New Casbanes and the First trans‐Cyclopropane seco‐Casbane from the Australian Rainforest Plant Croton insularis

Maslovskaya, Lidiya A.; Savchenko, Andrei I.; Pierce, Carly J.; Boyle, Glen M.; Gordon, Victoria; Reddell, Paul; Parsons, Peter G.; Williams, Craig M.

doi:10.1002/chem.201804904

Cited by 15 publications

(8 citation statements)

References 34 publications

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“…It is noteworthy that both cis ‐ and trans ‐cyclopropane‐bearing casbanes were isolated from the same collection in the present work. This interesting phenomenon was also observed with terrestrial plants [20b] . The stereochemical diversities on cyclopropane motif could be rationalized by the cyclisation mechanism of casbene synthase [15a] or/and the photoisomerization of the cyclopropane [21] .…”

Section: Discussionsupporting

confidence: 52%

Nanolobatone A, An Unprecedented Diterpenoid and Related New Casbanoids from the Hainan Soft Coral Sinularia nanolobata

Liu

Zhao

et al. 2023

Chemistry A European J

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Nanolobatone A, featuring an unprecedented tricyclo[10.3.0.01,2]pentadecane carbon skeleton, along with four new polyoxygenated and four unusual endoperoxide‐bridged casbane‐type diterpenoids were isolated from the Hainan soft coral Sinularia nanolobata. The structures of the new compounds were established by extensive spectroscopic analysis, X‐ray diffraction analysis, and time‐dependent density functional theory/electronic circular dichroism calculations. A plausible biosynthetic pathway of new isolates was proposed. Bioassays revealed that nanolobatone A showed weak antibacterial activity against the Gram‐positive bacteria Streptococcus pyogenes.

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Section: Discussionsupporting

confidence: 52%

Nanolobatone A, An Unprecedented Diterpenoid and Related New Casbanoids from the Hainan Soft Coral Sinularia nanolobata

Liu

Zhao

et al. 2023

Chemistry A European J

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“…Negative controls (vehicle only) were run with every cell survival experiment, while positive controls (doxorubicin, docetaxel, cisplatin, PMA, and EBC-46) were periodically carried out to ensure the quality of the data. Vehicle-only control results in a <5% change in cell survival, whereas the positive control inhibited cell survival at nanomolar concentrations as expected …”

Section: Methodssupporting

confidence: 55%

“…Vehicle-only control results in a <5% change in cell survival, whereas the positive control inhibited cell survival at nanomolar concentrations as expected. 26 Miticidal Assay. Cynaviminoside A (6) and cynaviminoside B (7), predissolved in DMSO, was diluted with saline (0.9% NaCl) to make a 40% DMSO stock solution (400 μM).…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…The cytotoxicity of cynavimigenin B ( 8) was evaluated against four human cancer cell lines and normal human primary cells [i.e., primary human foreskin fibroblast (NFF), breast cancer (MCF7), melanoma (MM96L), colon cancer (HT29), and cervical carcinoma (HeLa)], via previously reported methodology, 26 but it did not possess any significant cytotoxic activity (IC 50 > 10 μM) against the cell lines examined.…”

Section: ■ Results and Discussionmentioning

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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“…Until recently, the only phytochemical studies of B. polystachyon undertaken were using either GCMS or high-performance thin-layer chromatography (HPTLC) analysis of the corresponding essential oil. Given our interest in the phytochemistry of Australian arid and tropical zone plants, we embarked on a 1 H NMR-guided fractionation study of B. polystachyon , whereupon the new labdane diterpenoids, stachyonic acids, were successfully isolated . The carboxylic acids were observed as a 95:5 E / Z mixture, and complete separation of the major E isomer, stachyonic acid A ( 1 ), required a combination of chemical derivatization and argentation chromatography [AgNO 3 -impregnated silica gel (SNIS)] .…”

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confidence: 99%

Basimarols A, B, and C, Highly Oxygenated Pimarane Diterpenoids from Basilicum polystachyon

Tan¹,

Xue

Savchenko³

et al. 2019

J. Nat. Prod.

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The highly oxygenated pimarane diterpenoids basimarols A, B, and C (3–5) were isolated from the plant species Basilicum polystachyon, which was collected within the Australian arid zone. Structure elucidation was performed using a suite of spectroscopic techniques, including X-ray crystallography. Anticancer and anti-DENV activity of 3–5 was explored, but only limited activity was observed. More extensive antiviral evaluation of stachyonic acid A (1), which was also isolated from B. polystachyon, revealed broad spectrum antiviral activity against West Nile virus (Kunjin strain, WNVKun) and human influenza viruses H1N1 and H3N2.

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New Casbanes and the First trans‐Cyclopropane seco‐Casbane from the Australian Rainforest Plant Croton insularis

Cited by 15 publications

References 34 publications

Nanolobatone A, An Unprecedented Diterpenoid and Related New Casbanoids from the Hainan Soft Coral Sinularia nanolobata

Nanolobatone A, An Unprecedented Diterpenoid and Related New Casbanoids from the Hainan Soft Coral Sinularia nanolobata

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

Basimarols A, B, and C, Highly Oxygenated Pimarane Diterpenoids from Basilicum polystachyon

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