Cytotoxic and Radical Scavenging Nor-Dammarane Triterpenoids from Viburnum mongolicum

Abstract

The ethanol extract of the whole plants of Viburnum mongolicum afforded six new nor-dammarane triterpenoids: 3β,12β-dihydroxy-25,26,27-trinordammara-22-en-24,20-olide (1), 3β,12β-dihydroxy-24α-methoxy-25,26,27-trinordammara-20,24-epoxy (2), 3β-O-acetyl-12β-hydroxy-23,24,25,26,27-hexanordammarane-20-one (3), 12β-O-acetyl-15α-hydroxy-17β-methoxy-3-oxo-20,21,22-23,24,25,26,27-octanordammanrane (4), 12β-O-acetyl-15α,17β-dihydroxy-3-oxo-20,21,22-23,24,25,26,27-octanordammanrane (5), and 12β,15α-dihydroxy-3-oxo-17-en-20,21,22-23,24,25,26,27-octanordammanrane (6), together with two known nor-dammarane triterpenoids, 12β-hydroxy-3-oxo-24α-methoxy-25,26,27-trinordammara-20,24-epoxy (7) and 3β,12β-dihydroxy-23,24,25,26,27-hexanordammarane-20-one (8). The structures of the isolated compounds were established based on 1D and 2D (1H-1H COSY, HMQC, and HMBC) NMR spectroscopy, in addition to high resolution mass spectrometry. The isolated compounds were tested in vitro for cytotoxic potential against seven tumor cell lines and radical scavenging activities. Compounds 4–6 exhibited significant cytotoxic activities against all tested tumor cell lines and radical scavenging activities against ABTS·+ radicals comparable with the standard drug Trolox.

Recent Advance on Chemistry and Bioactivities of Secondary Metabolites from Viburnum Plants: An Update

“…The assays for evaluating their cytotoxic activities in vitro against A‐549, BGC‐823, HepG2, HL‐60, MCF‐7, SMMC‐7721 and W480 showed that compounds 61 and 62 with an acetyl group at C‐12 possessed strong cytotoxic activities against all the tumor cell lines with IC 50 values of 11.3–18.3 μM and 12.3–17.1 μM, respectively, which were in good agreement with those aforementioned in V. hainanense . Additionally, the free hydroxy group of those nor‐dammarane triterpenoids might play a key role in ABTS⋅ + scavenging activity, such as compounds 58 , 61 and 62 possessing significant activities with IC 50 values of 54.6, 59.2 and 68.1 μM, respectively, using Trolox as a positive control (IC 50 =80.1 μM) [26] . Five nor‐dammarane triterpenoids ( 56 , 59 , 68 , 70 and 71 ), together with compounds 78 and 79 , were isolated from the leaves of Viburnum sambucinum .…”