There was a significant improvement in health status, including dry cough, sputum cough, ague, sore throat, weakness, muscular pain, headache, and dyspnea at week 2, in curcumin-piperine group more than in placebo group, according to Gholamreza Askari et al., “The efficacy of curcumin-piperine co-supplementation on clinical symptoms, duration, severity, and inflammatory factors in COVID-19 outpatients: a randomized double-blind, placebo-controlled trial,” Trials (2022) 23:472, https://doi.org/10.1186/s13063-022-06375-w, JIF 2.728 (top 76% journals in Medicine, Research & Experimental).
The medicinal properties of curcumin obtained from Curcuma longa L. cannot be utilised because of poor bioavailability due to its rapid metabolism in the liver and intestinal wall. In this study, the effect of combining piperine, a known inhibitor of hepatic and intestinal glucuronidation, was evaluated on the bioavailability of curcumin in rats and healthy human volunteers. In humans after a dose of 2 g curcumin alone, serum levels were either undetectable or very low. Concomitant administration of piperine 20 mg produced much higher concentrations from 0.25 to 1 h post drug, the increase in bioavailability was 2000%. The study shows that in the dosages used, piperine enhances the serum concentration, extent of absorption and bioavailability of curcumin in humans with no adverse effects, according to G. Shoba et al., “Influence of piperine on the pharmacokinetics of curcumin in animals and human volunteers,” Planta Medica, 1998 May;64(4):353-6, https://doi.org/10.1055/s-2006-957450, JIF 3.007 (top 36% journals in Plant Sciences and top 47% journals in Integrative & Complementary Medicine).
Curcumin acts as an antioxidant, anti-inflammatory, anticarcinoma, antimicrobial, antiviral, hypoglycemic and wound healer. It has shown therapeutic efficacy in numerous chronic diseases and in some kinds of cancer in vitro and in vivo. Despite much evidence of its efficacy and safety, curcumin has not yet been approved as a therapeutic agent due to its low bioavailability, instability at physiological pH, insolubility in water, slow uptake by cells and rapid metabolism inside cells. Piperine (20mg) 20 times enhances the bioavailability of Curcumin (2g), according to Angelo Siviero et al., “Curcumin, a golden spice with a low bioavailability,” Journal of Herbal Medicine, Volume 5, Issue 2, June 2015, Pages 57-70, https://doi.org/10.1016/j.hermed.2015.03.001, JIF 2.542 (top 35% journals in Integrative & complementary Medicine).