Mechanistic pathways underlying the antidiabetic potential of sea grapes (Caulerpa spp.): a systematic review across experimental and human evidence

Sea grapes ( Caulerpa lentillifera and Caulerpa racemosa ) are edible green seaweeds of interest for glycaemic control, but the evidence is dispersed across heterogeneous assays and primarily in preclinical models. We conducted a PRISMA 2020 systematic review (PROSPERO CRD420251121741), searching PubMed, Scopus, and Web of Science from inception to 1 August 2025, with citation chasing. Studies evaluating sea-grape foods/processed products, extracts/fractions for glycaemic outcomes or diabetes-relevant mechanisms were synthesised using a tier-aware hierarchy (enzyme/cell/animal/human) reflecting their proximity to glycaemic regulation. Forty-nine studies were included, dominated by animal and enzyme-tier evidence with three human studies. Findings were most consistent for proximal mechanisms—α-glucosidase and α-amylase inhibition and attenuation of postprandial glycaemic excursions—whereas insulin sensitivity and glucose uptake pathways were supportive but preclinical-only. Antioxidant and anti-inflammatory outcomes were common but less diabetes-specific and rarely confirmed in humans. Sea grapes show promise for postprandial glycaemic control, but translation into functional-food applications requires food-grade standardised preparations, compositional characterisation, harmonised outcomes, and adequately powered meal-challenge trials.