Mutagenicity Study of Semi-Synthetic 7-Hydroxymitragynine from Mitragyna speciosa Using Salmonella typhimurium and Escherichia coli (WP2 uvrA) by the Ames Test

Abstract

Kratom (Mitragyna speciosa, Korth), found in Southeast Asia, has been traditionally used in Thai medicine to alleviate abdominal pain, dysentery, diarrhea, and muscle aches, and as a sedative. Its primary active compounds are alkaloids, with mitragynine being the most abundant. Another derivative, 7-hydroxymitragynine (7-OHMG), exhibits more potent activity than mitragynine, making it suitable for medical and public health applications. However, safety data regarding the active compounds from this plant remain limited. This study aimed to investigate the mutagenicity of a semi-synthetic kratom extract (7-OHMG) using the Ames test with Salmonella typhimurium strains (TA98, TA100, TA1535, TA1537) and Escherichia coli (WP2uvrA). The test was conducted at six concentrations (15, 50, 150, 500, 1,500 and 5,000 µg/plate) both with and without metabolic activation. The results indicated no mutagenic activity in any of the 5 bacterial strains, either with or without metabolic activation. Specifically, the number of revertant colonies for strains TA98, TA100, and WP2uvrA did not double, and for strains TA1535 and TA1537, it did not triple, relative to the negative control. Furthermore, no abnormalities were observed in the background lawn for any strain at any concentration. While the World Health Organization has identified 7-OHMG as a substance requiring safety monitoring, this study provides crucial preliminary safety data. These findings serve as a foundational guideline for the further development of 7-OHMG into high-quality, internationally accepted pharmaceuticals or health products. This could enable its practical use in modern medicine and foster innovation in Thai herbal products.