Ingredients Of Ginkgo Biloba

The main active ingredients of Ginkgo biloba

1 Flavonoids in Ginkgo Biloba
The flavonoids in Ginkgo biloba are composed of flavonoids and their glycosides, biflavonoids and catechins [4]. So far, 40 kinds of flavonoids have been isolated, including 28 kinds of flavonoids and glycosides, which are composed of quercetin, kaempferin, isorhamnetin, myricetin, luteolin, apigenin and its mono- and di- , Triglycoside composition, including cinnamyl flavonoid glycosides.
Monoflavonoids are mainly glycosides formed by kaempferol, quercetin and isorhamnetin with various sugar groups, and their structures all contain 5, 7, 4′-trihydroxy and 3-glycosyl linked sugar groups. Hydroxyl group, while the sugar group can be monosaccharide, disaccharide, trisaccharide, most of which are glucose and rhamnose [2], most of which are quercetin, kaempferol and their glycosides.
There are 6 kinds of Ginkgo biflavonoids, namely Ginkgoflavin, Isoginkgoflavin, Amantoflavin, Ginkgoflavin, Ciadoflavin and 5′-methoxyginkgoflavin. They are connected by 5′, 8″, and the molecule contains 1 to 3 methoxy groups. Such compounds are usually regarded as the characteristic chemical constituents of gymnosperms.
Catechins are divided into four types according to the difference in the optical activity of the 2-position carbon atom on the parent nucleus and whether the 5′-position contains a hydroxyl group: catechin, epicatechin, gallocatechin, and epigallocatechin. The nuclear structure is as follows. In addition, there are dimers 4,8″-catechingallocatechin and 4,8″-gallocatechingallocatechin.

2 Terpene lactone compounds of Ginkgo biloba
Terpene lactones are another important bioactive compounds in Ginkgo biloba leaves. Six terpene lactones have been isolated, collectively referred to as ginkgolides. Ginkgo biloba terpene lactones are diterpenoids and sesquiterpenoids.
Diterpenoids were isolated and identified from Ginkgo biloba leaves and bark by Nakanishi et al. in 1967 by 1H NMR, CD and its physical and chemical means. BN52021), ginkgolide C (BN52022) and ginkgolide M (BN52023), wherein ginkgolide M was isolated from the bark.
Later, Weinges et al. isolated a new diterpene lactone compound ginkgolide J (BN52024) from leaves in 1987. They all consist of six five-membered rings and a spiro[4,4]nonane carbon skeleton, containing a tert-butyl group, differing in the number and position of hydroxyl groups (on C-1, C-3 or C-7). Sesquiterpenes are another class of compounds that Weinges isolated and identified from Ginkgo biloba leaves and are structurally related to the diterpenoid ginkgolide, also known as bilobalide.
Therefore ginkgolides are composed of ginkgolides A, B, C, J, M and bilobalide.

3 Polyprenol esters of Ginkgo biloba
Polyprenol (polyp renols) is a bioactive ester compound with medicinal development prospects in Ginkgo biloba leaves, and widely exists in animals and plants in the form of homologues. Among them, polyprenol in mammals is called polyterpene alcohol. (dolichols). In 1982, Yasushi Tanaka et al. [9] first isolated polypentenol esters from Ginkgo biloba leaves, and the number of isopentenyl units in the molecule was 14-22. In 1992, Wang Chengzhang et al. [10] isolated seven polypentenol acetates from Ginkgo biloba leaves, all of which were birch polyprenol-type structures (betulap re2 nol), namely ω2(trans)22(cis)n2cis (α) , which proves that the number of structural units of polyprenol from Ginkgo biloba leaves in my country is 14-22.

4 Polysaccharides in Ginkgo Biloba
Josef et al. [11] isolated water-soluble neutral polysaccharide GF1, water-soluble acidic polysaccharide GF2 and GF3 components from Ginkgo biloba leaves. GF1 is composed of arabinose, mannose, glucose and galactose; GF2 is composed of rhamnose in addition to the four monosaccharides that make up GF1; GF3 is composed of arabinose, rhamnose and galactose. Huang Guikuan et al[12] obtained two kinds of polysaccharides from the aqueous extract of Ginkgo biloba, and confirmed that a polysaccharide of Ginkgo biloba was relatively relative to Ginkgo biloba polysaccharides by gel filtration, high performance liquid chromatography analysis, sodium periodate oxidation, Smith degradation, infrared spectroscopy and other methods. The molecular mass is 1.7 × 105 , and it contains glucose, rhamnose, and xylose, and the ratio of the substances is 49.82:28.40:21.75. The sugar group is β-(1v 6) (1v 3) ( 1v 4) linked; another polysaccharide is glucan, the relative molecular mass is 1. 4 × 104 , and the sugar groups are linked by α-(1v 4) (1v 3) (1v 6).

5 Alkylphenolic acids in Ginkgo biloba
According to the report of Ellnain2Wojtaszek in Poland, there are mainly 7 kinds of phenolic acid compounds in Ginkgo biloba leaves, namely protocatechuic acid (p rotocate2chuic acid), p-hydroxybenzoic acid (p2hydroxybenzoic acid), vanillic acid (vanillic acid), caffeic acid (caffeic acid) ), p-coumaric acid (p2coumaric acid), ferulic acid (ferulic acid), chlorogenic acid (chlorogenic acid), etc. In recent years, the biological activities of phenolic acids and their esters have attracted extensive attention. Among them, ferulic acid, coumaric acid and chlorogenic acid have antibacterial and anti-inflammatory effects, and protocatechuic acid is an antifungal substance.
Ginkgo biloba alkylphenols and alkylphenolic acids belong to long-chain phenolic compounds, which are salicylic acids substituted with saturated or unsaturated long-chain alkyl groups at the 6-position, and their chemical structures are as follows.
These substances have sensitization, immunotoxicity and cytotoxicity, and are the main toxic components in Ginkgo biloba.

6 Organic acids in Ginkgo biloba
Ginkgo biloba mainly contains fatty acids, hydroxy acids, amino acids, glucaric acid, shikimic acid and 62hydroxykynurenic acid (6-HKA). Among them, 6-HKA is a broad-spectrum central nervous system amino acid neurotransmitter (such as NMDA and AMPA) antagonist, which can alleviate the symptoms of cerebral hypoxia. 6-HKA has a high affinity for AMPA receptors (AMPARs), and can enter the brain tissue under the condition of impaired blood-brain barrier integrity. It is an important biologically active component of Ginkgo biloba.

7 Chemical Composition of Ginkgo Biloba Essential Oil
Zhang Hongjiu et al. reported the volatile components of 40-year-old Ginkgo biloba leaves for the first time, among which the main components were hexadecanoic acid (23.48%), cedar brain (15.19%), 6, 10, 14-trimethyl- 2-Pentadecanone ( 10. 89 % ) , Butyl isobutanol phthalate ( 9. 99 % ) , Myristic acid ( 3. 91 % ) , α-Cedrene (2. 69 % ) , nerolidol (1.95%) and β-eucalyptol (1.29%). Wang Chengzhang et al[15] collected 3 to 5 years old ginkgo seedling leaves and identified 44 chemical components by GC and GC-MS, mainly consisting of 46.17% ketones, 31.14% hydrocarbons, 5.61% alcohols , 1.78% aldehydes, 5.41% acids and 1.1% esters. Among the ketones, hexahydrofarnesone had the highest content, accounting for 11.15%, followed by neroli ketone (8.68%) and β-ionone (5.24%).

8 Other nutrients of ginkgo biloba
Ginkgo biloba contains a variety of nutrients, especially protein, sugar, vitamin C, vitamin E, carotene, carotenoids, proanthocyanidins and so on. On a dry basis, the leaf contains protein 10.9%-15.5%, total sugar 7.5%-8.7%, reducing sugar 4.6%-5.6%, vitamin C 66.8-129% 2 mg/100 g, vitamin E 6.17~8.05 mg/100 g. In addition, it contains 17 kinds of amino acids, ginkgo alcohol (10-nonacosanol), ginkgo ketone, octacosanol, beta-sitosterol, stigmasterol, alkaloids, etc.