Lipoxygenase Inhibitor From Endophytic Fungus Cladosporium ramotenellum Associated With Argemone mexicana L

Argemone mexicana is one of the known herbaceous plants hosting bioactive isoquinoline alkaloids. In the current study, an endophytic fungal isolate was studied for anti-inflammatory potential and the identification of its bioactive molecule. An endophytic fungus AMEF-14 was obtained from this plant and identified as Cladosporium ramotenellum based on microscopy and molecular tools. The extract of the isolate was investigated for the anti-inflammatory potential by nitric oxide, trypsin, protein denaturation, and HRBC stabilization methods. The extract was separated into six fractions via column chromatography and tested for inhibition of the lipoxygenase (LOX) enzyme. Among all, Fraction 5 showed maximum inhibition with an IC₅₀ value of 24.3 ± 0.88 µg/mL. The inhibitory kinetics revealed the K_m and V_max values as 0.0058 ± 1.14 mM and 2.776 ± 0.40 µmol/min, in the absence of Fraction 5. However, in the presence of Fraction 5, K_m remains constant, and V_max values decrease with increasing concentration, indicating a noncompetitive type of inhibition. The active compound of fraction was identified as berberine via NMR, high-resolution mass spectrometry, high-performance liquid chromatography (HPLC), Fourier-transform infrared (FTIR), and UV. Hence, endophytes can be a nonperishable source for the production of anti-inflammatory alkaloids.