Yang Peng, Liu Ding-Quan, Liang Tong-Jun, Li Jia, Zhang Hai-Yan, Liu Ai-Hong, Guo Yue-Wei, Mao Shui-Chun
School of Pharmacy, Nanchang University, Nanchang 330006, PR China.
Lushan Botanical Garden, Jiangxi Province & The Chinese Academy of Sciences, Lushan 332900, PR China.
Bioorg Med Chem. 2015 Jan 1;23(1):38-45. doi: 10.1016/j.bmc.2014.11.031. Epub 2014 Nov 27.
Three diterpenoids, including a pair of epimers, racemobutenolids A and B (1 and 2), and 4',5'-dehydrodiodictyonema A (3), an α-tocopheroid, α-tocoxylenoxy (8), and an 28-oxostigmastane steroid, (23E)-3β-hydroxy-stigmasta-5,23-dien-28-one (11), together with 12 known compounds, were isolated from the green alga Caulerpa racemosa. The structures of the new compounds were elucidated by detailed analysis of spectroscopic data, and by comparison with data for related known compounds. The epimers (1 and 2) are two unusual diterpenoid lactones bearing a β-methyl-γ-substituted butenolide moiety, and 3 and 8 represent the first naturally occurring natural products with a hematinic acid ester group and 3,5-dimethylphenoxy functionality, respectively. The enzyme inhibitory activities of the isolated compounds were evaluated in vitro against PTP1B and related PTPs (TCPTP, CDC25B, LAR, SHP-1, and SHP-2). Compounds 3, 5, 6, and 9-14 exhibited different levels of PTP1B inhibitory activities with IC50 values ranging from 2.30 to 50.02μM. Of these compounds, 3, 9, and 11 showed the most potent inhibitory activities towards PTP1B with IC50 values of 2.30, 3.85, and 3.80μM, respectively. More importantly, the potent PTP1B inhibitors 3, 9, and 11 also displayed high selectivity over the highly homologous TCPTP and other PTPs. Also, the neuroprotective effects of the isolates against Aβ25-35-induced cell damage in SH-SY5Y cells were investigated. Compounds 10, 11, and 14 exhibited significant neuroprotective effects against Aβ25-35-induced SH-SY5Y cell damage with 11.31-15.98% increases in cell viability at 10μM. In addition, the cytotoxic activities of the isolated compounds were tested against the human cancer cell lines A-549 and HL-60.
从绿藻总状蕨藻中分离出三种二萜类化合物，包括一对差向异构体消旋丁烯醇内酯A和B（1和2）、4',5'-脱氢二网地藻A（3）、一种α-生育酚类化合物α-生育酚烯氧基（8）以及一种28-氧代豆甾烷类固醇（23E）-3β-羟基-豆甾-5,23-二烯-28-酮（11），同时还分离出12种已知化合物。通过对光谱数据的详细分析以及与相关已知化合物数据的比较，阐明了这些新化合物的结构。差向异构体（1和2）是两种不同寻常的二萜类内酯，带有β-甲基-γ-取代的丁烯醇内酯部分，3和8分别代表首次天然存在的具有补血酸酯基和3,5-二甲基苯氧基官能团的天然产物。对分离出的化合物进行体外实验，评估其对蛋白酪氨酸磷酸酶1B（PTP1B）及相关蛋白酪氨酸磷酸酶（TCPTP、细胞周期蛋白依赖性激酶25B（CDC25B）、白细胞共同抗原相关磷酸酶（LAR）、蛋白酪氨酸磷酸酶非受体型1（SHP-1）和蛋白酪氨酸磷酸酶非受体型2（SHP-2））的抑制活性。化合物3、5、6以及9至14表现出不同程度的PTP1B抑制活性，半数抑制浓度（IC50）值在2.30至50.02μM之间。其中，化合物3、9和11对PTP1B表现出最强的抑制活性，IC50值分别为2.30、3.85和3.80μM。更重要的是，强效PTP1B抑制剂3、9和11对高度同源的TCPTP和其他蛋白酪氨酸磷酸酶也表现出高选择性。此外，还研究了这些分离物对Aβ25-35诱导的SH-SY5Y细胞损伤的神经保护作用。化合物10、11和14对Aβ25-35诱导的SH-SY5Y细胞损伤表现出显著的神经保护作用，在10μM浓度下细胞活力增加11.31%至15.98%。此外，测试了分离出的化合物对人癌细胞系A-549和HL-60的细胞毒性活性。
