Phytochemical Composition and Antioxidant Activity of Edible Red Alga Hypnea musciformis from Bangladesh

Seaweeds have valuable pharmacological properties attributed to the presence of various bioactive compounds. In this study, the phytochemical composition and antioxidant activity of various crude extracts of Hypnea musciformis were determined. Phytochemical screening, Fourier transform infrared (FT‐IR) and Gas chromatography‐mass spectrometry (GC‐MS) analysis were performed to identify the chemical composition of the crude extracts. Antioxidant activity was assayed by total antioxidant capacity for phosphomolybdenum, 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH), 2,2‐Azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid (ABTS) and reducing power (RP) assays. The various extracts contained terpenoid, saponin, phlobatannin, cardiac glycosides, phenolics and flavonoids at varying concentrations. FT‐IR results confirmed the presence of phenols, carboxylic acid, ketones, ethers, aromatics, amides and sulfonates. GC‐MS of organic extracts showed that the extracts contain numerous high and low molecular weight compounds. Methanol extract showed the highest phenolic content and antioxidant activity measured by different assays such as phosphomolybdenum (8.2 mg ascorbic acid equivalent), DPPH (79.34%), ABTS (80.21%) and RP (2.36 absorbance at 700 nm) followed by butanol, chloroform and ethyl acetate. Furthermore, methanol and butanol extracts inhibited radical‐induced DNA damage. Practical Applications Hypnea musciformis is widely known source for carrageenan but phytochemical composition and functional activities of this seaweed have not been well studied. Extraction of functional compound depends on solvent and method employed. Results found that the extract showed the presence of diversified phytochemical composition with its potent antioxidant activity at varying degrees. Our results can be used in the future to identify, isolate and characterize the specific compounds responsible for antioxidant activity.