Bio-pesticidal and Antimicrobial Coumarins from Angelica dahurica (Fisch. Ex Hoffm)

Angelica dahurica (Fisch. Ex Hoffm) is an important traditional Chinese herb which is widely used in curing acne, ulcers, carbuncles, rheumatism, headaches and toothaches. A systematic antifungal bioassayguided fractionation of the ethyl acetate extract from A. dahurica led to the isolation of six coumarins, namely, suberosin, bergapten, alloimperatorin, xanthotoxol, 5-methoxy-8-hydroxypsoralen and pabulenol. These coumarins were subsequently subjected to evaluation for antifungal, antibacterial, antimalarial, antileishmanial and mosquito larvicidal activities. Bergapten and xanthotoxol showed good antifungal activity against Phomopsis viticola, with 99.8% and 73.0% fungal growth inhibition at the concentration of 30 μM. Among all the compounds tested against Phomopsis obscurans, bergapten and suberosin showed the highest antifungal activity with 61.0% and 88.3% inhibition at a 30 μM concentration, respectively. 5-Methoxy-8-hydroxypsoralen displayed toxicity against Streptococcus iniae with an IC50 of 11.6 mg/L and MIC values of 2.32 mg/L. Suberosin and alloimperatorin displayed moderate activity against Leishmania donovani promastigotes with IC50 of 4.43 μg/mL and 20.43 μg/mL. Herein, the antifungal activities of suberosin against P. obscurans and xanthotoxol against P. viticola, the antileishmanial activities of suberosin and alloimperatorin, and the antibacterial activity 5-methoxy-8-hydroxy-psoralen against the fresh water fish pathogen S. iniae were reported for the first time.