Ultrasonic‐Assisted Ionic Liquid Extraction of Four Biflavonoids from Ginkgo biloba L.

Abstract

In the study, four main biflavonoids (bilobetin (BIL), ginkgetin (GIN), isoginkgetin (IGIN) and sciadopitysin (SCI)) were extracted from Ginkgo biloba L. by ultrasonic-assisted ionic liquid extraction (UAILE). The above four biflavonoids from Ginkgo biloba L. were simultaneously determined by the established high performance liquid chromatography (HPLC) approach. Next, three novel ionic liquids (ILs) were synthesized by onestep method from benzoxazole and three acids or salts. The structure of ILs were characterized by elemental analysis, infrared spectroscopy and nuclear magnetic resonance. Moreover, the thermal stability of ILs was evaluated by thermogravimetric analysis. Through screening the extraction effect of 9 different ILs, [EPy]BF 4 was screened as the optimal extraction agent. Through single factor and response surface analysis, the optimum extraction conditions of the four kinds of biflavonoids from Ginkgo biloba L. were further investigated. The optimum conditions were as follows: 0.148 mol/L IL concentration, 25 min extraction time, 1 : 14 g/ml solid-liquid ratio, and 280 W ultrasonic power. The extraction rates of BIL, GIN, IGIN and SCI in Ginkgo biloba L. were 2.44 mg/g, 4.33 mg/g, 6.50 mg/g and 13.97 mg/g, respectively. Compared with ethanol-UAE, infiltration extraction (IE) and percolation extraction (PE), UAILE not only could obtain more biflavonoids, but also could save the extraction time. In addition, the results of recovery test indicated that the recovered IL could be repeatedly extracted for 6 times. In general, three novel ILs were first synthesized in this study. The UAILE was first applied to extract the four biflavonoids in G. biloba L. This study provided a valuable reference for further investigation on G. biloba L.

Tissue-Specific Profiling of Biflavonoids in Ginkgo (Ginkgo biloba L.)

“…A similar high amount of sciadopitysin compared to amentoflavone in leaves was reported by Pandey et al [ 23 ] in ginkgo trees of different ages. The low content of amentoflavone is probably the reason why this biflavonoid was generally not detected in leaves in other studies [ 19 , 21 , 22 ]. Amentoflavone was also the least abundant biflavonoid in the seed parts where biflavonoids were detected in seed petioles and sarcotesta, according to our data.…”

“…One of the earliest HPLC-DAD methods for separating biflavonoids from ginkgo leaves was developed by Briancon-Scheid et al [ 19 ], the HPLC-DAD method for the simultaneous determination of four (bilobetin, ginkgetin, isoginkgetin, sciadopitysin) biflavonoids. Kaur et al [ 20 ] developed a method for the simultaneous determination of three biflavonoids (bilobetin, sciadopitysin, and ginkgetin) from ginkgo leaves, and recently Lei et al [ 21 ] focused on four biflavonoids (bilobetin, ginkgetin, isoginkgetin, sciadopitysin), as did Wang et al [ 22 ]. Pandey et al [ 23 ] reported only two biflavonoids (amentoflavone and sciadopitysin) in a crude extract of ginkgo leaves.…”

Biflavonoids: Important Contributions to the Health Benefits of Ginkgo (Ginkgo biloba L.)

“…Table 3 provides examples of selected reports on the presence of biflavonoids in various ginkgo plant parts and the used extraction and identification methods. Various organic solvents such as acetone, methanol, ethanol and petroleum ether have been used for the isolation of biflavonoids [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ]. Recent data also show that sustainable extraction technologies [ 43 ] and modern extraction techniques [ 42 ] can be useful for the extraction of biflavonoids from ginkgo.…”

“…Various organic solvents such as acetone, methanol, ethanol and petroleum ether have been used for the isolation of biflavonoids [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 ]. Recent data also show that sustainable extraction technologies [ 43 ] and modern extraction techniques [ 42 ] can be useful for the extraction of biflavonoids from ginkgo. The method of choice for the separation of compounds is liquid chromatography.…”

“…Lei et al [ 43 ] extracted four biflavonoids—bilobetin, gingketin, isoginkgetin and sciadopitysin—from the leaves of ginkgo, of which sciadopitysin was the most abundant. The same biflavonoids in leaves were reported by Beck and Stengel [ 40 ].…”