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

Comparative Evaluation of the Content of Antioxidant Polyphenolic Compounds in Selected Bulgarian Medicinal Plants

Polyphenols are strong antioxidants of plant origin that exhibit protective role against the development of several chronic degenerative diseases. Quantitative data on the content of polyphenolic antioxidants in Bulgarian medicinal plants are sporadic and unsystematic.

The aim of the study is to determine polyphenols content in series of extracts, infusions and decocts of selected Bulgarian medicinal plants and fruits and to compare their polyphenolic profile.

Materials and Methods: In the present study 18 Bulgarian medicinal plants and fruits have been analyzed for Total Phenolic and Total Flavonoids content, along with HPLC analysis for their level of the individual flavonoids (+)-Catechin, (-)-Epicatechin and Rutin. Comparative evaluation of the content of antioxidant polyphenolic compounds was performed by hierarchical cluster analysis.

The results show that infusions of Hawthorn (Crategus monogyna) flowers have the highest values of Total Phenolic and Total Flavonoids content, forming a separate Cluster in the analysis of the Agglomeration schedule coefficients. Within fruits, data for Total Phenolics and Total Flavonoids content are more homogenic as the cluster analysis shows distribution of 6 elements in a high mean value group. Elderberry (Sambicus nigra) flowers and fruits are the richest source of Rutin in the selected plants studied.

Conclusion: In the present study new data for polyphenolic content in selected Bulgarian medicinal plants and fruits are presented and their degree of similarity in methanolic extracts, infusions and decocts have been assessed in order to provide new data for development of effective antioxidant medicinal plant compositions.

Cosmetic potentials of Prunus domestica L. leaves

BACKGROUND

The current study presents new insight on the phytochemical content and biological activities of five Prunus domestica L. varieties ('Quetsche blanche de Létricourt', 'Mirabelle de Nancy', 'Perdrigon violet', 'Mirabelle de Provence', 'Reine-claude dorée').

RESULTS

The plum leaves were found to possess promising anti-aging activities by their capacity to inhibit 1,1-diphenyl-2-picrylhydrazyl (DPPH), elastase, hyaluronidase and lipoxygenase. After solid phase extraction (SPE), chlorogenic acid, rutin, quercetin and their derivatives were putatively identified by high-performance liquid chromatography coupled with tandem mass spectrometry using an electrospray ionization source (HPLC/ESI-MS/MS).

CONCLUSION

The plum leaf, a by-product, provides an interesting valuable resource for use as a natural cosmetic product or as a food supplement. © 2017 Society of Chemical Industry.

Phenolic compounds in Rosaceae fruit and nut crops

The demand for new fruit cultivars with high levels of phytochemicals, in particular phenolic compounds, has received increasing attention from biochemists, pharmaceutical companies, plant breeders, and the general public due to their health benefits. This review focuses on the economically important Rosaceae, which contains varying proportions and concentrations of these compounds. The paper discusses the common phenolics in the Rosaceae including phenolic acids, flavonols, flavanols, anthocyanins, and dihydrochalcones. The nonextractable phenolics are also presented but not discussed in detail. The metabolism and bioavailability of phenolics, as well as human and environmental factors that affect their concentration and composition, are highlighted. Furthermore, the paper presents different approaches for biofortification and posits that breeding may be the most viable and sustainable option as it improves other fruit quality traits simultaneously and increases confidence in adoption of new cultivars with enhanced consumer appeal.

Identification of phenolic compounds in plum fruits (Prunus salicina L. and Prunus domestica L.) by high-performance liquid chromatography/tandem mass spectrometry and characterization of varieties by quantitative phenolic fingerprints

Plums (Prunus domestica L. and Prunus salicina L.) are edible fruits mostly consumed in America, China, and Europe. We have used LC-MS(n) to detect and characterize the phenolic compounds in plum varieties. Forty-one phenolics were detected comprising caffeoylquinic acids, feruloylquinic acid, p-coumaroylquinic acids, methyl caffeoylquinates, methyl p-coumaroylquinate, caffeoylshikimic acids, catechin, epicatechin, rutin, esculin, quercetin, quercetin-3-O-hexosides, dimeric proanthocyanidins, trimeric proanthocyanidins, caffeoyl-glucoside, feruloyl-glucoside, p-coumaroyl-glucoside, vanillic acid-glucosides, 3,4-dihydroxybenzoyl-glucoside, quercetin-3-O-pentosides, quercetin-3-O-rhamnoside, quercetin-pentoside-rhamnosides, and 3-p-methoxycinnamoylquinic acid. This is the first time when 3-p-methoxycinnamoylquinic acid is reported in nature. Chlorogenic acids and proanthocyanidins were the major phenolics present in plums. Furthermore, HPLC with DAD and chemical reaction detection was used to generate quantitative phenolic fingerprints from the fruit flesh of 33 plum varieties. The predominant compound was 3-caffeoylquinic acid in nearly all varieties studied; generally, however, the qualitative and quantitative profiles showed high diversity even among closely related progenies.

Occurrence and content of hydroxycinnamic and hydroxybenzoic acid compounds in foods

Phenolic acid compounds seem to be universally distributed in plants. They have been the subject of a great number of chemical, biological, agricultural, and medical studies. Hydroxycinnamic acid compounds occur most frequently as simple esters with hydroxy carboxylic acids or glucose, while the hydroxybenzoic acid compounds are present mainly in the form of glucosides. Furthermore, phenolic acids may occur in food plants as esters or glycosides conjugated with other natural compounds such as flavonoids, alcohols, hydroxyfatty acids, sterols, and glucosides. Also, hydroxycinnamic acid amides appear to be common constituents. The occurrence of the different natural phenolic acid compounds in foods is reviewed, and data of the content in fruit, vegetables, and spices are given. The distribution of the main phenolic acid compounds in food plants as well as their changes during development and maturation of fruits are considered. Furthermore, the hydroxycinnamic acids bound to cell wall polymers, the phenolic acid compounds in coffee, cereals, oil seed, and tree nuts, and the analysis of phenolic acid derivatives are reviewed.

[Occurrence of chlorogenic acids in potatoes]

Ten varieties of potato cultivated under the same conditions were analyzed for the occurrence of chlorogenic acids by high performance liquid chromatography. 3-O-caffeoylquinic acid (n-chlorogenic acid) is the predominant compound with 22-71 ppm, (on average of 41 ppm) depending on variety. 4-O-caffeoylquinic acid (phi 11 ppm), 5-O-caffeoylquinic acid (phi 7 ppm), 3,4-dicaffeoylquine acid (phi 3 ppm), and at times 3,5-dicaffeoylquinic acid (in traces) were also demonstrated. Caffeic acid compounds are not distributed uniformly in the potato tuber. They occur in strongly decreasing concentration from the outer sections to the inner ones. About 50% of these compounds are located in the potato peel and the adjoining tissue.

[On the occurrence of proanthocyanidins, leucoanthocyanidins and catechins in vegetables (author's transl)]

22 species of vegetables grown in Germany were investigated and only rhubarb contained (+)-catechin besides traces of (-)-epicatechin. The catechin concentrations were lower in the stalks than in the leaves and decreased during plant growth. Proanthocyanidins (dimers and oligomers of polyhydroxy-flavan-3-ols) were only found in the testa of broad beans, beans, and peas with coloured flowers, and in rhubarb stalks. Leucoanthocyanidins (polyhydroxy-flavan-3,4-diols) could not be found in any vegetable.

[The phenolics of fruits. VIII. Changes in flavonol concentrations during fruit development (authors transl)]

In black currants the contents of quercetin- and especially of myricetin glycosides increased during ripeness very considerably. The myricetin level in ripe fruits of cultivated blueberries and the quercetin level in ripe berries of privet was higher than in unripe. However, the concentrations of kaempferol and quercetin glycosides were in most of the fruits (e.g. red and white currants, sour cherries, plums, cultivated blueberries, elderberries) smaller than in unripe fruits. Anthocyanin formation is therefore not combined with an accumulation of flavonols (perhaps with the exception of myricetin).

[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.