In this task, you are given a sentence. You are expected to recognize the name of any form of chemical substances. Although there might be several correct answers, you need to write one of them.

Example Input: Green tea catechin leads to global improvement among Alzheimer's disease-related phenotypes in NSE/hAPP-C105 Tg mice.
Example Output: catechin

Example Input: Environmental pesticide exposure modulates cytokines, arginase and ornithine decarboxylase expression in human placenta.
Example Output: ornithine

Example Input: Tumor necrosis factor-alpha potentiates the cytotoxicity of amiodarone in Hepa1c1c7 cells: roles of caspase activation and oxidative stress.
Example Output:
amiodarone