Therapeutic Evaluation of Alginate from Brown Seaweeds: A Comparative Study of Turbinaria ornata and Hormophysa cuneiformis

Abstract

Background: Alginate is a naturally occurring anionic polysaccharide extracted from brown marine algae and widely explored for biomedical applications due to its biocompatibility and functional versatility. This study aims to extract and compare alginates from two Red Sea brown algae, Turbinaria ornata (TA) and Hormophysa cuneiformis (HA), and to evaluate how structural differences influence their therapeutic properties. Methods: Alginate was isolated by sequential acid-alkaline extraction and characterized using FTIR, XRD, TGA, elemental analysis, and HPLC. Biological activities were assessed through antioxidant, anti-inflammatory, antidiabetic, neuroprotective, and hepatoprotective assays, supported by molecular docking and gene ontology interaction analysis. Results: Distinct physicochemical variations were observed between HA and TA. TA exhibited stronger antioxidant (IC₅₀ = 25.89 µg/mL), anti-inflammatory (COX-1 IC₅₀ = 69.61 µg/mL), antidiabetic (α-amylase IC₅₀ = 45.14 µg/mL), and hepatoprotective activities (IC₅₀ = 118.21 µg/mL), whereas HA displayed superior neuroprotective potential through butyrylcholinesterase inhibition (IC₅₀ = 39.01 µg/mL). Molecular docking supported the in vitro findings by confirming interactions with key protein targets associated with oxidative stress and metabolic pathways. Conclusions: Structural variation between species-derived alginates directly impacts their biological activities. TA represents a promising candidate for metabolic and anti-inflammatory therapies, while HA may be more suitable for neuroprotective interventions. These results emphasize the importance of source-specific alginate selection for developing targeted pharmaceutical applications.

Keywords: COX-1 inhibition; anti-inflammatory; antidiabetic; antioxidant; hepatoprotective; molecular docking; neuroprotective; polysaccharide.

Figure 1

FTIR spectra of alginate extracted from Hormophysa cuneiformis (HA) and Turbinaria ornata (TA). Dashed lines indicate identical peak positions observed in both samples.

Figure 2

X-ray diffraction (XRD) patterns of alginate extracted from (a) Hormophysa cuneiformis and (b) Turbinaria ornata.

Figure 3

Thermogravimetric analysis (TGA) curves of alginate extracted from (a) Hormophysa cuneiformis (b) Turbinaria ornata, showing thermal decomposition behavior as a function of temperature.

Figure 4

Regulatory cellular classes targeted by alginate.

Figure 5

Key cellular events and Gene Ontology (GO) biological processes associated with alginate treatment were analyzed using Metascape.

Figure 6

Gene-gene interactions and colocalization of genes affected by Alginate predicted by GeneMANIA.

Figure 7

Inhibition of butyryl choline esterase (BChE) by alginate extracted from Hormophysa cuneiformis and Turbinaria ornata compared with rivastigmine. Data are presented as mean ± SD (n = 3). Different letters above the bars indicate statistically significant differences among groups according to one-way ANOVA followed by Tukey’s post hoc test (p < 0.05).

Figure 8

Inhibition of COX-1 activity by alginate extracted from H. cuneiformis (HA) and Turbinaria ornata (TA) compared with Diclofenac. Data are presented as mean ± SD (n = 3). Different letters above the bars indicate statistically significant differences among groups according to one-way ANOVA followed by Tukey’s post hoc test (p < 0.05).

Figure 9

Inhibition of α-amylase activity by alginate extracted from H. cuneiformis (HA) and T. onata (TA) compared with Acarbose. Data are presented as mean ± SD (n = 3). Different letters above the bars indicate statistically significant differences among groups according to one-way ANOVA followed by Tukey’s post hoc test (p < 0.05).

Figure 10

Inhibition of DPPH activity by alginate extracted from H. cuneiformis (HA) and T. onata (TA) compared with Ascorbic acid standard. Data are presented as mean ± SD (n = 3). Different letters above the bars indicate statistically significant differences among groups according to one-way ANOVA followed by Tukey’s post hoc test (p < 0.05).

Figure 11

Inhibition of α-amylase activity by alginate extracted from H. cuneiformis (HA) and T. onata (TA) compared with Silymarin. Data are presented as mean ± SD (n = 3). Different letters above the bars indicate statistically significant differences among groups according to one-way ANOVA followed by Tukey’s post hoc test (p < 0.05).