Chemical composition and antimicrobial activity of essential oils of Ocimum basilicum, Ocimum canum and Ocimum gratissimum in function of harvesting time

BACKGROUND: The aim of present the study was to investigate the chemical composition and the antimicrobial activity of essential oils of Ocimum basilicum, Ocimum canum and Ocimum gratissimum from Benin as affected by harvesting time. The chemical composition of hydrodistillated essential oils were analyzed by GC-FID (gas chromatography – flame ionization detector) and GC-MS (gas chromatography-mass spectrometry). Disc diffusion and broth microdilution assays were used to evaluate the antibacterial activity of essential oils against two foodborne pathogens. RESULTS: Based on the composition analysis, major components were as follows: estragol (43.0 -44.7 %) and linalool (24.6 -29.8 %) in O. basilicum oils; carvacrol (12.0 -30.8 %) and p-cymene (19.5 -26.2 %) in O. canum oils; thymol (28.3 -37.7 %) and γ-terpinene (12.5 -19.3 %) in O. gratissimum oils. The tested oils and their components exhibited notable antimicrobial activities against Listeria monocytogenes and Salmonella typhimurium. The O. canum and O. gratissimum oils collected at 7h and 19h showed significant higher activities against L. monocytogenes and S. typhimurium (MICs and MBCs 0.34 – 2.5 µL/mL) (p < 0.05), whereas O. basilicum showed lower activity (MICs and MBCs 2.0 – 8.0 µL/mL) at any daytime of harvest, the weakest being at 19h (MIC and MBC 12.0 – 32.0 µL/mL). CONCLUSION: The daytime of harvest can influence the composition of oils and their activities on bacteria

When Inequality is Equitable: Validity, Propriety and Third Party Allocations

The author summarizes theories of equity and distributive justice that predict actors use legitimate distribution rules to act to maintain or to restore equity. He elaborates those ideas, distinguishing legitimacy based on validity (socially supported) from propriety (acceptance by the focal actor). Experimental research showed strong effects of both types of legitimacy on behavior, with validity having slightly stronger effects.This research was supported by a grant from the National Science Foundation (SOC #7817^3<»), Morris Zelditch, Jr.» Principal Investigator. Computations were supported by a grant from the Office of the Dean of Graduate Studies and Research at Stanford University

Recent metabolomic developments for antimalarial drug discovery.

peer reviewedMalaria is a parasitic disease that remains a global health issue, responsible for a significant death and morbidity toll. Various factors have impacted the use and delayed the development of antimalarial therapies, such as the associated financial cost and parasitic resistance. In order to discover new drugs and validate parasitic targets, a powerful omics tool, metabolomics, emerged as a reliable approach. However, as a fairly recent method in malaria, new findings are timely and original practices emerge frequently. This review aims to discuss recent research towards the development of new metabolomic methods in the context of uncovering antiplasmodial mechanisms of action in vitro and to point out innovative metabolic pathways that can revitalize the antimalarial pipeline

Arbuscular mycorrhizal fungi impact the production of alkannin/shikonin and their derivatives in Alkanna tinctoria Tausch. grown in semi-hydroponic and pot cultivation systems

IntroductionAlkanna tinctoria Tausch. is a medicinal plant well-known to produce important therapeutic compounds, such as alkannin/shikonin and their derivatives (A/Sd). It associates with arbuscular mycorrhizal fungi (AMF), which are known, amongst others beneficial effects, to modulate the plant secondary metabolites (SMs) biosynthesis. However, to the best of our knowledge, no study on the effects of AMF strains on the growth and production of A/Sd in A. tinctoria has been reported in the literature.MethodsHere, three experiments were conducted. In Experiment 1, plants were associated with the GINCO strain Rhizophagus irregularis MUCL 41833 and, in Experiment 2, with two strains of GINCO (R. irregularis MUCL 41833 and Rhizophagus aggregatus MUCL 49408) and two native strains isolated from wild growing A. tinctoria (R. irregularis and Septoglomus viscosum) and were grown in a semi-hydroponic (S-H) cultivation system. Plants were harvested after 9 and 37 days in Experiment 1 and 9 days in Experiment 2. In Experiment 3, plants were associated with the two native AMF strains and with R. irregularis MUCL 41833 and were grown for 85 days in pots under greenhouse conditions. Quantification and identification of A/Sd were performed by HPLC-PDA and by HPLC-HRMS/MS, respectively. LePGT1, LePGT2, and GHQH genes involved in the A/Sd biosynthesis were analyzed through RT-qPCR.ResultsIn Experiment 1, no significant differences were noticed in the production of A/Sd. Conversely, in Experiments 2 and 3, plants associated with the native AMF R. irregularis had the highest content of total A/Sd expressed as shikonin equivalent. In Experiment 1, a significantly higher relative expression of both LePGT1 and LePGT2 was observed in plants inoculated with R. irregularis MUCL 41833 compared with control plants after 37 days in the S-H cultivation system. Similarly, a significantly higher relative expression of LePGT2 in plants inoculated with R. irregularis MUCL 41833 was noticed after 9 versus 37 days in the S-H cultivation system. In Experiment 2, a significant lower relative expression of LePGT2 was observed in native AMF R. irregularis inoculated plants compared to the control.DiscussionOverall, our study showed that the native R. irregularis strain increased A/Sd production in A. tinctoria regardless of the growing system used, further suggesting that the inoculation of native/best performing AMF is a promising method to improve the production of important SMs