Lignans from the Australian Endemic Plant Austrobaileya scandens

Abstract

The sole species of the vascular plant family Austrobaileyaceae, Austrobaileya scandens, is endemic to the tropical rainforest of northeastern Queensland, Australia. A single lead-like enhanced fraction of A. scandens showed potent inhibition against human prostate cancer PC3 cells. Chemical investigation of this plant resulted in the isolation of two new aryltetralin lignans, austrobailignans 8 and 9 (1 and 2), and the synthetic compound nicotlactone B (3), newly identified as a natural product together with nine known lignans (4-12). Their structures were established on the basis of spectroscopic analyses. Absolute configurations of the new compounds were determined by quantum chemical electronic circular dichroism (ECD) calculations employing time-dependent density functional theory. The ECD calculations were also used to assign the absolute configuration of marphenol K (4) and revise the absolute configuration of kadsurindutin C (20). Ten out of the 12 isolated compounds inhibited the growth of PC3 cells with IC50 values ranging from micromolar to nanomolar. Marphenol A (5) was found for the first time to induce apoptosis and arrest the S cell cycle phase of PC3 cells.

Lignans from Saururus chinensis with Inhibitory Effects on Nitric Oxide Production

“…The NOESY correlations from H 3 -9 to H-7 and H-8′ and from H-8 to H-6 and H 3 -9′ suggested the α-orientation of H-7 and H-8′ and the β-orientation of H-8 (Figure ). The absolute configuration of 3 was elucidated as 7 R ,8 R ,8′ S from the ECD spectrum, in which a distinctive negative Cotton effect at 272 nm and a positive Cotton effect at 297 nm were observed . In addition, the calculated ECD for (7 R ,8 R ,8′ S )- 1 was similar to the experimental result of 1 (Figure S20, Supporting Information).…”

“…8,9 As part of an ongoing search for anti-inflammatory agents from higher plants, a MeOH extract of the aerial parts of S. chinensis was investigated and afforded 21 compounds including eight new lignans (1−8) and a new cyclic carbonate (9) together with 12 known compounds (10−21). Among them, the known compounds were identified as ent-sauchinone (10), 10 machilin D (11), 11 (1R,2R)-2-[2,6-dimethoxy-4-((E)-prop-1-enyl)phenoxy]-1-(3,4,5-trimethoxyphenyl)propyl acetate (12), 12 (1R,2R)-2-(4-allyl-2,6-dimethoxyphenoxy)-1-(3,4,5trimethoxyphenyl)propyl acetate (13), 12 (−)-raphidecursinol B (14), 13 saururinone (15), 14 dihydroguaiaretic acid (16), 15 (−)-austrobailignan (17), 14 saururin B (18), 16 saucerneol I (19), 17 elemicin (20), 18 and myristicin (21), 18 by comparison of their NMR, MS, and electronic circular dichroism (ECD) data with published values. Herein are described the isolation and structure elucidation of the nine new compounds (1−9) as well as the inhibitory effects of all 21 compounds isolated against lipopolysaccharide (LPS)-induced nitric oxide (NO) production in murine macrophage RAW 264.7 cells.…”

LC-MS guided isolation of three pairs of enantiomeric alkaloids from Macleaya cordata and their enantioseparations, antiproliferative activity, apoptosis-inducing property

“…Cell cycle arrest was an important sign for inhibition of proliferation and the series of events that took place in a cell leading to its division and duplication 11 , 12 . In order to explore whether the growth inhibition induced by 2 was caused by the regulation of the HL-60 cell cycle, the cell cycle distribution in the presence of 2 was detected by flow cytometry (Fig.…”

Asymmetric synthesis of trans-4,5-disubstituted γ-butyrolactones involving a key allylboration step. First access to (−)-nicotlactone B and (−)-galbacin

“…Treatment of 12 (ratio 89/11) with MeONa in MeOH for 18 h at room temperature resulted in the inversion of configuration at chiral center C3 (ratio of 8/ 92 in favour of 13) (Scheme 5). It is interesting to note that 13, also named (−)-nicotlactone B, 27 is a natural product present in the Australian endemic plant Austrobaileya scandens whose asymmetric synthesis had not yet been reported. The reduction of 13 with DIBAL-H, followed by an acidic treatment in the presence of methylorthoformate and para-toluenesulfonic acid (APTS) in methanol led to γ-lactol methyl ether 14 in 67% yield as an anomeric mixture.…”