100% Pure Natural Eucommiae Foliuml Oil Essential Oil For Skin Care
Lignans and their derivatives are the key components of EU [7]. To date, 28 lignans (such as bisepoxylignans, monoepoxylignans, neolignans, and sesquilignans) have been isolated from bark, leaves, and seeds of EU. Iridoid glycoside, a class of secondary metabolites, is the second main component of EU. Iridoids are typically found in plants known as glycosides. Twenty-four iridoids have been isolated and identified from EU (Table 1). These isolated compounds include geniposidic acid, aucubin, and asperuloside which have been reported to have wide pharmacological properties [8–10]. Two new compounds of iridoids, Eucommides-A and -C, have recently been isolated. These two natural compounds are considered as conjugates of iridoid and amino acids. However, the mechanism underlying their activity is not available [11].
2.2. Phenolic Compounds
Phenolic compounds which are derived from the foods have been reported to have positive impact on human health [12, 13]. About 29 phenolic compounds have been isolated and identified from EU [14]. Total content of phenolic compounds (in gallic acid equivalents of all the extracts) was analyzed using the Folin-Ciocalteu phenol reagent. Effects of seasonal variation on the contents of some compounds and antioxidants have been reported. Within the same year, higher contents of phenolics and flavonoids were discovered in the leaves of EU in August and May, respectively. Rutin, quercetin, geniposidic acid, and aucubin existed in higher concentration in May or June [15]. Moreover, higher activity of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity and metal ion chelating ability were found in the leaves of EU harvested in August. Increased content of food antioxidants was also reported in May when compared to other periods of the year [15]. The leaf of EU has been found to be a rich source of aminoacids, vitamins, minerals, and flavonoids such as quercetin, rutin, and geniposidic acid [11, 16]. A total of 7 flavonoids have been isolated from Eucommia plants [17]. Rutin and quercetin are the most important flavonoids [18]. Flavonoids are important compounds which are common in nature and are considered as secondary metabolites and function as chemical messengers, physiological regulators, and cell cycle inhibitors.
2.3. Steroids and Terpenoids
Six steroids and five terpenoids have been extracted and categorized from EU. These include β-sitosterol, daucosterol, ulmoprenol, betalin, betulic acid, ursolic acid, eucommidiol, rehmaglutin C, and 1,4α,5,7α-tetrahydro-7-hydroxymethyl-cyclopenta[c]pyran-4-carboxylic methyl ester which was specifically isolated from the bark of EU [19]. Loliolide has also been isolated from the leaves [20].
2.4. Polysaccharides
Polysaccharides from EU for 15 days at the concentrations of 300–600 mg/kg were reported to exhibit protective effects on kidneys as observed by malonaldehyde and glutathione levels after renal perfusions [21]. Histological examination also showed evidence of antioxidative properties. Extracts from the bark of EU using 70% ethanol also showed protective effects against cadmium at 125–500 mg/kg [22]. Histological examination also showed that EU in combination with Panax pseudoginseng at 25% and 50% weight, respectively, for six weeks at a dose rate of 35.7–41.6 mg/kg exerted light protective effects on glomerular filtration rate [8]. Two new polysaccharides have been separated from EU, which are eucomman A and B [23].
2.5. Other Ingredients and Chemicals
Amino acids, microelements, vitamins, and fatty acids have also been isolated from EU [17, 21–23]. Sun et al. also discovered new compounds such as n-octacosanoic acid, and tetracosanoic-2,3-dihydroxypropylester from EU [24].
Fatty acid composition of oil extracted from the seed of EU showed different concentrations of polyunsaturated fatty acids such as linoleic acid, linolenic acid (56.51% of total fatty acids, TFAs), and linolelaidic acid (12.66% of TFAs). Meanwhile, the main monounsaturated fatty acid isolated from the seed was found to be isoleic acid (15.80% of TFAs). Dominant saturated fatty acids isolated include palmitic acid and stearic acid which represent 9.82% and 2.59% of TFAs, respectively