Chemical Composition, Antioxidant, Antimicrobial, and Phytotoxic Potential of Eucalyptus grandis x E. urophylla Leaves Essential Oils

Eucalyptus grandis x E. urophylla was a unique hybridization in China. However, the chemical and pharmacological properties were rarely reported. Therefore, in this work, we used a steam distillation method to obtain essential oils from leaves of E. grandis x E. urophylla, and further evaluated the antioxidant, antimicrobial, and phytotoxic potential of the essential oil. Gas chromatography mass spectrometry (GC-MS) was applied to investigate the chemical composition of E. grandis x E. urophylla essential oil (EEO) and the results showed that the main components of EEO were monoterpenes followed by sesquiterpenes. Among them, alpha-pinene accounted about 17.02%. EEO could also well scavenge 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2, 2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) free radicals showing a good free radical clearance ability. In addition, EEO efficiently inhibited the growth of six kinds of bacteria as well as seven kinds of plant pathogens, especially Salmonella typhimurium and Colletotrichum gloeosporioides. Moreover, the seedling germination of Raphanus sativus, Lactuca sativa, Lolium perenne, and Bidens pilosa was significantly suppressed by EEO, thus, indicating essential oils from eucalyptus possessed an excellent phytotoxic activity. This study may give a better understanding on EEO and provide a pharmacological activities analysis contributing to the further research of EEO as a functional drug in agronomic and cosmetic industries.

Automated summary

This study extracted essential oils from leaves of a unique hybridization of Eucalyptus grandis x E. urophylla, and evaluated its antioxidant, antimicrobial, and phytotoxic potential. The essential oil was found to be mainly composed of monoterpenes and possess good free radical scavenging ability, antimicrobial activity, and phytotoxicity against various plant pathogens. This research provides valuable insights for further exploration of the essential oil as a functional drug in agricultural and cosmetic industries.