Phloroglucinol Derivatives from the Fruits of Eucalyptus globulus and Their Cytotoxic Activities

• Published in: Chemistry & biodiversity Vol. 15; no. 6; pp. e1800052 - n/a
• Main Authors: Pham, Thi‐Anh, Shair Mohammad, Imran, Vu, Van‐Tuan, Hu, Xiao‐Long, Birendra, Chaurasiya, Ulah, Aftab, Guo, Cui, Lü, Xian‐Yu, Ye, Wen‐Cai, Wang, Hao
• Format: Journal Article
• Language: English
• Published: Switzerland Wiley Subscription Services, Inc 01.06.2018
• Subjects: Absolute configuration; Apoptosis; Assaying; Bax; Bax protein; BCl2; Cancer; Caspase; caspase‐3; Circular dichroism; Cytotoxicity; Dichroism; eucalyptin B; Eucalyptus; Eucalyptus globulus; Fruits; Lungs; Magnetic resonance spectroscopy; NMR spectroscopy; Phloroglucinol; Proteins; Skin; Toxicity; Tumor cell lines; Tumor cells; BCl2; Eucalyptin B; apoptosis; Bax and caspase-3; Eucalyptus globulus; cytotoxicity
• ISSN: 1612-1872; 1612-1880
• DOI: 10.1002/cbdv.201800052

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.