Fig. 2

Immunomodulating activity of S. cordifolia ion exchange and size fractionated aqueous fractions (SCAF) on lymphocytes (splenocytes) in vitro. A Lymphoproliferation in response to SCAF0–5 treatment was measured using Alamar blue and results were expressed as proliferation index (OD treated cells divided by OD negative control cells). B Antibody secretion (IgG) following incubation with SCAF0–5 was measured by ELISA and results were expressed as optical density at 450 nm. Concanavalin A (Con A) was used as a positive control at a pre-determined optimal final concentration of 5 μg/ml and complete media was used as a negative non-proliferative control (0 μg/ml). All statistical analysis was carried out using a one-way ANOVA with Tukey’s Multiple Comparison Test to compare differences between samples and negative controls (*p < 0.05, **p < 0.01, ***p < 0.001, n = 3). Groups: SCAF 0 (crude polysaccharide fraction of S. cordifolia); SCAF 1: Low ionic strength < 100 kDa; SCAF 2: medium ionic strength and between 10 and 100 kDa; SCAF 3: medium ionic strength and > 100 kDa; SCAF 4 high ionic strength and between 10 kDa–100 kDa; SCAF 5: high ionic strength and < 100 kDa