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

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.

EBC-232 and 323: A Structural Conundrum Necessitating Unification of Five In Silico Prediction and Elucidation Methods

Structurally unique halimanes EBC-232 and EBC-323, isolated from the Australian rainforest plant Croton insularis, proved considerably difficult to elucidate. The two diastereomers, which consist an unusual oxo-6,7-spiro ring system fused to a dihydrofuran, were solved by unification and consultation of five in silico NMR elucidation and prediction methods [i.e., ACDLabs, olefin strain energy (OSE), DP4, DU8+ and TD DFT CD]. Structure elucidation challenges of this nature are prime test case examples for empowering future AI learning in structure elucidation.

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

Dysphania is a genus of plants endemic to the Australian continent, occurring primarily in arid and temperate zones. Despite their prevalence, very little in the way of phytochemical and/or bioactivity investigation of native Dysphania has been performed. Herein reported is the isolation and elucidation of (6E,9E)-zerumbone epoxide and a hitherto unreported isomer, (6Z,9E)-zerumbone epoxide, from D. kalpari. In addition, a novel isodaucane sesquiterepene, kalparinol, was isolated from both D. kalpari and D. rhadinostachya. The coisolation of the humulene and isodaucane skeletons, combined with the lack of any cadalane systems, could suggest an alternate novel biogenetic pathway originating from zerumbone, which is unlike any other proposals for the isodaucene system.

Humulene Diepoxides from the Australian Arid Zone Herb Dysphania: Assignment of Aged Hops Constituents

Dysphania is an abundant genus of plants, many of which are endemic to the Australian continent, occurring primarily in arid and temperate zones. Despite their prevalence, very few investigations into the phytochemistry of native Dysphania have been undertaken. Described herein, is the isolation and elucidation of two enantiomeric diastereomers of humulene diepoxide C from D. kalpari and D. rhadinostachya, of which unassigned diastereomers of humulene diepoxide C have been previously reported as components in beer brewed from aged hops. In addition, two (+)-humulene diepoxiols (humulene diepoxiol C-I and C-II) were isolated from D. rhadinostachya. Analysis of Chinook hops oil confirmed the presence of both humulene diepoxide C-I and C-II as trace components, and in turn enabled GC-MS peak assignment to the relative stereochemistry. Anticancer assays did not reveal any significant activity for the (+)-humulene diepoxides. Antifungal assays showed good activity against a drug-resistant strain of C. auris, with MIC₅₀ values of 8.53 and 4.91 μm obtained for (+)-humulene diepoxide C-I and C-II, respectively.

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

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, WNV_Kun) and human influenza viruses H1N1 and H3N2.

Stachyonic Acid: A Dengue Virus Inhibitor from Basilicum polystachyon

Stachyonic acid A, arising from the first in-depth phytochemical investigation of the herb Basilicum polystachyon, was found to display potent inhibitory activity against dengue virus, with limited cytotoxicity. Andrographolide, a known dengue virus inhibitor and closely related labdane-type diterpene, is structurally more complex but displayed poor antiviral activity in the PRNT assay, and increased cytotoxicity in comparison. Furthermore, a Diels-Alder reaction with PTAD identified the active pharmacophore of stachyonic acid to be the conjugated diene.

An improved preparation of phorbol from croton oil

Background: Croton oil is the only commercial source of the diterpenoid phorbol (1a), the starting material for the semi-synthesis of various diesters extensively used in biomedical research to investigate cell function and to evaluate in vivo anti-inflammatory activity. While efficient chemoselective esterification protocols have been developed for phorbol, its isolation from croton oil is technically complicated, and involves extensive manipulation of very toxic materials like the oil or its native diterpenoid fraction. Results: The preparation of a crude non-irritant phorboid mixture from croton oil was telescoped to only five operational steps, and phorbol could then be purified by gravity column chromatography and crystallization. Evidence is provided that two distinct phorboid chemotypes of croton oil exist, differing in the relative proportion of type-A and type-B esters and showing different stability to deacylation. Conclusion: The isolation of phorbol from croton oil is dangerous because of the toxic properties of the oil, poorly reproducible because of differences in its phorboid profile, and time-consuming because of the capricious final crystallization step. A solution for these issues is provided, suggesting that the poor-reproducibility of croton oil-based anti-inflammatory assays are the result of poor quality and/or inconsistent composition of croton oil.

EBC-318 and 339: bicyclo[10.2.1]alkanes from Croton insularis

EBC-318 and EBC-339 were isolated from Croton insularis, an Australian rain forest plant. EBC-318 is characterised by a bridgehead double bond.

EBC-316, 325–327, and 345: New Pimarane Diterpenes from Croton insularis Found in the Australian Rainforest

Five new pimarane and related-type diterpenes (i.e. EBC-316, 325–327, and 345 (10–15)), together with two known pimaranes (EBC-221 (8) and EBC-346 (9)), were isolated from the stems of Croton insularis, found in the Australian rainforest. All pimarane diterpenes disclosed herein are suggested to be biogenetically related to the same keto-Jacobs–Reynolds intermediate 2, via ring A and C oxidation. Anticancer activities of compounds 11–13 are reported.

Unprecedented 1,14-seco-crotofolanes from Croton insularis: oxidative cleavage of crotofolin C by a putative homo-Baeyer-Villiger rearrangement

EBC-162 isolated from Croton insularis, obtained from the northern rainforest of Australia, was structurally affirmed as crotofolin C (4). Novel oxidative degradation products, EBC-233 and EBC-300, which are the first crotofolane endoperoxides, were also isolated. Both endoperoxides were found to be stable intermediates, which are proposed to undergo an unprecedented homo-Baeyer-Villiger biosynthetic rearrangement to give a new class of 1,14-seco-crotofolane diterpenes. Prolonged storage of all isolates assisted in authenticating their natural product status. Anticancer activities of reported compounds are presented.

Isolation and confirmation of the proposed cleistanthol biogentic link from Croton insularis

The proposed cleistanthol biosynthetic intermediate en route to spruceanol, and other related family members, was isolated for the first time from Croton insularis, confirming the Jacobs-Reynolds hypothesis. Anticancer evaluation of the new isolates and their aerial oxidation products is also reported.

[Acute tuberculous bronchiolitis in a patient with generalized miliary tuberculosis]

A case study of an acute tuberculous bronchiolitis (a rarely encountered form of generalized miliary tuberculosis), whose aggravated progressing resulted in fatal outcome 2 months after the onset of the initial disease signs, is described. The prevalence of non-specific infectious-and-allergic manifestations is a clinical-and-morphological peculiarity within the case study, which confirms a diversity of morphological changes occurring in the organism in tuberculosis infection. The etiological- and pathogenetic specific features of acute tuberculous bronchiolitis in children and in adults are under discussion; in particular, a possible role of a preceding viral infection is evaluated. It is one of the cases of hematogenic generalization in primary tuberculosis of adults, observed by the authors, when an involvement of the pulmonary and parenchymatous organs as well as of arachnoids and substances of the cerebrum was registered. The presence of generalized vasculitis with fibrinoid swelling and with necrosis of collagenous fibers of medium (and with the development of pan-vasculitis in the discussed case) is typical of all such observations.

Mono- and disubstituted N,N-dialkylcyclopropylamines from dialkylformamides via ligand-exchanged titanium-alkene complexes

Dibenzylformamide was treated with cyclohexylmagnesium bromide in the presence of either titanium tetraisopropoxide or methyltitanium triisopropoxide and a variety of cyclic and acyclic alkenes and alkadienes to give new mono- and disubstituted as well as bicyclic dialkylcyclopropylamines (Tables 1-3) in yields ranging from 18 to 90 % (in most cases around 55 %). 3-Benzyl-6-(N,N-dibenzylamino)-3-azabicyclo[3.1.0]hexane (10 a) and the orthogonally bisprotected 3-tert-butoxycarbonyl-6-(N,N-dibenzyl)-3-azabicyclo[3.1.0]hexane (10 d) as well as the analogous 6-(N,N-dibenzylamino)bicyclo[3.1.0]hexane (12) were obtained as pure exo diastereomers in particularly high yields (87, 90, and 88 %, respectively) from N-benzylpyrroline (15 a), N-Boc-pyrroline (15 d; Boc=tert-butyloxycarbonyl) and cyclopentene (19). 1,3-Butadiene (52) and substituted 1,3-butadienes were also aminocyclopropanated quite well to give 2-ethenylcyclopropylamines in good yields (51-64 %). Except for alkenyl- and aryl-substituted compounds, N,N-dibenzylcyclopropylamines can be debenzylated by catalytic hydrogenation to the primary cyclopropylamines as demonstrated for 10 a and 10 d to yield the fully deprotected 10 e (93 %) and mono-Boc-protected 10 f (98 %), respectively. The latter are interesting templates for combinatorial syntheses of libraries of small molecules with a well defined distance of 4.3 A between two nitrogen atoms.