Evaluation of the Chemical Compounds and Antioxidant and Antimicrobial Activities of the Leaves of Eichhornia crassipes (Water Hyacinth)

Background: Water hyacinth (WH) is an aquatic weed and one of the most productive plants on earth, causing serious environmental problems. Herein, some nutritional and phytochemical constituents of WH were investigated. Methods: Chemical analysis of Eichhornia crassipes was carried out to determine total ash, humidity, crude protein, fat, fiber, and carbohydrate contents. Total phenolic and total flavonoid contents of the hydro-methanolic and aqueous extracts of the plant were determined using the Folin Ciocalteu and aluminum chloride colorimetric methods, and HPLC was performed to quantify eight phenolic compounds. The antioxidant and antimicrobial activities of the extracts were also evaluated. Results: The dry matter, total ash, crude protein, crude fiber, nitrogen-free extract, and ether extract contents of WH constituted 9.4, 12.9, 24, 11.5, 49.9, and 1.7%, respectively. The total phenolic contents of the hydro-methanolic and aqueous extracts were 491.2 ± 31.9 and 258.3 ± 10.8 mg gallic acid equivalents/g of dried extract, respectively. The total flavonoid content of the hydro-methanolic extract (76.8 ± 7.8) was higher than that of the aqueous extract (46.1 ± 6). Ferulic acid was found to be the most abundant phenolic compound in both extracts. The antioxidant activities of the hydro-methanolic and aqueous extracts were determined to be 221.52 and 97.07 mg ascorbic acid equivalent/g dry weight, respectively. The aqueous and hydro-methanolic extracts showed the highest antibacterial activity against Escherichia coli, Pseudomonas aeruginosa, respectively. Conclusions: In conclusion, the present study indicated the applicability of WH as a natural source of antioxidants and antimicrobial agents.