Extraction, Characterization, and Evaluation of the Cytotoxic Activity of Piperine in Its Isolated form and in Combination with Chemotherapeutics against Gastric Cancer.

Gastric cancer is one of the most frequent types of neoplasms worldwide, usually presenting as aggressive and difficult-to-manage tumors. The search for new structures with anticancer potential encompasses a vast research field in which natural products arise as promising alternatives. In this scenario, piperine, an alkaloid of the Piper species, has received attention due to its biological activity, including anticancer attributes. The present work proposes three heating-independent, reliable, low-cost, and selective methods for obtaining piperine from Piper nigrum L. (Black pepper). Electronic (SEM) and optical microscopies, X-ray diffraction, nuclear magnetic resonance spectroscopies (13C and 1H NMR), and optical spectroscopies (UV-Vis, photoluminescence, and FTIR) confirm the obtention of piperine crystals. The MTT assay reveals that the piperine samples exhibit good cytotoxic activity against primary and metastasis models of gastric cancer cell lines from the Brazilian Amazon. The samples showed selective cytotoxicity on the evaluated models, revealing higher effectiveness in cells bearing a higher degree of aggressiveness. Moreover, the investigated piperine crystals demonstrated the ability to act as a good cytotoxicity enhancer when combined with traditional chemotherapeutics (5-FU and GEM), allowing the drugs to achieve the same cytotoxic effect in cells employing lower concentrations. These results establish piperine as a promising molecule for therapy investigations in aggressive gastric cancer, both in its isolated form or as a bioenhancer.

Structural and Thermal Characteristics of Buriti Tree Gum (Mauritia flexuosa).

A polysaccharide was isolated from the exudate of a buriti tree trunk (Mauritia flexuosa). The molecular structure, thermal stability, morphology, crystallinity, and elemental composition of the product were investigated through spectroscopic techniques, such as Fourier-transform infrared spectroscopy (FTIR), nuclear magnetic resonance (NMR 1H and 13C), and energy-dispersive X-ray spectroscopy (EDS); thermogravimetric analysis (TG), differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and X-ray diffraction (XRD). In addition to NMR molecular modeling studies, were performed to confirm the 1H and 13C chemical shifts to Gal and Xyl conformers. Buriti tree gum (BG) is an arabinogalactan, containing Rha, Ara, Xyl, and Gal, and degrades almost completely (98.5%) at 550 °C and has a maximum degradation peak at 291.97 °C, with a mass loss of 56.33%. In the temperature range of 255-290 °C, the energy involved in the BG degradation process was approximately 17 J/g. DSC indicated a glass transition temperature of 27.2 °C for BG, which had an irregular and heterogeneous morphology, with smooth or crumbling scaly regions, demonstrating the amorphous nature of BG that was confirmed by the XRD standard. EDS revealed the presence of carbon and oxygen, as well as calcium, magnesium, aluminum, silicon, chlorine, and potassium, in the BG composition.