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:

A new guaianolide from Artemisia roxburghiana. A new member of 5αH,6βH,7αH,11αH-guaian-12,6α-olides, 11-epi-8α-hydroxyarborescin, together with a mixture of (24R)- and (24S)-cycloart-25-en-3b,24-diols, palmitic acid and 1-octacosanol were isolated from the leaves of Artemisia roxburghiana Bess. (Asteraceae) of Vietnam. Their structures were determined on the basis of spectroscopic methods.
{"Chemical": ["palmitic acid", "5\u03b1H,6\u03b2H,7\u03b1H,11\u03b1H-guaian-12,6\u03b1-olides", "(24R)- and (24S)-cycloart-25-en-3b,24-diols", "11-epi-8\u03b1-hydroxyarborescin", "guaianolide", "1-octacosanol"]}