Four New Diterpenoids from the Roots ofEuphorbia pekinensis

Hinokione: an abietene diterpene with pancreatic β cells regeneration and hypoglycemic activity, and other derivatives with novel structures from the woods of Agathis dammara

In this study, 14 abietene and pimarene diterpenoids were isolated from the woods of Agathis dammara. Among them, 4 new compounds, dammarone A-C and dammaric acid A (1-4), were firstly reported, respectively. The structure of the new compounds was determined by HR ESI-MS and 1D/2D NMR spectroscopy, and their absolute configuration was determined by electronic circular dichroism (ECD) exciton chirality method. The hypoglycemic effect of all compounds was evaluated by transgenic zebrafish model, and the structure-activity relationship was discussed. Hinokione (7, HO) has low toxicity and significant hypoglycemic effects on zebrafish, the mechanism is mainly by promoting the differentiation of zebrafish pancreatic endocrine precursor cells (PEP cells) into β cells, thereby promoting the regeneration of pancreatic β cells.

Euphorbia pekinensis Rupr. roots: a comprehensive review of botany, traditional uses, phytochemistry, pharmacology, quality control, and toxicology

Euphorbia pekinensis Rupr. is a traditional herb generally distributed in most areas of China, north Korea and Japan. The dried roots of Euphorbia pekinensis Rupr. (REP), famous as 'Jing Da Ji' () have been applied as traditional herb medicines to expel water and rheum; disperse swelling, dissipate binds and to treat edoema, pleural effusions, uraemia, nephritis, cirrhosis with ascites, as well as other diseases. Recent advances in botany, traditional uses, phytochemistry, pharmacology, quality control, and toxicology of E. pekinensis roots are methodically outlined and current limitations as well as future perspectives also are discussed in order to guide scientifical investigation and rational application of REP. Up to now, 79 structurally diverse compounds have been obtained and characterised from REP, principally including diterpenoids, triterpenoids, tannins, phenols, and 29 volatile constituents. Among which, diterpenoids are considered as primary characteristic and active constituents. The extracts and individual compounds from REP have demonstrated significant pharmacological effects such as diuretic and purgative, anti-inflammatory, and cytotoxic effects. REP are widely used in traditional medicine due to diverse chemical constituents with obvious pharmacological effects. Modern phytochemical and pharmacological studies justified and explained relevant traditional uses of REP and offer worthy clues for new medical fields of industrial application. Nevertheless, a great number of thorough and detailed investigations should be carried out in active constituents, mechanisms of action, quality-marker, toxicology assessment, and detoxification mechanisms of REP.

Yuexiandajisu diterpenoids from Euphorbia ebracteolata Hayata (Langdu roots): An overview

The roots of the plant Euphorbia ebracteolata Hayata (Yue Xian Da Ji) are commonly used in traditional Chinese medicine to treat multiple diseases such as chronic liver diseases, oedema, pulmonary diseases and cancer. It is the main ingredient of the TCM called Langdu which can be prepared also from roots of E. fischeriana Steud. and occasionally from Stellera chamaejasme species. Numerous bioactive natural products have been isolated from E. ebracteolata including a large diversity of diterpenoids with anti-inflammatory and anticancer properties. One little series of compounds has been named yuexiandajisu (A, B, C, D, D₁, E, F) which comprises two casbane-, one isopimarane-, two abietane-, and two rosane-type diterpenes including a dimeric molecule. The origin, structural diversity and properties of these little-known natural products is discussed here. Several of these compounds have been identified in the roots of other Euphorbia species, notably the potent phytotoxic agent yuexiandajisu C. The abietane diterpenes yuexiandajisu D-E exhibit marked anticancer properties but their mechanism of action remains unresolved. The dimeric compound, renamed yuexiandajisu D₁, also exhibit anti-proliferative properties against cancer cell lines, unlike the rosane diterpene yuexiandajisu F. The structural or functional analogy with other diterpenoids is discussed.

Integration of LC/MS, NMR and Molecular Docking for Profiling of Bioactive Diterpenes from Euphorbia mauritanica L. with in Vitro Anti-SARS-CoV-2 Activity

In spite of tremendous efforts exerted in the management of COVID-19, the absence of specific treatments and the prevalence of delayed and long-term complications termed post-COVID syndrome still urged all concerned researchers to develop a potent inhibitor of SARS-Cov-2. The hydromethanolic extracts of different parts of E. mauritanica were in vitro screened for anti-SARS-Cov-2 activity. Then, using an integrated strategy of LC/MS/MS, molecular networking and NMR, the chemical profile of the active extract was determined. To determine the optimum target for these compounds, docking experiments of the active extract's identified compounds were conducted at several viral targets. The leaves extract showed the best inhibitory effect with IC₅₀ 8.231±0.04 μg/ml. The jatrophane diterpenes were provisionally annotated as the primary metabolites of the bioactive leaves extract based on multiplex of LC/MS/MS, molecular network, and NMR. In silico studies revealed the potentiality of the compounds in the most active extract to 3CLpro, where compound 20 showed the best binding affinity. Further attention should be paid to the isolation of various jatrophane diterpenes from Euphorbia and evaluating their effects on SARS-Cov-2 and its molecular targets.

Phytochemical and pharmacological review of diterpenoids from the genus Euphorbia Linn (2012-2021)

ETHNOPHARMACOLOGICAL RELEVANCE

Euphorbia is one of the major genera in angiosperms, which is widely distributed all over the world, including Asia, Africa and Central and South America. The roots or tubers of Euphorbia are famous for medicinal purposes, especially in China. Many of them, such as Euphorbia pekinensis Rupr, Euphorbia fischeriana Steud and Euphorbia Kansui S.L.Liou ex S.B.Ho. . are used as Chinese herbal medicines.

AIM OF THE STUDY

This paper reviews the diterpenoids isolated from the genus Euphorbia species and the pharmacological activities of these compounds to evaluate its traditional use and potential future development.

MATERIALS AND METHODS

Information on the studies of the genus Euphorbia Linn was collected from scientific journals, books and reports via library and electronic data search (Scifinder, Web of Science, PubMed, Elsevier, Scopus, Google Scholar, Springer, Science Direct, Wiley, ACS, CNKI and Kew Plants of the Word Online). Meanwhile, it was also obtained from published works of material medica, folk records, ethnophmacological literatures, Ph.D. and Masters dissertations.

RESULTS

Known as the main constituents of the genus Euphorbia Linn, Diterpenoids possess many pharmacological properties such as anti-inflammation, antiviral activities and cytotoxicity. To date, various types of diterpenoids were identified from this genus, including isopimarane, rosane, abietane, ent-kaurane, ent-atisane. cembrane, casbane, lathyrane, myrsinane, jatropholane, tigliane, ingenane, jatrophane, paraliane, pepluane, and euphoractin.

CONCLUSIONS

This review describes 14 types of diterpenoid isolated from 45 Euphorbia species from 2012 to 2021, a total of 615 compounds. Among them, mainly include jatrophane (171), lathyrane (92), myrsinane (62), abietane (70), ent-atisane (36), ent-kaurane (7), tigliane (26) and ingenane (19). The possible biological pathways of these compounds were presumed. At the same time, more than 10 biological activities of these compounds were summarized, such as anti-inflammation, antiviral activities and cytotoxicity.

Euphorbia diterpenoids: isolation, structure, bioactivity, biosynthesis, and synthesis (2013-2021)

Covering: 2013 to 2021As the characteristic metabolites of Euphorbia plants, Euphorbia diterpenoids have always been a hot topic in related science communities due to their intriguing structures and broad bioactivities. In this review, we intent to provide an in-depth and extensive coverage of Euphorbia diterpenoids reported from 2013 to the end of 2021, including 997 new Euphorbia diterpenoids and 78 known ones with latest progress. Multiple aspects will be summarized, including their occurrences, chemical structures, bioactivities, and syntheses, in which the structure-activity relationship and biosynthesis of this class will be discussed for the first time.

Characterization of undescribed melanoma inhibitors from Euphorbia mauritanica L. cultivated in Egypt targeting BRAFV600E and MEK 1 kinases via in-silico study and ADME prediction

Three undescribed diterpenes including two ent-abietanes, euphomauritanol A, and euphomauritanol B, and one jatrophane, euphomauritanophane A, in addition to eight previously described metabolites were isolated from the MeOH-CH₂Cl₂ (1:1) extract of the Euphorbia mauritanica. The chemical structures of isolates were established based on the spectroscopic means including FT-IR, HRMS, 1D and 2D NMR. The absolute stereochemistry of the undescribed diterpenes was deduced by experimental and calculated TDDFT-electronic circular dichroism (ECD). The anti-proliferative effects of the isolated diterpenes were evaluated against B16-BL6, Hep G2, and Caco-2. The euphomauritanol A, euphomauritanol B, and euphomauritanophane A significantly inhibited the growth of murine melanoma B16-BL6 cell lines with IC₅₀ 10.28, 20.22, and 38.81 μM, respectively with no responses against the other cells. These activities were rationalized by molecular docking of the active compounds in BRAF^V600E and MEK1 active sites. Moreover, the in-silico pharmacokinetics predictions by Swiss ADME revealed that the active compounds possessed favorable oral bioavailability and drug-likeness properties.

Pimarane, abietane, and labdane diterpenoids from Euphorbia pekinensis Rupr. and their anti-tumor activities

Chemical investigation of the roots of Euphorbia pekinensis Rupr. led to the isolation of five undescribed labdane diterpenoids "(4S, 5S, 9R, 10S, 13R)-18-O-galloyl-labda-8(17), 14(15)-dien-13-ol; (4S, 5S, 9R, 10S, 13R)-13-hydroxy-labda-8(17), 14(15)-dien-18-one; (4S, 5S, 9R, 10S, 13R)-18-O-acetyl-labda-8(17), 14(15)-dien-13-ol; (4S, 5S, 9R, 10S)-labda-8(17), 13(16), 14(15)-trien-18-ol; (5R, 6R, 9R, 10S, 13R)-labda-8(17), 14(15)-dien-6,13-diol", two undescribed pimarane diterpenoids "(2R, 5S, 9R, 10S, 12R, 13R)-2,12-dihydroxy-isopimara-7,15-dien-3-one; (5S, 9R, 10S, 12R, 13R)-2, 12-dihydroxy-isopimara-1, 7, 15-trien-3-one)", together with nine known diterpenoids, including three pimarane-type "(3β,11α,13α)-3,11-dihydroxypimara-7,15-diene-2,12-dione; (11R, 12S)-2,11,12-trihydroxy-ent-isopimara-1,7,15-trien-3-one; isopimara-7,15-dien-3β-ol)", five abietane-type "helioscopinolide A-C; helioscopinolide E; helioscopinolide I″, and one lathyrane-type "jolkinol B". The structures of these compounds were elucidated by analysis of HRESIMS, 1D NMR, 2D NMR, and X-ray diffraction. These sixteen compounds were evaluated for cytotoxic activity in vitro against three human cancer cell lines, U-937, LOVO, and K-562. Jolkinol B exhibited IC₅₀ of 3.60 μM and 8.44 μM against U-937 and LOVO cell lines, (4S, 5S, 9R, 10S, 13R)-18-O-galloyl-labda-8(17), 14(15)-dien-13-ol displayed IC₅₀ of 5.92 μM against U-937 cell lines, isopimara-7,15-dien-3β-ol showed IC₅₀ of 0.87 μM against K-562 cell lines.

Diterpenoids from the genus Euphorbia: Structure and biological activity (2013-2019)

Euphorbiaceae is one of the largest families of higher plants, including 7500 species, and many of them are used as medicines in China. From 2013 to 2019, a total of 455 previously undescribed diterpenoids were isolated from 53 species of Euphorbia, and some skeleton types were first discovered from the genus Euphorbia. Most of the diterpenoids isolated from Euphorbia spp. have been tested for their biological activity, and some of them were first reported for Euphorbia diterpenoids in recent years, such as neuroprotection, antimalarial activity and inhibition of osteoclast formation. In this review, we summarize all the isolated diterpenoids from the genus Euphorbia according to their skeleton types, classify all these diterpenoids into 26 normal classes and 37 novel skeleton types, and summarize their biological activity.

Eupholides A-H, abietane diterpenoids from the roots of Euphorbia fischeriana, and their bioactivities

The roots of Euphorbia fischeriana known as "Langdu" in traditional Chinese medicine have been used for the treatment of tuberculosis in China. Through a bioactive phytochemical investigation of the roots of E. fischeriana, 15 diterpenoids were obtained by various chromatographic techniques. On the basis of wide spectroscopic data, including NMR, UV, IR, HR-ESI-MS, ECD and X-ray crystallography, all of the isolated compounds were elucidated to be ent-abietane diterpenoid analogs, including undescribed eupholides A-H and seven known diterpenoids. In the bioassay for anti-tuberculosis, eupholides F-H moderately inhibited the proliferation of Mycobacterium tuberculosis H37Ra, with the MIC determined to be 50 μM. Furthermore, eupholides G, ent-11α-hydroxyabieta-8(14), 13(15)-dien-16,12α-olide, and jolkinolide F significantly inhibited the lyase activity of human carboxylesterase 2 (HCE 2), with IC₅₀ values of 7.3, 150, and 34.5 nM, respectively.

Phytotoxic ent-Isopimarane-Type Diterpenoids from Euphorbia hylonoma

Thirteen new ent-isopimarane-type diterpenoids, 1-10 and 14-16, and seven known diterpenoids, 11-13 and 17-20, were isolated from the roots of Euphorbia hylonoma. Among these compounds, four pairs of C-12 epimers (1 vs 2, 4 vs 5, 12 vs 13, and 14 vs 15) were identified. The structures of the new diterpenoids were elucidated using spectroscopic data analyses, electronic circular dichroism, and single-crystal X-ray diffraction data. The phytotoxic effects of compounds 1-20 on the growth of the roots and shoots of Poa annua and Festuca arundinacea seedlings were evaluated. Among the tested diterpenoids, 18 was the most active for inhibiting the growth of P. annua seedlings, and this compound was as active as glyphosate.

Laxative Effects of Total Diterpenoids Extracted from the Roots of Euphorbia pekinensis Are Attributable to Alterations of Aquaporins in the Colon

This study was designed to evaluate the toxic effects of total diterpenoids extracted from the roots of Euphorbia pekinensis (TDEP) on the mouse colon and to clarify the mechanism. Dried powdered roots of E. pekinensis were extracted with chloroform, and then the extract (6.7 g) was subjected to column chromatography and preparative TLC, giving TDEP. Using the HPLC-DAD method, the purity of TDEP was determined as 85.26%. Mice were orally administered with TDEP (3.942, 19.71 and 39.42 mg/kg), after which fecal water content and colon water content were examined. Both of them increased over time after TDEP administration, accompanied by severe diarrhea. Three hours after TDEP administration, the animals were sacrificed to obtain their colons. The mRNA and protein expression levels of aquaporin 1 (AQP1), AQP3 and AQP4 in the colon were measured using real-time RT-PCR and Western blotting, respectively. TDEP significantly increased the levels of AQP3 and AQP4, but decreased that of AQP1 in dose-dependent manners. Similarly, Pekinenin C, a casbane diterpenoid, significantly increased AQP3 protein and mRNA expressions in human intestinal epithelial cells (HT-29). Histopathological examination revealed that the colon was not significantly damaged. The laxative effects of E. pekinensis were associated with the alterations of AQPs in the colon by TDEP.

Diterpenoids of terrestrial origin

This review covers the isolation and chemistry of diterpenoids from terrestrial as opposed to marine sources and includes labdanes, clerodanes, abietanes, pimaranes, kauranes, cembranes and their cyclization products. The literature from January to December, 2016 is reviewed.