Iridoids and sesquiterpenoids from Valeriana jatamansi and their anti-influenza virus activities

Abstract

Twenty-one new iridoids, jatamansidoids A-U (1-12, 21-26, 32, 35 and 36), two new natural ones, jatamansidoids V (37) and W (38), eighteen known ones (13-20, 27-31, 33 and 34), together with three patchoulol-type sesquiterpenoids (39-41), were isolated from the roots and rhizomes of Valeriana jatamansi. Structurally, compounds 1-7 were the first examples of iridoids from V. jatamansi with unique α, β, γ, δ-unsaturated aldehyde fragment between C-11, C-4, C-5, C-9 and C-8; compound 8 was an unprecedented iridoid derivative with a methyl group (Me-10) at C-1, rather than C-8, and its plausible biogenetic pathway was proposed in this paper; compounds 22 and 23 were the first examples of Δ⁴⁽⁵⁾-iridoids simultaneously replaced by oxygen-containing groups at C-3, C-6 and C-7; compound 24 was the first iridoid with both 6,7- and 1,10-epoxy fragments. The structures and absolute configurations of new compounds were elucidated based on extensive spectroscopic techniques and quantum chemical calculation. Furthermore, compounds 13-15 and 39-41 exhibited potent anti-influenza virus activities with H1N1 and H3N2 strains, with IC₅₀ values of 0.21-1.48 µM.

Keywords: Anti-influenza virus; Caprifoliaceae; Iridoids; Sesquiterpenoids; Valeriana jatamansi.