2.2. Extraction of crude sulfated polysaccharide fractions
SPs fractions S1 and S2 were extracted from the red seaweed Pterocladia capillacea. Twenty grams of the dried, ground seaweeds were suspended in 400 mL of distilled water, adjusted to pH 4 using 1N HCl solution and then shaken for 48 h at room temperature using a rotatory shaker (VWR advanced digital shaker, 5000 ADV). The extracts were filtered through cheese cloth and neutralized to pH 7 with a saturated solution of Na2CO3, then dialyzed against distilled water in dialysis bags for 48h. The dialyzed solution was then centrifuged (Heraeus-Christ, GMBH336 Osteode Ma Harz No.39189) at 12000 × g for 15 min at −10 °C, and the supernatant containing the extracted polysaccharide was then treated with 4 volumes of absolute ethanol. The precipitated product which is a high molecular weight fraction S1(M), was collected after centrifugation. Both S1(M) and the supernatant which is a low molecular weight fraction S2(M) were then lyophilized, weighed and stored.