Isolation and Characterization of Antidermatophytic Bioactive Molecules from Piper longum L. Leaves

Piper longum L. (Piperaceae) commonly known as “long pepper” is a well known medicinal plant in ayurveda. Different parts of this plant, such as root, seed, fruit, whole plant etc. are used traditionally in various ailments. Here we have investigated the antidermatophytic activity of sequentially extracted petroleum ether, chloroform, methanol and water extracts from P. longum leaf against Trichophytonmentagrophytes, T. rubrum, T. tonsurans, Microsporum fulvum and M. gypseum. Better activity of chloroform and methanol extracts was observed. The chloroform extract was selected for further study and the MIC value was recorded as 5.0 mg ml⁻¹ against the test organisms. In the chloroform extract, tannins and phenolic compounds were detected. Further activity-guided fractionation of chloroform extract by silica gel column chromatography yielded nine major fractions. Among these, fraction-1, 4, 5 and 7 showed higher antidermatophytic activity. Fraction-4 on further purification by repeated column chromatography yielded a potential antidermatophytic fraction showing MIC value of 0.625 mg ml⁻¹ against T. mentagrophytes and T. rubrum as determined by broth microdilution method. The major compounds were identified as 1,2-benzenedicarboxylic acid, bis(2-ethylhexyl) ester (C₂₄H₃₈O₄] (41.45 %), 2,2-dimethoxybutane (C₆H₁₄O₂] (13.6 %) and β-myrcene (C₁₀H₁₆) (6.75 %) based on GC–MS data.