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:

Assay of phenolic compounds from four species of ber (Ziziphus mauritiana L.) fruits: Comparison of three base hydrolysis procedure for quantification of total phenolic acids. The present study was undertaken to investigate the flavonoid profile in four species of ber (Ziziphus mauritiana Lamk.) fruit. The 12 flavonoids identified were quercetin 3-O-robinobioside, quercetin 3-O-rutinoside, quercetin 3'-O-galactoside, quercetin 3'-O-glucoside, quercetin 3'-O-rhamnoside, quercetin 3'-O-pentosylhexoside, quercetin 3-O-6'malonylglucoside, quercetin 3'-O-malonylglucoside, luteolin 7-O-6'malonylglucoside, luteolin 7-O-malonylglucoside, myricetin 3-O-galactoside, and naringenin tri glycoside. This is the first report on extraction of nine additional flavonoids from the ber fruits. In addition, we also compared the impact of three different base hydrolysis techniques namely ultrasonic assisted base hydrolysis (UABH), microwave assisted base hydrolysis (MWABH), and pressurised liquid assisted base hydrolysis (PLABH) for the quantification of total phenolic acids. Nine phenolic acids, protocatechuic acid, p-hydroxybenzoic acid, ferulic acid, chlorogenic acid, vanillic acid, caffeic acid, vanillin, ortho- and para-coumaric acids, were identified and quantified. The three major phenolic acids identified in all four ber species were p-coumaric acid, vanillin and ferulic acids. Higher amounts (p<0.05) of total phenolic acids in all cultivars were obtained with the PLABH technique as compared to other two procedures (UABH and MWABH).
{"Chemical": ["quercetin 3-O-robinobioside", "quercetin 3\u0027-O-malonylglucoside", "quercetin 3\u0027-O-pentosylhexoside", "vanillin", "chlorogenic acid", "luteolin 7-O-6\u0027malonylglucoside", "flavonoid", "naringenin tri glycoside", "ferulic acids", "flavonoids", "phenolic", "vanillic acid", "quercetin 3\u0027-O-galactoside", "caffeic acid", "quercetin 3\u0027-O-glucoside", "ferulic acid", "quercetin 3-O-6\u0027malonylglucoside", "p-hydroxybenzoic acid", "ortho- and para-coumaric acids", "p-coumaric acid", "phenolic acids", "quercetin 3\u0027-O-rhamnoside", "quercetin 3-O-rutinoside", "luteolin 7-O-malonylglucoside", "myricetin 3-O-galactoside", "protocatechuic acid"]}