Metabolic stability and metabolic enzyme phaenotypes of lanceolatin B in liver microsomes of different species by UPLC-MS/MS / 中国中药杂志

To investigate the metabolic stability and parameters in vitro of lanceolatin B in liver microsomes of rats, human, Beagle dogs, and monkeys, and to identify the phaenotypes of CYP enzymes of lanceolatin B by using the liver microsome incubation system in vitro. After incubated with different species of liver microsomes, lanceolatin B was quantified by UPLC-MS/MS method to evaluate its metabolic stability and metabolic kinetic parameters in vitro. Lanceolatin B was incubated with specific inhibitors of CYP450 isoforms (CYP2E1, 2C19, 1A2, 2D6, 2C9, 3A4, and 2A1) to determine the phaenotypes of metabolic enzymes. The results showed that lanceolatin B was metabolized in the liver microsomes of rats and monkeys but not in the human and Beagle dogs. Their in vitro half-life T1/2 and intrinsic clearance rate CLint in rat and monkey liver microsomes were 11.57,8.07 min, and 0.12,0.17 mL•min⁻¹•mg⁻¹ without significant difference. The results of metabolic phenotyping indicated that CYP1A2 was mainly involved in the metabolism of lanceolatin B. There existed a difference in the metabolism of lanceolatin B in different types of liver microsomes. Several of CYP450 isoforms metabolized lanceolatin B together in liver microsomes of rats, in which CYP1A2 was the major enzyme mainly responsible for the metabolism of lanceolatin B.

In vitro metabolism of anti-tumor compound E7 in different species of liver microsomes / 中国中药杂志

To investigate the metabolic stability of E7 in liver microsomes of human, Beagle dog, Cynomolgus monkey and SD rats, and compare the metabolic differences between different species. Selective chemical inhibitors were used to determine the effects of different inhibitors on E7 metabolic rate, and predict the main enzymes involved in E7 metabolism in rat liver microsomes. The experimental results showed that the in vitro half-lives (T1/2) of E7 in liver microsomes of human, dog, monkey and rats were 57.75, 69.30, 16.90,30.13 min respectively. Their intrinsic clearance rate was 0.004 8, 0.004 0, 0.016 4 and 0.009 2 mL•min⁻¹•mg⁻¹ respectively. Hence, it could be speculated that the metabolic rate of E7 was similarly slow in human and dog liver microsomes; while it was similarly fast in monkey and rat liver microsomes. There was significant difference in metabolic rate of E7 between different species. The results showed that CYP2E1, CYP2A6, CYP1A2 and CYP2D6 might participate in metabolism of E7, while the contribution of polymorphic CYP3A4 was small.

Identification of aminoalcohol-diterpenoid alkaloids in Aconiti Lateralis Radix Praeparata and study of their cardiac effects / 药学学报

In order to affirm the cardioactive components in Fuzi, we identified a group of aminoalcohol- diterpenoid alkaloids in Fuzi using ultra high-performance liquid chromatography coupled with electrospray ionization mass spectrometer (UPLC-ESI-MS) method. Among a total of forty-one isolated ingredients, thirteen major aminoalcohol-diterpenoid alkaloids were identified by comparing their retention times and MS spectra with those of the reference substances. Moreover, Fuzi samples from different places of origin and with different processing methods were examined and their components displayed a pattern of high similarity, though the relative abundance varies probably due to their different processing methods. Furthermore, the cardiac effect of each identified alkaloid was individually evaluated using the isolated bullfrog heart perfusion experiment. Among the thirteen aminoalcohol diterpenoid alkaloids tested, six of them significantly enhanced the amplitude rates. Taken together, we affirm that the cardioactive components in Fuzi are aminoalcohol-diterpenoid alkaloids, shedding light on future studies of the mechanisms and development of these cardioactive compounds.

Liposomal honokiol, a potent anti-angiogenesis agent, in combination with radiotherapy produces a synergistic antitumor efficacy without increasing toxicity

Honokiol is an active compound purified from magnolia that has been shown to induce cell differentiation, apoptosis, and anti-angiogenesis effects, as well as an enhancement in tumor growth delay in combination with chemotherapeutic agents in several mouse xenograft models. Our goal was to investigate the radiosensitization effect of honokiol on lung carcinoma. The radiosensitization effect of liposomal honokiol in Lewis lung carcinoma cells (LL/2) was analyzed using an in vitro clonogenic survival assay. For an in vivo study, Lewis lung carcinoma-bearing C57BL/6 mice were treated with either liposomal honokiol at 25 mg/kg or 5 Gy of single tumor radiation, or a combination of both over 12 days of treatment. The tumor growth delay and the survival time were evaluated. In addition, histological analysis of tumor sections was performed to examine changes by detecting the microvessel density and apoptosis in tumor tissues. In the clonogenic survival assay, LL/2 cells treated with IC50 Lipo-HNK for 24 h showed a radiation enhancement ratio of 1.9. After 12 days of combination treatment, the tumor volume decreased 78% and produced an anti-tumor activity 1.3-fold greater than a predicted additive effect of honokiol and radiation alone. This combination treatment also caused an 8.7 day delay in tumor growth. The cell cycle distribution and histological analysis demonstrated that liposomal honokiol has an anti-tumor effect via inducing apoptosis and inhibiting angiogenesis. Liposomal honokiol can enhance tumor cell radiosensitivity in vitro and in vivo, indicating that radiotherapy combined with liposomal honokiol can lead to greater anti-tumor efficacy.