Optimum conditions for Radix Rehmanniae polysaccharides by RSM and its antioxidant and immunity activity in UVB mice

Optimization of Radix Rehmanniae polysaccharides (RRPs) was done using response surface methodology (RSM). Optimum extraction conditions for maximizing the determination of Radix Rehmanniae polysaccharides were: extraction temperature 100 °C, extraction time 2 h and ratio of liquid to solid 6. The model had a satisfactory coefficient of R2 (=0.9815) and was verified experimentally. The results suggested that the conditions were mild and useful for extraction yield of Radix Rehmanniae polysaccharides. Pharmacological experiment showed that Radix Rehmanniae polysaccharides could enhance serum interleukin-2 (IL-2), interleukin-4 (IL-4) and interleukin-10 (IL-10) levels, skin glutathione (GSH), superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-Px) activities, and decrease skin malondialdehyde (MDA) level in ultraviolet B (UVB) ray treated mice, this study suggests that Radix Rehmanniae polysaccharides extract may prove to be a useful therapeutic option in the reversal of skin diseases.