Chemical characterization of sulfated polysaccharides from Gracilaria gracilis and Ulva lactuca and their radical scavenging, metal chelating, and cholinesterase inhibitory activities

Figures & data

Table 1. Chemical composition of polysaccharides

Parameter	PGCL	PULV
Total carbohydrate (g/100g)	33.52 ± 1.53^a	27.41 ± 2.11^b
Total protein (%)	1.49 ± 0.6^a	4.3 ± 0.56^b

Values represent means of triplicate readings; values with the same letter along the same row are not significantly (P > 0.05) different. PGCL: Gracilaria gracilis; PULV: Ulva lactuca.

Table 2. Average relative values (% weight) for elemental distribution of polysaccharides

Element	PGCL	PULV
C	29.49 ± 1.06^a	24.58 ± 0.67^b
O	43.91 ± 0.50^c	47.87 ± 0.40^b
Na	0.75 ± 0.09^a	4.56 ± 0.14^b
Mg	1.09 ± 0.11^a	2.21 ± 0.10^b
Al	0.08 ± 0.07^c	0.16 ± 0.04^c
Si	7.44 ± 0.19	-
P	2.37 ± 0.30^a	0.63 ± 0.05^b
S	5.10 ± 0.24^a	9.67 ± 0.16^c
Cl	1.22 ± 0.09^b	1.61 ± 0.07^c
K	7.18 ± 0.0.26^a	6.35 ± 0.17^b
Ca	1.36 ± 0.0.26^a	2.37 ± 0.19^b

Values represent means of triplicate readings; values with the same letter along the same row are not significantly (P > 0.05) different. PGCL: G. gracilis; PULV: U. lactuca

Figure 1. EDX spectra of polysaccharides from G. gracilis (a) and U. lactuca (b) and the intensity of corresponding elements detected

Figure 2. FTIR spectra of PGCL (G. gracilis) and PULV (U. lactuca)

Table 3. Sugar composition (%) of polysaccharides

Monosaccharides	PULV	PGCL
Galactose	4.47	3.33
Ribose	5.11	7.03
Arabinose	3.79	6.89
Rhamnose	19.98	-
Xylose	1.01	0.06
Glucose	0.16	6.16
Mannose	0.25	-
Allose	-	0.21
Galactonic acid	-	0.22
Glucopyranuronic acid	-	0.33
Arabinonic acid	-	0.34

- Not determined.

Figure 3. GC-MS chromatogram of polysaccharide from G. gracilis.

Figure 4. GC-MS chromatogram of polysaccharide from U. lactuca.

Figure 5. Radical scavenging and metal chelating activities of polysaccaharides from some seaweeds. PGCL: Gracilaria gracilis; PULV: Ulva lactuca; GAC: Gallic acid

Table 4. IC₅₀ values (µg/mL) cholinesterase inhibitory activity of PGCL and PULV

Parameter	PGCL	PULV	GAL
AChE	132.73 ± 2.44^a	106.93 ± 1.45^b	54.41 ± 2.52^d
BChE	124.93 ± 2.24^a	93.45 ± 2.33^b	55.85 ± 1.23^c

Values represent means of triplicate readings; values with the same letter along the same row are not significantly (P > 0.05) different. PGCL: Gracilaria gracilis; PULV: Ulva lactuca.; GAL: Galathanmine.

Figure 6. Cholinesterase inhibitory activities of polysaccharides from some seaweeds. PGCL: G. gracilis; PULV: U. lactuca; GAL: galanthamine