Bioprospecting and Repurposing of Leaf Biomass to Support Sustainable Biopharmacy: Evaluation of Seasonal Chemical Variations and Biological Activities of Six Eucalyptus Essential Oils

Authors: MIGACZ, IZABEL - State University Of Ponta Grossa; Wang, Mei; FAORO, JANAINE - Federal University Of Big Dourados (UFGD); DOS SANTOS, SIDNEY - Federal University Of Big Dourados (UFGD); FORMAGIO, ANELISE - Federal University Of Big Dourados (UFGD); KASSUYA, DOUTORA - Federal University Of Big Dourados (UFGD); RHEMAN, JUNAID - University Of Mississippi; PERERA, WILMER - Camag Scientific, Inc; GONCLAVES, VITORIA - State University Of Ponta Grossa; CHAVES, DOUGLAS - Federal Rural University Of Rio De Janeiro; RAMAN, VIJAYASANKAR - University Of Mississippi; FARAGO, PAULO - State University Of Ponta Grossa; KHAN, IKHLAS - University Of Mississippi; MANFRON, JANE - State University Of Ponta Grossa

Submitted to: International Journal of Environmental Research and Public Health
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/7/2024
Publication Date: 6/22/2024
Citation: Migacz IP, Wang M., Faoro JAM, dos Santos E, Formagio ASN, Kassuya CAL, Rheman JU, Perera W, Gonçalves VC. Chaves DSA, Raman V, Farago PV, Khan IK, Manfron J. Bioprospecting and repurposing of leaf biomass to support sustainable biopharmacy: Evaluation of seasonal chemical variations and biological activities of six eucalyptus essential oils. Int J Environ Res 18, 74, 2024. https://doi.org/10.1007/s41742-024-00628-z (407785)
DOI: https://doi.org/10.1007/s41742-024-00628-z

Interpretive Summary: Eucalyptus L'Her is an extensive genus of the Myrtaceae family, encompassing around 800 species. These species are not only native to Australia but have also been grown globally, owing to their wide-ranging applications. It is a well-known fact that plants produce essential oils (EOs) to adapt to harsh weather conditions and defend against animals with chemicals. Among various aromatic plant species, Eucalyptus is especially notable for having EOs in its leaves and stems. It is concerning that only 300 out of the 800 species have undergone chemical composition evaluation, leaving a staggering 280 species without comprehensive research. This research was motivated by the growing interest in natural compounds that can prevent oxidation and inflammation, as well as reduce the use of synthetic pesticides. As a result, alternative methods with biological activities were investigated, leading to the application of EOs extracted from the residue of the wood industry. The purpose of this study was to investigate the chemical composition of six different Eucalyptus: E. badjensis, E. benthamii, E. dunnii, E. grandis, E. globulus, and E. saligna essential oil obtained from leaves collected seasonally, as well as to analyze their antioxidant, anti-inflammatory, and insecticidal properties.

Technical Abstract: It is crucial to recognize the immense value of the Eucalyptus tree in both the timber industry and as a prospective source of essential oils with an extensive range of health benefits, such as pain relief, anti-inflammatory properties, and insect repellent. The species E. globulus is the most commercially employed due to its high level of 1,8-cineol, also named eucalyptol. Undoubtedly, edaphic and climatic factors have an impact on the chemical composition of these plant species and, consequently, on their biological activities. This research is a significant breakthrough as it investigates the chemical profile of essential oils obtained from various Eucalyptus species during different seasons. With nearly 800 species in the Eucalyptus family, many of which remain unexamined, the study focuses on six species: E. badjensis, E. benthamii, E. dunnii, E. grandis, E. globulus, and E. saligna. All these species were grown in the same location and at the same stage of development. The hydrodistillation method was utilized in a Clevenger apparatus for extracting the essential oils, and GC-MS and HPTLC techniques were employed to analyze the chemical composition of each species. The yield of essential oils ranged from 0.7% to 2.43% (w/v) and varied across different species. E. badjensis exhibited the highest yield during the summer season, while E. grandis had the lowest yield during winter. The species E. badjensis displayed a consistent composition throughout all four seasons, with 1,8-cineol being the predominant component. Notably, the proportion of 1,8-cineol in E. badjensis was 77% in spring (SP), 70% in summer (SU), 95% in fall (AU), and 89% in winter (WI). Similarly, E. globulus also exhibited 1,8-cineol as its primary constituent, with proportions fluctuating slightly across seasons at 85%, 80%, 81%, and 86% respectively. The proportions and constituents of various species differed significantly. Notably, a-pinene (36% SP, 41% AU, and 42% WI) and globulol (23% SU) were the most significant compounds in E. benthamii. Conversely, 1,8-cineol (43% SP and 59% SU) and a-pinene (43% AU and 41% WI) dominated in E. dunnii. 1,8-cineol (85%, 80%, 81%, 86%) is the primary compound in E. globulus throughout the four seasons. o-Cymene (21% SP and 20% SU) and a-pinene (22% AU and 34% WI) were the major compounds in E. grandis, whereas E. saligna had spathulenol (17% SP) and o-cymene (22% SU, 20% AU, and 31% WI). HPTLC was used as a swift technique to monitor the chemical composition of essential oils in various Eucalyptus species during the study of seasonality. GC/MS and HPTLC analysis showed that different Eucalyptus species displayed unique chemical compositions, while both the chemical profile and productivity of all analyzed EOs were affected by seasonality. This finding is demonstrated in the principal components cluster. The analysis of six species has revealed that the essential oils of E. benthamii are the most potent in thwarting the infestation of Cimex lectularius. Additionally, all six EOs demonstrated antioxidant activity in the ABTS model. The E. benthamii, E. dunnii and E. grandis demonstrated significant anti-inflammatory activity in experimental models.