https://biointerfaceresearch.com/ 7921 Article Volume 11, Issue 1, 2021, 7921 - 7931 https://doi.org/10.33263/BRIAC111.79217931 Screening of Plants Hydro-Alcoholic Extracts from Kerman for their Inhibition of β-Glucuronidase Activity Ahmad Gholamhoseinian 1,2 , Fariba Sharififar 3 , Hamide Jalaeeian 1,4 , Beydolah Shahouzehi 4,5,* 1 Department of Clinical Biochemistry, Kerman University of Medical Sciences, Kerman, Iran 2 Physiology Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran 3 Department of Pharmacognosy, School of Pharmacy, Kerman University of Medical Science, Kerman, Iran 4 Student Research Committee, Kerman University of Medical Science, Kerman, Iran 5 Cardiovascular Research Center, Institute of Basic and Clinical Physiology Sciences, Kerman University of Medical Sciences, Kerman, Iran * Correspondence: b.shahozehi@kmu.ac.ir; bshahouzehi@gmail.com; Scopus Author ID 36470992900 Received: 15.06.2020; Revised: 4.07.2020; Accepted: 5.07.2020; Published: 9.07.2020 Abstract: In neonatal jaundice, β-glucuronidase converts conjugated bilirubin into the unconjugated form and increases its level in the blood. Many natural compounds have been identified as β- glucuronidase inhibitors. The aim of this study was to evaluate the effect of hydro-methanolic extracts of 100 plants on β-glucuronidase. The β-glucuronidase activity was measured by a spectrophotometric method using Phenolphthalein glucuronide and 4-nitrophenyl β-D-glucuronide. Kinetic study of the enzyme was performed in the presence and absence of the plant extract. It was revealed that from hydro- methanolic (70%) extracts, Rosa damascena and Ipomoea tricolor showed more than 85% inhibitory effect on β-glucuronidase. Rosa damascena showed competitive inhibition, and Ipomoea tricolor showed non-competitive inhibition. The K m and V max values for β-glucuronidase were 23.32 mM and 0.814 mM min -1 , respectively. When using 4-nitrophenyl β-D-glucuronide, Stevia and Cerasus avium showed more than 65% inhibitory effect on β-glucuronidase. Both Stevia and Cerasus avium showed non-competitive inhibition. The K m and V max values for β-glucuronidase were 16.98 mM and 0.936 mM min -1 , respectively. None of the plant extracts showed an activation effect on the enzyme. The data suggest that these plants might be good candidates for the treatment of neonatal jaundice and its related diseases. Keywords: β-glucuronidase; Neonatal jaundice; Phenolphthalein Glucuronide; 4-Nitrophenyl β-D- glucuronide. © 2020 by the authors. This article is an open-access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/). 1. Introduction Jaundice is caused by high levels of bilirubin in the blood due to infection, genetic factors, and preterm delivery [1-4]. The jaundice is derived from the Greek word jaune, which is recognized by yellowing the skin and eye scrubs due to the increased amount of serum bilirubin pigments [3,5]. Jaundice can be detected with a wide variety of benign or threatening disorders. Bilirubin level above 2.5-5 mg/dL is a symptom of jaundice [3,6,7]. However, the central nervous system is at high risk when the unconjugated bilirubin level is between 10-20 mg/dL, which requires treatment [2,4,7,8]. Jaundice may be due to various diseases, including genetic syndrome, liver diseases, autoimmune disorders, gallstones, hepatitis, pancreatic