Ginkgo biloba (leaf)

Nomenclature

Ginkgo biloba L.   Ginkgoaceae  
Standardized common name (English): ginkgo  
Pinyin name(s): yin xing; bai guo (seed); yin xing ye (leaf)

Botanical Voucher Specimen

Source: MOBOT, Tropicos.org	Source: Botanical Voucher Specimen Library, Alkemists Laboratories	Source: Botanical Voucher Specimen Library, Alkemists Laboratories	Source: Botanical Voucher Specimen Library, Alkemists Laboratories

Organoleptic Characteristics

Flavor: Slightly bitter. Aroma: Slight. Source: Steven Yeager, Mountain Rose Herbs

Macroscopic Characteristics

Dark green to yellowish green; Leaves fan-shaped with tapering cuneate base; Center of apex notched and dividing blade into distinct lobes; Petiole long, with upper surface grooved. Leaf surface glabrous without midrib, and has wrinkled appearance. Source: Steven Yeager, Mountain Rose Herbs Source: PlantaPhile Source: PlantaPhile

Microscopic Characteristics

Stomate of Ginkgo biloba leaf with large thick-walled guard cells viewed under 1000x with Acidified Chloral Hydrate solution. Stomate of Ginkgo biloba leaf has large thick-walled guard cells [and] as well contains large rosettes of Calcium Oxalate crystals. Source: Elan M. Sudberg, Alkemist Laboratories	Calcium oxalate crystal, polarized, 200X in glycerin:dionized water solution. Epidermis has irregularly sinuous walls, often with palisade parenchmya, stomata deeply sunken surrounded by 6-8 subsidiary cells, various sizes of calcium oxalate cluster crystals abundant. Source: Amy Brush, Traditional Medicinals http://www.traditionalmedicinals.com

High Performance Thin Layer Chromatographic Identification

Ginkgo biloba HPTLC UV 365 nm Ginkgo (leaf) Ginkgo biloba Lane Assignments Lane 1(3μl) Ginkgo biloba (leaf) (Vouchered Sample); Lane 2(3μl) Sophora japonica (fruit); Lane 3(3μl) Ginkgo biloba (leaf); Lane 4(3μl) Ginkgo biloba (leaf); Lane 5(3μl) Ginkgo biloba (leaf); Lane 6(3μl) Ginkgo biloba (leaf) (USA); Lane 7(3μl) Ginkgo biloba (leaf) (China) authenticated by macroscopic, microscopic &/or TLC studies according to the reference sources cited below held at Alkemists Pharmaceuticals, Costa Mesa, CA.  Stationary Phase Silica gel 60, F254, 10 x 10 cm HPTLC plates  Mobile Phase ethyl acetate: glacial acetic acid: formic acid: water [10/1.1/1.1/2.4]  Sample Preparation Method 0.3 g + 3 ml 100% grain EtOH sonicated + heated @ 50° C ~ 1 hr.  Detection Method Natural Product Reagent + PEG -> UV 365 nm  Reference see British Pharmacopoeia, 2003 Source: Elan M. Sudberg, Alkemist Laboratories

Supplementary Information

Ginkgo (leaf extract) (Ginkgo biloba) standardized to flavonol glycosides and terpenes. 

General Characteristics AHPA recommends in its Known Adulterants list that appropriate steps be taken to assure that this raw material is free of the noted adulterant. Contact AHPA for additional information regarding relevant analytical methods or follow this link for more information. 

Reported Adulterants Ginkgo (Ginkgo biloba) leaf extract with added flavonol glycosides or aglycones (e.g., rutin, quercetin, etc.).

Source: AHPA Known Adulterants

Other Publications

HPLC identification, Ma, et al., 2016

An effective identification and quantification method for Ginkgo biloba flavonol glycosides with targeted evaluation of adulterated products,

Abstract. Ginkgo biloba L. (Ginkgoaceae) leaf extract is one of the most popular herbal products on the market, as it contains flavone glycosides (≥ 24%) and terpene lactones (≥ 6%), which are proposed to have significant physiological effects. Unfortunately, the challenging financial climate has resulted in a natural health product market containing adulterated ginkgo products. 42 ginkgo samples were analyzed to establish an HPLC profile for authentic ginkgo and common ginkgo adulterants, and to develop a method capable of easily detecting adulteration in ginkgo commercial products. In this study an efficient and targeted HPLC analysis method was established that is capable of distinguishing flavonol glycosides and aglycones simultaneously for the evaluation of ginkgo powdered extracts (PEs) and finished products in a single, 13 min run. Thirteen ginkgo leaf samples, fifteen standardized powdered extracts, and fourteen commercially available ginkgo products have been analyzed using this new HPLC method. Chromatograms were compared to six standard reference materials: one flavonol glycoside (rutin), three aglycones (quercetin, kaempferol and isorhamnetin), and two isoflavones (genestin and genistein). The quantitative chromatographic data was interpreted by principal component analysis (PCA), which assisted in the detection of unexpected chromatographic features in various adulterated botanical products. Only three of the commercially available ginkgo finished products tested in this study were determined to be authentic, with flavonol glycoside rutin, and aglycones quercetin, kaempferol, and isorhamnetin found to be common adulterants in the ginkgo powdered extract and finished product samples. Despite evidence of adulteration in most of the samples, each of the samples discussed herein met most of the current pharmacopeial standards. It is therefore critical that a preliminary evaluation be utilized to detect adulteration in commercial ginkgo products, prior to the acid hydrolysis procedure utilized in the current testing methods.

UPLC/MS and HPTLC identification, Avula, et al., 2015

Identification of Ginkgo biloba supplements adulteration using high performance thin layer chromatography and ultra high performance liquid chromatography-diode array detector-quadrupole time of flight-mass spectrometry,

Abstract. Ginkgo biloba is one of the most widely sold herbal supplements and medicines in the world. Its popularity stems from having a positive effect on memory and the circulatory system in clinical studies. As ginkgo popularity increased, non-proprietary extracts were introduced claiming to have a similar phytochemical profile as the clinically tested extracts. The standardized commercial extracts of G. biloba leaf used in ginkgo supplements contain not less than 6% sesquiterpene lactones and 24% flavonol glycosides. While sesquiterpene lactones are unique constituents of ginkgo leaf, the flavonol glycosides are found in many other botanical extracts. Being a high value botanical, low quality ginkgo extracts may be subjected to adulteration with flavonoids to meet the requirement of 24% flavonol glycosides. Chemical analysis by ultra high performance liquid chromatography-mass spectrometry revealed that adulteration of ginkgo leaf extracts in many of these products is common, the naturally flavonol glycoside-rich extract being spiked with pure flavonoids or extracts made from another flavonoid-rich material, such as the fruit/flower of Japanese sophora (Styphnolobium japonicum), which also contains the isoflavone genistein. Recently, genistein has been proposed as an analytical marker for the detection of adulteration of ginkgo extracts with S. japonicum. This study confirms that botanically authenticated G. biloba leaf and extracts made therefrom do not contain genistein, and the presence of which even in trace amounts is suggestive of adulteration. In addition to the mass spectrometric approach, a high performance thin layer chromatography method was developed as a fast and economic method for chemical fingerprint analysis of ginkgo samples.