Composition of tocochromanols in kernels recovered from different sweet cherry (Prunus avium L.) cultivars: RP-HPLC/FLD and RP-UPLC-ESI/MSn study

Reversed phase HPLC with UHPLC benefits for the determination of tocochromanols in the seeds of edible fruits in the Rosaceae family

Rosaceae family includes several edible fruit species processed in vast quantities and generates large amounts of seeds valuable in tocopherols. In the present study, the composition of tocochromanols in the seeds of 141 samples was determined by reversed phase high-performance liquid chromatography (RPLC) with diode array detector (DAD), fluorescence detector (FLD) and confirmed by mass detector (MS). The thirteen species belonging to the Rosaceae family were classified by multivariate statistical analysis, hierarchical cluster analysis (HCA) and principal component analysis (PCA) into two groups based on tocochromanols content. Group 'A' includes pears (Pyrus communis), sweet cherry (Prunus avium), sour cherry (Prunus cerasus), apricots (Prunus armeniaca), hexaploid plums (Prunus domestica), diploid plums (Prunus cerasifera), raspberry (Rubus idaeus), and rose hip (Rosa rugosa); while group 'B' quince (Cydonia oblonga), Japanese quince (Chaenomeles japonica), strawberry (Fragaria × ananassa), dessert apples (Malus domestica), and crab apples (Malus spp.). Two rapid (6-7 min) and low pressure (7.2-8.1 MPa) separation methods were developed and validated using two core-shell columns (i) C18 and (ii) F5. The F5 achieved a separation of β and γ isomers while the C18 column did not.

Tocopherols in Cultivated Apple Malus sp. Seeds: Composition, Variability and Specificity

The seeds of 111 Malus sp. different fruit use (dessert and cider apples) cultivars/genotypes developed in 18 countries were analysed to evaluate composition of tocopherol homologues and identify crop-specific profile, including diploid, triploid, and tetraploid apple cultivars with and without scab-resistance to ensure high genetic diversity. The percentage of individual tocopherols was as follows: alpha-tocopherol (alpha-T) (38.36%), beta-tocopherol (beta-T) (40.74%), gamma-tocopherol (gamma-T) (10.93%), and delta-tocopherol (delta-T) (9.97%), represented by average measurements of 17.48, 18.56, 4.98, and 4.54 mg/100 g dry weight, respectively. The values of the variation coefficient showed high variability for delta (0.695) and gamma (0.662) homologue content, whereas measurements of alpha-T and beta-T were less variable (coefficient of variation 0.203 and 0.256, respectively). The unweighted pair group method with arithmetic mean (UPGMA) revealed three main cultivar groups characterised by almost equal content of all four tocopherol homologues (Group I), high concentrations of alpha-T and beta-T, but very low content of gamma-T and delta-T (Group II), and relatively high average content of alpha-T and beta-T, but higher gamma-T and delta-T content (Group III). Specific tocopherol homologues showed association with certain valuable traits, such as harvesting time (total content of tocopherols) and resistance to apple scab (alpha-T and total content of tocopherols). This study represents the first large-scale tocopherol homologue (alpha, beta, gamma, and delta) screening in apple seeds. The dominant tocopherol homologues in cultivated apple cultivars are alpha-T and beta-T, with the prevalence of alpha-T or beta-T depending on genotype. It is a unique finding due to the rare occurrence of beta-T in the plant world and is considered a unique feature of the species.

Fatty acid profile and in vitro biological properties of two Rosacea species (Pyrus glabra and Pyrus syriaca), grown as wild in Iran

The high demands for the consumption of edible oils have caused scientists to struggle in assessing wild plants as a new source of seed oils. Therefore, in this study, the oil yield, fatty acid and tocopherol compositions, antioxidant and antibacterial activities of the oils obtained from Iran's two endemic plants (Pyrus glabra and Pyrus syriaca) were investigated. The obtained oil yields from the P. glabra and P. syriaca seeds were 33 ± 0.51 and 26 ± 0.28 w/w%, respectively. Oleic acid (C18:1) with the amount of 49.51 ± 1.05% was the major fatty acid in the P. glabra oil, while the main fatty acids in the P. syriaca seed oil belonged to linoleic acid (C18:2) and oleic acid (C18:1) with the amounts of 46.99 ± 0.37 and 41.43 ± 0.23%, respectively. The analysis of tocopherols was done by HPLC, and the results indicated that the P. glabra and P. syriaca seed oils were rich in α-tocopherol (69.80 ± 1.91 and 45.50 ± 1.86 mg/100 g oil, respectively), constituting 86.24 and 89.01% of total detected tocopherols, respectively. The study on the reducing capacity of the oils indicated that the P. glabra oil had more reducing capacity than the P. syriaca oil. Moreover, the antioxidant activity of the P. glabra seed oil (43.4 ± 0.7 µg/ml) was higher than the P. syriaca seed oil (46.3 ± 1.2 µg/ml). Also, the investigation of the antibacterial activities indicated that the P. glabra and P. syriaca oils have an inhibitory effect on the studied bacteria. The results indicate that the oils of these plants can be appropriate sources of plant oils which can act as natural antibacterial agents.

Sea buckthorn (Hippophae rhamnoides L.) vegetative parts as an unconventional source of lipophilic antioxidants

The profile of lipophilic antioxidants in different vegetative parts (leaves, shoots, buds and berries) was studied in sea buckthorn (Hippophae rhamnoides L.) male and female plants collected in the end of spring. Five lipophilic compounds, i.e. three tocopherol homologues (α, β and γ), plastochromanol-8 and β-carotene, were identified in each vegetative part of male and female sea buckthorn plants at the following concentrations: 7.25-35.41, 0.21-2.43, 0.41-1.51, 0.19-1.79 and 4.43-24.57 mg/100 g dry weight basis. Additionally, significant amounts of α-tocotrienol (1.99 mg/100 g dry weight basis) were detected in buds. The α-tocopherol and β-carotene were predominant lipophilic antioxidants in each vegetative part, accounting for 78.3-97.0% of identified compounds. The greatest amounts of lipophilic antioxidants were found in leaves, especially of female plants. Nevertheless, apart from leaves, also shoots of plants of both sexes seem to be a good source of α-tocopherol and β-carotene.

Impact of Cultivar on Profile and Concentration of Lipophilic Bioactive Compounds in Kernel Oils Recovered from Sweet Cherry (Prunus avium L.) by-Products

Lipophilic bioactive compounds in oils recovered from the kernels of seven sweet cherry (Prunus avium L.) cultivars, harvested at single location in 2013, were studied. Oil yield in sweet cherry ranged between 30.3-40.3 % (w/w) dw. The main fatty acids were oleic acid (39.62-49.92 %), linoleic acid (31.13-38.81 %), α-eleostearic acid (7.23-10.73 %) and palmitic acid (5.59-7.10 %), all four represented approximately 95 % of the total detected fatty acids. The ranges of total tocochromanols and sterols were between 83.1-111.1 and 233.6-419.4 mg/100 g of oil, respectively. Regardless of the cultivar, the γ-tocopherol and β-sitosterol were the main lipophilic minor bioactive compounds. The content of the carotenoids and squalene were between 0.38-0.62 and 60.9-127.7 mg/100 g of oil, respectively. Three significant correlations were found between oil yield and total contents of sterols (r = -0.852), tocochromanols (r = -0.880) and carotenoids (r = -0.698) in sweet cherry kernel oils. The oil yield, as well as the content of lipophilic bioactive compounds in oil was significantly affected by the cultivar.

Impact of Species and Variety on Concentrations of Minor Lipophilic Bioactive Compounds in Oils Recovered from Plum Kernels

The profile of bioactive compounds (carotenoids, tocopherols, tocotrienols, phytosterols, and squalene) in oils recovered from the kernels of 28 plum varieties of hexaploid species Prunus domestica L. and diploid plums Prunus cerasifera Ehrh. and their crossbreeds were studied. Oil yields in plum kernels of both P. cerasifera and P. domestica was in wide ranges of 22.6-53.1 and 24.2-46.9% (w/w) dw, respectively. The contents of total tocochromanols, carotenoids, phytosterols, and squalene was significantly affected by the variety and ranged between 70.7 and 208.7 mg/100 g of oil, between 0.41 and 3.07 mg/100 g of oil, between 297.2 and 1569.6 mg/100 g of oil, and between 25.7 and 80.4 mg/100 g of oil, respectively. Regardless of the cultivar, β-sitosterol and γ-tocopherol were the main minor lipophilic compounds in plum kernel oils and constituted between 208.5 and 1258.7 mg/100 g of oil and between 60.5 and 182.0 mg/100 g of oil, respectively. Between the studied plum species, significant differences were recorded for δ-tocopherol (p = 0.007), 24-methylenecycloartanol (p = 0.038), and citrostadienol (p = 0.003), but they were insufficient for discrimination by PCA.