Antioxidant and Anticancer Activities of Extracts Derived from Four Kinds of Lichen

The antioxidant and anticancer activities of various extracts and crude polysac-charides derived from four kinds of medicinal lichen were evaluated preliminarily in this study. The antioxidation activities were detected by DPPH radical-scavenging,OH·radical-scavenging, and reducing power.Results showed that the methanol extracts of Lethariella cladonioides and Umbilicaria tornata had higher DPPH radical-scavenging ability (IC₅₀ = 0.7847 mg/mL and IC₅₀= 0.5595 mg/mL, respectively) than that of other extracts; the OH·radical-scavenging capacity of the methanol extract of Umbilicaria tornata (IC₅₀ = 0.5747 mg/mL) was higher than Vc (IC₅₀ = 0.6126 mg/mL); the OH·radical-scavenging capacity of the chloroform extract of Umbilicaria tornata, ethyl acetate extract of Lethariella cladonioides, and methanol extract of Thamnolia subuliformis were equal to Vc; the extracts derived from the four lichens all had a certain degree of reducing power, which were positively correlated with the quality concentration of the extracts. Polysaccharides of the four lichens exhibited significant antiproliferative activity against HeLa, A375, and Hep G2 cells by the MTT method. The crude polysaccharide of Umbilicaria tornata exhibited the most significant antiproliferative activity against Hep G2 cells in the four lichens (IC₅₀ = 0.2567 mg/mL); the crude polysaccharide of Lethariella cladonioides exhibited the most significant antiproliferative activity against HeLa cells in the four lichens (IC₅₀ = 0.4332 mg/mL).