Extraction, Yield, and Phytochemical Screening of Ethanolic Extract of Red Algae (Gracilaria gracilis)

Abstract

Red algae (Gracilaria gracilis) is a marine macroalgae (Rhodophyta) widely distributed along Indonesian coastal waters, recognized for its diverse secondary metabolites with pharmacological potential. This study aimed to determine the extraction yield and identify secondary metabolite classes in the 96% ethanolic extract of G. gracilis obtained by maceration. Dried algal simplicia (1,500 g) was macerated with 96% ethanol (1:5 w/v) for 3 × 24 h with periodic agitation, filtered through Whatman No. 42, and concentrated using a rotary vacuum evaporator at 40 °C. Phytochemical screening was performed qualitatively for flavonoids (Mg/HCl), alkaloids (Mayer reagent), phenolics (FeCl₃ 5%), steroids (Liebermann–Burchard), saponins (foam stability), and tannins (FeCl₃ 1%). Maceration yielded 84.3 g of thick extract (yield: 5.62%). Flavonoids, phenolics, steroids, saponins, and tannins were confirmed present; alkaloids were not detected. These findings establish a phytochemical baseline for G. gracilis, supporting further bioactivity studies and pharmaceutical development of this species.