A Review of the Ethnomedicinal Uses, Biological Activities, and Triterpenoids of Euphorbia Species

The genus Euphorbia is one of the largest genera in the spurge family, with diversity in range, distribution, and morphology. The plant species in this genus are widely used in traditional medicine for the treatment of diseases, ranging from respirational infections, body and skin irritations, digestion complaints, inflammatory infections, body pain, microbial illness, snake or scorpion bites, pregnancy, as well as sensory disorders. Their successes have been attributed to the presence of diverse phytochemicals like polycyclic and macrocyclic diterpenes with various pharmacological properties. As a result, Euphorbia diterpenes are of interest to chemists and biochemists with regard to drug discovery from natural products due to their diverse therapeutic applications as well as their great structural diversity. Other chemical constituents such as triterpenoids have also been reported to possess various pharmacological properties, thus supporting the traditional uses of the Euphorbia species. These triterpenoids can provide potential leads that can be developed into pharmaceutical compounds for a wide range of medicinal applications. However, there are scattered scientific reports about the anticancer activities of these constituents. Harnessing such information could provide a database of bioactive pharmacopeia or targeted scaffolds for drug discovery. Therefore, this review presents an updated and comprehensive summary of the ethnomedicinal uses, phytochemistry, and the anticancer activities of the triterpenoids of Euphorbia species. Most of the reported triterpenoids in this review belong to tirucallane, cycloartanes, lupane, oleanane, ursane, and taraxane subclass. Their anticancer activities varied distinctly with the majority of them exhibiting significant cytotoxic and anticancer activities in vitro. It is, therefore, envisaged that the report on Euphorbia triterpenoids with interesting anticancer activities will form a database of potential leads or scaffolds that could be advanced into the clinical trials with regard to drug discovery.

Targeting renal OATs to develop renal protective agent from traditional Chinese medicines: Protective effect of Apigenin against Imipenem-induced nephrotoxicity

Imipenem (Imp) is a widely used broad-spectrum antibiotic. However, renal adverse effects limit its clinical application. We previously reported that organic anion transporters (OATs) facilitated the renal transport of Imp and contributed its nephrotoxicity. Natural flavonoids exhibited renal protective effect. Here, we aimed to develop potent OAT inhibitors from traditional Chinese medicines (TCMs) and to evaluate its protective effect against Imp-induced nephrotoxicity. Among 50 TCMs, Tribuli Fructus, Platycladi Cacumen, and Lycopi Herba exhibited potent inhibition on OAT1/3. After screening their main components, Apigenin strongly inhibited Imp uptake by OAT1/3-HEK293 cells with IC50 values of 1.98 ± 0.36 μM (OAT1) and 2.29 ± 0.88 μM (OAT3). Moreover, Imp exhibited OAT1/3-dependent cytotoxicity, which was alleviated by Apigenin. Furthermore, Apigenin ameliorated Imp-induced nephrotoxicity in rabbits, and reduced the renal secretion of Imp. Apigenin inhibited intracellular accumulation of Imp and sequentially decreased the nephrocyte toxicity in rabbit primary proximal tubule cells (rPTCs). Apigenin, a flavone widely distributed in TCMs, was a potent OAT1/3 inhibitor. Through OAT inhibition, at least in part, Apigenin decreased the renal exposure of Imp and consequently protected against the nephrotoxicity of Imp. Apigenin can be used as a promising agent to reduce the renal adverse reaction of Imp in clinic.

Aruncin B: Synthetic Studies, Structural Reassignment and Biological Evaluation

A ring-closing alkene metathesis (RCM)/ oxyselenation-selenoxide elimination sequence was established to the sodium salts E- and Z-25 of the originally proposed structure for the recently isolated cytotoxin aruncin B (1), as well as to the sodium salt Z-34 of a related ethyl ether regioisomer; however, none of their corresponding free acids could be obtained. Their acid sensitivity, together with detailed analysis of the spectroscopic data indicated that profound structural revision was necessary. This led to reassignment of aruncin B as a Z-γ-alkylidenebutenolide Z-36. Although a related RCM/ oxyselenation-selenoxide elimination sequence was used to confirm the γ-alkylidenebutenolide motif, a β-iodo Morita-Baylis-Hillman reaction/ Sonogashira cross-coupling-5-exo-dig lactonisation sequence was subsequently developed, due to its brevity and flexibility for diversification. Aruncin B (36), together with 14 γ-alkylidenebutenolide analogues, were generated for biological evaluation.

Growth inhibitory effect of paratocarpin E, a prenylated chalcone isolated from Euphorbia humifusa Wild., by induction of autophagy and apoptosis in human breast cancer cells

Five flavones, including four flavonoids and one prenylated chalcone (paratocarpin E), were isolated from E. humifusa. and their chemical structures were established by spectroscopic analyses. We assessed the efficacy of these compounds against the growth of human breast cancer, leukemic, kidney cancer cell lines. Among them, paratocarpin E showed significant cytotoxicity against these cancer cell lines with an IC₅₀ of 19.6μM on the growth of MCF-7 cells. Paratocarpin E treatment of MCF-7 cells resulted in typical apoptotic features via increasing expression of activated caspase-8 and -9 and PARP cleavage. Moreover, paratocarpin E altered the expression of Bax and Bcl-2, leading to the release of cytochrome c from the mitochondria into the cytosol, suggesting that the mitochondria-mediated apoptosis was initiated. In addition, paratocarpin E increased the MDC-positive autophagic vacuoles, the ratio of LC3-II/LC3-I protein levels of Beclin-1, but decreased p62 expression, indicating the potent pro-autophagic effects of paratocarpin E in MCF-7 cells. Mechanistically, cell death induced by paratocarpin E is able to induce apoptosis of MCF-7 cells by activating p38 and JNK signaling pathway while inhibiting Erk pathway. Furthermore, paratocarpin E promotes the activation and nuclear translocation of NF-κB, which plays an important role in balancing paratocarpin E-mediated apoptosis and autophagy. The molecular docking study also revealed that paratocarpin E bound to Fas and NF-κB complex. These findings provide initial evidences that paratocarpin E can be used as a potential anti-cancer drug in future for breast cancer therapy.

Antihepatic Fibrosis Effect of Active Components Isolated from Green Asparagus (Asparagus officinalis L.) Involves the Inactivation of Hepatic Stellate Cells

Green asparagus (Asparagus officinalis L.) is a vegetable with numerous nutritional properties. In the current study, a total of 23 compounds were isolated from green asparagus, and 9 of these compounds were obtained from this genus for the first time. Preliminary data showed that the ethyl acetate (EtOAc)-extracted fraction of green asparagus exerted a stronger inhibitory effect on the growth of t-HSC/Cl-6 cells, giving an IC50 value of 45.52 μg/mL. The biological activities of the different compounds isolated from the EtOAc-extracted fraction with respect to antihepatic fibrosis were investigated further. Four compounds, C3, C4, C10, and C12, exhibited profound inhibitory effect on the activation of t-HSC/Cl-6 cells induced by TNF-α. The activation t-HSC/Cl-6 cells, which led to the production of fibrotic matrix (TGF-β1, activin C) and accumulation of TNF-α, was dramatically decreased by these compounds. The mechanisms by which these compounds inhibited the activation of hepatic stellate cells appeared to be associated with the inactivation of TGF-β1/Smad signaling and c-Jun N-terminal kinases, as well as the ERK phosphorylation cascade.

Anti-inflammatory components of Euphorbia humifusa Willd

Two new compounds, euphorbinoside (1) and dehydropicrorhiza acid methyl diester (2), along with 24 known compounds (3-26) were isolated from Euphorbia humifusa Willd. The effects of these compounds on soluble epoxide hydrolase (sEH) inhibitory activity were evaluated. Flavonoid compounds (10-21) exhibited high sEH inhibitory activity. Among them, compounds 12, 13, and 19 greatly inhibited sEH enzymatic activity, with IC50 values as low as 18.05±1.17, 18.64±1.83, and 17.23±0.84 μM, respectively. In addition, the effects of these compounds on lipopolysaccharide (LPS)-induced nitric oxide (NO) and tumor necrosis factor alpha (TNF-α) production by RAW 264.7 cells were investigated. Compounds 3-6, 8, 18, 20-23, and 25-26 inhibited the production of both NO and TNF-α, with IC50 values ranging from 11.1±0.9 to 45.3±1.6 μM and 14.4±0.5 to 44.5±1.2 μM, respectively.

Cytotoxic anthraquinone dimers from Melandrium firmum

Two new anthraquinone dimers, melrubiellin A (1) and melrubiellin B (2), were isolated from the aerial part of Melandrium firmum Rohrbach, along with seven known compounds (3-9). The structures of these compounds were elucidated by spectral analyses, including 1D and 2D NMR (COSY, HMQC, HMBC and NOESY) experiments. Compound 1 and 2 exhibited significant cytotoxicity towards HeLa, NCI-H460, Hep G2, Hep 3B and MKN-28 cell lines with IC50 values ranging from 5.26 to 81.16 μM.

A new guaianolide from Artemisia roxburghiana

A new member of 5αH,6βH,7αH,11αH-guaian-12,6α-olides, 11-epi-8α-hydroxyarborescin, together with a mixture of (24R)- and (24S)-cycloart-25-en-3b,24-diols, palmitic acid and 1-octacosanol were isolated from the leaves of Artemisia roxburghiana Bess. (Asteraceae) of Vietnam. Their structures were determined on the basis of spectroscopic methods.

Triterpenoids

This review covers the isolation and structure determination of triterpenoids including squalene derivatives, protostanes, lanostanes, holostanes, cycloartanes, dammaranes, euphanes, tirucallanes, tetranortriterpenoids, lupanes, oleananes, friedelanes, ursanes, hopanes, isomalabaricanes and saponins; 574 references are cited.