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:

Marine natural products with anti-HIV activities in the last decade. Marine organisms have been proven to be excellent sources of biologically active compounds against HIV. This review gives an overview of 132 natural products from marine sources obtained during the last decade (2002-2011), which exhibit anti-HIV activity toward different biological targets. Sponges contribute more than half of all anti-HIV natural products from marine organisms, mainly as alkaloids and cyclic depsipeptides. In addition, some macromolecules are considered as potential anti-HIV agents, including lectins from algae and marine invertebrates, as well as sulfated polysaccharides from algae. In the reviewed marine natural products, many active ingredients act as HIV entry inhibitors, one class of new anti-HIV agents, and may be regarded as potential candidates for the development of novel anti-HIV agents. The other features of development in the marine original anti-HIV natural products in this ten years are also discussed.
{"Chemical": []}