Identification of anthocyanin compounds in 10 Grape Cultivars (Vitis Vinifera L) By HPLC-DAD Method

Grapes are a significant source of phenolic compounds, Genetic factors primarily determine anthocyanins, and in grapes, skin color is a critical and influential factor in the large germplasm of grapes. Since about 250 cultivars of 800-1000 grape cultivars are grown in Iran, studying anthocyanin compounds in the available germplasm resources is crucial. Therefore, this study was carried out to investigate the profile and diversity of different polyphenolic and anthocyanin compounds in some colored grapevine cultivars (V. vinifera L).

In this study the cultivars Flame, Crimson, Red Globe, Sahebi ghoochan, Ghare Shire, Sahebi Urmia, Syah Ghare Bagh, Rish baba, Flame seedless and Lale Bidane were investigated. The amount of phenol in the pulp was measured by the Folin-Ciocalteu method, and total flavonoids were measured by aluminum chloride calorimetry method. Total anthocyanin was measured with a spectrophotometer at 760 nm. The evaluation of the individual anthocyanin compounds was done by HPLC-DAD. Analysis of variance for all morphological traits was performed with the software IBM SPSS 26 using the one-way method ANOVA. The correlation among varieties, PCA analysis, and the scatter plot of the distribution according to PC1/PC2 were made with the statistical software SPSS. The distance values were calculated using the Euclidean method, and the dendrogram was generated using the UPGMA method of the NCSS statistical software (NCSS.12).

The percentage of total phenols, flavonoids, and anthocyanins in the berries of the studied cultivars were 48, 43, and 9, respectively. The results showed that the highest concentrations of total phenols were found in the cultivars “Crimson” (16.94 mg GAE/100 g), “Red Globe” (13.74 mg GAE/100 g), and “Flame” (13.58 mg GAE/100 g). The highest content of total flavonoids was found in “Flame” (36.47 mg100 g-1) and “Red Globe” (10.05 mg 100g-1), also the highest content of anthocyanins was found in “Ghare Shire”, “Syah Ghare Bagh”, “Lale Bidane” and “Sahebi Urmia” with 6.09, 6.59, 3.58 and 2.01 mg kg -1, respectively. Among the varieties studied, the lowest content of total anthocyanins, flavonoids, and phenol respectively was observed in “Flame” with 0.23 mg kg-1 and “Syah Ghare Bagh” with 5.8 mg/kg, and in “Sahebi ghoochan” with 2.88 mg kg-1. The composition of pelargonidin and its derivatives was not identified. The concentration of malvidin in “Flame” and “Red Globe” was trace and was not observed in “Sahebi Urmia” and “Lale Bidane”. The correlation results show that the highest positive and significant correlations were between delphinidin 6-acetyl glucoside and cyanidin 6-acetyl glucoside (r=0.99). Malvidin showed the highest correlation with delphinidin and petunidin. According to the dendrogram of cluster analysis of ten red cultivars for anthocyanins, they were divided into two main groups. The first group consisted of the two cultivars “Syah Ghare Bagh” and “Ghare Shire”, further away from the other eight cultivars of the second group.

The studied cultivars showed significant differences in the individual anthocyanin compounds and the amount of phenol, flavonoids, and total anthocyanins. According to the results, peonidin and malvidin had the highest concentrations in the studied cultivars; In “Syah Ghare Bagh”, the highest concentration of peonidin was found at 54.08 mg kg DW -1, and in “Ghare Shire” malvidin with 42.78 mg kg DW -1. In addition “Syah Ghare Bagh” and “Ghare Shire”' had the highest total anthocyanin concentration. Consequently, these genotypes were located in a separate group by distance from most cultivars based on cluster analyses.