The fruits of Cornus mas and Cornus officinalis have been known and appreciated in folk medicine for years and have a high biological value, which is mainly connected with their polyphenols and iridoids content. However, hybrids of C. mas × C. officinalis have not been investigated. The aim of this study was to evaluate the iridoids, anthocyanins, and flavonols content, and antioxidant capacity of Cornus mas, Cornus officinalis, and C. mas × C. officinalis. Iridoids and flavonoids were quantified by the High-Performance Liquid Chromatography (HPLC) method. Antioxidant capacity (AC) was measured using 2,2-diphenyl-1-picrylhydrazyl (DPPH^•), 2,2′-azino-bis (3-ethyl benzothiazoline-6-sulfonic acid (ABTS^•+), and ferric reducing antioxidant power (FRAP) tests. Total phenolic content (TPC) was evaluated using the Folin–Ciocalteu reagent. Among the C. mas cultivars and C. officinalis genotypes, there was considerable variation in the content of iridoids, flavonoids, and AC. Interspecific hybrids C. mas × C. officinalis contained more iridoids than C. mas and more anthocyanins than C. officinalis and additionally had higher AC and TPC than C. officinalis and most C. mas. AC, TPC, and the presence of iridoids, anthocyanins, and flavonols in hybrids C. mas × C. officinalis are reported for the first time. The Cornus species deserve special attention due to their highly biologically active substances, as well as useful medicinal properties.

The stone of Cornus mas L. remains the least known morphological part of this plant, whereas the fruit is appreciated for both consumption purposes and biological activity. The stone is considered to be a byproduct of fruit processing and very little is known about its phytochemical composition and biological properties. In this study, the complete qualitative determination of hydrolyzable tannins, their quantitative analysis, total polyphenolic content, and antioxidant properties of the stone of C. mas are presented for the first time. The 37 identified compounds included the following: various gallotannins (11), monomeric ellagitannins (7), dimeric ellagitannins (10), and trimeric ellagitannins (7). The presence of free gallic acid and ellagic acid was also reported. Our results demonstrate that C. mas stone is a source of various bioactive hydrolyzable tannins and shows high antioxidant activity which could allow potential utilization of this raw material for recovery of valuable pharmaceutical or nutraceutical substances. The principal novelty of our findings is that hydrolyzable tannins, unlike other polyphenols, have been earlier omitted in the evaluation of the biological activities of C. mas. Additionally, the potential recovery of these bioactive chemicals from the byproduct is in line with the ideas of green chemistry and sustainable production.

Iridoids are natural monoterpenoids, widely distributed in ornamental plants, herbs, and medicinal plants, but particularly in the green parts of plants. Their significance arises from diverse biological activities (anti-inflammatory, antioxidative, anti-cancer, anti-atherogenic, antidiabetic, neuroprotective, etc.) which have been well-documented and point out to the natural-origin, non-toxic compounds for the use in disease prevention and treatment. Nonetheless, iridoids are scarce in edible fruits and are not perceived as important phytocompounds of dietary fruits and food products. However, they do occur in some common edible fruits – olive, noni, berries, and a few less-common, but unique fruits – Japanese cornel, cornelian cherry, kousa dogwood, haskap berry, and guelder rose. In this review, we present the current state of knowledge regarding the identification and content of iridoids in edible fruits, their predominant activities, and above all, the possibilities and effects of iridoids’ application in foods, drinks, and pharmaceuticals. The consulted literature shows that iridoids or iridoid-rich fruits can be successfully applied to broaden the variety of foods, as functional additives, and possibly as future pharmaceuticals of natural origin. Therefore, iridoids deserve an important role in a healthy diet and disease prevention. GRAPHICAL ABSTRACT

This study defined the physicochemical attributes, composition, and antioxidant capacity of four Polish cultivars of cornelian cherry (CC) at six stages of development and ripening. A total of 52 metabolites were identified by UPLC-ESI-qTOF-MS/MS and quantified by HPLC-PDA. In general, phenolic acids, hydrolyzable tannins, flavonols, iridoids, antioxidant activity, organic acids, and vitamin C decreased, while anthocyanins, malic acid, sugars, and titratable acidity increased. For the first time, we determined the evolution of the CC chemical properties and the metabolic behavior and quantified the individual compounds, and groups of compounds during ripening, in particular gallotannins, ellagitannins, iridoids, and organic acids. The main novelty of our study is that CC is a valuable resource for utilization at different degrees of maturity. We showed that unripe fruits in particular deserve valorization, as they contained the highest content of total bioactive phytocompounds (5589.1–6779.6 mg/100 g dw)—primarily phenolic acids > iridoids > tannins—and the highest antioxidant capacity. The intermediate stages were the most abundant in vitamin C (341.1–495.6 mg/100 g dw), ellagic acid (5.9–31.6 mg/100 g dw), gallotannins (47.8–331.1 mg/100 g dw), and loganic acid (1393.0–2839.4 mg/100 g dw). The ripe fruits contained less bioactive phytocompounds (1403.7–1974.6 mg/100 g dw)—primarily iridoids > phenolic acids > tannins > anthocyanins—and the lowest antioxidant capacity. On the other hand, ripe fruits showed the highest content of anthocyanins (30.8–143.2 mg/100 g dw), sugars (36.4–78.9 g/100 g dw), malic acid (5.5–12.2 g/100 g dw), and, favorably for the nutritional applications, the highest sugar-to-acids ratio (3.0–6.4). Our work illustrates in detail that quality attributes and the content of health-promoting phytocompounds in CC depend on the ripening stage and on the cultivar. These results advance the scientific knowledge about CC. Our findings can be helpful to select the optimal properties of CC for the development of diverse functional foods and phytopharmaceuticals applied in the prevention of civilization diseases.

Despite the fact that phytochemicals of Cornaceae species have long been discussed as possible auxiliary agents in contemporary treatment, the insights on their properties remain relatively scarce. This study focuses on Cornus mas L. (Cornelian cherry), the extracts of which are reported to exert a pleiotropic effect shown in both in vivo and in vitro studies. This study aimed to explore the cytotoxic effect of extracts from fruits of red (Cornus mas L. ‘Podolski’) and yellow (Cornus mas L. ‘Yantarnyi’ and ‘Flava’) Cornelian cherries on two melanoma cell lines (A375 and MeWo). The extracts were characterized in the context of the concentration of bioactive compounds of antioxidative properties. Cytotoxicity was investigated with the use of the following two assays: SRB and MTT. An additional, alternative protocol for the SRB assay was used in this study so as to account for possible bias. Cytotoxicity was assessed as a difference in the whole time series of cell viability, instead of analyzing differences in raw values (often found in the literature). Both extracts from Cornus mas L. induced cytotoxicity in both A375 and MeWo cell lines, although the response of these cells was different. Moreover, based on this study, there is no evidence for claiming a different magnitude of cytotoxicity between these two extracts.

The aim of the study was to assess the effect of time (20–50 min) and temperature (160–220 °C) of roasting on the physicochemical and antioxidant properties of cornelian cherry (Cornus mas L.) stones and to select extraction solvents (water and 50% and 80% methanol) to obtain reliable results. To maintain the highest content of bioactive compounds with a high level of antioxidant properties, roasting at a temperature of 160–180 °C for 30–40 min should be considered optimal. Incorrect selection of roasting parameters (>40 min and >200 °C) causes a significant reduction in the bioactive properties of roasted stones. Regression analysis showed a different nature of changes in the determined features during the roasting process at 160 °C than at other temperatures. The use of methanol, especially at a high concentration (80%), to assess the content of bioactive compounds in roasted cornelian cherry stones provides more reliable results.