You will be shown an abstract from a biomedical research paper. Given this abstract, your task is to extract all unique entities of the following types: ["Chemical"].

Please return the output as a JSON object of the format: {"Chemical": ["Arsenic", ...]}. The keys should be entity types and values should be lists of extracted entities belonging to the corresponding type. If you cannot find entities belonging to a specific type, the value should be [].

Only output the JSON object and do not include any additional text.

Abstract:

Two new alkaloid galactosides from the kernel of Prinsepia uniflora. Two new alkaloid galactosides have been isolated from the kernel of Prinsepia uniflora. Their structures were elucidated as 5-[(α-D-galactopyranosyloxy) methyl]-1H-pyrrole-2-carbaldehyde (1) and 6-[(α-D-galactopyranosyloxy) methyl]-3-pyridinol (2) by various spectroscopic means including HR-ESI-MS, IR, 1D and 2D NMR. The determined structures were characterized with a unit of galactose which is rarely seen in the previously isolated pyrrole and pyridinol compounds.
{"Chemical": ["alkaloid galactosides", "galactose", "5-[(\u03b1-D-galactopyranosyloxy) methyl]-1H-pyrrole-2-carbaldehyde", "pyridinol", "pyrrole", "6-[(\u03b1-D-galactopyranosyloxy) methyl]-3-pyridinol"]}