Corema album (L.) D. Don is a dioecious perennial shrub of the Ericaceae family, endemic of the Iberian Peninsula Atlantic coastal dunes. It is a branched bush, that can reach up to 1 m, with a spherical (5–8 mm diameter) and white acidic edible berries (Portuguese white crowberries, Atlantic pearls, beachberries or “camarinhas” in Portuguese).
The Portuguese coastline is rich in many indigenous maritime plants with a high potential to become novel functional food ingredients (or sources of these). Corema album
(L.) D. Don is a dioecious perennial shrub of the Ericaceae family, endemic of the Iberian Peninsula Atlantic coastal dunes. It is a branched bush, that can reach up to 1 m, with white acidic edible berries (Portuguese white crowberries or “camarinhas” in Portuguese), 5–8 mm in diameter [1
]. The genus Corema
was included in the Ericaceae family in 1959 since traditionally it belonged to the Empetraceae family, which comprises two more genus—Empetrum
. The two species of Corema
genus, C. conradii
Torrey and C. album
(L.) D. Don ex Steudel, can be found in Atlantic coastlines—C. conradii
in the eastern coast of North America and C. album
in the Iberian Peninsula and in the Azores islands (subsp. azoricum
Pinto da Silva) [2
berries are known to be exceptional sources of nutrients and phytochemicals. Their dietary intake is highly recommended since it is associated with the prevention of chronic and degenerative diseases [3
]. The nutraceutical potential of berries is due to their phytochemical composition. High levels of phenolic compounds have been identified, particularly phenolic acids (benzoic and caffeic acids being the most predominant), flavonols (especially quercetin 3-O
-hexoside and rutin), anthocyanins (delphinidin 3-O
-hexoside, cyanidin 3-O
-glucoside, and cyanidin 3-O
-pentoside), and tannins [4
]. This confers them beneficial biological properties, namely antioxidant, antimicrobial, and anticancer activities, rendering them promising chemopreventive agents against anti-inflammatory and anti-neurodegenerative disorders, as well as cancer [7
]. The berries have also been described as a valuable source of fibers, water, and sugars [9
The human consumption of C. album
berries dates back to ancient times, having been used in traditional medicine as antipyretic [10
] and antiparasitic agents [11
]. Since they are not yet approved as novel food products—having not entered into the regular market—these types of berries are not consumed by the general population [12
]. However, they have been sold in Portuguese local markets, in the regions where Corema
exists. Even though this plant has gained the attention of the scientific community in the last few years, the number of published studies, at the molecular level, concerning the biological potential of C. album
berries and their nutritional value is still scarce, e.g., less than 10 papers, using Science Direct and Scopus digital databases by searching for specific keywords within the title (“Corema album
”) and (“antioxidant”) in abstract. A thorough characterization of these berries is essential for understanding their activity, as well as to allow their safe consumption either as fresh fruits or processed in the form of juices, jams, or jellies. Martin et al. (2020) reported the first spectroscopic study of fresh C. album
berries, assigning distinct vibrational fingerprints to the skin and the seeds that revealed the differences in their content in phenolic derivatives, unsaturated fatty acids, and waxy polymers [13
Since the evaluation of the biological properties of the different parts of C. album
berries, as well as their spectroscopic characterization, is still scarce, the present study aims at filling this gap, particularly for extracts from fresh pulp, seed residue, and seed oil. Actually, only two studies are found in the literature for C. album
pulp and seed [4
], with a small number of antioxidant activity tests, without any vibrational spectroscopic characterization, and with no separation between the seed residue and the seed oil. Solvent extraction with methanol was the method of choice since this combination is routinely used for phytochemicals extraction with good yields [15
]. Currently, antioxidant activity was measured for isolated extracts from the pulp (also tested for antimicrobial activity), seed residue, and seed oil, and the results were related to the main chemical constituents determined by both Fourier transform infrared (FTIR) and Raman vibrational spectroscopies. Apart from probing its separated constituents, the establishment of a relationship between composition and health beneficial effects is innovative for this edible fruit.
2. Total Phenolic, Flavonoid, and Monomeric Anthocyanin Content
The fresh berries pulp (FBP) extract presents the lower phenolic, flavonoid, and anthocyanin contents when compared to the berries seed residue (BSR) and berries seed oil (BSO) extracts (Table 1). The results show that the seeds are much richer in phenolic and flavonoid compounds and that the reddish BSR extract has the highest total monomeric anthocyanin content (TMAC) value.
Table 1. Total phenolic content (TPC, mg GAE/g extract), total flavonoid content (TFC, mg QCE/g extract), and total monomeric anthocyanin content (TMAC, mg C3GE/g extract) of pulp and seed extracts of C. album berries.
||9.9 ± 0.1 c
||1.7 ± 0.4 c
||0.06 ± 0.02 b
||41.0 ± 0.5 a
||19.6 ± 0.7 b
||4.6 ± 0.8 a
||17.6 ± 2.1 b
||79.6 ± 2.3 a
||1.6 ± 0.8 b
3. Antioxidant Activity
The BSR extract presents a higher radical scavenging ability both against the DPPH radical and the ABTS radical cation (Table 2), followed by the FBP extract and by the BSO, which presents the lowest antioxidant activity. Noteworthy is the EC50 value for the BSR in the DPPH assay, which is in the same range as the EC50 calculated for BHT. Moreover, only the BSR extract presents the capability to inhibit lipid peroxidation, though to a lower extent than the standard antioxidant BHT.
Table 2. Free radical scavenging activity (DPPH and ABTS) and inhibition of lipid peroxidation of pulp and seed extracts of C. album berries presented as EC50 values (mg/mL).
||3.1 ± 0.2 a
||0.15 ± 0.04 b
||1.09 ± 0.03
||2.0 ± 0.2
||0.10 ± 0.03 b
||0.17 ± 0.03
||0.009 ± 0.005
In the β-carotene–linoleic acid bleaching assay, the BSR extract presents a higher inhibition of the β-carotene oxidation than the other extracts (Figure 1). Nevertheless, it is still considerably less active than BHT (EC50 = 0.005 ± 0.002 mg/mL). The BSO extract showed a higher level of β-carotene oxidation inhibition when compared to the FBP extract.
Figure 1. Linoleic acid/β-carotene bleaching inhibitory activity of extracts of different parts of C. album berries. FBP, fresh berries pulp (dotted); BSR, berries seed residue (vertical bar); BSO, berries seed oil (horizontal bar). Values represent the mean ± standard deviation of three independent experiments obtained after 2 h of reaction and for the highest concentration of each extract. Bars with different lowercase letters (a–c) indicate significant differences (Tukey’s post hoc test, p < 0.05).
Regarding the metal ion chelator ability, the results presented in Table 3 reflect the trend already observed for the BSR extract. It shows to be more potent than the other analyzed extracts regarding the ferric and cupric reducing powers, as well as the ability to chelate iron, though to a lower extent than the EDTA chelator. All the extracts are more effective in reducing copper than iron, with FRAP values ranging from 6.8 to 54.7 mg TE/g extract and CUPRAC values in the 24.7–146.6 mg TE/g extract range.
Table 3. Metal chelating activity (EC50, mg/mL) and ferric (FRAP) and cupric (CUPRAC) reducing powers (mg TE/g extract) of pulp and seed extracts of C. album berries.
||Metal Chelating Activity
||12.0 ± 0.7 b
||24.7 ± 2.0 c
||4.2 ± 0.2
||54.7 ± 4.9 a
||146.6 ± 5.9 a
||6.8 ± 1.1 b
||127.3 ± 2.4 b
||0.015 ± 0
This entry is adapted from 10.3390/plants10091761