Six New Dammarane Triterpenoids from Viburnum cylindricum

Abstract

One new dammarane triterpenoid, cylindrictone A (1), as well as five new nor-dammarane triterpenoids cylindrictone B -F (2 -6) were isolated from the leaves of Viburnum cylindrium, together with three known compounds 3b-hydroxy-hexanordammaran-20-one (7), 3a-hydroxyoctanordammar-12-en-17-one (8), and neoalsogenin B (9). Their structures were identified by extensive NMRspectroscopic (especially 2D-NMR) and mass-spectrometric experiments, and the structure of 3 was further confirmed by a single-crystal X-ray analysis. The compounds exhibited no activity against human promyelocytic leukemia HL60 cell.Introduction. . Viburnum cylindricum is distributed in tropical Asia. A literature search revealed that phytochemical and pharmacological studies have rarely been undertaken within this species [9]. As a part of our work, we continued our phytochemical investigations of the genus viburnum. The AcOEt-soluble material of a Me 2 CO extract of the leaves of V. cylindricum furnished six new dammarane-type triterpenoids, 1 -6, and three known compounds, namely 3b-hydroxyhexanordammaran-20-one (7) [10], 3a-hydroxyoctanordammar-12-en-17-one (8) [11], and neoalsogenin B (9) [12]. The six new compounds are endowed with five different skeletons, such as normal dammarane triterpenoid, 1, trinordammarane triterpenoid, 2, 3, and 4, hexanordammarane tertripenoid, 5, and octanordammarane tertripenoid, 6. In the present article, we report the structural characterization of the compounds 1 -9 and their anti-cancer activities.

Seven New Phenolic Glucosides from Viburnum cylindricum

“…best of our knowledge, all the known compounds were isolated from this plant for the first time, except for 3,3',4',7-tetrahydroxyflavon [34]. In contrast to our previous results [6] [7], no dammarane-type triterpenoids and furofuran lignans were identified in the course of this study. This may be due to the different geographical origin of the plant material.…”

Protostane‐Type Triterpenoids from Alisma orientale

“…Except for two carbonyl groups ( δ (C) 206.5 and 218.1) and one double bond ( δ (C) 131.3 and 144.7), five methyls, six methylenes, three methines (including an oxygenated one at δ (C) 69.0), and four quaternary carbons were also observed in the 13 C‐NMR spectrum ( Table and SI ), which indicated the skeleton of 1 to be a degraded tetracyclic triterpenoid. Taking into account the above NMR data combined with the molecular formula, compound 1 could be assigned as a 20,21,22,23,24,25,26,27‐octanorprotostane triterpenoid, similar to the 20,21,22,23,24,25,26,27‐octanordammarane triterpenoids, which was found in protostane triterpenoids for the first time. The HMBC data ( Figure and SI ) from CH 2 (1), CH 2 (2), H–C(5), Me(28), and Me(29) to the carbonyl group at δ (C) 218.1 suggested that this carbonyl group was located at C(3).…”

Cytotoxic and Radical Scavenging Nor-Dammarane Triterpenoids from Viburnum mongolicum

“…1 H-NMR signals for six methyl groups [ δ H 1.45, 0.99, 0.91, 0.89, 0.84 and 0.79 (each, s)] and for two oxygenated CH groups [ δ H 3.21 (H-3) and 3.62 (H-12)] were observed ( Table 1 ). The characteristic 13 C-NMR spectrum, which was similar to that of the known compound cylindrictone B [ 25 ], indicated the 27 skeleton carbons in 1 as composed of six methyls, seven methylenes, eight methines (two oxygenated and two olefinic), five quaternary carbons and one C=O group ( δ C 172.1). The distinct difference was that the ketone carbon signal at C-3 in cylindrictone B was replaced by an oxygenated methine ( δ H 3.21; δ C 78.5) in 1 , which was supported by the observation of a CH 2 -CH 2 -CH - O spin system in the 1 H, 1 H-COSY spectrum and the HMBC correlations between C-3 ( δ C 78.5) with H-1 ( δ H 1.03 and 1.69), H-5 ( δ H 0.78), H-28 ( δ H 0.79) and H-29 ( δ H 0.99) ( Figure 2 ).…”