Comparative analyses of transcriptome sequencing and carcinogenic exposure toxicity of nicotine and 6-methyl nicotine in human bronchial epithelial cells.

Electronic cigarettes have become a purported safer alternative to the conventional cigarettes in recent years. Nicotine is the main component of electronic cigarettes, and other nicotinic compounds are synthesized as alternatives to nicotine. However, scientific data on the potential health effects of electronic cigarettes are scarce. Herein, we evaluated the cytotoxicity of nicotine and its analog 6-methyl nicotine (6-MN) on human bronchial epithelial cells (BEAS-2B cells) in vitro. Furthermore, we performed transcriptome sequencing to systematically assess the effects of nicotine and 6-MN on BEAS-2B cells. The cytotoxicity assay revealed that BEAS-2B cells were more sensitive to 6-MN than to nicotine. Transcriptome sequencing revealed 1208 differentially expressed cancer-related proteins (CRP) in the 6-MN groups relative to that with CRP in the control group. In addition, 6-MN had a greater negative effect on the CRP expression than nicotine. Bioinformatic analysis revealed that the differentially expressed genes and proteins in the 6-MN group were significantly enriched in the cancer-related pathways, unlike those in the nicotine group. Further validations of some lung cancer-related proteins, such as NF-κB p65, EGFR, and MET, were conducted by immunoblotting and real-time PCR, which revealed that 6-MN may have a greater negative effect on tumor development and metastasis than nicotine. Taken together, our findings suggest that new electronic cigarettes with 6-MN might offer some advantages over conventional electronic cigarettes containing nicotine.

Antileukemic effects of indigo naturalis constituents by "target constituent knock-out" coupled with semipreparative liquid chromatography and quadrupole time-of-flight mass spectrometry.

A novel approach is presented to identify constituents with antileukemic properties in extracts of Indigo naturalis (Qingdai in Chinese). Target compounds (A+ , BC+ , and ABC+ ) that knocked out specific constituents displayed antileukemic effects in a total extract of I. naturalis and negative constituents (A- , BC- , and ABC- ) that knocked out target compounds were separated, identified and knocked out by semipreparative liquid chromatography (semipreparative HPLC) and quadrupole time-of-flight mass spectrometer. Quantitative methods were used to evaluate the content of each knocked-out constituent in the total extract (D). Subsequently, interactions between the antileukemic effects of knocked-out constituents and D were screened and evaluated at the cellular level. Negative constituents including A- (65.47% ± 1.20%), BC- (54.61% ± 2.43%) and ABC- (67.49% ± 3.28%) displayed a greater inhibitory effect than D (47.16% ± 0.072%), which was not knocked out after 24 h of incubation, whereas the target compounds had not superior. Target compounds may have caused an antagonistic effect on the corresponding negative constituents. After 48 h, inhibition of proliferation by D (75.48% ± 3.78%) increased compared with that by negative constituents, whereas the antagonistic effect of target components on negative constituents was diminished. This result may reflect competitive antagonism. Comparing the reactions after 24 and 48 h, the inhibitory ratio of ABC- (79.29% ± 1.22%) in these knocked-out constituents and D was always the highest. With different concentrations tested after 48 h, ABC- significantly increased the rate of apoptosis on K562 cells (P < 0.01), indicating that in addition to indirubin, tryptanthrin and isorhamnetin, other antileukemic constituents may be present. Our study presents an approach that is a truer reflection of the antileukemic effects of knocked-out constituents in I. naturalis supported by reference to pharmacodynamic actions and the quality of I. naturalis. The approach may be useful for the analysis of other herbal extracts found in traditional Chinese medicine.

New Polyketides With Anti-Inflammatory Activity From the Fungus Aspergillus rugulosa.

Two new polyketide compounds, asperulosins A and B (1-2), and one new prenylated small molecule, asperulosin C (3), along with nine known compounds (4-12), were isolated and identified from a fungus Aspergillus rugulosa. Their structures were extensively elucidated via HRESIMS, 1D, and 2D NMR analysis. The absolute configurations of the new compounds were determined by the comparison of their electronic circular dichroism (ECD), calculated ECD spectra, and the detailed discussion with those in previous reports. Structurally, compounds 1 and 2 belonged to the polyketide family and were from different origins. Compound 2 was constructed by five continuous quaternary carbon atoms, which occur rarely in natural products. All of the isolates were evaluated for anti-inflammatory activity against the production of nitric oxide (NO) in lipopolysaccharide (LPS)-induced RAW264.7 cells. Among those, compounds 1 and 5 showed a significant inhibitory effect on NO production with IC50 values of 1.49 ± 0.31 and 3.41 ± 0.85 µM, respectively. Additionally, compounds 1 and 5 markedly increased the secretion of anti-inflammatory cytokine IL10 while suppressing the secretion of pro-inflammatory cytokines IL6, TNF-α, IFN-γ, MCP-1, and IL12. Besides, 1 and 5 inhibited the transcription level of pro-inflammatory macrophage markers IL6, IL1ß, and TNF-α while remarkably elevating the anti-inflammatory factor IL10 and M2 macrophage markers ARG1 and CD206. Moreover, 1 and 5 restrained the expression and nuclear translocation of NF-κB, as well as its downstream signaling proteins COX-2 and iNOS. All these results suggest that 1 and 5 have potential as anti-inflammatory agents, with better or comparable activities than those of the positive control, dexamethasone.