Anti-inflammatory potential of aconitine produced by endophytic fungus Acremonium alternatum

Argemone mexicana belonging to family Papaveraceae is a traditional medicinal plant widely utilized by tribal people in India for treating various ailments like skin infections, wounds and inflammation. This plant is very rich in alkaloidal content, which has a great potential in the treatment of anti-inflammatory disorders. Therapeutically promising bioactive molecules are often produced by endophytic fungi associated with medicinal plants. In this investigation, endophytic fungi were isolated from various parts of A. mexicana and screened for alkaloidal content. Among these, one of the fungal isolate, Acremonium alternatum AMEF-5 producing maximum alkaloids showed significant anti-inflammatory activity. Fractionation of this crude fungal extract through column chromatography yielded eight fractions, which were further screened for anti-inflammatory activities. Fraction 3 exhibited significant anti-inflammatory activity by the inhibition of lipoxygenase enzyme (IC₅₀ 15.2 ± 0.09 µg/ml), scavenging of the nitric oxide radicals (IC₅₀ 11.38 ± 0.35 µg/ml), protein denaturation (IC₅₀ 14.93 ± 0.4 µg/ml), trypsin inhibition (IC₅₀ 12.06 ± 0.64 µg/ml) and HRBC stabilization (IC₅₀ 11.9 ± 0.22 µg/ml). The bioactive alkaloid in fraction 3 was identified as aconitine which was confirmed by UV, FTIR, HPLC, HRMS, ¹H NMR, and ¹³C NMR analysis. This study demonstrates that endophytic fungi serve a potential source for sustainable production of therapeutically important alkaloids.