Phenolic bioactive-linked antioxidant, anti-hyperglycemic, and antihypertensive properties of sweet potato cultivars with different flesh color

Authors: CHINTHA, PRADEEPIKA - North Dakota State University; SARKAR, DIPAYAN - North Dakota State University; PECOTA, KENNETH - North Carolina State University; Dogramaci, Munevver; HATTERMAN-VALENTI, HARLENE - North Dakota State University; SHETTY, KALIDAS - North Dakota State University

Submitted to: Journal of Horticulture, Environment and Biotechnology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/30/2023
Publication Date: 7/8/2023
Citation: Chintha, P., Sarkar, D., Pecota, K., Dogramaci, M., Hatterman-Valenti, H., Shetty, K. 2023. Phenolic bioactive-linked antioxidant, anti-hyperglycemic, and antihypertensive properties of sweet potato cultivars with different flesh color. Journal of Horticulture, Environment and Biotechnology. https://doi.org/10.1007/s13580-023-00515-0.
DOI: https://doi.org/10.1007/s13580-023-00515-0

Interpretive Summary: Improving consumption and daily intake of vegetables rich with antioxidants is critical to counter growing prevalence of non-communicable chronic diseases such as type 2 diabetes, cardiovascular diseases, and certain types of cancer. Among root vegetables, sweet potatoes are becoming increasingly popular in global food market. However, the health benefits of sweet potatoes vary widely between different flesh colors and among different commercial varieties. Therefore, the aim of this study was to screen sweet potato cultivars with three different flesh colors (white, orange, and purple) for specific health attributes. Purple sweet potato cultivar screened in this study had very high health promoting bioactive profile and high antioxidant activity, while anti-diabetic and anti-hypertensive qualities were observed in all sweet potato cultivars. The results of this study indicate that different flesh colored sweet potatoes are good dietary sources that can be integrated in dietary support strategies to counter diet–linked chronic diseases and to improve wider consumer health.

Technical Abstract: Sweet potato is a rich source of antioxidant bioactives, like ß-carotene, vitamin C, anthocyanins, xanthophylls, and phenolics, which are relevant for providing dietary protections against chronic oxidative stress-associated diseases, such as type 2 diabetes. Therefore, integrating sweet potatoes in dietary strategies to counter chronic oxidative stress induced metabolic breakdowns and reduce type 2 diabetes associated health risks has wider health relevance. However, the health protective phenolic bioactive profile and associated antioxidant and anti-diabetic properties of sweet potatoes vary widely between different flesh color and among cultivars. Therefore, the aim of this study was to screen aqueous and ethanol (12%) extracts of sweet potato cultivars with different flesh colors (white-yellow, orange, and purple) for total soluble phenolic (TSP) content, phenolic profile, protein content, total antioxidant activity, anti-hyperglycemic function relevant a-amylase, a-glucosidase, and anti-hypertensive function related angiotensin-I-converting enzyme (ACE) inhibitory activities using rapid in vitro assay models. The purple-flesh cv. NIC 413 had significantly higher phenolic content (2.8 mg/100 g FW) and associated high antioxidant activity. Catechin, gallic, and dihydroxybenzoic acids were found in all cultivars, while chlorogenic acid was present only in purple-flesh cultivar. Moderate a-amylase (74-84 %), a-glucosidase (21-60 %), and ACE (10-88%) enzyme inhibitory activities were observed across all sweet potato cultivars. The results of this in vitro screening study suggested that sweet potato cultivars like NIC 413, Murasaki, Evangeline, and Covington are good dietary source of phenolic antioxidants and can be relevant for anti-hyperglycemic and anti-hypertensive benefits to target type 2 diabetes associated health risks.