Cardioprotective compounds of red pitaya (Hylocereus polyrhizus) fruit

To determine whether polyphenols and antioxidant contents are the possible cardioprotective agents of red pitaya (Hylocereus polyrhizus) fruit, two thermal processing methods for this fruit were selected, and biologically active properties of fruits (phenolic content, scavenging activity and soluble dietary fibre) were measured. Pitaya cooked in oven at 95°C for 30 min had low phenolic content (62%, p<0.05) and scavenging activity (32%, p<0.05) with almost intact soluble dietary fibre content (92%, p = 0.993). Pitaya cooked in oven at 105°C for 60 min had low phenolic content (60%, p<0.05), scavenging activity (24%, p<0.05) and soluble dietary fibre content (42%, p<0.05). These two differently treated extracts of red pitaya (cooked at different temperatures for different duration of time) as well as fresh fruit were fed as supplement to hypercholesterolemic rats during a 6-week treatment in a curative study with the intention of finding the potential cardioprotective compounds of red pitaya. The results showed that treatments in different groups caused no significant change in serum triglyceride content. The fresh pitaya improved total and LDL-cholesterol, glucose level and serum antioxidant power in rats significantly (p<0.05). Likewise, serum total and LDL-cholesterol were significantly decreased by atorvastatin treatment (p<0.05). Moreover, atorvastatin treatment increased the serum total antioxidant power significantly (p<0.05). Supplementation of pitaya cooked in oven at 95°C for 30 min or at 105°C for 60 min did not significantly increase serum antioxidant power, and also the hypocholesterolemic effects were not significant. Although the components of red pitaya responsible for hypocholesterolemic effect are not completely clear, this study attributed this effect of red pitaya to be primarily due to its polyphenols and antioxidant contents.

Red pitaya, tropical fruits, cardioprotective compounds, hypercholesterolemia, curative study, polyphenols, antioxidant activity, soluble dietary fibre, Sprague-Dawley, male rat