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:

Synthesis of derivatives of methyl rosmarinate and their inhibitory activities against matrix metalloproteinase-1 (MMP-1). A series of MMP-1 inhibitors have been identified based upon a methyl rosmarinate scaffold using structure-based drug design methods. The best compound in the series showed an IC50 value of 0.4 μM. A docking study was conducted for compound (S)-10n in order to investigate its binding interactions with MMP-1. The structure-activity relationships (SAR) were also briefly discussed. Useful SAR was established which provides important guidelines for the design of future generations of potent inhibitors against MMP-1.
{"Chemical": ["methyl rosmarinate"]}