Malvidin is an O-methylated anthocyanidin responsible for the pigments in grapes and blueberries. It demonstrates antioxidant capacity with free radical scavenging properties in vitro. [1] [2] It also exhibits antihypertensive activity by inhibiting angiotensin I-converting enzyme, anti-inflammatory effects by blocking the NF-κB pathway, antiproliferative properties by inhibiting various tumor cell lines, and counteracts oxidative stress in neuronal cells.[1] [3] [4]

Reference:
[1]. Huang, W., Zhu, Y., Li, C., et al. Effect of blueberry anthocyanins malvidin and glycosides on the antioxidant properties in endothelial cells. Oxid.Med.Cell Longev. 2016:1591803, (2016).
[2]. Cui, C., Zhang, S., You, L., et al. Antioxidant capacity of anthocyanins from Rhodomyrtus tomentosa (Ait.) and identification of the major anthocyanins. Food Chemistry 139(1-4), 1-8 (2013).
[3]. Andriambeloson, E., Magnier, C., Haan-Archipoff, G., et al. Natural dietary polyphenolic compounds cause endothelium-dependent vasorelaxation in rat thoracic aorta. Journal of Nutrition 128, 2324-2333 (1998).
[4]. Shih, P.H., Wu, C.H., Yeh, C.T., et al. Protective effects of anthocyanins against amyloid β-peptide-induced damage in neuro-2A cells. Journal of Agricultural and Food Chemistry 59(5), 1683-1689 (2011).