Combretum quadrangulare Kurz has long been considered a precious herb, which is very useful in treating
various kinds of diseases on humans and aquatic animals. The study was conducted to evaluate the antioxidant and
antibacterial effects of ethanol extracts from Combretum quadrangulare Kurz fruit collected in Kien Giang province,
Vietnam. Research results showed that ethanol extract from Combretum quadrangulare Kurz fruit contained bioactive
compounds such as alkaloids, flavonoids, steroids and triterpenoids, tannins, and phenolics. In the ethanol extract
of Combretum quadrangulare Kurz fruit, the content of total phenolics and total flavonoids were recorded at 230.89 ±
2.36 mg GAE/g extract and 165.35 ± 5.80 mg QE/g extract, respectively. The survey results of in vitro antioxidant
capacity through four methods of DPPH, ABTS●+, RP and TAC indicated that the extracts of Combretum
quadrangulare Kurz fruit showed its good activity with EC50 values of 103.90 ± 0.40 µg/mL, 24.18 ± 0.06 µg/mL, 128.58 ± 0.20 µg/mL and 79.30 ± 1.40 µg/mL, respectively. The investigation results of in vivo antioxidant activity on fruit fly Drosophila melanogaster model showed that the fruit flies raised in the medium supplemented with 1 mg/mL extract of Combretum quadrangulare Kurz fruit had in vivo antioxidant effect under the conditions of oxidative stress
induced by Paraquat and H2O2. In addition, the extract from Combretum quadrangulare Kurz fruit also had the
ability to against the bacteria causing diseases in aquatic animals such as Edwardsiella ictaluri, Aeromonas hydrophila
and Streptococcus agalactiae.