Spirulina-derived peptide-calcium chelates: Process optimization, structural stability, and synergistic lipid...

Area of Science:

• Biochemistry
• Nutritional Science
• Pharmacology

Background:

• Peptide stability and bioavailability are critical for therapeutic efficacy.
• Spirulina platensis is a source of bioactive peptides with potential health benefits.
• Lipid-lowering agents are sought after for managing metabolic disorders.

Purpose of the Study:

• To develop a stable peptide-calcium chelate (SPH-Ca) from Spirulina platensis hydrolysates.
• To evaluate the lipid-lowering activity and stability of SPH-Ca.
• To elucidate the mechanisms underlying SPH-Ca's effects in vivo.

Main Methods:

• Response surface methodology for optimizing chelation conditions.
• FT-IR and XRD for structural characterization of SPH-Ca.
• In vitro pancreatic lipase inhibition assays.
• In vitro simulated gastrointestinal digestion.
• High-fat diet-induced Caenorhabditis elegans model for in vivo studies.
• Analysis of triglyceride, total cholesterol, and gut microbiota composition.

Main Results:

• Optimized SPH-Ca achieved 52.9% calcium binding capacity.
• SPH-Ca demonstrated potent pancreatic lipase inhibition (IC50 = 2.02 mg/mL) via non-competitive mechanism.
• SPH-Ca retained 68.7% inhibitory activity after simulated digestion, showing enhanced stability.
• In C. elegans, SPH-Ca reduced triglycerides by 75% and total cholesterol by 55%.
• SPH-Ca treatment led to 100% survival rate, indicating no toxicity.
• Lipid reduction was linked to AMPK pathway activation and gut microbiota modulation (enrichment of Paracoccus marcusii).

Conclusions:

• SPH-Ca is a stable and effective peptide-calcium chelate with significant lipid-lowering properties.
• The enhanced stability and bioavailability of SPH-Ca contribute to its therapeutic potential.
• SPH-Ca represents a promising functional ingredient for managing hyperlipidemia and related metabolic conditions.