The antioxidant properties, safety and bioavailability studies of a new developed product - mixed fruit juice (MFJ)

Abstract

The consumption of fruits has been correlated with better health and prevention of several diseases. Phytochemicals such as phenolic compounds and vitamins in fruits are believed to act as antioxidants that could reduce oxidative damage to biomolecules by modulating reactive free radicals. Since Malaysia is rich in a wide variety of tropical fruits, we should examine them in producing healthy and tasty juices. A new fruit juice named Mixed Fruit Juice (MFJ) was formulated from a combination of three tropical fruits (soursop, mango and kasturi lime).There is no information regarding the antioxidant activity, antioxidant compounds, safety parameters and bioavailability of the bioactive compounds in this product. Therefore, this study focuses on the measurement of antioxidant activity by using the common chemical methods (TPC, FRAP, DPPH) followed by the identification and quantification of phenolic acids by GC-MS. The safety and in vivo antioxidant effects of MFJ were done in normal and aged rats. Human intervention study was established in order to determine the bioavailability of the phenolic compounds in MFJ. Results show that MFJ contained 23.50±1.57 mg GAE/100g (TPC) and 18.77±0.46 mg TE/100g (FRAP) and DPPH value at 83.66±0.84%. The 28-day sub-chronic toxicological test showed no systemic toxicity attributable to the MFJ administration in normal rats. There was no significant effect in the haematological profiles and both liver and kidney function tests when compared to control rats. Furthermore, MFJ was able to modulate the antioxidant enzymes such as SOD, GPx and CAT in the blood and tissues (liver and brain) of aged rats. Aged condition reduces all the antioxidant enzymes in blood and tissues. The supplementation of MFJ in aged rats had increased the TAS, GPx and SOD values in the blood by 14%, 30% and 104%, respectively. In the liver, the CAT and SOD also increased by 33% and 22%, respectively. In addition, substantial increment was observed in the activity of enzymes in the brains of aged rats. GPx was found to increase by 75% in aged rats after receiving MFJ. Moreover, SOD had increased more than 100% in aged rats after receiving MFJ. In the bioavailability study, phenolic acids (p-coumaric acid, ferulic acid and caffeic acid) were found in conjugated form (plasma and urine) and mainly further metabolized to hippuric acid that was excreted in the urine after one hour of MFJ ingestion. Hippuric acid, the main metabolite in urine was found to increase by 25% compared to baseline. In addition, ferulic acid which is known as an antioxidant compound was also recovered in the urine at 16% in one hour. Thus, it is suggested that the absorption of phenolic acids may occur in the small intestine. In conclusion, this current study shows that MFJ was able to exert the antioxidant effects due to the content of phenolic acids which was proven bioavailable in humans.