Kalparinol, a Salvialane (Isodaucane) Sesquiterpenoid Derived from Native Australian <i>Dysphania</i> Species That Suggests a Putative Biogenetic Link to Zerumbone

Tan, Yuen Ping; Savchenko, Andrei I.; Agnew‐Francis, Kylie A.; Boyle, Glen M.; Bernhardt, Paul V.; Fraser, James A.; Williams, Craig M.

doi:10.1021/acs.jnatprod.9b01039

Cited by 6 publications

(4 citation statements)

References 52 publications

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“…The crude extract from C. viminale subsp. australe was subjected to 1 H NMR-guided fractionation (described previously), which focused on both the alkene and oxygenated methine 1 H NMR spectroscopic region. These fractions were further refined to give purified isolates containing seco -pregnanes ( 5 – 8 ), for which the structures were elucidated as detailed below.…”

Section: Resultsmentioning

confidence: 99%

“…Considering that very early attempts were unable to fully elucidate saponins from C. viminale subsp. australe , and the Cynanchum genus aligns with our continued efforts to survey the phytochemical composition of Australian desert and arid zone flora, an investigation of this species was undertaken. Disclosed herein is the isolation of four seco -pregnanes ( 5 – 8 ) (Figure ), including a new ring system, and an extensive biological activity investigation.…”

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confidence: 99%

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seco-Pregnane Glycosides from Australian Caustic Vine (Cynanchum viminale subsp. australe)

et al. 2023

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Cynanchum viminale subsp. australe, more commonly known as caustic vine, is a leafless succulent that grows in the northern arid zone of Australia. Toxicity toward livestock has been reported for this species, along with use in traditional medicine and its potential anticancer activity. Disclosed herein are novel seco-pregnane aglycones cynavimigenin A (5) and cynaviminoside A ( 6), together with new pregnane glycosides cynaviminoside B (7) and cynavimigenin B (8). Cynavimigenin B (8) contains an unprecedented 7-oxobicyclo[2.2.1]heptane moiety in the seco-pregnane series, likely arising from a pinacol-type rearrangement. Interestingly, these isolates displayed only limited cytotoxicity in cancer and normal human cell lines, in addition to low activity against acetylcholinesterase and Sarcoptes scabiei bioassays, suggesting that 5−8 are not associated with the reported toxicity of this plant species.Cynanchum is a large genus of plants belonging to the Apocynaceae family (milkweed family, formerly Sarcostemma 1,2 ), consisting of over 200 species distributed worldwide. 3 Cynanchum species have long been used in Asia as traditional medicine for the treatment of common and chronic diseases. 3 Australia is home to around 13 native species of Cynanchum, occurring most commonly in northern Australia, 1,2,4 and certain species, in particular C. viminale subsp. australe (R.Br.) Mere & Liede, are known to have been used by Aboriginal peoples for the treatment of several conditions, including the topical treatment of wounds, cuts, and sores. 5 In addition, crude extracts of C. viminale subsp. australe have been reported to display cancer cell line cytotoxicity activity 6 and are especially active against skin cancer. 7 Interestingly, C. viminale subsp. australe has been reported to display toxicity toward livestock to varying extents all depending on location and/or drought, 8 which is also the case for a closely related Australian species, C. brevipedicellatum. 1 Livestock toxicity has also been observed in South Africa arising from other Cynanchum species and subspecies of C. viminale and was attributed to an abundance of pregnane glycosides 9,10 in the plant latex, such as sarcovimisides A−C (1−3) from C. viminale 11 and cynafoside A (4) from C. af ricanum 12 (Figure 1). Structurally, pregnane glycosides consist of a C 21 pregnane aglycone with a hydroxy group at C-3 and a substituent at C-17 and typically also contain an additional O-linked substituent at C-12. 9,10 The glycoside unit is typically comprised of a linear chain of mixed sugars, commonly glucose, rhamnose, and dideoxy sugars such as oleandrose, cymarose, or digitoxose. 9,10 While the most common aglycone motif within this family is 14β-hydroxypregnane, an increasing number of 14,15-and 8,14-seco-pregnane aglycones have been reported, along with a wider range of pharmacological effects. 13 Considering that very early attempts were unable to fully elucidate saponins from C. viminale subsp. australe, 14 and the Cynanchum genus aligns with our continued effort...

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Section: Resultsmentioning

confidence: 99%

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confidence: 99%

seco-Pregnane Glycosides from Australian Caustic Vine (Cynanchum viminale subsp. australe)

et al. 2023

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“… [51] Structural modifications of zerumbone to diverse skeletal frameworks were achieved by various groups that include asymmetric epoxidation, [52] conjugate addition ,[53–55] transannular cyclisation, [56] ring cleavage, [57,58] ring expansion reaction, [51] to name a few (Scheme 2). In natural system, zerumbone serves as a starting material for biosynthetic diversification to other natural products such as kalparinol, alashanoids via zerumbone epoxide [59,60] …”

Section: Introductionmentioning

confidence: 99%

“…In natural system, zerumbone serves as a starting material for biosynthetic diversification to other natural products such as kalparinol, alashanoids via zerumbone epoxide. [59,60] In conjunction with our keen interest in transition metalcatalyzed synthetic transformations, and its application in NPs, we have utilized zerumbone for extensive structural diversifica-tion. Kitayama and Kunnumakkara et al, published a comprehensive review on the attractive reactivity of zerumbone and therapeutic potential of zerumbone, respectively.…”

Section: Introductionmentioning

confidence: 99%

Transition Metal/Lewis Acid Catalyzed Reactions of Zerumbone for Diverse Molecular Motifs

Biji

Prabha

Lankalapalli

et al. 2021

The Chemical Record

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Zerumbone is a naturally occurring humulene type sesquiterpene, isolated from the rhizomes of Zingiber zerumbet (L.) Smith with excellent therapeutic potential and is recognized as a valuable synthon for the construction of diverse array of natural product motifs. In this review, we intended to highlight our achievements in utilizing abundant natural product zerumbone and its derivatives for the development of pharmacologically relevant molecular scaffolds. We provided an account of the transition‐metal catalyzed 1,4‐conjugate addition reactions of zerumbone and its derivatives along with palladium‐catalyzed cross‐couplings, transition metal‐based Lewis acid promoted interrupted Nazarov cyclisation reaction with substituted indoles and transannular cyclizations, photo‐induced transformations of zerumbone and its epoxide.

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Tandem Photoisomerization and Transannular Cyclizations of Zerumbone Epoxide: A Model for Diversity-Oriented Synthesis Using Abundant Natural Products

2021

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Photoirradiation of (6E,9E)-zerumbone-2,3-epoxide afforded a diverse range of transannular cyclized products in the presence of a catalytic amount of Sc(OTf) 3 . At the behest of the geometrical isomers produced by photoirradiation, the diversity encompasses an unprecedented eudesmane core and oxo-bridged hydroxy-olefin skeletons. Structure elucidation and the stereochemical outcome of the products are described via extensive NMR analysis. The present study serves as a model for tandem photoisomerization and transannular cyclization of natural products with enone/dienone functionality.Letter pubs.acs.org/OrgLett

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Kalparinol, a Salvialane (Isodaucane) Sesquiterpenoid Derived from Native Australian Dysphania Species That Suggests a Putative Biogenetic Link to Zerumbone

Cited by 6 publications

References 52 publications

seco-Pregnane Glycosides from Australian Caustic Vine (Cynanchum viminale subsp. australe)

seco-Pregnane Glycosides from Australian Caustic Vine (Cynanchum viminale subsp. australe)

Transition Metal/Lewis Acid Catalyzed Reactions of Zerumbone for Diverse Molecular Motifs

Tandem Photoisomerization and Transannular Cyclizations of Zerumbone Epoxide: A Model for Diversity-Oriented Synthesis Using Abundant Natural Products

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