In vitro cytotoxicity evaluation of thiourea derivatives bearing Salix sp. constituent against HK-1 cell lines

Abstract

In searching for drugs from natural product scaffolds has gained interest among researchers. In this study, a series of twelve halogenated thiourea (ATX 1-12) via chemical modification of aspirin (a natural product derivative) and evaluated for cytotoxic activity against nasopharyngeal carcinoma (NPC) cell lines, HK-1 via MTS-based colorimetric assay. The cytotoxicity studies demonstrated that halogens at meta position of ATX showed promising activity against HK-1 cells (IC₅₀ value ≤15?µM) in comparison to cisplatin, a positive cytotoxic drug (IC₅₀ value =8.9?±?1.9?µM). ATX 11, bearing iodine at meta position, showed robust cytotoxicity against HK-1 cells with an IC₅₀ value of 4.7?±?0.7?µM. Molecular docking interactions between ATX 11 and cyclooxygenase-2 demonstrated a robust binding affinity value of ?8.1?kcal/mol as compared to aspirin’s binding affinity value of ?6.4?kcal/mol. The findings represent a promising lead molecule from natural product with excellent cytotoxic activity against NPC cell lines.     

Supply planning for industrial ecology and remanufacturing under uncertainty: a numerical study of leaded-waste recovery from television disposal

The use of waste as a raw material for manufacturing is hampered by the uncertainty associated with the availability of supply. Technological change and obsolescence further complicates the ability of decision makers to consider discarded durable products as a potential source of raw materials. This uncertainty complicates remanufacturing and industrial ecology. A problem since remanufacturing and industrial ecology need to be (and can be) profitable as well as environmentally desirable if they are to be encouraged. To address this problem the modelling of the waste flow of durable goods is considered. The disposal of televisions in the United States is used to illustrate the challenges and requirements for forecasting in an environment with supply uncertainty. This example is timely since the diposal of cathode ray tubes (CRTs) in municipal landfills is being banned and an alternate technology trajectory for televisions exists—the flat panel display and phase-out of analogue broadcasting in the US. This paper estimates the waste stream resulting from three different scenarios of CRT leaded-waste disposal patterns. The reuse of lead-containing CRT glass is found to offer potential. The elimination of this controversial waste stream, as a result of replacement by the adoption of flat panel television technology, is still decades away. The findings in this study indicate the range of the quantity of waste that will require an alternative infrastructure as it is displaced from municipal landfills. This study provides important information for both developing a collection infrastructure and processing alternatives to extract the residual value of the disposed of televisions.     

Rotational constants of the singlet electronic states of the TiO molecule

All the published measurements of the singlet systems of TiO have been surveyed and used in conjunction with recently obtained constants for the a¹Δ state to obtain improved rotational constants for all the singlet states. During the course of this analysis, new measurements were made of the 0-0 band of the δ(b¹Π-a¹Δ) system.     

The electronic spectrum of gaseous SnS

Observations of the spectrum of SnS excited in chemiluminescence have led to the characterization of two low-lying excited states of SnS, $\text{a}\text{Ω}\text{1(}{}^3\text{Σ}{}^{\mathrm{+}}\text{)}$, with T_e = 18 143.9 cm^?1, and $\text{A0}{}^{\mathrm{+}}\text{(}{}^3\text{Π}\text{)}$, with T_e = 22 021.3 cm^?1. Extended rotational analyses of the perturbed bands observed in the absorption spectrum enable assignments to be suggested for the components $\text{Ω}\text{0}{}^{\mathrm{+}}$ and 1 of ³Σ^? and $\text{Ω}\text{1}$ of ³Π.     

Flame spectroscopy of TiO: Photoluminescence of the α(C3Δ-X3Δ) system

Laser-induced photoluminescence has been observed from TiO molecules produced in a chemiluminescent flame. Using Ar⁺ and cw dye lasers, a detailed study has been made of photoluminescence of the α(C³Δ-X³Δ) system. Techniques are developed for assigning photoluminescence transitions involving states of high multiplicity in molecules with several isotopes. Assignment of a new C³Δ₃-a¹Δ transition places the a¹Δ state at 3444 ± 10 cm^?1 above the X³Δ state. Photoluminescence of the 0-0 band of the β(c¹Φ-a¹Δ) system, observed with 476.5 nm excitation, is shown to result from collisional relaxation of the C³Δ (v = 2) to c¹Φ (v = 0) states.     

Nitronate anion recognition and modulation of ambident reactivity by hydrogen-bonding receptors

Nitronate anions were shown to form complexes in DMSO with hydrogen-bonding receptors such as 1,3-dimethylthiourea 1 (K(a)= 120M(-1)) and bicyclic guanidinium 2 (K(a) = 3200M(-1)). A ditopic bis-thiourea exhibited increased association with substrates, that contained either two nitronates (K(a)= 7000M(-1)) or a combination of nitronate and carboxylate (K(a)=7200M(-1)). Complexation of nitronate resulted in a change in the ambident reactivity during alkylation with p-nitrobenzyl bromide. The predominant reaction pathway was shifted from oxygen alkylation to carbon alkylation as receptor binding strength increased. Kinetic analysis indicated an overall inhibition of nitronate reactivity, and this suggests that greater suppression of the oxygen pathway allows carbon alkylation to predominate.