Dehydroleucodine

Sesquiterpene lactones from Gynoxys verrucosa and their anti-MRSA activity.[Pubmed:21782013]

J Ethnopharmacol. 2011 Sep 2;137(2):1055-9.

ETHNOPHARMACOLOGICAL RELEVANCE: Because of its virulence and antibiotic resistance, Staphylococcus aureus is a more formidable pathogen now than at any time since the pre-antibiotic era. In an effort to identify and develop novel antimicrobial agents with activity against this pathogen, we have examined Gynoxys verrucosa Wedd (Asteraceae), an herb used in traditional medicine in southern Ecuador for the treatment and healing of wounds. MATERIALS AND METHODS: The sesquiterpene lactones leucodine (1) and Dehydroleucodine (2) were extracted and purified from the aerial parts of Gynoxys verrucosa, and their structure was elucidated by spectroscopic methods and single-crystal X-ray analysis. The in vitro anti-microbial activity of Gynoxys verrucosa extracts and its purified constituents was determined against six clinical isolates including Staphylococcus aureus and Staphylococcus epidermidis strains with different drug-resistance profiles, using the microtiter broth method. RESULTS: Compound 1 has very low activity, while compound 2 has moderate activity with MIC(50)s between 49 and 195 mug/mL. The extract of Gynoxys verrucosa has weak activity with MIC(50)s between 908 and 3290 mug/mL. CONCLUSIONS: We are reporting the full assignment of the (1)H NMR and (13)C NMR of both compounds, and the crystal structure of compound 2, for the first time. Moreover, the fact that compound 2 has antimicrobial activity and compound 1 does not, demonstrates that the exocyclic conjugated methylene in the lactone ring is essential for the antimicrobial activity of these sesquiterpene lactones. However, the weak activity observed for the plant extracts, does not explain the use of Gynoxys verrucosa in traditional medicine for the treatment of wounds and skin infections.

Anti-inflammatory activity and effect on gastric acid secretion of dehydroleucodine isolated from Artemisia douglasiana.[Pubmed:12963142]

J Ethnopharmacol. 2003 Oct;88(2-3):195-8.

The effect of Dehydroleucodine (DhL) on gastric acid secretion in rats was investigated at a dose of 40 mg/kg, while its anti-inflammatory effect was investigated in two experimental models: arthritis induced by Freund's adjuvant carrageenan- and cotton pellet-induced granuloma. DhL did not inhibit gastric acid secretion, suggesting that its anti-ulcerogenic effect can be attributed to its action on the mucosa defense factors. On the other hand, DhL inhibited both chronic and acute adjuvant carrageenan-induced inflammation phases, being most effective in the chronic phase. In the granuloma test, DhL also inhibited inflammation. It is suggested that the anti-inflammatory activity of DhL may be attributed to interference with multiple targets on the level of transcription factors, such as NF-kappaB, and cytokines.

Lethal effect of dehydroleucodine (DhL) on amphibian Bufo arenarum embryos.[Pubmed:22240414]

Food Chem Toxicol. 2012 Mar;50(3-4):672-4.

The Dehydroleucodine is a sesquiterpene lactone isolated from Artemisia douglasiana Besser which is used in popular medicine. Toxicity tests using embryos of amphibian have been widely used in order to predict toxic effects of different compounds. However, to our knowledge, there are not studies focussed on the toxic effects of Dehydroleucodine on Bufo arenarum, which is an anuran widely distributed in South America. The effect of Dehydroleucodine on the survival of embryos was evaluated in an acute test during the early life stage of B. arenarum embryos. Lethality and the degree of adverse effects were Dehydroleucodine dose-dependent. Overall, amphibian early life stages appeared to be more susceptible to the embryotoxicity associated with exposure to Dehydroleucodine, especially at concentration greater that 3mM. This increased susceptibility may result from the relatively high rate of cellular differentiation and morphogenesis that occurs at this early stage of development.

The effect of dehydroleucodine in adipocyte differentiation.[Pubmed:21963454]

Eur J Pharmacol. 2011 Dec 5;671(1-3):18-25.

Dehydroleucodine (DhL) is a sesquiterpene lactone of the guaianolide group with gastric cytoprotective activity. Recent studies have also demonstrated that DhL inhibits the proliferation of vascular smooth muscle cells. In this study we examined the effect of DhL in the differentiation of 3T3-L1 preadipocytes. The addition of DhL significantly inhibited the differentiation of 3T3-L1 preadipocytes along with a significant decrease in the accumulation of lipid content by a dramatic downregulation of the expression of adipogenic-specific transcriptional factors PPARgamma and C-EBPalpha. However, phosphorylation of AMPKalpha, Erk1/2 and Akt1 was not inhibited by DhL treatment. Interestingly, we also found that 11,13-dihydroDehydroleucodine, a derivative of DhL with inactivated alpha-methylene-gamma-lactone function, also inhibited the differentiation of 3T3-L1 preadipocytes. Taken together, these data suggest that DhL has an important inhibitory effect in cellular pathways regulating adipocyte differentiation by modulating the PPARgamma expression, which is known to play a pivotal role during adipogenesis.

Antidiarrheal activity of dehydroleucodine isolated from Artemisia douglasiana.[Pubmed:17683879]

Fitoterapia. 2008 Jan;79(1):1-5.

Dehydroleucodine (DhL), a sesquiterpene lactone obtained from Artemisia douglasiana, was screened for antidiarrheal effects. DhL inhibited castor oil-induced diarrhea in mice by judged by a decrease in the number of wet faeces in the DhL-treatment groups. DhL significantly reduced intestinal transit in mice. Yohimbine and phentolamine counteracted the inhibitory effect of DhL. It is suggested that alpha2-adrenergic receptors mediate the effect of DhL in intestinal motility. DhL reduced also intraluminal accumulation of fluid. Thus, the antidiarrheal activity of DhL is possibly related, at least in part, to its inhibitory action against gastrointestinal motility and the inhibition of enteropooling property.

Dehydroleucodine Induces a TP73-dependent Transcriptional Regulation of Multiple Cell Death Target Genes in Human Glioblastoma Cells.[Pubmed:27671304]

Anticancer Agents Med Chem. 2017;17(6):839-850.

BACKGROUND: Dehydroleucodine, a natural sesquiterpene lactone from Artemisia douglassiana Besser (Argentine) and Gynoxys verrucosa (Ecuador). OBJECTIVE: To define the molecular mechanisms underlying the effect of Dehydroleucodine on the human glioblastoma cells. METHOD: Various techniques (cDNA expression array, real-time quantitative PCR, chromatin immunprecipitation, luciferase reporter assay, use of phosphospecific antibodies, immunoprecipitation, immunoblotting, apoptosis and autophagy assays) were employed to define and validate multiple molecular gene targets affected in human glioblastoma cells upon Dehydroleucodine exposure. RESULTS: Dehydroleucodine exposure upregulated the total and phosphorylated (p-Y99) levels of TP73 in U87- MG glioblastoma cells. We found that TP73 silencing led to a partial rescue of U87-MG cells from the cell death induced by Dehydroleucodine. Upon the Dehydroleucodine exposure numerous gene targets were upregulated and downregulated through a TP73-dependent transcriptional mechanism. Some of these gene targets are known to be involved in cell cycle arrest, apoptosis, autophagy and necroptosis. Dehydroleucodine induced the TP73 binding to the specific genes promoters (CDKN1A, BAX, TP53AIP1, CYLD, RIPK1, and APG5L). Moreover, the exposure of U87-MG cells to Dehydroleucodine upregulated the protein levels of CDKN1A, BAX, TP53AIP1, CYLD, RIPK1, APG5L, and downregulated the CASP8 level. The formation of RIPK1 protein complexes and phosphorylation of MLKL were induced by Dehydroleucodine supporting the notion of multiple cell death mechanisms implicated in the tumor cell response to Dehydroleucodine. CONCLUSION: This multifaceted study led to a conclusion that Dehydroleucodine induces the phosphorylation of tumor protein TP73 and in turn activates numerous TP73-target genes regulating apoptosis, autophagy and necroptosis in human glioblastoma cells..

Dehydroleucodine inhibits tumor growth in a preclinical melanoma model by inducing cell cycle arrest, senescence and apoptosis.[Pubmed:26718258]

Cancer Lett. 2016 Mar 1;372(1):10-23.

Malignant melanoma represents the fastest growing public health risk of all cancer types worldwide. Several strategies and anti-cancer drugs have been used in an effort to improve treatments, but the development of resistance to anti-neoplastic drugs remains the major cause of chemotherapy failure in melanomas. Previously, we showed that the sesquiterpene lactone, Dehydroleucodine (DhL), promotes the accumulation of DNA damage markers, such as H2AX and 53BP1, in human tumor cells. Also DhL was shown to trigger either cell senescence or apoptosis in a concentration-dependent manner in HeLa and MCF7 cells. Here, we evaluated the effects of DhL on B16F0 mouse melanoma cells in vitro and in a pre-clinical melanoma model. DhL inhibited the proliferation of B16F0 cells by inducing senescence or apoptosis in a concentration-dependent manner. Also, DhL reduced the expression of the cell cycle proteins cyclin D1 and B1 and the inhibitor of apoptosis protein, survivin. In melanomas generated by subcutaneous injection of B16F0 cells into C57/BL6 mice, the treatment with 20 mg DhL /Kg/day in preventive, simultaneous and therapeutic protocols reduced tumor volumes by 70%, 60% and 50%, respectively. DhL treatments reduced the number of proliferating, while increasing the number of senescent and apoptotic tumor cells. To estimate the long-term effects of DhL, a mathematical model was applied to fit experimental data. Extrapolation beyond experimental time points revealed that DhL administration following preventive and therapeutic protocols is predicted to be more effective than simultaneous treatments with DhL in restricting tumor growth.

Dehydroleucodine inhibits vascular smooth muscle cell proliferation in G2 phase.[Pubmed:16309576]

Cell Mol Biol (Noisy-le-grand). 2005 Nov 8;51(6):525-30.

Vascular smooth muscle cell (VSMC) proliferation plays an important role in the development of atherosclerosis and in the vascular changes seen in hypertension. Dehydroleucodine (DhL) is a sesquiterpene lactone that inhibits cell proliferation in plant cells. In this paper, we study the effect of DhL in the proliferation of VSMCs stimulated with 10% fetal bovine serum (FBS). Very low concentrations of DhL (2-6 microM) inhibited VSMC proliferation and induced cell accumulation in G2. DhL did not affect the dynamics of 3H-thymidine incorporation, and did not modify either the activity of DNA polymerase or the incorporation of deoxyribonucleotides in an in vitro assay. Moreover, DhL did not induce apoptosis in VSMCs. These results indicate that DhL, in very low concentration, induces a transient arrest of VSMCs in G2. Our data show that VSMCs are especially sensitive to DhL effect, suggesting that DhL could be potentially useful to prevent the vascular pathological changes seen in hypertension and other vascular diseases.