Neuroprotective principles from Gastrodia elata.

Serum deprivation-induced neuronal-like PC12 cell apoptosis was used as an ischemic/hypoxic model to screen neuroprotective compounds from the rhizomes of Gastrodia elata, a traditional Chinese medicine. Two active compounds, bis(4-hydroxybenzyl)sulfide (1) and N6-(4-hydroxybenzyl)adenine riboside (2), together with 15 known compounds were obtained from the active fraction. Compound 2 was further elucidated by chemical synthesis. Compounds 1 and 2 potently prevented PC12 cell apoptosis in concentration-dependent manners with EC50 values of 7.20 microM and 3.7 x 10-8 M, respectively, and IC50 values of 42.90 microM (Ki 24.10 microM) and 4.660 microM (Ki 2.620 microM), respectively, in an adenosine A2A receptor binding assay.