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

► A polysaccharide (GP-I), with a molecular mass of 33 kDa, was purified from this plant. ► GP-I exhibited sensitive growth inhibition and induced apoptosis in HaCat cells. ► TNF-α, as a vital proinflammatory cytokine in psoriasis, was reduced in HaCat cells by GP-I. ► There was no growth inhibition induced by GP-I on the growth of Hs-68. ► GP-I was a promising antipsoriatic agent to be developed for psoriasis treatment.