Effect of Seasonal Variation on Chemical Composition, Antidiabetic and Antioxidant Potentials of Leaf Essential Oil of Eucalyptus globulus L.

Phytochemical Properties and Diverse Beneficial Roles of Eucalyptus globulus Labill.: A Review

“…Additionally, triterpene compounds that possess significant pharmaceutical applications have been previously identified in Eucalyptus leaves, bark, and fruits [62][63][64]. Leaves 1,8-cineole (80.2%), p-cymene (6.6%), and limonene (5%) [10] Leaves D-limonene (23.5%), m-cymene (24.8%), o-cymene (9.9 and 5.4%), 6-camphenol (7.2 and 10.7%), terpinen-4-ol (5.2 and 4.5%), and globulol (4.0 and 12.9%) [34] Leaves Eucalyptol (51.62%), α-pinene (23.62%), p-cymene (10%), β-myrcene (8.74%), terpinen-4-ol (2.74%), and γ-terpinene (2.59%) [22] Leaves 1,8-cineol (67.4 and 67.6%) and α-pinene (12.8 and 13.1%) [21] Fruits Aromadendrene (31.17%), 1,8-cineole (14.55%), globulol (10.69%), and ledene (7.13%) [43] Fruits Globulol (23.6%), aromadendrene (19.7%), 1,8-cineole (19.8%), and α-pinene (3.8%) [44] Bark Polyphenol and tannin [61] Deciduous bark Fatty acids, aliphatic alcohols, sterols, and triterpenoids [63] Bark Polygalloyl glucoses (gallotannins), catechin, epicatechin, ellagic acid, quercetin-3-o-rhamnoside, and isorhamnetin (phenolic compounds) [67] Stump Phenolic compounds and flavonoids [57] The anthelmintic activity of the essential oil from extracted leaves has been previously reported by Taur et al [41]. This has been ascribed to the occurrence of valuable phytoconstituents in the oil, such as borneol, linalool, cineol, geranyl acetate, anethol, and saffrol.…”

“…With regard to seasonal variations, Usman et al [34], found that the essential oil of E. globulus grown in north-central Nigeria had D-limonene and m-cymene chemotypes as the predominant compounds (23.5 and 24.8%, respectively) detected in the leaf oil procured in the dry and rainy seasons, respectively. For efficient oil extraction from E. globulus leaves, hydrodistillation was used to produce a higher amount of oil yield, such as 1.1 and 1.21% of essential oil (w/w, based on the fresh weight of the mature leaves) [4,15] rather than the oil obtained (0.2% w/w) from steam distillation [5].…”

“…The increasing awareness of synthetic antioxidants motivated a number of scholars, on a global scale, to identify alternative antioxidants of plant origin, to avoid the unfavorable effects of synthetic antioxidants [13,34,45]. In this regard, the antioxidant potential of different Eucalyptus plant parts (leaves, fruits, roots, and stump wood) as well as their essential oils were formerly reported as being able to be utilized to diminish oxidative stress-associated diseases, and also as food preservatives [13,31,47,57] The leaf essential oil of Nigerian-grown E. globulus exhibited a low antioxidant capacity via its potential to scavenge DPPH radicals, with elevated IC 50 values (136.87 µL/mL) as compared to the standard antioxidant ascorbic acid.…”

“…Salem et al [72] stated that the elevated antioxidant activity was detected at the full flowering and fructification stage; thus, a positive relationship existed between the essential oil content and its antioxidant potential. Furthermore, the essential oil of the aerial parts showed a potent DPPH scavenging capacity as well as moderate reducing power efficacy as compared with butylated hydroxyanisole (BHA) and ascorbic acid, respectively [11,34]. Additionally, the chelating ability of the ferrous ions of the essential oil extracted at the vegetative and full flowering stages was more prominent than that of the oil extracted at the fructification stage, which was attributed to the metal chelating impacts of 1,8-cineole, α-terpineol, and methyleugenol.…”

“…In a study conducted in Germany, the authors identified the main compound in the essential oil of hydro-distilled fruits to be; aromadendrene (Figure 1), which exerted anti- Eucalyptus leaf essential oil has drawn the attention of numerous researchers, as it represents a wide range of biological potentials, such as antibacterial efficacy toward both Gram-positive and Gram-negative bacteria [28,29] and considerable antibacterial potency against periodontal diseases [20,30]. Therefore, it can be incorporated into dental care products, as it is an anti-inflammatory agent [10,31]; has antifungal [16,28,32,33] and antidiabetic potential [34,35]; insecticidal [36][37][38][39], acaricidal, and repellent activities; is a biodegradable pesticide [40]; has bio-nematicide efficacy [7], phytopathogen control [8,23], and anthelmintic activity [41]; and it is a natural agent for food preservation [25]. Furthermore, this leaf essential oil has been previously applied in "folk medicine, in the treatment of respiratory problems, including, cold, cough, runny nose, sore throat, asthma, nasal congestion, bronchitis, and sinusitis" [42].…”