152243-70-4Relevant articles and documents
Cytotoxic triterpene saponins from the stem bark of Kalopanax pictus
Quang, Tran Hong,Ngan, Nguyen Thi Thanh,Minh, Chau Van,Kiem, Phan Van,Boo, Hye-Jin,Hyun, Jin-Won,Kang, Hee-Kyoung,Kim, Young Ho
, p. 177 - 182 (2012)
Three new compounds, 3β,6β,23-trihydroxyolean-12-en-28-oic acid 3-O-α-l-arabinopyranoside (1), kalopanaxsaponin L (2), and kalopanaxsaponin M (13), as well as eleven known compounds (3-12 and 14), were isolated from the stem bark of Kalopanax pictus. Their structures were determined on the basis of extentive spectroscopic analyses and acid hydrolysis. The cytotoxicity of the compounds was evaluated in three human carcinoma cell lines, including HL-60, HCT-116, and MCF-7. Compounds 1, 5-8, 10, and 11 exhibited significantly cytotoxic activity toward HL-60 cells, with IC 50 values ranging from 0.1 to 6.9 μM. Compounds 4-7 and 14 showed significant cytotoxicity against HCT-116 cells, with IC50 values ranging from 0.4 to 9.2 μM. Remarkably, the cytotoxic activities of compounds 5-7 against HCT-116 cells were greater than that of the anticancer chemotherapy drug, mitoxantrone (IC50 = 3.7 μM). Compounds 1, 3, 5, and 14 were cytotoxic toward MCF-7 cells with IC50 values in a range of 7.4-14.5 μM.
Application of Relay C?H Oxidation Logic to Polyhydroxylated Oleanane Triterpenoids
Bauer, Sophie,Berger, Martin,Knittl-Frank, Christian,Maulide, Nuno,Winter, Georg
, p. 1183 - 1189 (2020)
Although clinical applications of abundant feedstock triterpenoids such as oleanolic acid are limited because of poor solubility and bioavailability, synthetic access to higher hydroxylated oleanane terpenoids is challenging. We now report the use of relay C?H oxidation logic to mimic the processes carried out in nature by P450 monooxygenase enzymes. To this end, we used the C-23-OH as natural handle for a hydrogen-atom transfer to access C-6, enabling the first syntheses of highly oxidized natural products uncargenin C and protobassic acid as well as uncovering the anti-leukemic activity of a synthetic intermediate. Chemical modification of readily available, scarcely oxidized natural products not only enables access to higher and more valuable congeners but can also pave the way to pharmaceutically relevant derivatives with enhanced properties. Achieving site-selective oxidation of such natural products is an endeavor often controlled by the presence of directing elements. Because of this fact, the oxidation of C?H bonds remote from such elements is either unfeasible or requires more elaborate synthetic strategies. We report the use of relay C?H oxidation as a concept to achieve the oxidation of previously inaccessible ring B in the abundant feedstock oleanolic acid. This resulted not only in the first total synthesis of a number of polyhydroxylated natural triterpenoids but also revealed an anti-leukemic intermediate. The strategy presented here could become a very general approach in the synthesis of valuable triterpenoids. Although biological applications of abundant feedstock triterpenoids such as oleanolic acid are limited because of poor solubility, synthetic access to higher hydroxylated metabolites is challenging. We use relay C?H oxidation logic to mimic the processes carried out in Nature by P450 monooxygenase enzymes. To this end, we use the C-23-OH as natural handle for a hydrogen-atom-transfer access to C-6, enabling the first syntheses of highly oxidized natural products as well as uncovering the anti-leukemic activity of a synthetic intermediate.
