Piperine is a simple alkaloid isolated from the seeds of Piper nigrum. Piperine and its derivatives exhibited a wide range of biological properties such as antitumor activity, antioxidant activity, antiinflammatory activity, antimycobacterial activity, insecticidal activity, etc. Although five excellent reviews have recently been described by Srinivasan in 2007, Mao in 2011, Butt in 2013, and Meghwal in 2013, respectively, their topics were mainly focused on the biological effects. Therefore, in the present review, the progress in the structural modifications on the aliphatic chain and the amide moiety of piperine was reported. Meanwhile, the biological activities and structure-activity relationship of piperine and its derivatives were also described.

A novel nucleic acid isothermal amplification method based on saltatory rolling circle amplification (SRCA) for rapid and visual detection of Alicyclobacillus acidoterrestris in apple juice was established. Fourteen A. acidoterrestris strains and 44 non-A. acidoterrestris strains were used to confirm the specificity. The sensitivity of SRCA was 4.5 × 10 1 CFU/mL by observing the white precipitate with the naked eye, while it was 4.5 × 10 0 CFU/mL by fluorescence visualization. The detection limit of SRCA in artificially inoculated apple juice was 7.1 × 10 1 and 7.1 × 10 0 CFU/mL via visualization of the white precipitate and fluorescence, respectively. Compared with the traditional PCR method, SRCA exhibited at least a 100-fold higher sensitivity and 100-fold lower detection limit. Seventy samples were investigated for A. acidoterrestris contamination, and the results showed 100% sensitivity, 97.01% specificity, and 97.14% accuracy compared with those by the conventional microbiological cultivation method. Overall, this method is a potentially useful tool for visual and rapid detection of A. acidoterrestris.

pH-and temperature-sensitive nanogels (NGs) were prepared from sodium alginate (SA) and N-isopropylacrylamide (NIPAM), as the sensitivity at pH 5.5 and 31 °C. SA was pH-modified with glutamic acid (Glu) and ethylenediamine (EDA). The products Glu-SA (Glu-modified SA) and EGSA (EDA-and Glu-modified SA) were characterized by ninhydrin color reaction, infrared spectroscopy, and zeta potential, and the best reactant ratio was selected. Moreover, temperature-sensitive, pH-sensitive EGSA-NGs possessing a semiinterpenetrating network structure were prepared by radical polymerization using N-isopropylacrylamide. The morphology of EGSA-NGs was characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The cytotoxicity test shows the low cytotoxicity and high biocompatibility of the NGs. The newly prepared NGs were also subjected to pH-sensitive temperature-sensitive in vitro drug-loading and drug-release experiments. The pH-sensitive and temperature-sensitive experiments showed that the particle size of EGSA-NGs was reduced at pH 5.5 and above 31 °C. The drugloading and drug-release experiments also confirmed this finding, indicating that the newly synthesized NGs could release the drug according to the environmental changes. Therefore, the material has potential application value in solid tumor targeted therapy.

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