A Novel Auraptene-Enriched Citrus Peels-Based Blend with Enhanced Antioxidant Activity.

The aim of this study was to establish a convenient process to get auraptene-enriched blends from Citrus limon L. Osbeck (Rutaceae) peels powder with functional food and nutraceutical potential and antioxidant properties. The process consisted in the selective adsorption of auraptene by bentonite followed by desorption and evaporation of solvents to get the final product. HPLC analyses revealed an adsorption > 99% from lemon fruit peel powder and a 13.7-fold enrichment of the obtained composition respect to the parent food-derived sample. The antioxidant and radical scavenger activities of the Citrus peels based preparation were assayed by the DPPH and ABTS tests and reveal deffects higher than ascorbic acid and Trolox® used as the references. To the best of our knowledge, the findings described herein is the first example reported in the literature of solid phase adsorption experiments carried out on auraptene as a component of edible fruits.

UHPLC-UV/Vis Quantitative Analysis of Hydroxylated and O-prenylated Coumarins in Pomegranate Seed Extracts.

A simple and rapid analytical UHPLC methodology with spectrophotometric (UV/Vis) detection, coupled with different extraction procedures, has been perfected to investigate the presence of biologically active O-prenylated umbelliferone derivatives, such as auraptene and umbelliprenin, in pomegranate (Punica granatum L.) seed extracts. Absolute ethanol was the most efficient extraction solvent in terms of yields, after a short ultrasound-assisted. The highest concentration values recorded under these experimental conditions were 1.99 µg/g of dry extract and 6.53 µg/g for auraptene and umbelliprenin, respectively. The parent metabolite umbelliferone was also detected (0.67 µg/g). The extraction and UHPLC analytical methodology set up in the present study proved to be an efficient, powerful, and versatile technique for the simultaneous qualitative analysis and quantification of oxyprenylated coumarins in pomegranate seed extracts. The characterization of such secondary metabolites in the mentioned phytopreparation represents, to the best of our knowledge, the first example in the literature.

HPLC Analysis and Skin Whitening Effects of Umbelliprenin-containing Extracts of Anethum Graveolens, Pimpinella Anisum, and Ferulago Campestris.

Umbelliprenin has recently been shown to have great potential as a skin whitening agent. Wishing to investigate the same effect in plant species known to biosynthesize this coumarin, three plants belonging to the Apiaceae family, namely Anethum graveolens L. (dill), Pimpinella anisum L. (anise), and Ferulago campestris (Besser) Grecescu (field ferula) were screened by HPLC analysis for their respective content of umbelliprenin in extracts obtained with different solvent mixtures and by maceration and ultrasound-assisted processes. EtOH was shown to be the best solvent, providing umbelliprenin yields ranging from 1.7% to 14.4% (with respect to the total amount of extract obtained). Extracts with the highest content of this farnesyloxycoumarin were then assayed as modulators of melanogenesis in cultured murine Melan A cells employing the same umbelliprenin obtained by chemical synthesis as the reference. A parallelism between the content of the coumarin and the recorded depigmenting effect (60% for the EtOH extract of F. campestris as the best value) was revealed for all plants extracts when applied at a dose of 100 µg/mL. Our results demonstrate that the same potential of umbelliprenin can be ascribed also to umbelliprenin-enriched plant extracts which reinforces enforce the widespread use of phyto-preparations for cosmetic purposes (e.g., A. graveolens).

Oxyprenylated Secondary Metabolites as Modulators of Lipid and Sugar Metabolism.

O-Prenylcoumarins (3,3-dimethylallyl, geranyl-, farnesyl- and related biosynthetic derivatives) represent a class of rarely occurring natural compounds. Most of these secondary metabolites have been obtained from plant species belonging to the Rutaceae, Apiaceae, and Fabaceae families, and from fungi, and bacteria. In the last two decades, prenyloxycoumarins have been found to possess great potential in terms of pharmacological activities. The aim of this comprehensive review is to make a survey of the so far reported literature citations about these valuable phytochemicals and structurally related compounds about their modulatory properties of lipid and sugar metabolism. Literature data have been acquired from the main Internet database. Several oxyprenylated secondary metabolites have been surveyed. Among these, prenyloxycoumarins represented the main group displaying valuable effects as modulators of lipid and sugar metabolism. The title phytochemicals have been found in common fruits and vegetables already known to have beneficial effects, thus enforcing the nutraceutical role of these food plants. All compounds outlined in the present review article have a great potential in future for the prevention and management of acute and chronic metabolic disorders.