Coastal forests of Tanzania are endowed with edible wild fruit plant species that can be used as dietary supplements to humans. The antioxidant activities of two common wild fruits Vitex doniana and Saba comorensis from two coastal regions (Tanga and Coastal) were determined using diphenly-1-picrylhydrazyl (DPPH). The antioxidant activities for V. doniana ranged between 71.0 ± 0.4 and 49.11 ± 0.04 in fruit samples from Tanga and 65.6 ± 0.1 and 48.3 ± 0.1 in fruit samples from Coast region. The activity in S. comorensis ranged between 56.28 ± 0.02 and 44.22 ± 0.03 for fruit samples from Coast region and between 61.77 ± 0.00 and 51.8 ± 0.1 for fruit samples from Tanga. However, the differences in antioxidant activity between fruits from the two regions were not significant (P > .05) as they performed on the same latitudinal gradient influenced by the similar coastal habitat conditions. Data indicated a positive correlation between concentration of the fruit extracts and the free radical scavenging capacity where higher antioxidant activity was observed at 1000 µg/ml fruit extract concentration than in 62.5 µg/ml. The regression analysis indicated significant influence of the wild fruit extracts on antioxidant activity in fruit samples from Tanga than it was in fruit samples from Coast regions. The considerable antioxidant activity depicted by the fruits of both V. doniana and S. comorensis indicated their neutraceutical potential as natural antioxidants.

The fruits of V. doniana and S. comorensis were randomly collected from Pwani and Tanga regions. Laboratory analysis was done using the methods described by the Association of Official Analytical Chemists AOAC (1995 and 2000). The amount of protein was 7.13 ± 0.04% and 21.73 ± 0.02% in V. doniana fruits while the fat contents were 2.4 ± 0.00% and 1.9 ± 0.10% in V. doniana fruits. The amount of fats in S. comorensis fruits ranged from 0.00–0.01% for the fruit samples from both Pwani and Tanga regions, however the differences was not statistically significant (P > 0.05). The amounts of carbohydrates in V. doniana 23.98 ± 0.20% and in S. comorensis fruit samples (23.81 ± 0.38%) from Pwani Region were not statistically difference. The differences can be attributed to environmental and soil factors. S. comorensis fruit samples from Tanga had ash 4.20 ± 0.01% and moisture content 70.97 ± 0.04%. These values were higher than those observed for S. comorensis fruit samples from Pwani. The amount of ash is indicative of potential elements like sodium and potassium which are beneficial in human health for the development of bones. These fruits have significant amounts of carbohydrate and protein and hence healthy for consumption as part of human diet.