Bioactive plant compounds with activity against Treponema pallidum

Abstract

Objective: To analyze the therapeutic potential of bioactive natural products with activity against Treponema pallidum as potential sources for future complementary therapeutic strategies. Methods: An exploratory literature review was performed in the PubMed, ScienceDirect, and Scopus databases using the search terms “Treponema pallidum” AND (“bioactive natural products” OR “natural compounds” OR “plant extracts”), including both in vitro and in silico studies published between January 2005 and January 2025. After duplicates were removed and titles, abstracts, and full texts were screened, four studies met the inclusion criteria. Phthalic acid (1,2-benzenedicarboxylic acid) was the only isolated compound. Its pharmacokinetic and toxicological properties were evaluated using ADMETlab 2.0 and PreADMET, while oral bioavailability was assessed with SwissADME, producing a bioavailability radar and BOILED-Egg model. Results: Phthalic acid, obtained from Hibiscus rosa-sinensis flowers, showed a 24 mm inhibition zone at 10 μg/mL using the agar-well diffusion method. Among plant extracts, the acetone extract of Odina wodier exhibited the highest antimicrobial activity (MIC 0.78 μg/mL; MBC 1.52 μg/mL), followed by extracts from Moringa oleifera and Curculigo orchioides (MIC 3.12 μg/mL). Final considerations: Natural products show promise against T. pallidum; however, the predominance of crude extracts limits clinical application, and further isolation and safety studies are needed.