Efficacy and Tolerability Study of Natura-Alpha in the Treatment of Patients With Active Ulcerative Colitis

This will be a randomized, double-blind, placebo-controlled, parallel-design study. Eligible patients will have moderate to severe ulcerative colitis, defined as: * A Disease Activity Index (DAI) score of 6 to 10 (inclusive); * Endoscopic evidence of active ulcerative colitis (DAI mucosal appearance sub score of ≥2) as assessed by flexible sigmoidoscopy unless colonoscopy is clinically indicated; * Rectal bleeding (DAI sub score of ≥1); * Physician's Global Assessment (PGA) of moderate disease (DAI sub score ≥2). Patients will be randomized to receive placebo, 10 mg Natura-alpha or 20 mg Natura-alpha. Patients will self-administer their assigned dose orally for 28 consecutive days, twice per day (b.i.d) at approximately 8:00 am and 8:00 pm. The effectiveness and safety of Natura-alpha will be evaluated at baseline, and after 7, 14 and 28 days of treatment. Additional follow-up measurements will take place 7 and 28 days post cessation of treatment (Day 35 and Day 56, respectively). Stool samples for fecal calprotectin (FC) tests and optional blood samples (15 ml) for cytokine tests will be collected and analyzed at sponsor-selected sites and lab for exploratory analyses to be performed at a later date. Clinical response will be assessed by the Physician's Global Assessment (PGA) on the basis of sigmoidoscopy (Walkiewicz, Werlin et al. 2008) and mucosal appearance (DAI category). Sigmoidoscopy including histopathological examination to assess disease severity and changes in tissue inflammation will be conducted before and after treatment (Day 1, Day 28) by the same endoscopist at each site and read by one sponsor selected central pathologist. Truelove-Richards histological grading system will be applied for disease histological scoring (Pullan, Rhodes et al. 1994; Zhong, Huang et al. 2005; Liang and Ouyang 2008). Safety labs and adverse events (AEs) will be monitored for the duration of the study (including the 7 day follow up visit).