Fruits are rich in fiber and antioxidant compounds that can prevent and treat health disorders related to oxidative stress caused by high-fat high-cholesterol diet (HFHCD). Bouea macrophylla is a tropical fruit plant with edible juicy fruits. In this study, we conducted experiments to prove the effectiveness of B. macrophylla fruit juice (BMFJ) as an antioxidant agent in rats fed with HFHCD. Male Sprague Dawley rats were fed with HFHCD for 100 days and simultaneously orally supplemented with BMFJ. Atorvastatin was used as a positive control. At the end of the experiment, the blood and hepar were collected and assayed for malondialdehyde (MDA). The in vitro antioxidant activity of BMFJ was also evaluated using the DPPH method. Total phenols and flavonoids contents were determined using Folin Ciocalteu and AlCl3 methods, respectively. Results of the experiments showed that total phenols and flavonoids in BMFJ were 570 mg GAE/g and 31.89 mg QE/g, respectively, and the IC50 of radical scavenging activity was 564.271 ppm. The in vivo antioxidant evaluation showed that supplementation of BMFJ significantly prevents the increase of MDA levels, both in serum and liver of rats fed with HFHCD. These findings clearly indicate that supplementation of B. macrophylla fruit juice significantly prevents oxidative stress in rats fed with high-fat high-cholesterol diets through attenuation of lipid peroxidation.

Ziziphus mauritiana is a plant species belonging to the Rhamnaceae family. It is commonly found in tropical and subtropical regions of Asia, and in Indonesia, this plant grows wild and thrives on the islands of Bali, Lombok and Sumbawa. The fruits of Z. mauritiana are edible, however, in Indonesia, it is underutilized and has very low economic value. To evaluate its possibility to be developed as a functional food, this study was conducted to determine the total phenolics and flavonoids, dietary fiber, and nutrients contained in the fruit juice of Ziziphus mauritiana. Total phenols and flavonoids contents were determined using Folin Ciocalteu and AlCl3 methods, respectively. The in vitro antioxidant activity of the juice was evaluated using the DPPH method. The content of soluble and insoluble dietary fiber was determined using the standard AOAC analysis method, and proximates analysis was conducted in accordance with SNI 01-2891-1992.  The results of this study revealed that freeze-dried juice of Z. mauritiana fruit has total phenols content of 1690 mg GAE/100g, total flavonoids of 15.10 mg QE/100g, soluble dietary fiber of 0.61%, and insoluble dietary fiber 2.03%. However, the antioxidant activity of Ziziphus mauritiana fruit juice was weak with IC50 328.54 ppm. The proximate analysis revealed the crude fiber in the freeze-dried fruit juice was 0.56%, carbohydrates 82.43%, protein 3.34%, fats 0.31%, ash 3.62%, and water 10.30%. In conclusion, Ziziphus mauritiana fruit juice has a high content of total phenolic substances, high dietary fiber, and high nutritional value, therefore it has a good potential to be developed as a functional food.