Acylphloroglucinol Derivatives with a Tricyclo-[4.4.1.1^1,4] Dodecane Skeleton from Garcinia bracteata Fruits

Two novel polycyclic polyprenylated acylphloroglucinols (PPAPs), garcibractinones A (1) and B (2), as well as three known analogues doitunggarcinones A–B (3–4) and garcibracteatone (5) were isolated from Garcinia bracteata fruits. Their structures were elucidated by comprehensive spectroscopic methods and single crystal X-ray diffraction. Compounds 1 and 2 possess an unprecedented caged tricyclo-[4.4.1.11,4] dodecane skeleton, and their biosynthetic pathways are also proposed. Compounds 1–2 were tested for their inhibitory effects on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in RAW 264.7 macrophages.本研究从柄果藤黄（Garcinia bracteata）的果实中分离得到2个新型多环异戊烯酰基间苯三酚类化合物（polycyclic polyprenylated acylphloroglucinols，PPAPs），即garcibractinones A（1）与B（2），同时分离得到3个已知类似物doitunggarcinones A–B（3~4）及garcibracteatone（5）。所有化合物的结构均通过综合光谱学方法及单晶X射线衍射法得以解析。化合物1与2拥有前所未有的笼状三环[4.4.1.1¹,⁴]十二烷骨架，本研究同时提出了它们的生物合成途径。针对化合物1~2，本研究测试了其对脂多糖（lipopolysaccharide，LPS）诱导的RAW 264.7巨噬细胞一氧化氮（nitric oxide，NO）生成的抑制活性。