Phytochemical and Antioxidant Properties of some species of Passiflora edulis
Wekiya, Brian Cyrus
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Passiflora edulis is a fruit consumed by people across the world and studies have associated consumption of fruits with the prevention of chronic diseases such as cancer, cardiovascular diseases and diabetes. In Uganda there are different types of these fruits and little information is available about their bioactive components. This research was therefore carried out to analyze different phytochemicals and antioxidant activity of three types of passiflora edulis fruits. The fruit juice was obtained from the different types of fruits and used for different tests. They were identified as Species 1, Species 2 and Species 3 due to inability of assigning them botanical names as most of these are modified. Local names were as well assigned to them that is Purple, Masaka and Kabale for species 1, 2, 3 respectively. The presence of phytochemicals was determined using standard procedures. Total polyphenols were extracted using 70% ethanol at 70oC and amount analyzed using a spectrophotometric technique based on Folin Ciocalteau method. Gallic acid was used as a standard compound and the total polyphenols were calculated and expressed as mg/g Gallic acid equivalents and were found to be 105.53±1.7mgGAE/100g, 104.57±0.3mg GAE/100g, 84.14±2.0mgGAE/100g of juice of species 1, 2, 3 respectively. Beta carotene extract was prepared from juice using hot 95% ethanol at 60oC in a water bath for 30 minutes and extracted in a separating funnel using petroleum ether. The amount of beta carotene was found to be 769.35±58.55µg/100g, 1105.85±65µg/100g,469.25±53.85µg/100g for juice of species 1, 2 and 3 respectively. The amount of vitamin C was assayed by volumetric method using standard solution of DCPIP. Ascorbic acid was found to be 6.154mg/100g,10.277mg/100g,4.123mg/100g for juice of species 1, 2, 3 respectively. The antioxidant capacity was determined using DPPH scavenging free radical potential and IC50 were 29.6±3.7mg/ml,123.9±3.9 mg/ml, 83.3±0.7 mg/ml for species 1, 2, 3 higher than ascorbic acid 14.1±0.8mg/ml. Therefore, ascorbic acid had the highest antioxidant activity as compared to fruit species that were used. In Conclusion, Species 2 (Masaka) is a better source of beta carotene, polyphenols, vitamin C and antioxidant capacity as compared to the other two species (Purple and Kabale). Species 1(Purple) had the highest antioxidant activity compared to Species 2(Masaka) and 3(Kabale).