In vitro Antioxidant and Antidiabetic Activities of Leaf and Flower Extracts from Bombax ceiba

Context: Bombax ceiba is belonging to the family Bombacaceae. Dried stamen of this plant is used as vegetable and food ingredients for people in the Northern part of Thailand. There are very few reports on the biological activities in this plant, especially the flower parts. Objectives: The present study aimed to demonstrate the phytochemical screening and in vitro antioxidant and antidiabetic activities of crude extracts from B. ceiba. Materials and Methods: The leaf and flower part of B. ceiba were extracted using different solvents including water, 50% ethanol, and 95% ethanol. The phytochemical constituents were determined using standard qualitative methods. Total phenolic content (TPC) and total flavonoid content (TFC) were analyzed by colorimetric methods. 2,2‑diphenyl‑1‑picrylhydrazyl (DPPH) radical scavenging assay, 2,2‑azino‑bis‑(3‑ethylbenzothaizoline‑6‑sulphonate (ABTS) assay, and ferric reducing antioxidant power (FRAP) assay were used to investigate the in vitro antioxidant and antidiabetic activities of the extracts. For in vitro antidiabetic activities, α‑glucosidase and α‑amylase inhibitory effects were tested. Results: Phytochemical screening indicated the presence of alkaloids, flavonoids, coumarins, saponins, tannins, terpenoids, and cardiac glycosides in this plant. The highest TPC and TFC were found in 95% ethanol flower extract (2.73 ± 0.064 mg gallic acid equivalent/g and 28.25 ± 2.33 mg quercetin equivalent/g, respectively.). However, the highest antioxidant activity (DPPH and ABTS + assay) was found in 95% ethanol leaf extract (0.012 ± 0.0003, 0.009 ± 0.0005 mg/mL, respectively.) and FRAP assay was found in 95% ethanol flower extract (349.27 ± 35.16 mg trolox equivalent/g). The highest α‑glucosidase and α‑amylase inhibitory activities were found in 95% ethanol flower extract (0.001 ± 0.0012 and 0.0002 ± 0.0001 mg/mL, respectively). Conclusion: The crude extracts from B. ceiba showed the potent in vitro antioxidant and antidiabetic activities, especially the flower extracts. These findings confirm the ethnobotanical uses of B. ceiba as food and medicinal plants. Further studies on biological and pharmacological activities of this plant in the animal model and clinical trials must be carried out to confirm the use in medical aspects.