Investigation of phytochemicals and antioxidant capacity of selected Eucalyptus species using conventional extraction

Abstract

Eucalyptus species have found their place in traditional medicine and pharmacological research and they have also been shown to possess a large number of phenolic compounds and antioxidants. The present study sought to implement conventional extraction to yield maximal total phenolic content (TPC), total flavonoid content (TFC), proanthocyanidins, antioxidants, and saponins from E. robusta using different solvents. The most suitable extraction solvent was further employed for extracting phytochemicals from E. saligna, E. microcorys, and E. globulus to select the Eucalyptus species with the greatest bioactive compound content. The results emphasised the efficiency of water in extracting TPC ((150.60 ± 2.47) mg of gallic acid equivalents per g), TFC ((38.83 ± 0.23) mg of rutin equivalents per g), proanthocyanidins ((5.14 ± 0.77) mg of catechin equivalents per g), and antioxidants ABTS ((525.67 ± 1.99) mg of trolox equivalents (TE) per g), DPPH ((378.61 ± 4.72) mg of TE per g); CUPRAC ((607.43 ± 6.69) mg of TE per g) from E. robusta. Moreover, the aqueous extract of E. robusta had the highest TPC, TFC and antioxidant values among the other Eucalyptus species tested. These findings highlighted the efficiency of conventional extraction in extracting natural bioactive compounds from Eucalyptus species for pharmaceutical and nutraceutical applications.

Exploring the Least Studied Australian Eucalypt Genera: Corymbia and Angophora for Phytochemicals with Anticancer Activity against Pancreatic Malignancies

“…In the present study, all the tested eucalypts showed a higher saponin content compared to E . microcorys extract reported earlier …”

“…microcorys, and E . globulus when conventional extraction was employed . In the present study, TPC of aqueous A .…”

“…Angophora floribunda aqueous extract exhibited the greatest proanthocyanidin content among the tested eucalypts (59.56 ± 1.87 mg CAE/g) and was also significantly higher than the previously reported E . robusta aqueous extract . The lowest proanthocyanidin content was obtained from C .…”

“…robusta and E . microcorys aqueous leaf extracts, despite the use of identical extraction techniques and experimental parameters . A .…”

Optimum conventional extraction conditions for phenolics, flavonoids, and antioxidant capacity of Helicteres hirsuta Lour.

“…The findings of Goli et al revealed that the level of phenolic compounds from pistachio ( Pistachia vera ) hulls obtained by conventional solvent extraction (either in water or in methanol) was as high as ultrasound‐assisted extraction and approximately 5 times higher than supercritical fluid extraction. Moreover, total phenolic content (TPC) of Eucalyptus robusta aqueous extract achieved using conventional extraction was approximately 2.5‐fold higher than that using microwave‐assisted extraction . Hence, this study employed RSM to optimize the conventional extraction process, which is a simple and up‐scalable extraction method to extend to commercial production scale, to obtain the highest levels of phenolics, flavonoids, and antioxidant power within H. hirsuta L. Further, as extraction solvents play an important role for bioactive compound extraction within plant materials, preliminary experiments determined 40% (v/v) methanol to be the solvent of choice and was used throughout the study.…”