Phloroglucinol Derivatives from the Fruits of Eucalyptus globulus and Their Cytotoxic Activities |
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Authors: | Thi‐Anh Pham Imran Shair Mohammad Van‐Tuan Vu Xiao‐Long Hu Chaurasiya Birendra Aftab Ulah Cui Guo Xian‐Yu Lü Wen‐Cai Ye Hao Wang |
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Institution: | 1. State Key Laboratory of Natural Medicines, Department of TCMs Pharmaceuticals, School of Traditional Chinese Pharmacy, China Pharmaceutical University, Nanjing, P. R. China;2. Department of Pharmaceutics, School of Pharmacy, China Pharmaceutical University, Nanjing, P. R. China;3. Guangdong Province Key Laboratory of Pharmacodynamic Constituents of TCM and New Drug Research, Jinan University, Guangzhou, P. R. China |
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Abstract: | A new phloroglucinol derivative, named eucalyptin B ( 1 ), along with five related known compounds ( 2 – 6 ), was isolated from the fruits of Eucalyptus globulus. Their structures were elucidated by means of 1D‐ and 2D‐NMR spectroscopy, with the absolute configuration of 1 determined by electronic circular dichroism (ECD) calculations. All isolated compounds ( 1 – 6 ) were evaluated for their cytotoxic activities against lung (A549), breast (4T1), and skin (B16F10) cancer cell lines. On the basis of cell viability assay, the cytotoxic activity of eucalyptin B ( 1 ) was further confirmed by apoptosis assay. Additionally, after treatment with eucalyptin B ( 1 ), the apoptosis factor proteins (Bcl2 and Bax) and caspase‐3 levels in A549 cells were also determined by Western‐blot analysis. By cytotoxic assay, eucalyptin B ( 1 ) exhibited potent cytotoxicity against A549 cells with an IC50 value of 1.51 μm and induced concentration dependent apoptosis of up to 49%. Additionally, eucalyptin B ( 1 ) inhibited 5‐fold and increased 10‐folds in the level of Bcl2 and Bax, respectively. Furthermore, the 11‐fold increase in the level of caspase‐3 confirmed eucalyptin B ( 1 ) activated caspase dependent apoptosis pathway. In conclusion, the isolated compound eucalyptin B ( 1 ) has promising cytotoxic activity in tumor cells, especially in A549. |
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Keywords: |
Eucalyptus globulus
eucalyptin B cytotoxicity apoptosis BCl2 Bax caspase‐3 |
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