Optimized production and characterization of ulvan from Ulva Lactuca with in vitro biological activities

Abstract

Abstract Bioactive sulfated polysaccharides, including ulvan, known for their broad therapeutic uses, are abundant in green algae. In this study, Ulva lactuca ulvan was produced under optimized conditions involving temperature, pH, extraction time, and solvent concentration adjustments. The extracted ulvan ( U. lactuca ulvan, ULU) was identified using analytical methods such as Fourier Transform Infrared Spectroscopy (FTIR), Thermogravimetric Analysis (TGA), X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), High-Performance Liquid Chromatography (HPLC), and Energy-Dispersive X-ray Spectroscopy (EDX) to confirm its compositional stability. A maximum yield of 23.33 ± 0.28% was achieved, with rhamnose as the main sugar, accounting for 14.10 µg/g of dried weight. Ulvan’s biological activities are likely influenced by its sulfate content, which measured 35.35 ± 0.25%. The bioactivity of ULU was tested for anticancer, antioxidant, and antiviral effects. ULU showed significant anticancer activity against pancreatic cancer cells (Panc-1). At a dose of 1000 µg/ml, ULU achieved an inhibition rate of 86.15%, with an IC 50 of 123.51 ± 10.95 µg/ml, demonstrating substantial effectiveness in inhibiting pancreatic cancer cell growth. In antioxidant tests, ULU exhibited moderate free radical scavenging activity against DPPH, with a maximum inhibition rate of 88.31% ±2.64% at 1000 µg/ml and an IC 50 of 263.73 ± 9.41 µg/ml. These results highlight the benefits of improved extraction and optimized conditions, indicating that ULU has potential as a natural antioxidant, though with modest efficacy compared to ascorbic acid. ULU also demonstrated limited antiviral activity, with an inhibition rate of 40.25 ± 2.61% against Hepatitis A virus (HAV) at 50 µg/ml, as measured by the MTT assay. The cytotoxicity test showed a CC₅₀ value of 230.53 ± 2.09 µg/ml, indicating a moderate safety margin. Despite its limited antiviral effectiveness, further research into combining ULU with other drugs or exploring synergistic effects could enhance its therapeutic potential.