ber das Vorkommen der Hydroxybenzoes�ure-Verbindungen im Pflanzenreich und in pflanzlichen Lebensmitteln

[Flavonols and flavones of vegetables. V. Flavonols and flavones of root vegetables (author's transl)]

Root vegetables contain flavon(ol) glycosides in tracers up to small amounts, while the level of their leaves are in part considerable (to more than 1 g/kg, calculated as aglycon). Radish, rutabagas, scorzoneras, and beets contain less than 1 mg/kg kaempferol and/or quercetin; carrots less than 1 mg/kg apigenin and luteolin; celery roots ca. 75 mg apigenin/kg and 14 mg luteolin/kg; horseradish about 20 mg kaempferol/kg and small radish 1-10 mg kaempferol/kg, whereby all these flavones and flavonols occur as glycosides in the vegetables. In leaves of small radish, variety "Eiszapfen", we found besides isoquercitrin (quercetin-3-glucoside) a quercetin-3-0-diglycoside and a kaempferol-0-diglycoside, both with the sugars rhamnose and arabinose, by tlc.

[On the phenolic acids of vegetables. II. Hydroxycinnamic acids and hydroxybenzoic acids of fruit and seed vegetables (author's transl)]

Fruits of solanaceae (tomatoes, eggplant, and sweet peppers) almost exclusively contain hydroxycinnamic acid derivatives with caffeic acid dominating. Fruits of cucurbitaceae (cucumbers, melons, pumpkins, and zucchini) are extraordinary, because they show very low concentrations of phenolic acids (up to 10 mg/kg) accumulated in the peels. Peas and broad beans have relatively small contents of phenolic acids too. Their husks show like beans considerable concentrations of hydroxycinnamic acid derivatives with dominating p-coumaric acid. In the group of hydroxybenzoic acids derivatives of salicylic, gentisic and vanillic acid could be determined frequently, but mostly as traces.

[On the phenolic acids of vegetables. III. Hydroxycinnamic acids and hydroxybenzoic acids of root vegetables (author's transl)]

In carrots, celeriac, scorzoneras, and horse radish caffeic acid, in small radishes p-coumaric acid, in beets ferulic acid and in radishes probably ferulic acid is dominating after hydrolysis. The contents of phenolic acids in the roots are much smaller than in the corresponding leaves. Carrots, small radishes, horse radish and partially scorzoneras show higher concentrations of phenolic acids in outer tissue layers. In contrary to hydroxycinnamic acid derivatives the contents of hydroxybenzoic acid derivatives (p-hydroxybenzoic, vanillic, salicylic and gentisic acid) mostly were small. Partially hydroxycoumarins (aesculetin and scopoletin) identified.

[On phenolic acids of vegetables. I. Hydroxycinnamic acids and hydroxybenzoic acids of brassica-species and leaves of other cruciferae (author's transl)]

The contents of phenolic acids in vegetables of the species Brassica almost totally consist of hydroxycinnamic acid compounds. In contrary to other species of vegetables sinapic acid is dominant. Leaves of radish (Rhaphanus sativus var. sativus and var. niger) mainly contain compounds of caffeic and p-coumaric acid; leaves of horse radish show only traces of hydroxycinnamic acids. In the group of hydroxybenzoic acid derivatives traces of salicylic and gentistic acid could be determined in almost all species and frequently vanillic acid. Protocatechnic acid was only identified in red cabbage, especially in the head, syringic acid in gardencress and p-hydroxybenzoic acid in horse radish leaves. No other hydroxybenzoic acids or hydroxycoumarins could be detected.

The phenolics of fruits. VII. The phenolics of cherries and plums and the changes in catechins and hydroxycinnamic acid derivatives during the development of fruits

Quantitative data of hydroxycinnamic acids, hydroxybenzoic acids and hydroxycoumarins (after hydrolysis of derivatives) and of catechins are given. -Large quantities of catechins and hydroxycinnamic acid derivatives are found in the young fruit. Related to mg per kg fresh weight these concentrations soon decline sharply, especially during the progressive growth of the fruits. Related to mg per fruit, the concentrations of catechins increase progressively with fruit development, showing a loss when reaching maturity. The concentrations of hydroxycinnamic acids increase in a similar manner, but show in part a remarkable loss when examined after removal of the harder seeds.

[V. The phenolics of strawberries and their changes during development and ripeness of the fruits (author's transl)]

16 strawberry varieties contained ca. 10--70 mg (+)-catechin per kg freshweight, frequently up to 10 mg (-)-epicatechin, seldom (+)-gallocatechin and never (-)-epigallocatechin. The phenolic contents after hydrolysis were up to ca. 10 mg caffeic acid, ca. 10--15 mg p-coumaric acid, ca. 10--35 mg 4-hydroxybenzoic acid, up to 6 mg protocatechuic acid and ca. 10--40 mg gallic acid per 1000 g freshweight. From "Senga Sengana" ca. 10 mg/kg methyl gallate and ellagic acid were isolated. Salicylic acid, gentisic acid and vanillic acid were found in traces (1 mg/kg). The concentrations of all the examined phenolic acids, relating to the whole fruit (mg per fruit) increased, and, relating to fresh weight (mg per kg) decreased during the growth of the fruits with exception of 4-hydroxybenzoic acid. This acid appeared only in a relatively late stage of the fruit. The changes in catechins were similar. In the ripe fruit the catechin level was reduced a little.

[The phenolics of fruits. VI. The phenolics of currants, gooseberries and blueberries. Changes in phenolic acids and catechins during development of black currants (author's transl)]

Black, red, and white currants, gooseberries and cultivated blueberries contained only small amounts of catechins (total up to 30 mg per kg). Hydroxycinnamic acid derivatives, especially of caffeic and p-coumaric acid, occured mostly in higher concentrations. Furthermore, 4-hydroxygenzoic acid, protocatechuic acid and gallic acid were found after hydrolysis in currants and only protocatechuic acid in gooseberries in different levels. Salicyclic and gentisic acid were found in traces up to 2 mg per kg, occassionally vanillic acid, syringic acid or isoferulic acid. The concentrations of the examined phenolic acids in black currants related to the whole fruit (mg per fruit) increased, and related to fresh weight (mg per 1000 g) decreased during the growth of the fruits with the exception of protocatechuic acid, which appeared mostly in a last stage of the fruit.