Germacrene D Cyclization: An Ab Initio Investigation

Essential oils that contain large concentrations of germacrene D are typically accompanied by cadinane sesquiterpenoids. The acid-catalyzed cyclization of germacrene D to give cadinane and selinane sesquiterpenes has been computationally investigated using both density functional (B3LYP/6-31G*) and post Hartree-Fock (MP2/6-31G* *) ab initio methods. The calculated energies are in general agreement with experimentally observed product distributions, both from acid-catalyzed cyclizations as well as distribution of the compounds in essential oils

Chemotyping and Determination of Antimicrobial, Insecticidal, and Cytotoxic Properties of Wild-Grown Cannabis sativa from Nepal

Cannabis sativa was collected from a wildgrowing population in Biratnagar, Nepal. The essential oil was obtained by hydrodistillation and analyzed by gas chromatography – mass spectrometry. A total of 107 constituents were identified in the oil accounting for 94.2% of the composition. This Nepalese chemotype is characterized by a predominance of sesquiterpenoids (68.1%) dominated by (E)-caryophyllene (20.4%), α-humulene (7.0%), and α-bisabolol (5.8%), but a paucity of monoterpene hydrocarbons (0.9%). In particular, neither myrcene nor terpinolene were detected. The oil in the Nepalese Cannabis plants did contain small amounts of cannabidiol (1.6%), cannabichromene (0.2%) and Δ9-tetrahydrocannabinol (0.4%). The essential oil from Nepalese Cannabis sativa was screened for antimicrobial, cytotoxic, larvicidal, and insecticidal activity, and it appears as though C. sativa is relatively non-toxic

Who let the trolls out? Towards understanding state-sponsored trolls

Recent evidence has emerged linking coordinated campaigns by state-sponsored actors to manipulate public opinion on the Web. Campaigns revolving around major political events are enacted via mission-focused ?trolls." While trolls are involved in spreading disinformation on social media, there is little understanding of how they operate, what type of content they disseminate, how their strategies evolve over time, and how they influence the Web's in- formation ecosystem. In this paper, we begin to address this gap by analyzing 10M posts by 5.5K Twitter and Reddit users identified as Russian and Iranian state-sponsored trolls. We compare the behavior of each group of state-sponsored trolls with a focus on how their strategies change over time, the different campaigns they embark on, and differences between the trolls operated by Russia and Iran. Among other things, we find: 1) that Russian trolls were pro-Trump while Iranian trolls were anti-Trump; 2) evidence that campaigns undertaken by such actors are influenced by real-world events; and 3) that the behavior of such actors is not consistent over time, hence detection is not straightforward. Using Hawkes Processes, we quantify the influence these accounts have on pushing URLs on four platforms: Twitter, Reddit, 4chan's Politically Incorrect board (/pol/), and Gab. In general, Russian trolls were more influential and efficient in pushing URLs to all the other platforms with the exception of /pol/ where Iranians were more influential. Finally, we release our source code to ensure the reproducibility of our results and to encourage other researchers to work on understanding other emerging kinds of state-sponsored troll accounts on Twitter.https://arxiv.org/pdf/1811.03130.pdfAccepted manuscrip

Antiprotozoal Activity of Essential Oils

In the present scenario of protozoal infections, new drugs are urgently needed to treat and control infections such as malaria, sleeping sickness, Chagas disease, leishmaniasis and intestinal infections, which affect millions of people each year. In this review, we are focusing on articles related to antiprotozoal essential oils extracted from plants that have been published during the last 20 years. The data analyzed indicate that essential oils could be promising antiprotozoal agents, opening perspectives to the discovery of more effective drugs of vegetal origin for the treatment of diseases caused by protozoa

Tabebuia bahamensis: A Major Source of Pharmacologically Important Ursolic Acid

Leaves of Tabebuia bahamensis, collected on Abaco Island, Bahamas, were dried and extracted with dichloromethane to yield a crude extract. Using preparative flash column chromatography on silica gel, enabled the isolation of ursolic acid with an excellent yield of 2.06 percent based on the mass of dry leaves. Both the crude leaf extract and ursolic acid produced selective in-vitro cytotoxic activity on tumor cells from human mammary and bladder tissue. Ursolic acid also demonstrated antibacterial activity against Staphylococcus aureus

Conformational Analysis of Thioether Musks Using Density Functional Theory

A conformational analysis of nine macrocyclic thioether musks has been carried out using molecular mechanics (MMFF), density functional theory (DFT) using both B3LYP and M06 functionals, as well as Hartree-Fock and post-Hartree-Fock (MP2) ab initio methods. 6-Thia-, 10-thia- and 4-methyl-5-thia-14-tetradecananolide, 4-thia-, 7-thia-, 11-thia- and 12-thia-15-pentadecanolide and 6-thia- and 12-thia-16-hexadecanolide were modeled. Unfortunately, there was little agreement between the computational methods at the levels of theory used in this study

Attenuation of Cytotoxic Natural Product DNA Intercalating Agents by Caffeine

Many anti-tumor drugs function by intercalating into DNA. The xanthine alkaloid caffeine can also intercalate into DNA as well as form π-π molecular complexes with other planar alkaloids and anti-tumor drugs. The presence of caffeine could interfere with the intercalating anti-tumor drug by forming π-π molecular complexes with the drug, thereby blocking the planar aromatic drugs from intercalating into the DNA and ultimately lowering the toxicity of the drug to the cancer cells. The cytotoxic activities of several known DNA intercalators (berberine, camptothecin, chelerythrine, doxorubicin, ellipticine, and sanguinarine) on MCF-7 breast cancer cells, both with and without caffeine present (200 μg/mL) were determined. Significant attenuation of the cytotoxicities by caffeine was found. Computational molecular modeling studies involving the intercalating anti-tumor drugs with caffeine were also carried out using density functional theory (DFT) and the recently developed M06 functional. Relatively strong π–π interaction energies between caffeine and the intercalators were found, suggesting an “interceptor” role of caffeine protecting the DNA from intercalation