Curcumin and Fennel Essential Oil Improve Symptoms and Quality of Life in Patients with Irritable Bowel Syndrome

Background & Aims: Irritable Bowel Syndrome (IBS) patients still require effective treatment. The anti-inflammatory property of curcumin and the antispasmodic and carminative effect of fennel suggests that combination of these nutraceutical compounds would be useful in functional bowel disorders including IBS. We assessed the efficacy and tolerability of a combination of curcumin and fennel essential oil (CU-FEO) in IBS symptoms relief. Methods: 121 patients with mild-to-moderate symptoms of IBS defined by an Irritable Bowel Syndrome- symptom severity score (IBS-SSS) 100-300 and abdominal pain score 30-70 on a 100 mm Visual Analogue Scale (VAS), were randomly assigned to CU-FEO or placebo (2 capsules b.d. for 30 days). Primary endpoint was the mean decrease of IBS-SSS at the end of the treatment corrected for the mean baseline score (relative decrease). The impact of the treatment on quality of life was assessed through IBS-QoL questionnaire. Results: CU-FEO was safe, well-tolerated and induced symptom relief in patients with IBS; a significant decrease in the mean relative IBS-SSS was observed after 30 days of treatment (50.05 ± 28.85% vs 26.12 ± 30.62%, P<0.001). This result matched the reduction of abdominal pain and all the other symptoms of IBS-SSS. The percentage of symptom-free patients was significantly higher in the CU-FEO than in the placebo group (25.9% vs. 6.8%, P = 0.005). All domains of IBS-QoL improved consistently. Conclusion: CU-FEO significantly improved symptoms and quality of life in IBS patients over 30 days. Abbreviations: AEs: adverse events; CU-FEO: Curcumin-Fennel Essential Oil; GI: gastrointestinal; IBS: irritable bowel syndrome; IBS-D: irritable bowel syndrome-diarrhea; IBS-C: irritable bowel syndrome-constipation; IBS-SSS: Irritable Bowel Syndrome – symptom severity score; NF-kB: nuclear factor-κB; QoL: quality of life; UC: ulcerative colitis; VAS, Visual Analogue Scale.

Modulation of the gut microbiota composition by rifaximin in non-constipated irritable bowel syndrome patients: a molecular approach

Rifaximin, with its low systemic absorption, may represent a treatment of choice for irritable bowel syndrome (IBS), mainly due to its ability to act on IBS pathogenesis, through the influence on gut microbiota. The aim of the present study was to assess, by biomolecular tools, the rifaximin active modulation exerted on gut microbiota of non-constipated IBS patients. Fifteen non-constipated IBS subjects were treated with 550 mg rifaximin three times a day for 14 days. Stool samples were collected before starting the treatment, at the end of it, and after a 6-week washout period. Real-time polymerase chain reaction, denaturing gradient gel electrophoresis, and next-generation sequencing were applied to all the samples to verify and quantify possible microbial fluctuations. Rifaximin treatment did not affect the overall composition of the microbiota of the treated subjects, inducing fluctuations in few bacterial groups, balanced by the replacement of homologs or complementary bacterial groups. Rifaximin appeared to influence mainly potentially detrimental bacteria, such as Clostridium, but increasing the presence of some species, such as Faecalibacterium prausnitzii. A decrease in the Firmicutes/Bacteroidetes ratio after 14 days of treatment and bacterial profiles with higher biodiversity were observed during the follow-up compared to baseline. Rifaximin treatment, although effective on IBS symptom relief and normalization of lactulose breath test, did not induce dramatic shifts in the microbiota composition of the subjects, stimulating microbial reorganization in some populations toward a more diverse composition. It was not possible to speculate on differences of fecal microbiota modification between responders vs nonresponders and to correlate the quali-/quantitative modification of upper gastrointestinal microbiota and clinical response.

DNA topoisomerase I inhibition by camptothecin induces escape of RNA polymerase II from promoter-proximal pause site, antisense transcription and histone acetylation at the human HIF-1alpha gene locus

Top1 inhibition by camptothecin (CPT) perturbs RNA polymerase II (Pol II) density at promoters and along transcribed genes suggesting an involvement of Top1 in Pol II pausing. Here, we demonstrate that Top1 inhibition favors Pol II escape from a promoter-proximal pausing site of the human HIF-1α gene in living cells. Interestingly, alternative splicing at exon 11 was markedly altered in nascent HIF-1α mRNAs, and chromatin structure was also affected with enhanced histone acetylation and reduced nucleosome density in a manner dependent on cdk activity. Moreover, CPT increases transcription of a novel long RNA (5′aHIF1α), antisense to human HIF-1α mRNA, and a known antisense RNA at the 3′-end of the gene, while decreasing mRNA levels under normoxic and hypoxic conditions. The effects require Top1, but are independent from Top1-induced replicative DNA damage. Chromatin RNA immunoprecipitation results showed that CPT can activate antisense transcription mediated by cyclin-dependent kinase (cdk) activity. Thus, Top1 inhibition can trigger a transcriptional stress, involving antisense transcription and increased chromatin accessibility, which is dependent on cdk activity and deregulated Pol II pausing. A changed balance of antisense transcripts and mRNAs may then lead to altered regulation of HIF-1α activity in human cancer cells.

A specific transcriptional response of yeast cells to camptothecin dependent on the Swi4 and Mbp1 factors

Topoisomerase I (Top1) is the specific target of the anticancer drug camptothecin (CPT) that interferes with enzyme activity promoting Top1-mediated DNA breaks and inhibition of DNA and RNA synthesis. To define the specific transcriptional response to CPT, we have determined the CPT-altered transcription profiles in yeast by using a relatively low concentration of the drug. CPT could alter global expression profiles only if a catalytically active Top1p was expressed in the cell, demonstrating that drug interference with Top1 was the sole trigger of the response. A total of 95 genes showed a statistically-significant alterations. Gene Ontology term analyses suggested that the cell response was mainly to the inhibition of nucleic acid synthesis and cell cycle progression. Promoter sequence analyses of the 22 up-regulated genes and expression studies in gene-deleted strains showed that the transcription factors, Swi4p and Mbp1p, mediate at least partially the transcriptional response to CPT. The MBP1 gene deletion abrogates a transient cell growth delay caused by CPT whereas the SWI4 gene deletion increases yeast resistance to CPT. Thus, the findings show that yeast cells have a highly selective and sensitive transcriptional response to CPT depending on SWI4 and MBP1 genes suggesting a complex regulation of cell cycle progression by the two factors in the presence of CPT.

The effects of camptothecin on RNA polymerase II transcription: Roles of DNA topoisomerase I

Eukaryotic DNA topoisomerase I is active in transcribed chromatin domains to modulate transcription-generated DNA torsional tension. Camptothecin and other agents targeting DNA topoisomerase I are used in the treatment of human solid cancers with significant clinical efficacy. Major progress has been achieved in recent years in the understanding of enzyme structures and basic cellular functions of DNA topoisomerase I. Nevertheless, the precise enzyme functions and mechanisms during transcription-related processes remain unclear. The current understanding of the molecular action of camptothecin emphasizes the drug action against the enzyme and the production of irreversible breaks in the cellular DNA. However, the high drug potency is hardly fully explained by the DNA damage outcome only. In the recent past, several unexpected findings have been reported in relation to the role of eukaryotic topoisomerase I during transcription. In particular, the function of DNA topoisomerase I and the molecular effects of its inhibition on transcription-coupled processes constitute a very active research area. Here, we will briefly review relevant investigations on topoisomerase I involvement in different stages of transcription, discussing both enzyme functions and drug effects on molecular processes.