@uea.edu.ec
Professor. Life Sciences Faculty
Universidad Estatal Amazónica
Analytical Chemistry. Envionmental Sciences. Pharmaceutical Sciences. Agroindustry
Scopus Publications
Dixon Domingo Andi Grefa, Jenny Estefanía Guevara Sánchez, Luis Ramón Bravo Sánchez, Mario Simeón Pomares Alfonso, and Margarita Edelia Villanueva Tagle
Elsevier BV
Yasiel Arteaga-Crespo, Matteo Radice, Luis Ramón Bravo-Sanchez, Yudel García-Quintana, and Laura Scalvenzi
Elsevier BV
Yasiel Arteaga Crespo, Luis Ramón Bravo Sánchez, Yudel García Quintana, Andrea Silvana Tapuy Cabrera, Abdel Bermúdez del Sol, and Dorys Magaly Guzmán Mayancha
Elsevier BV
Reinier Abreu-Naranjo, Yasiel Arteaga-Crespo, Luis Ramón Bravo-Sanchez, Manuel Lázaro Pérez-Quintana, and Yudel García-Quintana
Springer Science and Business Media LLC
Elisa Jorge Rodríguez, Yanelis Saucedo-Hernández, Yvan Vander Heyden, Ernesto F. Simó-Alfonso, Guillermo Ramis-Ramos, María Jesús Lerma-García, Urbano Monteagudo, Luis Bravo, Mildred Medinilla, Yuriam de Armas,et al.
SAGE Publications
The present study describes the phytochemical profile and antioxidant activity of the essential oils of three Piperaceae species collected in the central region of Cuba. The essential oils of Piper aduncum, P. auritum and P. umbellatum leaves, obtained by hydrodistillation, were analyzed by gas chromatography-mass spectrometry. The main components of P. aduncum oil were piperitone (34%), camphor (17.1%), camphene (10.9%), 1,8-cineol (8.7%) and viridiflorol (7.4%), whereas that of P. auritum and P. umbellatum was safrole (71.8 and 26.4%, respectively). The antioxidant properties of the essential oils were also evaluated using several assays for radical scavenging ability (DPPH test and reducing power) and inhibition of lipid oxidation (ferric thiocyanate method and evaluation against Cucurbita seed oil by peroxide, thiobarbituric acid and p-anisidine methods). P. auritum showed the strongest antioxidant activity among the Piper species investigated, but lower than those of butylated hydroxyanisol and propyl gallate.
Sebastián Delgado Diaz, Luisa Vera Peña, Enrique González Cabrera, Marta Martínez Soto, Luisa M. Vera Cabezas, and Luis R. Bravo Sánchez
Elsevier BV
Lidiya Bebrevska, Luis Bravo, Jo Vandervoort, Luc Pieters, Arnold Vlietinck, and Sandra Apers
Georg Thieme Verlag KG
Pueraria lobata, also known as Kudzu (Japan) or Ge (China), is a medicinal plant widely used in Oriental traditional medicine. In this study the development, optimization and validation of an HPLC ethod for quality control of Pueraria flower plant material is presented. By means of this analytical method the three major compounds, i. e., the isoflavones tectorigenin 7- O-[beta- D-xylopyranosyl-(1 - 6)-beta- D-glucopyranoside], tectorigenin 7- O-beta- D-glucopyranoside and tectorigenin, were quantified, using the isoflavones genistin and genistein as external standards. The extraction procedure, the extraction solvent, the extraction yields and the HPLC conditions were evaluated and optimized. The samples were analyzed on an RP C18 column, and eluted with a binary system consisting of water and methanol using a linear gradient; detection was at 262 nm. Tectorigenin used in the recovery experiments was isolated and purified in the laboratory. The final method was fully validated according to the ICH guidelines in terms of linearity, precision and accuracy. The validation data showed that the precision, (RSD% (betweendays) of 3.1, 2.84 and 1.77 for the three major compounds, respectively), and the accuracy (recovery of 104.2 %) were acceptable. These validation results demonstrate the suitability of the method for the quality control of this crude drug.
Luis R Bravo-Sánchez, Jorge Ruiz Encinar, José I Fidalgo Martı́nez, and Alfredo Sanz-Medel
Elsevier BV