Molecular Identification of Leptospira interrogans and Its Treatment with Andrographis paniculata Extract

Background: Leptospirosis is a zoonotic disease that transmitted to humans by rodents and domestic animals that infected by Leptospira bacteria and considered as a endemic disease in South India and North-East India. Andrographis paniculata is an ancient herb with various therapeutic properties and has Andrographolide bioactive compound. Purpose: The aim of the present study is to isolate and molecular identification by ITS sequencing of the Leptospira interrogans from the soil sample of paddy field and to analyse the anti-leptospirosis activity of Andrographis paniculata extract in in vitro. Methods: Andrographis paniculata extract was extracted using methanol and screening of phytocompound was done by GC-MS analysis. Leptospira species was isolated from the soil sample and molecular identification was performed by 16s rRNA gene sequencing. BLAST and phylogenetic tree analysis confirmed the presence of Leptospira interrogans. Molecular Docking analysis was performed to study the interaction between the Andrographolide and Leptospira LRR protein. Anti-leptospirosis activities of Andrographis paniculata extracted using different solvents were determined by Minimum Inhibitory Concentration (MIC) methods. Results: The 16s rRNA sequencing and BLAST results confirmed the presence of Leptospirosis interrogans. The phylogenetic tree analysis showed the distance between the Leptospirosis species. Furthermore, the GCMS analysis of Andrographis paniculata methanolic extract showed the presence of phytocompound Andrographolide. Molecular docking analysis of Andrographolide with the LRR protein showed stable binding. The in vitro anti-leptospiral activity of different Andrographis paniculata extract showed the maximum inhibition at 500 μg/mL and the maximum MIC was observed at methanolic extract of A. paniculata at 31.2 μg/mL with 64.65 ± 7.33% of inhibition. Conclusion: From our study we concluded that Andrographis paniculata extracted using methanol has good anti-leptospirosis activity and Andrographolide will act as a good therapeutic agent against leptospirosis.