Investigation of Total Phenolic, Total Flavonoid Contents and Antioxidant Activities of Karankoku (Acrostichum aureum L.) Under Different Extraction Conditions

Abstract

There are numerous wild plant species in Sri Lanka that are edible and capable of improving consumer health. Acrostichum aureum L. (Karankoku) is an important wild edible plant species found especially in Sabaragamuwa province in Sri Lanka and, its nutritional properties are still not well explored. This study was carried out to determine the nutrient composition, antioxidant activity in different crude extracts and to screen the phytochemicals of A. aureum. Water, ethanol, and chloroform were used to prepare the crude extracts. The antioxidant activities of crude extracts were tested via TPC, TFC, DPPH, ABTS, and FRAP assays. AOAC standards were used to determine the proximate nutritional composition including, ash, moisture, crude protein, crude fat, and crude fiber. In DPPH, ABTS, and FRAP assays, the highest antioxidant activity in crude extracts was found in water extract followed by ethanol and chloroform extracts. Preliminary phytochemicals screening for crude extracts was done to determine the presence of alkaloids, tannin, saponin, flavonoid, and carbohydrate, protein compounds. Moisture and ash contents of the fresh herb were 81.426% and 3.92%, while crude fat, crude protein, and crude fiber content were 2.61%, 11.49%, and 32.78% in dry weight basis. The results showed that most of the screened phytochemicals in A. aureum are potent antioxidants and have the capability of free radical scavenging. The water extract in crude showed the highest radical scavenging activities with the value of DPPH assay (IC50 at 0.6178±0.1496 mg/ml), ABTS assay (IC50 at 0.08390±0.00178 mg/ml), and FRAP assay (62.98±13.75 mg TE/g). There was a good correlation between phenolic, flavonoid compounds with antioxidant activities.