Essential oil composition of seven Bulgarian Hypericum species and its potential as biopesticide

Authors: SEMERDJIEVA, IVANKA - Agricultural University Of Bulgaria; ZHELJAZKOV, VALTCHO - Oregon State University; DINCHEVA, IVAYLA - Agrobioinstitute; PIPERKOVA, NESHKA - Agricultural University Of Bulgaria; MANEVA, VASILINA - Institute Of Agriculture Karnobat; Cantrell, Charles; ASTATKIE, TESS - Dalhousie University; STOYANOVA, ALBENA - University Of Food Technologies; IVANOVA, TANYA - University Of Food Technologies

Submitted to: Plants
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/13/2023
Publication Date: 2/17/2023
Citation: Semerdjieva, I., Zheljazkov, V.D., Dincheva, I., Piperkova, N., Maneva, V., Cantrell, C.L., Astatkie, T., Stoyanova, A., Ivanova, T. 2023. Essential oil composition of seven Bulgarian Hypericum species and its potential as biopesticide. Plants. https://doi.org/10.3390/plants12040923.
DOI: https://doi.org/10.3390/plants12040923

Interpretive Summary: Hypericum species and especially H. perforatum are well known for their therapeutic applications. The present study assessed the essential oils (EO) composition, antifungal and aphid suppression activity of seven Bulgarian Hypericum species. The EOs were analyzed by GC–MS-FID analyses to determine the chemical constituents present. H. perforatum EO had significant repellent and insecticidal activity against two aphid species, the bird cherry-oat aphid and the English grain aphid. The tested EOs did not show significant activity against selected economically important agricultural fungal pathogens Fusarium spp., Botrytis cinerea, Colletotrichum spp., Rhizoctonia solani and A. niger. The EO of the Hypericum species found in the Bulgarian flora could be utilized for the development of new biopesticides for aphid control.

Technical Abstract: Hypericum species and especially H. perforatum are well known for their therapeutic applications. The present study assessed the essential oils (EO) composition, antifungal and aphid suppression activity of seven Bulgarian Hypericum species. The EOs were analyzed by GC–MS-FID analyses. Two experiments were conducted. In the first experiment, Hypericum perforatum, H. maculatum, H. hirsutum, and H. montbretii were used. Additionally, the EO composition of H. perforatum extracted via hydrodistillation (ClevA) and via commercial steam distillation (Com) were compared. The second experiment compared the EOs of H. perforatum, H. cerastoides, H. rumeliacum, H. calycinum (flower and leaves) extracted via hydrodistillation and collected with hexane. Overall, the EOs constituents belonged to four classes namely alkanes, monoterpenes, sesquiterpenes and fatty acids. The main class of compounds for H. maculatum and H. perforatum (Section Hypericum) were sesquiterpenes for both experiments except for H. perforatum (Com). and Hypericum montbretii (section Drosocarpium) EO which both had monoterpenes (38.09%) and sesquiterpenes (37.09%) as major groups, while H. hirsutum EO (section Taeniocarpium) contained predominately alkanes (67.19%). Fatty acids were the main compounds in H. cerastoides (section Campylopus), while monoterpenes were the most abundant class in H. rumeliacum and H. calycinum EOs. a-Pinene and germacrene D were the major EO constituents of all analyzed Hypericum species except for H. hirsutum and H. cerastoides. H. perforatum EO (Com) had significant repellent and insecticidal activity against two aphid species, Rhopalosiphum padi (bird cherry-oat aphid) and Sitobion avenae (English grain aphid) at concentrations of 0%, 1%, 2.5%, 3.5%, 4.5% and 5%. The tested EOs did not show significant activity against selected economically important agricultural fungal pathogens Fusarium spp., Botrytis cinerea, Colletotrichum spp., Rhizoctonia solani and A. niger. The EO of the Hypericum species found in the Bulgarian flora could be utilized for the development of new biopesticides for aphid control.