Direct ¹H-qNMR quantification of massoia lactone in endophytic Neocosmospora solani extracts and correlation with...

Quantitative analysis of metabolites in complex fungal extracts remains challenging due to the limited availability of authentic standards. In this work, a ¹H quantitative nuclear magnetic resonance (qNMR) method was developed for the direct quantification of massoia lactone in crude extracts of the endophytic fungus Neocosmospora solani Eb01. The method enabled selective integration of non-overlapping signals, allowing the quantification of massoia lactone without prior purification, yielding 52.46 mg g^-1 of extract. Complementary HS-SPME-GC-MS analysis identified 2-phenylethanol as the major volatile compound, while GC-MS confirmed massoia lactone as a major constituent of the organic fraction. The extract exhibited dose-dependent antifungal activity against phytopathogenic fungi, with a minimum inhibitory concentration of 2.00 mg mL^-1 against Aspergillus niger. These results demonstrate the applicability of qNMR for the reliable quantification of bioactive metabolites in complex matrices and support its use as a robust tool for the analytical standardisation of fungal-derived natural product extracts.