Dongming Peng

Carboxylation of multiwalled carbon nanotube attenuated the cytotoxicity by limiting the oxidative stress initiated cell membrane integrity damage, cell cycle arrestment, and death receptor mediated apoptotic pathway.

In this study, the effects of carboxylated multiwalled carbon nanotubes (MWCNTs-COOH) on human normal liver cell line L02 was compared with that of pristine multiwalled carbon nanotubes (p-MWCNTs). It was shown that compared with MWCNTs-COOH, p-MWCNTs induced apoptosis, reduced the level of intracellular antioxidant glutathione more significantly, and caused severer cell membrane damage as demonstrated by lactate dehydrogenase leakage. Cell cycles were arrested by both MWCNTs, while p-MWCNTs induced higher ratio of G0/G1 phase arrestment as compared with MWCNTs-COOH. Caspase-8 was also activated after both MWCNTs exposure, indicating extrinsic apoptotic pathway was involved in the apoptosis induced by MWCNTs exposure, more importantly, MWCNTs-COOH significantly reduced the activation of caspase-8 as compared with p-MWCNTs. All these results suggested that MWCNTs-COOH might be safer for in vivo application as compared with p-MWCNTs.

Hydroxylation of multi-walled carbon nanotubes reduces their cytotoxicity by limiting the activation of mitochondrial mediated apoptotic pathway

Hydroxylation of carbon nanotubes (CNTs) can enhance their dispersibility in water, and allows the capability to conjugate with other molecules for the expected applications. However, the cytotoxicity of hydroxylated CNTs has not been thoroughly investigated. Here, we compared the cytotoxicity of hydroxylated multi-walled carbon nanotubes (MWCNTs–OH) on a human cell line with that of pristine multi-walled carbon nanotubes (p-MWCNTs). We showed that while both MWCNTs–OH and p-MWCNTs induced apoptosis in a time- and dose-dependent manner, MWCNTs–OH triggered a significantly milder cytotoxic response than that of p-MWCNTs. We further showed that such attenuated response could be attributed to a reduced disruption of the mitochondrial membrane potential (MMP), leading to the attenuation of both cytochrome c (cyt-c) release and activation of caspases. These findings suggest that MWCNTs–OH, could be more biocompatible for in vivo applications than that of p-MWCNTs by limiting the activation of the mitochondrial mediated apoptotic pathway.

Synthesis and hypoglycemic activity of 9-O-(lipophilic group substituted) berberine derivatives.

A series of 9-O-(lipophilic group substituted) berberine derivatives were synthesized and evaluated for their cytotoxicity and hypoglycemic activity against HepG2 cells. All the results indicated that most of the synthesized compounds exhibited lower cytotoxicity and a certain degree of hypoglycemic activity. Especially the compounds 5g and 5h displayed dramatically increased hypoglycemic activity compared with berberine, and the cytotoxicity maintained or even lower than berberine, indicating that they are potential candidates for new anti-type 2 diabetes mellitus drugs.

Cefepime loaded O-carboxymethyl chitosan microspheres with sustained bactericidal activity and enhanced biocompatibility

Abstract Cefepime (CFP) is a frequently used antibiotic for prevention of post-surgery infection. Systemic delivery of CFP in a bulk dose usually shows effective therapeutic effects, while cytotoxicity can also be generated. To avoid the drawback of systemic delivery of antibiotic, local and controlled administration of drug is being employed to prolong therapeutic effects and reduce cytotoxicity by sustaining drug release and minimizing drug exposure. In this work, CFP loaded polymer O-carboxymethyl chitosan (OCMC) microspheres (CFP-OCMC-MPs) were fabricated and their antimicrobial activity against Staphylococcus aureus as well as biocompatibility were evaluated. The microspheres possessed the spherical surface with diameter approximately 7 μm. Fourier transforms infrared spectral and wide-angle X-ray diffraction analysis showed that CFP was steadily incorporated. The drug loading content and encapsulation efficiency of the microspheres were 21.4 ± 0.5% and 42.3 ± 0.7%, respectively. The drug release profiles were found to be biphasic with an initial burst release followed by a gradual release phase, following the Higuchi model. In addition, the CFP-OCMC-MPs were able to kill all the bacteria cultured in suspension within 24 h and exhibited long-lasting bactericidal activity as demonstrated by inhibition zone study. Compared to CFP, CFP-OCMC-MPs showed a milder toxicity toward osteoblast-like cells over an 8 day period. All these results suggest that CFP-OCMC-MPs are endowed with sustained treatment of bacterial infection and enhanced biocompatibility.

Hydroxylation of multi-walled carbon nanotubes: Enhanced biocompatibility through reduction of oxidative stress initiated cell membrane damage, cell cycle arrestment and extrinsic apoptotic pathway

Modification of CNTs with hydroxyl group promotes their applications in biomedical area. However, the impact of hydroxylation on their biocompatibility is far from being completely understood. In this study, we carried out a comprehensive evaluation of hydroxylated multi-walled carbon nanotubes (MWCNTs-OH) on the human normal liver L02 cell line, and compared it with that of pristine multi-walled carbon nanotubes (p-MWCNTs). Results demonstrated that compared with p-MWCNTs, MWCNTs-OH induced significantly lower oxidative stress as indicated by the level of intracellular antioxidant glutathione (GSH), subsequently lead to less cell membrane damage as demonstrated by lactate dehydrogenase (LDH) leakage assay, and showed slightly decreased arrestment of cell cycle distribution at G0/G1. More interestingly, MWCNTs-OH exhibited significantly lower tendency to activate caspase-8, a key molecule involved in the extrinsic apoptotic pathway. All these in vitro results demonstrated that hydroxylation of MWCNTs enhanced their biocompatibility compare with p-MWCNTs.

Berberine Derivatives with Different Pharmacological Activities via Structural Modifications

Berberine, a quaternary ammonium protoberberine alkaloid with an isoquinoline scaffold isolated from medicinal herbs, exhibits a wide spectrum of pharmacological activities. Berberine has been used in traditional Chinese medicine and Ayurvedic medicine. However, it has poor bioavailability, which seriously limits its application and development. The chemical transformation of natural products is an effective method to improve pharmacological activities. Researches have been carried out on the modification of berberine to obtain better pharmacological properties. In this paper, the structural modifications of berberine for different biological activities and its underlying mechanisms are reviewed.

Synthesis and anticancer activity of 9-O-pyrazole alkyl substituted berberine derivatives

BACKGROUND Berberine (BBR), an isoquinoline plant alkaloid isolated from plants such as Coptis chinensis and Hydrastis canadensis, own multiple pharmacological activities. OBJECTIVE In this study, seven BBR derivatives were synthesized and their anticancer activity against HeLa cervical and A549 human lung cancer cell lines were evaluated in vitro. METHODS The anti-cancer activity was measured by MTT assay, and apoptosis was demonstrated by the annexin V-FITC/PI staining assay. The intracellular oxidative stress was investigated through DCFH-DA assay. The molecular docking study was carried out in molecular operating environment (MOE). RESULTS Compound B3 and B5 showed enhanced anti-cancer activity compared with BBR, the IC50 for compound B3 and B5 were significantly lower than BBR, and compound B3 at the concentration of 64 or 128 µM induced apoptosis in HeLa and A549 cell lines. The reactive oxygen species (ROS) was generated in both cell lines when treated with 100 µM of all the compounds, and compound B3 and B5 induced higher activity in the generation of ROS, while compound B3 exhibited the highest activity, these results are in accordance with the cytotoxicity results, indicating the cytotoxicity were mostly generated from the oxidative stress. In addition, molecular docking analysis showed that compound B3 had the greatest affinity with Hsp90. Upon binding, the protective function of Hsp90 was lost, which might explain its higher cytotoxicity from molecular interaction aspect. CONCLUSION All the results demonstrated that compound B3 and B5 showed significantly higher anti-cancer ability than BBR, and compound B3 is a promising anticancer drug candidate.

Synthesis and anti-inflammatory effects of a series of novel 9-O-substituted berberine derivatives

Berberine owns multiple pharmacological activities, especially anti-inflammatory activity. To enhance the anti-inflammatory therapeutic efficiency of berberine, a series of novel 9-O-substituted berberine derivatives (5a–5d) were synthesized and their anti-inflammatory activities were evaluated. 13C-NMR, 1H-NMR, IR and high resolution mass spectrum (HRMS) results indicated that these derivatives were successfully synthesized. The xylene-induced inflammatory mice model demonstrated that these derivatives showed dose-dependent inhibition of ear inflammatory swelling. Comparing to berberine, ibuprofen and naproxen-modified berberine derivatives enhanced anti-inflammatory activities, while aspirin and nicotinic acid-modified berberine derivatives showed lower anti-inflammatory effects at the same dosages. This could be attributed to the enhanced inhibition of secretion of cytokines, including interleukin-6 and tumor necrosis factor-α, by ibuprofen and naproxen berberine derivatives, while aspirin and nicotinic acid berberine derivatives showed lower inhibition of tumor necrosis factor-α than berberine. These results suggest that ibuprofen and naproxen-modified berberine derivatives are promising new anti-inflammatory drug candidates.