| Polyspora longicarpa Chang, belonging to Polyspora of the Theaceae family, is distributed widely in the southwestern China and northern Vietnam and Cambodia. Our previous researches on Polyspora chrysandra Cowan and Polyspora kwangsiensis had provided a diverse array of new saponins and flavonoids, with a range of bioactivities such as cytotoxic, anti-inflammatory, hepatoprotective and hypoglycemic activities. Until now, there are no reports on chemical constituents and bioactivities of Polyspora longicarpa Chang.In our preliminary screening, the n-BuOH part of95%EtOH extract of the stems was found to exhibit anti-inflammatory and hypoglycemic activities. As part of searching for bioactive constituents, we investigated the n-BuOH part of95%EtOH extract of the stems. By using various chromatographic and spectroscopic techniques,20triterpenoid saponins had been isolated and elucidated. They were3-O-β-D-xylopyranosyl-(1→2)-a-L-arabinopyranosyl-(1→3)-[β-D-glucopyranosyl-(1→2)]-β-D-glucuronopyranosyl-16a-hydroxy-olean-12-en-28-oic acid (1),3-O-β-D-xylopyranosyl-(1→2)-α-L-arabino-pyranosyl-(1→3)-[β-D-galactopyranosyl-(1→2)]-β-D-glucuronopyranosyl-16a-hydroxy-olean-12-en-28-oic acid (2),3β-O-β-D-glucopyranosyl-(1→2)-[a-L-arabino-pyranosyl-(1→3)]-β-D-glucuronopyranosyl-16α-hydroxy-olean-12-en-28-O-β-D-gluco-pyranoside (3),3β-O-β-D-galactopyranosyl-(1→2)-[α-L-arabinopyranosyl-(1→3)]-β-D-glucuronopyranosyl-16α-hydroxy-olean-12-en-28-O-β-D-glucopyranoside (4),3β-O-a-L-rhamnopyranosyl(1→3)-β-D-glucopyranosyl-(1→2)-[a-L-arabinopyranosyl-(1→3)]-β-D-glucuronopyranosyl-16α-hydroxy-olean-12-en-28-O-β-D-glucopyranoside (5),3β-O-β-D-galacto-pyranosyl-(1→2)-[a-L-arabinopyranosyl-(1→3)]-β-D-glucurono-pyranosyl-16α,28-dihydroxy-olean-12-ene (6),3β-O-β-D-xylopyranosyl-(1→2)-a-L-arabinopyranosyl-(1→3)-[β-D-galactopyranosyl-(1→2)]-β-D-glucuronopyranosyl-16α,28-dihydroxy-olean-12-ene (7),3β-O-β-D-xylopyranosyl-(1→2)-a-L-arabino-pyranosyl-(1→3)-[β-D-glucopyranosyl-(1→2)]-β-D-glucuronopyranosyl-15a,16a,28-trihydroxy-21β,22α-diangeloyloxy-olean-12-ene (8),3β-O-β-D-galactopyranosyl-(1→2)-β-D-glucuronopyranosyl-16a-hydroxy-olean-12-en-28-O-β-D-glucopyranoside (9),3β-O-α-L-arabinopyranosyl-(1→3)-β-D-glucuronopyranosyl-16α-hydroxy-olean-12-en-28-O-β-D-glucopyranoside (10),3β-O-α-L-arabinopyranosyl-(1→2)-a-L-arabinopyranosyl-(1→3)-β-D-glucuronopyranosyl-16α-hydroxy-olean-12-en-28-O-β-D-glucopyranoside (11),3β-O-α-L-rhamnopyranosyl(1→2)-a-L-arabinopyranosyl-(1→3)-β-D-glucuronopyranosyl-16α-hydroxy-olean-12-en-28-O-β-D-glucopyranoside (12),30-O-β-D-xylopyranosyl-(1→2)-a-L-arabinopyranosyl-(1→3)-[β-D-galactopyranosyl-(1 →2)]-β-D-glucuronopyranosyl-16a-hydroxy-olean-12-en-28-O-β-D-glucopyranoside (13),3β-O-β-D-xylopyranosyl-(1→2)-a-L-arabinopyranosyl-(1→3)-[β-D-glucopyranosyl-(1→2)]-β-D-glucuronopyranosyl-16a,28-dihydroxy-22a-angeloyloxy-olean-12-ene (14),3β-O-β-D-xylopyranosyl-(1→2)-a-L-arabinopyranosyI-(1→3)-[β-D-galactopyranosyl-(1→2)]-β-D-glucuronopyranosyl-16a,28-dihydroxy-22α-angeloyloxy-olean-12-ene (15),3β-O-β-D-xylopyranosyl-(1→2)-a-L-arabinopyranosyl-(1→3)-[β-D-galactopyranosyl-(1→2)]-β-D-glucuronopyranosyl-15a,16a,28-trihydroxy-22a-angeloyloxy-olean-12-ene (16),3β-O-β-D-xylopyranosyl-(1→2)-a-L-arabinopyranosyl-(1→3)-[β-D-galactopyranosyl-(1→2)]-β-D-glucuronopyranosyl-15a,16a,28-tirhydroxy-21β-acetyl-22a-angeloyloxy-olean-12-ene (17),3β-O-β-D-xylopyranosyl-(1→2)-a-L-arabinopyranosyl-(1→3)-[β-D-glucopyranosyl-(1→2)]-β-D-glucuronopyranosyl-16a,28-dihydroxy-21β,22a-diangeloyloxy-olean-12-ene (18),3β-O-β-D-xylopyranosyl-(1→2)-a-L-arabinopyranosyl-(1→3)-[β-D-galactopyranosyl-(1→2)]-β-D-glucurono-pyranosyl-16a,28-dihydroxy-21β,22a-diangeloyloxy-olean-12-ene (19),3β-O-β-D-xylopyranosyl-(1→2)-a-L-arabinopyranosyl-(1→3)-[β-D-galactopyranosyl-(1-D-glucuronopyranosyl-15a,16a,28-dihydroxy-21β,22a-diangeloyloxy-olean-12-ene (20). Compounds1-8are new compounds, which were given the trival names longicarposide A-H, respectively. For the hypoglycemic bioassay, compound1and16inhibited aldose reductase with a rate over50%. For the cytotoxic bioassay, compounds8,14,15,16and18exhibited nonselective cytotoxicity against HCT-8, Bel-7402, BGC-823, A549and A2780cell lines while compounds17,19and20exhibited selective cytotoxicity.Our previous investigations on the constituents and bioactivities of Clausena lansium (Lour.) Skeels had found a series of carbazole alkaloids which showed excellent neuroprotective activities in vitro. The new compound claulansine F exhibited better neuroprotective activities than the positive drug edaravone toward the apoptosis of rat cortical neuron. It acted as a free radical scavenger against reactive oxygen species (ROS) like edaravone and protected PC12cells in a dose-dependent manner against toxicity induced by sodium nitroprusside. In order to perform further researches on animal modle, toxicity, mechanism and structure-activity relationship,we carried out a synthetic study for the preparation claulansine F.A nine-step route was developed with2-methy-5-nitroaniline as the starting material, leading to the total synthesis of claulansine F with the overall yield3.3%. The coupling of prepared arylamine with commercial4-iodoanisole via a palladium-catalyzed Buchwald-Hartwig amination led to the diarylamine. An air-mediated oxidative cyclization catalyzed by palladium had been applied to the foundation of the carbazole skeleton. Claulansine F, obtained by total synthesis for the first time, has been characterized by comparison of its spectroscopic data with those of the natural product. Further investigations of bioactivities on the intermediates and Claulansine F were carried out in this thesis. Claulansine F significantly decreased the area of infarction induced by cerebral ischemia in the brain of rats, which indicated that the mechanism of free radicals scavenging still worked in vivo. |
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