Inhibitory effect of essential oils obtained from plants grown in Colombia on yellow fever virus replication in vitro

<p>Abstract</p> <p>Background</p> <p>An antiviral drug is needed for the treatment of patients suffering from yellow fever. Several compounds present in plants can inactive <it>in vitro </it>a wide spectrum of animal viruses.</p> <p>Aim</p> <p>In the present study the inhibitory effect of essential oils of <it>Lippia alba, Lippia origanoides, Oreganum vulgare </it>and <it>Artemisia vulgaris </it>on yellow fever virus (YFV) replication was investigated.</p> <p>Methods</p> <p>The cytotoxicity (CC₅₀) on Vero cells was evaluated by the MTT reduction method. The minimum concentration of the essential oil that inhibited virus titer by more than 50% (MIC) was determined by virus yield reduction assay. YFV was incubated 24 h at 4°C with essential oil before adsorption on Vero cell, and viral replication was carried out in the absence or presence of essential oil. Vero cells were exposed to essential oil 24 h at 37°C before the adsorption of untreated-virus.</p> <p>Results</p> <p>The CC₅₀values were less than 100 μg/mL and the MIC values were 3.7 and 11.1 μg/mL. The CC₅₀/MIC ratio was of 22.9, 26.4, 26.5 and 8.8 for <it>L. alba, L origanoides, O. vulgare and A. vulgaris</it>, respectively. The presence of essential oil in the culture medium enhances the antiviral effect: <it>L. origanoides </it>oil at 11.1 μg/mLproduced a 100% reduction of virus yield, and the same result was observed with <it>L. alba, O. vulgare </it>and <it>A. vulgaris </it>oils at100 μg/mL. No reduction of virus yield was observed when Vero cells were treated with essential oil before the adsorption of untreated-virus.</p> <p>Conclusion</p> <p>The essential oils evaluated in the study showed antiviral activities against YFV. The mode of action seems to be direct virus inactivation.</p

The location routing problem with facility sizing decisions

The location routing problem (LRP) integrates operational decisions on vehicle routing operations with strategic decisions on the location of the facilities or depots from which the distribution will take place. In other words, it combines the well-known vehicle routing problem (VRP) with the facility location problem (FLP). Hence, the LRP is an NP-hard combinatorial optimization problem, which justifies the use of metaheuristic approaches whenever large-scale instances need to be solved. In this paper, we explore a realistic version of the LRP in which facilities of different capacities are considered, i.e., the manager has to consider not only the location but also the size of the facilities to open. In order to tackle this optimization problem, three mixed-integer linear formulations are proposed and compared. As expected, they have been proved to be cost- and time- inefficient. Hence, a biased-randomized iterated local search algorithm is proposed. Classical instances for the LRP with homogeneous facilities are naturally extended to test the performance of our approach.Peer ReviewedPostprint (published version

Estudio de la composición química y la actividad biológica de los aceites esenciales de diez plantas aromáticas colombianas

En este estudio se determinó la composición química de los aceites esenciales (AEs) de las hojas de 10 plantas aromáticas colombianas. Los AEs se aislaron empleando la técnica de hidrodestilación asistida por la radiación de microondas (MWHD) y la identificación de los componentes de los AEs se realizó mediante el análisis por cromatografía de gases – espectrometría de masas (GC-MS), utilizando dos columnas (DB-5 y DB-Wax). La identificación de los compuestos se basó en los índices de Kovàts y en la comparación de los espectros de masas con los de las bases de datos QuadLib2004, NIST 2002, Wiley 138k

Combining heuristics with simulation and fuzzy logic to solve a flexible-size location routing problem under uncertainty

The location routing problem integrates both a facility location and a vehicle routing problem. Each of these problems are NP-hard in nature, which justifies the use of heuristic-based algorithms when dealing with large-scale instances that need to be solved in reasonable computing times. This paper discusses a realistic variant of the problem that considers facilities of different sizes and two types of uncertainty conditions. In particular, we assume that some customers’ demands are stochastic, while others follow a fuzzy pattern. An iterated local search metaheuristic is integrated with simulation and fuzzy logic to solve the aforementioned problem, and a series of computational experiments are run to illustrate the potential of the proposed algorithm.This work has been partially supported by the Spanish Ministry of Science (PID2019-111100RB-C21/AEI/10.13039/501100011033). In addition, it has received the support of the Doctoral School at the Universitat Oberta de Catalunya (Spain) and the Universidad de La Sabana (INGPhD-12-2020).Peer ReviewedPostprint (published version

Composición química de extractos obtenidos por destilaciónextracción simultánea con solvente de hojas e inflorescencias de nueve especies y/o variedades de albahacas (ocimum spp.)

Se determinó la composición química de extractos obtenidos por destilaciónextracción simultánea con solvente (SDE) de nueve especies y/o variedades de Ocimum spp. (albahacas moradas, reina, híbrida, cítrica y americana; síguemes morado y blanco). La identificación de los compuestos se realizó por GC-MS y por comparación de sus espectros de masas con los de las bases de datos QuadLib, NIST02 y Wiley138 e índices de retención de Kovàts. Los siguientes fueron los compuestos mayoritarios identificados en los extractos: eucaliptol, linalol, nerol, geraniol, neral, geranial, estragol, eugenol y transcinamato de metilo