Brightness of melanin-based plumage coloration is a cue to oxidative stress in Himalayan Black Bulbuls(Hypsipete leucocephalus nigerrimus)

Background: Melanin?based coloration is often found to be associated with variations in physiological and behavio?ral traits that are essential in avian communication.However,the function of melanin?based traits to their bearers has been investigated less than that of carotenoid?based ones.It is commonly believed that expression of melanin?based pigmentation is genetically controlled.However,whether it could be modulated by physical condition has remained controversial.In this study,we demonstrate that the level of melanin?based plumage pigmentation could be nega?tively correlated with an individual's oxidative stress level.Methods: In this study,we used two groups of Black Bulbuls(Hypsipetes leucocephalus nigerrimus) obtained from a pet?shop in 2010 and 2011 to examine the correlation between the melanin?based plumage coloration and the ratio of lymphocytes to heterocytes,which is an indicator of the oxidative stress experienced by an individual.Results: We found a negative correlation between oxidative stress levels and expression of melanin?based pigmen?tation on the breast and scapular feathers,but the correlation only appeared in the 2011 group,individuals of which had higher oxidative stress level and brighter plumage(i.e.more melanins) than those of the 2010 group.Conclusions: Our data suggest that melanin?based plumage could reflect an individual's physical condition in certain situations.Therefore,melanin?based plumage coloration could have a function in Himalayan Black Bulbuls' communication.

Chemical constituents from Kalanchoe hybrida and their cytotoxicity

Objective：Kalanchoe hybrida（Crassulaceae）is naturalized throughout all the island of Taiwan in China.The preliminary bioassay-guided fractionation of the crude extract of K.hybrida exhibited that the chloroform and n-butanol fractions possessed potent cytotoxicity against MCF-7,NCI-H460,and SF-268 tumor cell lines at 50μg/m L concentration.Therefore,K.hybrida was selected as a target and the chemical constituents from the chloroform and n-butanol fractions of the crude extracts of K.hybrida were identified.The potential constituents were examined for their cytotoxicity against the tumor cell lines.Methods：A combination of conventional chromatographic techniques was performed on the crude extract of K.hybrida.The chemical structures of the purified constituents were identified on the basis of spectroscopic and spectrometric analysis.Results：The purification results had led to the characterization of totally 37 compounds.The isolated compounds 1,2,and 4–12 were examined for their cytotoxicity in vitro,and bufadienolides 4–8 and flavonol glycoside 11 displayed significant cytotoxicity towards all the tested tumor cell lines among these tested compounds.Conclusion：The results indicated that these principles should be responsible for the bioactivity of corresponding partial fractions.The potential constituents could be further investigated to explore the new natural lead drugs.