• Sequential extraction of Caulerpa spp. yielded fractions with distinct stability • C. lentillifera non-polar extracts retained >90% flavonoids vs 68-93% polar loss • C. racemosa hexane ABTS increased 16-fold vs 3-fold in ethanol post-digestion • FTIR-PCA distinguished Caulerpa fractions by glycosylation (61-72% variance) . Conventional single-solvent extraction yields heterogeneous bioactive profiles with limited digestive stability. This study investigated sequential extraction effects on phytochemical composition, antioxidant activity, and bioaccessibility of Caulerpa lentillifera and C. racemosa var. corynephora , edible green seaweeds consumed in Southeast Asia. Dried seaweeds were sequentially extracted using hexane, ethyl acetate, and 70% ethanol, followed by in vitro gastrointestinal digestion. Total phenolic content (TPC) increased substantially post-digestion, with C. racemosa var. corynephora hexane extract achieving 413.00 mg GAE/100 g DW and demonstrating the highest bioaccessible fraction. Conversely, total flavonoid content (TFC) decreased in polar extracts (68-93% loss) but remained stable in C. lentillifera hexane and ethyl acetate extracts (>90% retention), consistent with non-glycosylated profiles. Antioxidant responses varied by mechanism: DPPH activity was best preserved in water extracts through matrix synergy, while ABTS showed dramatic increases (3-16-fold) inversely related to baseline values, and FRAP demonstrated balanced enhancement in sequential extracts. FTIR-PCA (61-72% variance explained) confirmed chemical differentiation driven primarily by glycosylation status rather than lipophilicity, with hexane and ethyl acetate fractions co-clustering as non-glycosylated compounds. Species-specific differences included higher ash content in C. racemosa var. corynephora (49.36% vs. 43.58%) and elevated protein in C. lentillifera (18.55% vs. 15.01%). Sequential extraction enables targeted bioactive isolation with predictable digestive stability based on glycosylation status, supporting development of seaweed-based functional foods with enhanced nutritional value. .
Kachenpukdee et al. (Wed,) studied this question.