Structural Determination of a New Cycloartane Glycoside from Asplenium ruprechtii

We characterized a new cycloartane glycoside, herein known as aspleniumside F ( 1 ), along with five known compounds as kaempferol‐3‐ O ‐[(6‐ O ‐( E )‐feruloyl)‐ β ‐D‐glucopyranosyl]‐(1→2)‐ β ‐D‐galacopyranoside ( 2 ), quercetin‐3‐ O ‐[(6‐ O ‐( E )‐feruloyl)‐ β ‐D‐glucopyranosyl]‐(1→2)‐ β ‐D‐glucopyranoside ( 3 ), kaempferol‐3‐ O ‐[(6‐ O ‐( E )‐caffeoyl)‐ β ‐D‐glucopyranosyl]‐(1→2)‐ β ‐D‐glucopyranoside ( 4 ), kaempferol‐3‐ O ‐[(6‐ O ‐( E )‐caffeoyl)‐ β ‐D‐glucopyranosyl]‐(1→2)‐ β ‐D‐glucopyranosyl‐7‐ O ‐ β ‐D‐glucopyranoside ( 5 ), and kaempferol‐3‐ O ‐[(6‐ O ‐ p ‐coumaroyl)‐ β ‐D‐glucopyranosyl]‐(1→2)‐ β ‐D‐glucopyranosyl‐ 7 ‐ O ‐ β ‐D‐glucopyranoside ( 6 ), from Asplenium ruprechtii Sa. Kurata, a folk medicine widely used to treat Thromboangiitis obliterans in China, Japan, and Korea. Based on spectroscopic, mainly 1D‐, 2D‐NMR and (+)‐HR‐ESI‐MS, analyses as well as through comparisons with previous reports, its chemical structure was determined as 3 β ,24,30‐tri‐ β ‐D‐glucopyranosyl‐23,25‐dihydroxycycloartane (= (23 R ,24 R )‐3 β ,24‐bis‐( β ‐D‐glucopyranosyloxy)‐23,25‐dihydroxy‐9 β ‐9,19‐cyclolanostan‐29‐yl β ‐D‐glucopyranoside). According to the 1 H coupling constant of anomeric protons and co‐TLC of the acid hydrolysate with D‐glucose, all three glycoside groups in 1 were revealed as β ‐D‐glucopyranosyl. Furthermore, SOD‐like antioxidant activity evaluation via IC 50 of 12.43, 6.78, 9.12, 6.94 and 4.85 μM revealed that compounds 2 – 6 had bioactivity.