Decalepis hamiltonii (Swallow root) has been used extensively for medicinal properties in Ayurveda, the ancient Indian system of medicine. In the present study, we isolated pectic polysaccharides from D. hamiltonii root and for better biological activities, polysaccharides were modified using acid precipitation method. The Modified Swallow Root Pectic Polysaccharide (MSRPP) had higher polyuronic content and lower neutral sugar content. The MSRPP contains main neutral sugars were arabinose and galactose and homogeneity and revealed to be as arabinogalacturonan type having galacturonic acid and arabinose back bone with galactose branching analyzed by FT-IR, GC-MS and NMR analysis. The effects of MSRPP on murine macrophages (RAW) demonstrated potent immunomodulatory activity, induced production of reactive oxygen species, nitric oxide, TNFα, and IL-6. Furthermore, modulation of macrophage function by MSRPP was mediated through activation of NFĸB. Together, our results showed that swallow root enriched source of varieties of bioactive compounds and MSRPP as an immunotherapeutic adjuvant and anti-metastatic activities.