Two new dihydrochalcones, 4-hydroxy-2,4'-dimethoxydihydrochalcone (1) and 3,4'-dihydroxy-2,4,6-trimethoxydihydrochalcone (2), and a new homoisoflavane, 7,3'-dihydroxy-8,4'-dimethoxyhomoisoflavane (3), along with 12 known compounds (4-15), were isolated from the red resin of Dracaena cochinchinensis (Chinese dragon's blood). Their structures were assigned by a variety of spectroscopic techniques. Diversity of cleavage pathways were proposed for dihydrochalcones and homoisoflavanes based on the mass spectroscopic behaviors of those identified compounds using hybrid ion trap-time of flight mass spectrometry. All the compounds were evaluated for their inhibitory effects on nitric oxide production in lipopolysaccharide-induced RAW 264.7 macrophages, and compound 9 exhibited mild inhibition of NO production in this assay with IC₅₀ value of 50.3 μM.
Keywords: 2,4,4′-trihydroxydihydrochalcone (PubChem CID: 10801179); Chinese dragon's blood; Dihydrochalcone; Dracaena cochinchinensis; Homoisoflavane; Loureirin A (PubChem CID: 5319081); Loureirin B (PubChem CID: 189670); Loureirin C (PubChem CID: 14157896); Loureirin D (PubChem CID: 13939318); Mass fragmentation pathway.
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