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Arenobufagin, an active component isolated from the traditional Chinese medicine Chan Su, exhibits anticancer influences in several human malignancies. However, the effects and action mechanisms of arenobufagin on non-small-cell lung cancer (NSCLC) are still unknown. In this study, we reported that arenobufagin acted through activation of Noxa-related pathways and promoted apoptotic cell death in human NSCLC cells. Our results revealed that arenobufagin-induced apoptosis was caspase-dependent, as evidenced by the fact that caspase-9, caspase-3 and poly (ADP-ribose) polymerase (PARP) were cleaved, and pretreatment with a pan-caspase inhibitor Z-VAD-FMK inhibited the pro-apoptosis effect of arenobufagin. Mechanistically, we further found that arenobufagin rapidly upregulated the expression of the pro-apoptosis protein Noxa, and abrogated the anti-apoptosis protein Mcl-1, a major binding partner of Noxa in the cell. More importantly, the knockdown of Noxa greatly blocked arenobufagin-induced cell death, highlighting the contribution of this protein in the anti-NSCLC effects of arenobufagin. Interestingly, arenobufagin also increased the expression of p53, a direct transcriptional activator for the upregulation of the Noxa protein. Taken together, our results suggest that arenobufagin is a potential anti-NSCLC agent that triggers apoptotic cell death in NSCLC cells through interfering with the Noxa-related pathway., Competing Interests: The authors declare no conflict of interest.

Compounds in the form of precipitation (CFP) are universally formed during the decocting of Chinese prescriptions, such as Huang-Lian-Jie-Du-Tang (HLJDT). The formation rate of HLJDT CFP even reached 2.63% ± 0.20%. The identification by liquid chromatography mass spectrometry (LC-MS(n)) proved that the main chemical substances of HLJDT CFP are baicalin and berberine, which is coincident with the theory that the CFP might derive from interaction between acidic and basic compounds. To investigate the formation mechanism of HLJDT CFP, baicalin and berberine were selected to synthesize a simulated precipitation and then the baicalin-berberine complex was obtained. Results indicated that the melting point of the complex interposed between baicalin and berberine, and the UV absorption, was different from the mother material. In addition, ¹H-NMR integral and high-resolution mass spectroscopy (HR-MS) can validate that the binding ratio was 1:1. Compared with baicalin, the chemical shifts of H and C on glucuronide had undergone significant changes by ¹H-, (13)C-NMR, which proved that electron transfer occurred between the carboxylic proton and the lone pair of electrons on the N atom. Both HLJDT CFP and the baicalin-berberine complex showed protective effects against cobalt chloride-induced neurotoxicity in differentiated PC12 cells. It is a novel idea, studying the material foundation of CFP in Chinese prescriptions.

Psidium guajava leaves have a diverse phytochemical composition including flavonoids, phenolics, meroterpenoids and triterpenes, responsible for the biological activities of the medicinal parts. In particular, flavonol glycosides show beneficial effects on type II diabetes mellitus. A simple and efficient HSCCC method has been developed for the preparative separation of five flavonoid glycosides and one diphenylmethane glycoside from P. guajava. A solvent system composed of n-hexane-ethyl acetate-methanol-water (0.7:4:0.8:4, v/v/v/v) was optimized for the separation. The upper phase was used as the stationary phase, and the lower phase was used as the mobile phase. Under the optimized conditions, hyperoside (15.3 mg), isoquercitrin (21.1 mg), reynoutrin (65.2 mg), quercetin-3-O-β-D-arabinopyranoside (71.7 mg), quercetin-3-O-α-L-arabinofuranoside (105.6 mg) and 2,4,6-trihydroxy-3,5-dimethylbenzophenone 4-O-(6''-O-galloyl)-β-D-glucopyranoside (98.4 mg) were separated from crude sample (19.8 g). The structures of all the isolates were identified by ESI-MS, 1H- and 13C-NMR analyses and their purities (>95%) were determined using HPLC.