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Extraction, Chemical Composition, and Antifungal Activity of Essential Oil of Bitter Almond

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ABSTRACT

The essential oil from the powder residual of dried bitter almond, a novel and environmentally-friendly fungicide, was successfully extracted in a 0.7% yield by hydro-distillation under optimized conditions. The chemical composition of bitter almond essential oil (BAEO) was analyzed by gas chromatography–mass spectrometry (GC–MS). Twenty-one different components representing 99.90% of the total essential oil were identified, of which benzaldehyde (62.52%), benzoic acid (14.80%), and hexadecane (3.97%) were the most abundant components. Furthermore, the in vitro and in vivo antifungal activities of BAEO against common plant pathogenic fungi were evaluated by the mycelium linear growth rate method and pot test, respectively. It was documented that 1 mg/mL of BAEO could variously inhibit all tested pathogenic fungi with the inhibition rates of 44.8%~100%. Among the tested 19 strains of fungi, the median effective concentration (EC50) values of BAEO against Alternaria brassicae and Alternaria solani were only 50.2 and 103.2 μg/mL, respectively, which were higher than those of other fungi. The in vivo antifungal activity of BAEO against Gloeosporium orbiculare was much higher than Blumeria graminis. The protective efficacy for the former was up to 98.07% at 10 mg/mL and the treatment efficacy was 93.41% at 12 mg/mL. The above results indicated that BAEO has the great potential to be developed as a botanical and agricultural fungicide.

No MeSH data available.


Disease index of cucumber and wheat seedlings. GO, Gloeosporium orbiculare; BG, Blumeria graminis.
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ijms-17-01421-f004: Disease index of cucumber and wheat seedlings. GO, Gloeosporium orbiculare; BG, Blumeria graminis.

Mentions: By comparing the protective effect of BAEO (Table 6) against Gloeosporium orbiculare with that of therapeutic effect (Table 7), in general, a tendency of gradually increasing activity was observed in most cases when the concentration of BAEO was increased from 4 to 12 mg/mL (Figure 4 and Figure 5); the growth trend of the former was much faster than that of the latter, hence BAEO could be utilized to protect cucumber from fungal invasion. There was an abnormal phenomenon for Gloeosporiumorbiculare in that the protective efficacy of BAEO at 12 mg/mL was less than that of BAEO at 10 mg/mL, which presumably indicates that higher concentrations of BAEO may lead to tissue damage and infection spread. Based on these findings, it is likely that the most effective concentration of BAEO is 10 mg/mL, making the leaf blades of cucumber resist the fungal infection.


Extraction, Chemical Composition, and Antifungal Activity of Essential Oil of Bitter Almond
Disease index of cucumber and wheat seedlings. GO, Gloeosporium orbiculare; BG, Blumeria graminis.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5037700&req=5

ijms-17-01421-f004: Disease index of cucumber and wheat seedlings. GO, Gloeosporium orbiculare; BG, Blumeria graminis.
Mentions: By comparing the protective effect of BAEO (Table 6) against Gloeosporium orbiculare with that of therapeutic effect (Table 7), in general, a tendency of gradually increasing activity was observed in most cases when the concentration of BAEO was increased from 4 to 12 mg/mL (Figure 4 and Figure 5); the growth trend of the former was much faster than that of the latter, hence BAEO could be utilized to protect cucumber from fungal invasion. There was an abnormal phenomenon for Gloeosporiumorbiculare in that the protective efficacy of BAEO at 12 mg/mL was less than that of BAEO at 10 mg/mL, which presumably indicates that higher concentrations of BAEO may lead to tissue damage and infection spread. Based on these findings, it is likely that the most effective concentration of BAEO is 10 mg/mL, making the leaf blades of cucumber resist the fungal infection.

View Article: PubMed Central - PubMed

ABSTRACT

The essential oil from the powder residual of dried bitter almond, a novel and environmentally-friendly fungicide, was successfully extracted in a 0.7% yield by hydro-distillation under optimized conditions. The chemical composition of bitter almond essential oil (BAEO) was analyzed by gas chromatography–mass spectrometry (GC–MS). Twenty-one different components representing 99.90% of the total essential oil were identified, of which benzaldehyde (62.52%), benzoic acid (14.80%), and hexadecane (3.97%) were the most abundant components. Furthermore, the in vitro and in vivo antifungal activities of BAEO against common plant pathogenic fungi were evaluated by the mycelium linear growth rate method and pot test, respectively. It was documented that 1 mg/mL of BAEO could variously inhibit all tested pathogenic fungi with the inhibition rates of 44.8%~100%. Among the tested 19 strains of fungi, the median effective concentration (EC50) values of BAEO against Alternaria brassicae and Alternaria solani were only 50.2 and 103.2 μg/mL, respectively, which were higher than those of other fungi. The in vivo antifungal activity of BAEO against Gloeosporium orbiculare was much higher than Blumeria graminis. The protective efficacy for the former was up to 98.07% at 10 mg/mL and the treatment efficacy was 93.41% at 12 mg/mL. The above results indicated that BAEO has the great potential to be developed as a botanical and agricultural fungicide.

No MeSH data available.