Purification of a polysaccharide from Gynostemma pentaphyllum Makino and its therapeutic advantages for psoriasis

In current study, a water-soluble polysaccharide (GP-I), with a molecular mass of 33 kDa, was purified from Gynostemma pentaphyllum. Gas chromatography (GC) analysis suggested that it was composed of Glc, Gal, Man, Rha and Ara with a ratio of 5.3: 4.2: 3.0: 0.7: 0.8. The GP-I (25, 50, 100, 200 and 400 μg/ml) was found to have significant anti-proliferative effects on HaCat cells in a dose-dependent manner, as measured by MTT assay. On the contrary, Trypan blue exclusion experiment indicated that GP-I had no cytotoxicity to HaCat cells. Moreover, the decrease of mitochondrial membrane potential (MMP) in GP-I treated cells was also observed, indicating apoptosis in HaCat cells. Besides, tumor necrosis factor-α (TNF-α), a vital pro-inflammatory cytokine in psoriasis, in the supernatant of HaCat cells was dramatically reduced by GP-I. Collectively, these findings suggested that GP-I was a promising agent to be developed for psoriasis treatment in clinical therapy.