Chemical composition and antifungal activity of essential oils from three Himalayan Erigeron species

- Himalayan Erigeron essential oils have dominant presence of polyacetylenic esters.
- The antifungal activity was tested against soil born phytopathogenic fungi.
- The oils showed inhibition of spore germination (IC50 value 120.7-300.4 μg/mL).
- The activity may be accredited mainly to the presence of acetylenic esters.
- Results demonstrate potential of Erigeron oils as eco-friendly natural fungicides.

Three Himalayan Erigeron (Asteraceae) species viz Erigeron mucronatus, Erigeron annuus and Erigeron karwinskianus growing in sub-alpine region revealed occurrence of isomeric polyacetylenic constituents viz., matricaria and lachnophyllum esters which accounted for 83.3%, 69.3% and 30.1% of the essential oils from these species, respectively, in addition to mono- and sesquiterpenoids as minor constituents. The antifungal activity tested by poisoned food (PF) techniques against Fusarium oxysporum, Helminthosporium maydis, Rhizoctonia solani, Alternaria solani and Sclerotinia sclerotiorum demonstrated significant inhibition of the mycelial growth of all strains (p < 0.05). The oils (500 μg/mL) showed significant antifungal effect against tested fungi in the growth inhibition range of 37.6-85.5% with respective IC50 values ranging from 88.8 to 660.0 μg/mL as compared to standard fungicides (100% inhibition) with IC50 value in the range of 32.2-129.4 μg/mL. Significant inhibition of spore germination was noticed for F. oxysporum, Curvularia lunata and Albugo candida which were highly susceptible to E. annuus oil with their IC50 values 120.7, 253.5 and 300.4 μg/mL, respectively. Thus, the results obtained in this study demonstrate the potential of essential oils from Himalayan Erigeron species as non-toxic, eco-friendly and biodegradable natural fungicides.