Nutritional and phytochemical screening, and total phenolic and flavonoid content of Diplazium esculentum (Retz.) Sw. from Philippines

The nutritional content and phytochemical composition of Diplazium esculentum (Retz.) Sw., known as “pako” in the Philippines, were determined to ascertain its use as an ingredient in culinary dishes in the country. Pako, also known as fiddlehead fern, is patronized by locals as an ingredient in vegetable dishes and salads. Standard AOAC methods showed that the fresh plant samples contain 91.82 % moisture, 1.42 % ash, 0.28 % crude fat, 0.87 % crude protein, and 0.72 % crude fiber while oven dried plant samples contain 17.39 % ash, 3.40 % crude fat, 10.67 % crude protein, and 9.06 % crude fiber. Qualitative phytochemical screening detected the presence of alkaloids, reducing sugars, anthraquinones, anthranol glycosides, cyanidins, phenols, saponins, and proteins in both the ethanolic and aqueous leaf extracts, while cardiac glycosides, leucoanthocyanins, phytosterols, diterpenes, and triterpenes were only detected in the ethanolic extract. Using the Folin-Ciocalteu method, the total phenolic contents were 125.60 ± 13.44 and 11.65 ± 0.87 mg gallic acid equivalents per 100 g air-dried sample for the ethanolic and aqueous extracts, respectively. The corresponding total flavonoid contents were 110.81 ± 11.16 and 16.21 ± 0.72 mg quercetin equivalents per 100 g air-dried sample for the ethanolic and aqueous extracts, respectively.