Characterization of Volatile and Polar Compounds of Jiaogulan Tea [Gynostemma pentaphyllum (Thunb.) Makino] by Hyphenated Analytical Techniques

Eugene K. Blythe1,*, Betul Demirci2, Fatih Goger2 and Nurhayat Tabanca3,*

1Coastal Research and Extension Center, Mississippi State University, South Mississippi Branch Experiment Station, Poplarville, Mississippi 39470, USA

2Department of Pharmacognosy, Faculty of Pharmacy, Anadolu University, Eskisehir, 26470, Turkey

3U.S. Department of Agriculture-Agricultural Research Service, Subtropical Horticulture Research Station, Miami, Florida 33158, USA

*Corresponding authors: E-mail: blythe@pss.msstate.edu; nurhayat.tabanca@ars.usda.gov

Abstract

Jiaogulan [Gynostemma pentaphyllum (Thunb.) Makino] is a Chinese medicinal plant from southern Asia that has rapidly gained popularity and interest for its health-promotive and therapeutic properties. The volatile composition of jiaogulan tea was analyzed by using headspace-solid phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). A total of 29 volatile components were detected in the jiaogulan tea, with major compounds being benzaldehyde (15.3 %), 1,8-cineole (8.7 %), 6-methyl-5-hepten-2-one (7.8 %), (Z)-3-hexenal (7.6 %) and a-ionone (6.3 %). The chemical characterization of methanolic extract and 5 % infusion from the G. pentaphyllum leaves was determined by using LC-ESI-MS/MS systems. Chlorogenic acids, flavonoids and gypenosides were determined. The compounds quercetin 3-O-hexoside, isorhamnetin rutinoside and kaempferol dimethyl ether were identified in the extracts for the first time. Phenolic content was determined by gallic acid equivalents and antioxidant activity of the extracts was evaluated by DPPH, b-carotene/linoleic acid and ABTS radical scavenging assays. Both extracts showed weak antioxidant activity.

Keywords

Gypenosides, Gynosaponins, Volatiles, HS-SPME, LC-ESI-MS/MS, Antioxidant activity.

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