Chromobacterium violaceum (C. violaceum) is a Gram‑negative bacterium commonly found in tropical and subtropical environments, such as soil and water. It is known for producing a distinctive violet pigment known as violacein, which is regulated by its quorum sensing (QS) system. The present study examined the compound, Pithecellobium dulce (P. dulce), and its inhibitory effects on the quantity of violacein pigment generated by C. violaceum CV12472. P. dulce is recognized as a potent natural compound with significant inhibitory effects against various pathogens. The present study explored the antimicrobial and antibiofilm properties of P. dulce (seed and fruit) against C. violaceum CV12472 through a series of in vitro experiments. These experiments included minimum inhibitory concentration (MIC) tests, biofilm inhibition assays, violacein pigment assay and growth curve analysis, providing valuable insight into the potential of P. dulce as a natural therapeutic agent in combating microbial infections. MIC assay revealed that both the seed and fruit extracts effectively inhibited bacterial growth at 20 mg/ml. Furthermore, biofilm inhibition was observed, with P. dulce seed extract significantly reducing biofilm formation by 58.91 and 29.68% at 10 and 5 mg/ml, respectively, without affecting planktonic growth. Additionally, the present study demonstrated that P. dulce seed extract inhibited violacein production by 80.66% at 10 mg/ml, confirming its anti‑QS properties. However, the fruit extract did not exhibit any notable effect on biofilm or pigment production. These findings suggest that P. dulce seed extract disrupts key bacterial survival mechanisms, thus suggesting its potential for use as s natural alternative for managing biofilm‑associated infections caused by antibiotic‑resistant pathogens. To the best of our knowledge, the present study is the first report of P. dulce seed extract inhibiting QS‑regulated virulence factors in C. violaceum. The findings of the present study highlight the potential use of plant‑based compounds in the fight against antibiotic resistance and bacterial virulence.

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