Secoheliosphanes A and B and Secoheliospholane A, Three Diterpenoids with Unusual seco-Jatrophane and seco-Jatropholane Skeletons from Euphorbia helioscopia

Abstract

Secoheliosphanes A (1) and B (2) and secoheliospholane A (3), possessing an unusual 7,8-seco-jatrophane skeleton and an unprecedented 9,10-seco-7,10-epoxyjatropholane skeleton, respectively, were isolated from the whole plants of Euphorbia helioscopia, along with two biogenetically precursors, a new jatrophane diterpene, 2-epi-euphornin I (4) and a known jatrophane diterpene, euphoscopin A (5). Structures of 1-4 including absolute configurations were elucidated on the basis of spectroscopic data, X-ray crystallography, and chemical conversion. Compounds 1 and 2 were prepared from 4 and 5, respectively, confirming their structural assignments. Notably, 1 and 2 presented the first examples of seco-jatrophane-type diterpenoids and 3 featured a novel 5/6/7/7-fused tetracyclic ring skeleton. Among them, compound 2 showed modest activity against HSV-1 with IC value of 6.41 μM.

Jatrophane and rearranged jatrophane-type diterpenes: biogenesis, structure, isolation, biological activity and SARs (1984–2019)

“…Among all, 9 displayed moderate activity against HSV-1 with IC 50 value of 6.41 lM. The bioassay data demonstrated that secojatrophane skeleton (8, 9, and 17) has stronger antiviral activity against HSV-1 than its precursor (242) possessing jatrophane skeleton (Mai et al 2017b). Esposito et al (2016) Deacetylserrulatin B and euphosquamosin C (350) strongly inhibited the drug-efflux activity of the primary ABC-transporter CaCdr1p, an effect that was translated into increased sensitivity to fluconazole.…”

Antimicrobial Diterpenes: Recent Development From Natural Sources

“…Five diterpenoids isolated from Euphorbia helioscopia L [Euphorbiaceae] were tested for their antiviral potential against HSV-1, and among them, compound 149 showed moderate activity against HSV-1 with an IC 50 value of 6.41 μM. The SAR study of the diterpenes revealed that seco-jatrophane skeleton exhibited more potent antiviral activity against HSV-1 than the jatrophane skeleton ( Mai et al, 2018 ).…”

Euphorhelipanes A and B, Triglyceride-Lowering Euphorbia Diterpenoids with a Bicyclo[4.3.0]nonane Core from Euphorbia helioscopia

“…Inspired by the presence of the 3,3-dimethylhept-4-en-2-one side chain, which is a fragment commonly observed in the 12-membered macrocycle of jatrophanes, a putative biosynthetic pathway of 1 and 2 is proposed from the accompanying major jatrophanes, euphoscopin A ( 3 ) and epieuphoscopin A ( 4 ) (Scheme ). Briefly, 3 and 4 are susceptible to an enzyme-catalyzed retro-aldol reaction followed by selective hydrolysis of the acetyl esters to generate the 7,8- seco -jatrophane-type intermediate i . The cleavage of the C-4–C-15 bond of i accompanied by the formations of the Δ 3(4) double bond and the 15-ketocarbonyl by Grob fragmentaion afforded intermediate ii .…”

“…Its aerial parts are used as a traditional Chinese medicine for treatment of warts, bacillary dysentery, and tumors . Previous chemical investigations of this species revealed that abietane, lathyrane, and jatrophane diterpenoids were the main metabolites, and some of them possessed fascinating structures and intriguing activities. − For instance, heliosterpenoid A and heliojatrone B, possessing a new 5/6/4/6 ring system and an unprecedented trans -bicyclo­[8.3.0]­tridecane core, respectively, were identified as potent ATP binding cassette transporter B1 (ABCB1) inhibitors. , Secoheliosphane B, possessing an unusual 7,8- seco -jatrophane skeleton, showed modest activity against HSV-1 . In our continuing efforts toward discovering structurally interesting and biologically significant diterpenoids from Euphorbiaceae plants, − two new diterpenoids with an unusual bicyclo[4.3.0]­nonane core were isolated from the aqueous ethanol extract of the whole plants of E. helioscopia .…”