HPLC determination of piperine in pepper and in pepper extracts

Summary HPCL quantitation of piperine in pepper and in pepper extracts is described. This is optimised on nitratedsulphonated phenyl silica gel with phloracetophenone as internal standard.     

胡椒碱的提取、纯化及其抗癌活性的研究

本文利用溶剂法提取胡椒果中的胡椒碱成分,通过重结晶法纯化活性胡椒碱,并对其纯度和抗癌活性进行表征。结果表明,经分离纯化得到的胡椒碱纯度高达99.94%,并具有良好的抗癌效果。此外,运用密度泛函理论中B3LYP方法对胡椒碱的几何结构、相对能、热力学分布进行优化计算,建立和分析了胡椒碱的理论模型。所建立的能量最低的稳定胡椒碱理论模型符合热力学分布结果。     

胡椒碱的极谱分析研究

在ｐＨ２．２的Ｂｒｉｔｔｏｎ－Ｒｏｂｉｎｓｏｎ缓冲溶液中，胡椒碱在－１．１０Ｖ（ｕｓ．ＳＣＥ）左右产生一灵敏的极谱波，导数峰电流与胡椒碱浓度在０．０５－８μｇ／ｍｌ范围内呈良好的线性关系。本法操作简便，快速，灵敏，选择性较好。用于天然胡椒果实中胡椒碱的测定，得到了满意结果。本文对极谱波性质及电极反应机理进行了研究。     

锰(Ⅱ)-胡椒碱-溴化十六烷基三甲基胺三元体系的荧光特性及应用

The fluorescence characteristics of the complex of piperine with cation in micellar system were studied. At the same time, the influence of experimental condition on the fluorescence intensity was also studied. The experiments indicated that piperine had very low fluorescence signal itself. But in pH 8.77 Na₂HPO₄-NaH₂PO₄ buffer solution, both Mn(Ⅱ) and cationic surfactant cetyltrimethylammonium bromide can enhance the fluorescence intensity and stability of piperine. Based on this, a sensitive method has been developed for the quantitative determination of piperine in Mn(Ⅱ)-piperine-cetyltrimethylammonium bromide ternary system. Under the optimum conditions, there is a linear relationship between the enhancement of fluorescence intensity and the concentration of Mn(Ⅱ). The optimal conditions are as follows: the concentration of Mn(Ⅱ) is 2.5×10-4 mol·L-1 and the concentration of cetyltrimethylammonium bromide is 5×10-4 mol·L-1. The fluorescence intensity was determined by a 1 cm quartz cell with the excitation wavelength of 352 nm and the emission wavelength of 452 nm. The linear range of concentration of piperine was 2.02-10.1 μg·mL-1 with the relative coefficient of 0.998 5 and the detection limit of 0.060 2 μg·mL-1. The relative standard deviation (RSD) was 1.10%. The proposed method has been successfully applied to the quantitative determination of piperine in the Mongolian medicine Piper longum L, and the recovery was within the range of 97.6%-102.0%. The results were very satisfactory.     

胡椒酸丁二醇单脂与牛血清白蛋白相互作用的研究

运用荧光及紫外-可见吸收光谱法研究了胡椒酸丁二醇单酯(简称BPM)与牛血清白蛋白(BSA)的相互作用。实验结果表明,胡椒酸丁二醇单酯与BSA形成基态复合物导致BSA内源性荧光猝灭,猝灭机理主要为静态猝灭和非辐射能量转移,其猝灭速率常数为Kq为1.077×1013L/(mol.s)(25℃)、0.946×1013L/(mol.s)(37℃)。利用荧光猝灭反应测得结合常数KA为2.6×106(25℃)、3.4×106(37℃),结合位点数n为1.30(25℃)、1.33(37℃)。根据Frster能量转移理论得到结合距离r=2.92nm(25℃)、2.66nm(37℃)和能量转移效率E=0.45(25℃)、0.43(37℃)。通过热力学参数计算,确定胡椒酸丁二醇单酯与BSA的相互作用是熵增加和吉布斯自由能降低的自发过程,主要作用力是疏水作用力。     

胡椒生物碱提取、几何结构以及红外光谱的研究

以海南胡椒果为原料,95%乙醇溶液为溶剂,采用回流法提取胡椒生物碱。通过调节pH值除去胡椒酸,乙醚除去脂溶物,用丙酮为溶剂重结晶纯化胡椒生物碱,并用高效液相色谱仪检测其纯度,以及对胡椒生物碱进行了红外光谱表征。同时运用密度泛函B3LYP/6-31G(d, p)方法,对胡椒生物碱的结构进行优化、频率和能量的计算,得到四种构型(构型Ⅰ胡椒碱、构型Ⅱ异胡椒碱、构型Ⅲ异胡椒脂碱和构型Ⅳ胡椒脂碱)的64种构象的稳定结构,并利用吉布斯自由能计算常温(298.15 K)下四种构型分子体系稳定构象的热力学平衡分布。并对实验红外光谱与理论红外光谱的特征峰进行了对比。结果表明,所提取的胡椒生物碱主要以构型Ⅰ中的构象1结构存在,即胡椒碱结构;经纯化后得到胡椒碱含量为7%,纯度达99%。经分析建立的胡椒生物碱提取、分离和纯化方法效果良好,建立的胡椒生物碱模型能与实验结果相吻合。该研究对指导胡椒生物碱的提取、结构模型的建立、表征和应用有重大意义。     

Piperine loaded zinc oxide nanocomposite inhibits the PI3K/AKT/mTOR signaling pathway via attenuating the development of gastric carcinoma: In vitro and in vivo studies

Gastric cancer (GC) is the fifth most cancer type and the third most cause of cancer-associated deaths worldwide along with the 5-year survival rate is less the 30%. This investigation was aimed to synthesis the piperine-loaded zinc oxide nanocomposite (ZnO-Pip-NC) and investigating its anticancer activity against the GC by in vitro and in vivo models by the inhibiting the apoptotic and PI3K/Akt/mTOR signaling pathways. The synthesized ZnO-Pip-NC was characterized by different techniques. The cytotoxicity of zinc oxide, piperine and the formulated ZnO-Pip-NC was tested against the AGS cells by MTT assay. The intracellular ROS level, mitochondrial membrane potential, and apoptotic cell necrosis in the AGS cells was examined by fluorescent staining techniques. The expression of apoptotic and PI3K/Akt/mTOR signaling markers were inspected by western blotting and the expression of pro0inflammatory markers analyzed by RT-PCR technique. The antioxidant levels were examined by standard methods and histopathology of gastric mucosa was analyzed. The ZnO-Pip-NC treatment appreciably inhibited the AGS cell viability. ZnO-Pip-NC treated cells also exhibited excessive intracellular ROS, diminished MMP, nuclear damages, and apoptosis induction in AGS cells. The enhanced expression of pro-apoptotic proteins and inhibition of PI3K/Akt/mTOR signaling pathway was noted in ZnO-Pip-NC treated cells. In vivo studies proved that the ZnO-Pip-NC noticeably restored the antioxidants in the GC animals and also prevented the gastric mucosa and inhibited the GC tumor formation. In conclusion, the findings of this investigation confirmed the anticancer potential of ZnO-Pip-NC against the GC via inhibiting the PI3K/Akt/mTOR signaling pathway.     

胡椒碱与牛血清白蛋白的相互作用

采用荧光光谱技术研究了胡椒碱与牛血清白蛋白（BSA）的相互作用。根据测定不同温度下胡椒碱对BSA的猝灭常数,证实了荧光猝灭过程为静态猝灭,由热力学参数焓变（ΔH）小于零和熵变（ΔS）大于零,推断出胡椒碱与BSA之间主要靠静电引力相结合,生成自由能变（ΔG）为负值,表明胡椒碱与BSA的作用过程是一个自发过程;并应用同步荧光光谱技术考察了胡椒碱对BSA构象的影响。