of the rhamnose unit.…”

Antiviral Activity of Four New Resin Glycosides Calysolins XIV–XVII from <i>Calystegia soldanella</i> against Herpes Simplex Virus

“…In addition, the antiviral activities of these compounds were evaluated against the herpes simplex virus type 1 (HSV-1). [14][15][16] As part of an ongoing study of the resin glycosides, we further examined the constituents of this plant to clarify whether ester-type dimers are present. This report deals with the isolation and structural elucidation of four new resin glycosides named calysolins XIV (1), XV (2), XVI (3), and XVII (4).…”

“…15,16) The EC 50 values of all the compounds were 14 to 54-fold higher than acyclovir, which has been used for the treatment of HSV infections (Table 3). However, all the compounds showed relatively strong cytotoxicity (IC 50 ), and their selectivity index (IC 50 /EC 50 ) values were ca.…”

Calystegia soldanella Extract Exerts Anti-Oxidative and Anti-Inflammatory Effects via the Regulation of the NF-κB/Nrf-2 Pathways in Mouse Macrophages

“…For a long time, C. soldanella has been reported to exert antipyretic, disinfecting, and diuretic effects, as well as various other physiological activities, including antioxidative, anti-inflammatory, antiviral, and antifungal activities; it has also been known to inhibit the expression of protein tyrosine phosphate 1 B [12][13][14][15]. Compounds isolated from C. soldanella include resin glycoside, anthocyanins, caffeic acid, and coumaric acid [16,17]. While various physiological activities of C. soldanella have been reported, as described above, the Nrf-2 activation-mediated anti-inflammatory effects of C. soldanella extract and the mechanisms underlying these effects have not yet been reported.…”