Procyanidins Flavonoids

Theae folium Tea Camellia sinensis (L,) KUN1"ZB Theaceae MD 2.5%-4d% caffeine 0.02%-0.03% theophylline 0.05% theobromine Polyphenols tannins catechin type (10% 20%), dimeric thcaBavins, oligomeric procyanidins flavonoid glycosides Fig. 29,30... 

Contains plant acids (16-18%) composed mainly of r/-tartaric acid (up to ca. 18%), with minor amounts of /-mahc acid. Citric acid has also been reported as a major component in the old literature, though it has not been detected in Indian tamarind (youngken). Other constituents include polyphenolics (catechin, epicatechin, and procyanidin), flavonoids (taxifolin, apigenin, eriodictyol, luteolin, and naringenin), sugars (20-40%), pectin, protein (2.8%), fat, vitamins (e.g., Bi and C), minerals (Ca, K, P, etc.), and tartrate (merck ... 

Fig. 3. The regular structure of a procyanidin-type condensed tannin showing characteristic 4,8 interflavonoid bonds linking the flavonoid units.

Proanthocyanidins are an important group of di- to oligomeric flavonoids in plants. Four proanthocyanidins (procyanidin B3, prodelphinidin B4, ECG-(4 8)-ECG and GC-(4 8)-EGCG) were determined quantitatively in tea. The amounts in fresh tea leaves were between 1 and 2 g/kg per compound (Nakabayashi, 1991). The occurrence of proanthocyanidins may serve as a criterion for the differentiation between fermented and non-fermented teas (Kiehne et al, 1997). 

Thousands of polyphenols from fruits (grapes, apples, etc.), vegetables (horse beans), and teas have been identified, many having good coloring properties, especially anthocyanins and some flavonoids. Well-documented reviews discuss the coloring capacities of some polyphenols including procyanidins. - Detailed presentations of anthocyanin and flavonoid properties and analysis are included in Sections 2.3, 4.3, and 6.3. The soluble proanthocyanidins of the colored horse bean Viciafaba L. seed coats were isolated and separated by solvent partition. 

Anthocyanins are Che most easily assayed and commonly studied derivatives of aromatic amino acids (Figure 1). Glyphosate drastically reduces accumulation of anthocyanin flavonoids in treated tissues (6, 19) (Figure 3). Levels of rutin and procyanidin, both flavonoids, are reduced in glyphosate-treated buckwheat hypocotyls (6). Glyphosate would presumably similarly affect levels of flavonoids and flavonoid derivatives that are known to be allelochemicals. 

Some flavonoids, such as procyanidins, have antidiabetic properties because they improve altered glucose and oxidative metabolisms of diabetic states (Pinent and others 2004). Extract of grape seed procyanidins (PE) administered orally to streptozotocin-induced diabetic rats resulted in an antihyperglycemic effect, which was significantly increased if PE administration was accompanied by a low insulin dose (Pinent and others 2004). The antihyperglycemic effect of PE may be partially due to the insuli-nomimetic activity of procyanidins on insulin-sensitive cell lines. 

The NOESY experiment has also been very useful for revealing the presence of rotational conformers of dimeric flavonoids and flavone C-glycosides (Figure 2.3). Strong exchange crosspeaks between equivalent protons of each conformer revealed the rotational equilibriums. This NOE phenomenon was first noted by Hatano et al. in two conformers of procyanidin dimers. The volume of the NOESY crosspeaks is related to the distance... 

Wine also contains a complex mix of catechins, flavonols, procyanidins, and flavanones. Red wine contains higher flavonoid levels than white or rose wines. Procyanidins usually represent 50% of the flavonoids found in red wine, followed by catechins (37%). A similar profile is observed with beer where again procyanidins dominate accounting for 42% of total flavonoid content. 

The flavonoid database described in this chapter was applied to 4-day weighed food records obtained from healthy Scottish men n = 41) and women ( = 52) to provide a provisional estimate of flavonoid intake in Scotland. All subjects consumed foods containing flavonols, procyanidins, and catechins, dietary intakes of which are given in Table 4.15. The main flavonol consumed was quercetin, accounting for 66 and 63% of the total flavonol intake of 18.8 mg/day. Primary sources of flavonols were from black tea (42.7%), onions (14.3%), apples (10.2%i), and lager (7.2%i) (Table 4.16). 

A comprehensive and critical review of food flavonoid literature has led to the development of a food composition database for flavonols, flavones, procyanidins, catechins, and flava-nones. This database can now be used and continuously updated to estimate flavonoid intake of populations, to identify dietary sources of flavonoids, and to assess associations between flavonoid intake and disease. However, there is a need for better food composition data for flavones, procyanidins, and flavanones as current literature is sparse particularly for citrus fruits, fruit juices, and herbs. In addition, anthocyanin food composition data are lacking although validated methods of determination are becoming available. 

Arnaudinaud, V. et al.. Total synthesis of isotopically labeled flavonoids. Part 5. Gram-scale production of C-labeled (—)-procyanidin B3, Tetrahedron Lett., 42, 5669, 2001. 

N.A. Crataegus laevigata C. monongyna Jacq. C. oxyacantha L. Flavonoid glycosides, procyanidins, catechins, triterpenoid acid, pectins, amygdalin, proanthocyanidins, emulsin, tartaric acid, tannins, crataegus acid, rutin, coumarins, quercitin, amines 99,100,231,278,279 Therapeutic treatment of heart insufficiency, hypotensive, coronary blood supply, arrhythmia. 

Hypertension is an important risk factor for coronary heart disease and stroke. Since ancient times, hypertensive patients have been treated orally with plant extracts based on folk medicine. However, and despite their in vitro vasodilator effects, little information about the protective effects of flavonoids on hypertension is available in the literature. Flavonoids have been considered as active principles of several antihypertensive plant extracts (e.g. rhamnoglycoside of limocitrin isolated from Citrus limonum, kaempferol 4 -0-glucose and hyperin from Euphorbia maddeni, moracenins from Morus alba, procyanidin glycoside from Rhamnus lycioides) [150,151]. In all cases, only the acute antihypertensive effects after i.v. administration in anaesthetised normotensive and/or hypertensive animals have been described. In addition to the direct vasodilator effects discussed above, the inhibition of angiotensin-converting enzyme reported... 

Fractionate phenolic acids and flavonoids using Sephadex LH-20 column. For phenolic acids and flavonol glycosides, filter the fruit juice through 0.45-/nm (type HA) filter. For procyanidins apply juice onto the Sephadex LH-20 column, wash with 20% MeOH (30 ml), then elute with MeOH (15 ml), concentrate to dryness, redissolve in 2 ml H20, and filter through 0.45-/nm (type HA) filter. 

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