Anti-UV Activity of Alkaline Extract of the Leaves of Sasa senanensis Rehder

We have previously reported several lignin-like activities of the alkaline extract of the leaves of Sasa senanensis Rehder (SE), such as anti-HIV and radical scavenging activity. As an extension, possible SE protection of cells from ultraviolet (UV)-induced injury (referred to "anti-UV activity") was investigated. HSC-2, human oral squamous cell carcinoma cells, were exposed to UV irradiation in phosphate-buffered saline containing SE or its fractions, and then incubated for 48 hours in fresh regular culture medium to determine the viable cell number by the MTT method. SE was separated by gel filtration chromatography into the following four fractions: polysaccharide, large and small lignin-carbohydrate complexes and lower molecular weight polyphenol fractions (Fr. I). The anti-UV activity of SE was slightly less than that of sodium ascorbate, but higher than that of gallic acid, (-)-epigallocatechin gallate, chlorophyll a and chlorophyllin. The combination of SE and sodium ascorbate gave synergistic anti-UV activity. On gel filtration fractionation, the majority of the anti-UV activity was recovered from Fr. I, which was eluted as a single peak on high performance liquid chromatography (HPLC). The anti-UV activity of SE further suggests its potential as an alternative medicine.