Characteristics of red macroalgae, Caloglossa beccarii DeToni from freshwater for food as safe and other applications in Thailand

Abstract

Caloglossa beccarii DeToni is a freshwater red algae which contains dark brown filament and lives on surface of rocks at the bottom of shallow stream in different parts of Thailand, especially, in the southern region. The acute toxicity, nutritional value, antioxidant activity and phytochemical properties for high potential edible alga were reported. Acute toxicity was examined with a single oral administration of the extract at a dose of 2 and 5 g.kg-1 body weight. Mortality, behavior, body weight, total food intake, and any abnormalities presented in visceral organs, were observed. The extract resulted in no mortality or abnormalities. Among proximate analysis, the algae were rich in mineral (calcium, potassium, manganese, iron and magnesium), carbohydrate (fiber and polysaccharide) and protein (arginine and leucine). It also offered a high level of vitamin C and linolenic acid. The antioxidant activities were shown in all extracts. The highest TPC, DPPH and ABTS activities were in aqueous (20.868 ±0.68 mgGAE.g extract-1), methanolic (IC50 = 0.086±0.01 mg.mL-1) and ethanolic extract (IC50 = 0.178 ±0.01 mg.mL-1). A potential source of phycocyanin and phycoerythrin was shown. These results indicated that C.beccarii contains various bioactive compounds which are safe with useful characters.