Essential Oil Composition and in vitro Antifungal Activities of Essential Oil of Aerial Part of Ocimum americanum L. Collected from Kumaun Region of India

The essential oil of aerial part of Ocimum americanum L. was extracted by hydrodistillation process using Clevenger apparatus and analyzed by GC and GC-MS techniques. The yield of volatile oil was obtained as 0.27% (w/w) and a total 25 compounds were reported which constituted 96.28% of the total essential oil composition. Estragole is identified as major compound (69.54%) and linalool is reported as 5.28%. In the analysis of antifungal activities, the treatment appears to be most effective against Fusarium oxysporum and Rhizoctonia solani, with moderate effects on Bipolaris maydis and Curvularia lunata. Sclerotinia sclerotiorum, however, remains largely unaffected by the treatment across all concentrations, indicating that it may require different or higher concentrations for effective control. The essential oil of Ocimum americanum exhibits the strongest antifungal activity against F. oxysporum, with the lowest IC50 value of 95.3675 ppm. This suggests that F. oxysporum is the most susceptible to the essential oil, requiring the least concentration to inhibit 50% of fungal growth. In contrast, the essential oil shows the weakest activity against S. sclerotiorum, with an IC50 value of 634.294 ppm, indicating that it requires a higher concentration to achieve the same level of inhibition.