Bioavailability of vitamins C, E and pro-vitamin A in extracts of fluted pumpkin (Telfairia occidentalis), tomato (Lycopersicum esculentum) and eggplant (Solanum melongena)

Abstract

Background: Vegetables, an important source of our diet contain some beneficial antioxidants.

Objectives: This study evaluated pro-vitamin A, vitamins E and C content of extracts of tomato, fluted pumpkin and eggplant and bioavailability of these antioxidants in rats.

Methods: The antioxidant content of the vegetable aqueous extracts, serum, liver, faecal and urinary antioxidants were determined using standard procedures.

Results: The aqueous extract of tomato had the highest pro-vitamin A content (0.33±0.01mg/100ml) and fluted pumpkin extract had the highest vitamins E and C (5.07±0.04mg/100ml) and (40±0.02mg/100ml) respectively. The faecal and urinary vitamin A for the rats fed vegetable extracts was higher than their intake. Rats fed tomato extract consumed more (0.09±0.02mg) pro-vitamin A and had the highest liver vitamin A (2.33±0.01mg). This group of rats also had the least vitamin E intake (0.20±0.00mg) with high urinary (0.34±0.01mg) and faecal (0.65±0.01mg) excretions leading to negative vitamin E retention. In addition, rats fed tomato extracts consumed highest vitamin C (10.10±0.80mg) which contributed to the high serum concentration of vitamin C (0.85±0.00mg).

Conclusion: Further studies on the specific bioavailability of vitamin A and vitamin E (?-, ?, ?- and ?- tocopherols) differentials in the vegetable extracts should be carried out.