Comparative analysis of bioactive compounds in three grape varieties of local and introduced origin: Prospects for their use in functional foods

Abstract

Background: Grapes (Vitis vinifera L.) are one of the major fruit crops in the world and are an excellent source of biologically active phytochemicals with known nutritional and therapeutic effects. The most significant bioactive substances that contribute to color characteristics, antioxidant capacity, and various health-enhancing effects of grapes are phenolic compounds and anthocyanins. Genetic and environmental factors also play an important role in the composition and concentration of these compounds, which in turn affects their applicability in functional foods. Objective: The purpose of the current research was to compare the phenolic and anthocyanin profiles of three local and introduced grape varieties (Halwani, Kamali, and Red Globe) using high-performance liquid chromatography (HPLC) and to assess their prospective use as sources of bioactive compounds for functional food development. Methods: Ripe grapefruits were used to obtain phenolic and anthocyanin compounds, which were measured using HPLC under standardized analytical conditions. Five anthocyanin compounds (cyanidin, peonidin, malvidin, delphinidin and petunidin) and six phenolic compounds (rutin, catechin, apigenin, kaempferol, caffeic acid and gallic acid) were identified and quantified. To establish significant differences between cultivars, statistical analysis was performed. Samples of approximately 10 g were transferred into 100 mL vials. Then, 50 mL of dimethyl sulfoxide (DMSO) was added, and the vials were mixed in a vortex mixer for 1 min. The vials were placed in the dark for 10 min, and methanol containing 2% HCl and 0.5 mg/mL tert-butylhydroquinone (15 mL) was added. The vials were mixed using a vortex mixer for 5 min. Finally, the supernatant solutions were filtered through a 0.2 μm syringe filter into a small glass vial for HPLC analysis. Results: Significant differences (p ≤ 0.05) were observed among grape cultivars in both phenolic and anthocyanin composition. The highest concentrations of catechin (186.76 ppm), rutin (123.83 ppm), gallic acid (99.56 ppm), caffeic acid (20.83 ppm), and delphinidin (118.56 ppm) were found in Halwani. Catechin was the most abundant phenolic compound, whereas delphinidin was the most abundant anthocyanin in all cultivars. Kamali tended to exhibit the lowest levels of most of the bioactive compounds. Conclusions: The findings indicate that there is a significant difference in phytochemical composition across grape cultivars. The Halwani cultivar showed greater accumulation of phenolic compounds and anthocyanins, indicating its potential as a natural source of antioxidants for functional foods, nutraceuticals, and natural food colorants. The results are useful in cultivar selection in food industries and breeding programs aimed at the improvement of nutritional quality. Novelty of the Study: This study provides a comparative HPLC characterization of phenolic compounds and anthocyanins in two local grape cultivars (Halwani and Kamali) and one introduced cultivar (Red Globe) grown under the same conditions. The direct comparison demonstrates the superior phytochemical profile of the local Halwani cultivar, highlighting its potential as a valuable source of natural antioxidants for functional food and nutraceutical applications while providing new information for cultivar selection and breeding programs. Keywords: Grapes, Functional food, Phenolics, Anthocyanins, Antioxidant compounds, HPLC.