Department of Biology, Chiang Mai University, Chiang Mai 50202, Thailand.
J Nat Prod. 2010 Nov 29;73(11):1833-8. doi: 10.1021/np100474y. Epub 2010 Nov 4.
The isolation of two new Stemona alkaloids, 1-hydroxyprotostemonine and stemocurtisine N-oxide, and a new benzofuran, stemofuran L, from the root extracts of Stemona curtisii is reported. The major known alkaloids from this plant extract, stemocurtisine, stemocurtisinol, and oxyprotostemonine, were also isolated along with oxystemokerrine N-oxide. The nonalkaloid components of this extract included a new benzofuran derivative, stemofuran L, the known stemofurans F, J, and K, dihydro-γ-tocopherol, and stigmasterol. Stemocurtisine and stemocurtisinol were converted to their respective N-oxides by oxidation. Stemocurtisine was converted to a tetracyclic derivative by oxidative cleavage of the γ-butyrolactone ring, while stemocurtisinol gave a novel lactam derivative by oxidative cleavage of the C-4 side chain under basic conditions. The acetylcholinesterase inhibitory activities of some known and new alkaloids and their derivatives are also reported. All were 10-20 times less active as acetylcholinesterase inhibitors than the pyrrolo[1,2-a]azepine Stemona alkaloids stemofoline and 1',2'-didehydrostemofoline. None of the stemofuran compounds showed significant antibacterial or antifungal activities.
从武靴藤根提取物中分离得到两种新的石蒜生物碱，1-羟基原番茄碱和石蒜扣库辛 N-氧化物，以及一种新的苯并呋喃，石蒜呋喃 L。从该植物提取物中分离得到的主要已知生物碱还有扣库辛、扣库辛醇和氧原番茄碱，以及氧化斯蒂莫克里宁 N-氧化物。该提取物的非生物碱成分包括一种新的苯并呋喃衍生物石蒜呋喃 L，已知的石蒜呋喃 F、J 和 K、二氢-γ-生育酚和豆甾醇。通过氧化将扣库辛和扣库辛醇转化为各自的 N-氧化物。通过氧化断裂 γ-丁内酯环，扣库辛转化为四环衍生物，而扣库辛醇在碱性条件下通过氧化断裂 C-4 侧链生成一种新的内酰胺衍生物。还报道了一些已知和新生物碱及其衍生物的乙酰胆碱酯酶抑制活性。所有这些生物碱作为乙酰胆碱酯酶抑制剂的活性均比吡咯并[1,2-a]氮杂卓石蒜生物碱石蒜灵和 1'，2'-二去氢石蒜灵低 10-20 倍。石蒜呋喃类化合物均无明显的抗菌或抗真菌活性。
