Cestrum nocturnum Flower Extracts Attenuate Proliferation and Induce Apoptosis in Malignant Cells through Inducing DNA Damage and Inhibiting Topoisomerase II Activity.

Most of the existing chemotherapeutic drugs have plenty of side effects. Chinese herbal medicine has been used for pharmaceutical and dietary therapy for thousands of years with more effective and fewer side effects. Cestrum nocturnum (CN) has long been used to treat digestive diseases for centuries in China. Our previous study first proved that the n-butanol part isolated from the flowers of CN produced an inhibitory effect on the proliferation of malignant cells. However, the fractions responsible for the antiproliferation effect of n-butanol part from CN flowers and related mechanisms remain unknown. Thus, in this study, we extracted fractions C4 and C5 from n-butanol part of CN flowers and investigated their immune toxicity and antitumor activities. It was found that fractions C4 and C5 exhibited great cytotoxicity to cancer cell lines but had low immune toxicity towards T and B lymphocytes in vitro. The tested fractions also attenuated proliferation and induced apoptosis at G0/G1 and G2/M phases in Bel-7404 cells through inducing DNA damage and inhibiting topoisomerase II relaxation activity. These results suggest that fractions C4 and C5 may represent important sources of potential antitumor agents due to their pronounced antitumor effects and low immune toxicity.

[Experimental study on antitumor effect of extracts from Cestrum nocturnum in vivo].

OBJECTIVE: To observe the antitumor effects of extracts from Cestrum nocturnum (CN) in vivo. METHODS: The S180-mice model was used to observe the tumor-inhibition rate of CN and the H22-mice model was used to test the survival time. RESULTS: The experiment in S180-mice demonstrated that the n-butanol and polysaccharides extracts from CN had obvious effects on tumor inhibition. Its inhibitory rates were 52.30%, 46.75%, 42.28%, 43.19%, 37.96% and 31.82% respectively in the mice administrated the n-butanol and polysaccharides extracts from CN with 30 mg/kg, 20 mg/kg and 15 mg/kg weight dosage. It was noted that tumor formation postponed in mice treated with the n-butanol and polysaccharides extracts from CN compared with the control panel and tumor growth became slower; The n-butanol and polysaccharides extracts from CN could also greatly enhance the life span of mice with H22 ascitic tumors by 116.43%, 44.52%, 20.54%, 109.52%, 112.61% and 115.01%, respectively. The inhibit effects of n-butanol fraction extracts from CN had direct relationship with dose, while the polysaccharides fraction extracts from CN had no obvious relationship with dose. CONCLUSION: The n-butanol and polysaccharides extracts of CN are able to inhibit tumor growth and prolong the lifetime of the tumor-bearing mice in a dose-dependent pattern.