Study On The Chemical Constitutents And UPLC Fingerprint Of Eucalyptus Robusta

The plant Eucalyptus robusta Smith (Myrtaceae) is native to Australia, which widelydistributed and cultivated in southern regions of China. The leaves of this plat are used as a folkmedicine for the treatment of dysentery, malaria, and other bacterial diseases. Antibacterial,anti-inflammatory and antioxidant-related activities were proved by recent pharmacologicalstudies of the Eucalyptus robusta leaf crude extract. Previous phytochemical investigationsshowed that essential oils, triterpenes, flavones and phloroglucinols were the main chemicalcomponents.Recently, our group reported the isolation of two new acylphloroglucinol-terpene derivativesfrom the petroleum ether soluble fraction of the ethanol extract of the leaves of E. robusta. As anongoing program, we had systematically investigated the chemical constituents of the n-butanolsoluble fraction of this pant, which led to the isolation of22compounds and19of them wereidentified by the extensive spectroscopic analyses and chemical techniques. Their structures wereelucidated as robustaside A (ER-B-1), robustaside B (ER-B-2), robustaside C (ER-B-3),robustaside D (ER-B-4), robustaside E (ER-B-5), chromene glucoside (ER-B-6),(-)-2S-8-methyl-5,7,4’-trihydroxyflavanone-7-O-β-D-glucoside (ER-B-7), quercetin-4’-gallicate-3-O-α-L-arabinoside (ER-B-8), kaempferol (ER-B-9), quercetin (ER-B-10), kaempferol-3-O-α-L-arabinoside (ER-B-11), guaijaverin (ER-B-12), trifolin (ER-B-13), hyperin (ER-B-14),quercetin3-O-(6’-n-butyl)-glucuronide (ER-B-15),4-O-methylellagicnacid3’-O-α-rhamnoside(ER-B-16), trans-4-hydroxycinnamic acid (ER-B-17),(-)-oleuropeic acid (ER-B-18) and gallicacid (ER-B-19). Among them, ER-B-1~ER-B-5are five new acylphloroglucinol glycosides.ER-B-7and ER-B-8are two new flavonoid glycosides. ER-B-6and ER-B-11~ER-B-15areisolated from this plat for first time. Especially, ER-B-1is the first example ofacylphloroglucinols bearing a rare oxetene unit.Furthermore, an UPLC fingerprint chromatogram method of the leaves of E. robusta was alsoestablished. The method was developed on a Waters ACQUITY UPLC HSS T3column (2.1mm×100mm,1.8μm) with gradient mobile phase of acetonitrile-0.5%formic acid at the flow rateof0.4mL/min with wavelength at365nm. The column temperature was40C.