Phytochemical Screening, In vitro Antioxidant Activities and Zebrafish Embryotoxicity of Abelmoschus esculentus Extracts

Background: Abelmoschus esculentus (L.) Moench (A. esculentus) commonly known as okra is being used as a medicinal plant traditionally, due to its phytochemical content that exhibits significant biological activities. Objective: The present study was undertaken to determine phytochemicals, antioxidant activity and embryotoxic effects of hexane extract (HE), chloroform extract (CE), methanol extract (ME), and aqueous extract (AE) of A. esculentus cultivated in Malaysia. Materials and Methods: A. esculentus extracts were screened for the phytochemicals while in vitro antioxidant activities were evaluated by performing 1,1-diphenyl-2-picrylhidrazyl (DPPH) assay and reducing power assay. Meanwhile, the embryotoxicity were accessed by exposing zebrafish embryos to the extracts and developmental endpoint recorded with median lethal concentration (LC₅₀). Results: The phytochemical screening showed the presence of flavonoids, tannins, phenols, saponins, anthraquinones, alkaloids and reducing sugars. The highest phenolic content was obtained in the CE at 143.85 μg (GAE)/mg extract. Whereas the HE depicted the highest flavonoid content at 63.76 μg (QE)/mg extract. At 1000 μg/mL, ME showed the highest free radical scavenging activity at 28.86 % and reducing power at 0.271, in both DPPH and reducing power assay, respectively. While the CE presented a significant embryotoxic effect on zebrafish with the LC₅₀ at 236.07 μg/mL. The morphological malformation of embryos, scoliosis and pericardial oedema were observed at 500 μg/mL of HE and ME treatment. Conclusion: As a result, with various ranges of phytochemical compounds, antioxidant capacities and lower toxic effects of A. esculentus extracts may be efficient in reducing the inflammation precursors that drive chronic inflammatory illnesses.