Nur Liana Md Nasir1, Norizah Awang1, Nik Aina Syazana Nik Zainuddin1, Chin Long Poo1, Mohd Rahimi Ashraf Abd Rahman1, Siti Khadijah Mustapha Kamal1, Mei Siu Lau1, Siti Soleha Ab dullah1, Elda Nurafnie Ibnu Rasid1, Hussin Muhammad1*
1. Toxicology and Pharmacology Unit, Herbal Medicine Research Centre, Institute for Medical Research, National Institutes of Health, Ministry of Health, Setia Alam, 40170 Shah Alam, Selangor, Malaysia
*Corresponding author: Hussin Muhammad.
ABSTRACT
INTRODUCTION: Dioscorea hispida (DH), locally known as “ubi gadong”, belongs to the family Dioscoreaceae. DH contains several bioactive compounds, including diosgenin, dioscorine, and water-soluble polysaccharides. The steroidal saponins in DH have been reported to exert various pharmacological activities, such as anthelmintic and anti-inflammatory effects. However, despite these reported activities, its genotoxicity remains limited, warranting evaluation to ensure therapeutic safety.
OBJECTIVE(S): The aim of this study was to evaluate the genotoxicity potential of DH tuber aqueous extract (DHAE) using Salmonella typhimurium and Escherichia coli strains.
MATERIALS & METHODS: The study was conducted in accordance with the OECD Guideline for Testing of Chemicals, Method 471: Bacterial Reverse Mutation Test. The mutagenic potential of DHAE was determined using S. typhimurium tester strains TA98 and TA1537 for detecting frameshift mutation, and strains TA100, TA1535, along with E. coli WP2 uvrA for detecting base-pair-substitution mutation. The assay was performed with both positive and negative controls, in the presence and absence of an in vitro metabolic activation system (S9 mixture). DHAE was tested at concentrations ranging from 313 to 5000 µg/plate. All experiments were conducted in triplicate, and data were analysed for mean and standard deviation using Microsoft Excel.
RESULTS: No precipitation was observed on the agar at any of the tested concentrations, and the contamination control plates confirmed the absence of microbial contamination. The dose-finding test indicated that DHAE did not inhibit bacterial growth at any concentrations. Exposure to DHAE did not increase revertant colonies from the concentration of 313 to 5000 µg/plate for all tested strains.
CONCLUSION: DHAE was found to exhibit no mutagenic activity in the bacterial reverse mutation assay, up to the highest concentration of 5000 µg/plate, both in the presence and absence of the metabolic activation system. Future studies should incorporate mammalian cell and animal models to comprehensively evaluate its genotoxicity potential.
KEYWORDS: Dioscorea hispida, Genotoxicity, Bacterial Reverse Mutation Test
