Anticandidal Compound Identified by LCMS/MS Isolated from an Endophytic Fungus Emericella sp. from Azadirachta indica

With the advent of new diseases in a span of few years, mankind has been forced to think about alternative medicines. Traditional therapy which deals with medicinal plants has gained importance in such scenario. In the present study, Emericella sp.  has been isolated for the first time from Azadirachta indica, having anticandidal potential. The ethanolic extract of fungal biomass exhibited anticandidal activity with 50 mm inhibition zone. Metabolite was purified by column chromatography. Peak at RT 20.4 min obtained by LC was  subjected to MS in positive and negative ionization modes. Ionization in positive mode gave a single molecular ion peak (M+H)⁺ at m/z value of 556.2 with relative intensity of 100%. Fragmentation was performed by applying different collision dissociation energies (CID) of 5, 15, 20, and 25. The fragmentation was observed for all energy levels applied. Ionisation in negative mode gave molecular ion peak at m/z 554.2 which didn’t fragment further on applying different collision dissociation energies. Eight compounds matched with the chemical database of  NIST library having molecular mass of 555. The structures of all the eight compounds were drawn with the help of Chemdraw. The fragmentation of these structures were performed on the basis of possibility in fragment loss pattern manually. The fragmentation pattern of the molecule under investigation whose structure is to be elucidated matched with the compound I-Leucine, N-(4-trifluoromethylbenzoyl)-octadecyl ester at energy level of  25 CID. The molecular formula of the compound is C₃₂H₅₂F₃NO_3, molecular mass 555.39 and molecular weight  555.76. The IR Spectra of the purified compound depicted the functional groups present in the molecule as: ν_{max, cm} ^–1  3417-3218 (NH₂), 2957-2853 (CH₃ attached to keto group), 1659 (Stretching of NH₂-C=O),  1562 (NH bending of  secondary amide), 1383 (CH₃ bending),  1125 (-CH of Aromatic rings).

To the best of our knowledge the compound isolated and tentatively identified as  I-Leucine, N-(4-trifluoromethylbenzoyl)-octadecyl ester has been reported for the first time from an endophytic fungi, Emericella sp, isolated from A. indica. The molecule may be used as a lead molecule to develop potential drug(s) for candidal infections because of its specific activity against Candida.