There is a clear trend towards increasing consumption of juices as they can reduce imbalance of redox potential and provide necessary health benefits to consumers. Levels of karwanda ( Carissa congesta Wight) and vegetable juices were varied to prepare nine different formulations of ash gourd-karwanda (AgK) and bottle gourd-karwanda blends (BgK) of higher nutritive, sensory qualities and storability. Total polyphenols (TP), antioxidant activity (AOA), total soluble solids and acidity were increased significantly ( p ≤ 0.05) with addition of karwanda. AgK blend (35:35) and BgK blend (35:30) were selected based on their higher overall acceptability, TP and AOA. AgK blends had higher α-amylase (31%) while BgK blends had higher α-glucosidase (43%) inhibitory activities. Concentration of TP and anthocyanins decreased significantly ( p < 0.05), AOA remained unchanged and anti-inflammatory activities decreased (33–38%) in AgK and BgK blends during accelerated storage at 50 °C for 12 days. Addition of sugar in BgK blend decreased stability of TP (11%), flavonoids (31%) and anthocyanins (8%). During in vitro gastrointestinal digestion, TP, flavonoids and anthocyanins reduction rate was significantly higher for BgK blend with sugar.