Perturbing the O–H…O Hydrogen Bond in 1-oxo-3-hydroxy-2-propene

Ab initio MP2/aug’-cc-pVTZ calculations have been carried out to identify and characterize equilibrium structures and transition structures on the 1-oxo-3-hydroxy-2-propene: Lewis acid potential energy surfaces, with the acids LiH, LiF, BeH2, and BeF2. Two equilibrium structures, one with the acid interacting with the C=O group and the other with the interaction occurring at the O–H group, exist on all surfaces. These structures are separated by transition structures that present the barriers to the interconversion of the two equilibrium structures. The structures with the acid interacting at the C=O group have the greater binding energies. Since the barriers to convert the structures with interaction occurring at the O–H group are small, only the isomers with interaction occurring at the C=O group could be experimentally observed, even at low temperatures. Charge-transfer energies were computed for equilibrium structures, and EOM-CCSD spin–spin coupling constants 2hJ(O–O), 1hJ(H–O), and 1J(O–H) were computed for equilibrium and transition structures. These coupling constants exhibit a second-order dependence on the corresponding distances, with very high correlation coefficients.

Are Hydrogen Peroxide, Hypochlorite and Peracetic Acid Potential Endocrine Disruptors?

Arylsulfatase and β-glucuronidase are two important enzymes in human, which play important role on dynamic equilibrium of steroidal estrogens. This work probably for the first time reported that hydrogen peroxide (H2O2), hypochlorite and peracetic acid (PAA) could effectively inhibit the activities of arylsulfatase and/or β-glucuronidase. The 50 percent of inhibitions (IC50) of H2O2, and PAA on arylsulfatase were found to be 142.90±9.00, 91.83±10.01, and 43.46±2.92 μM, respectively. The corresponding respective IC50 of hypochlorite and PAA on β-glucuronidase were 704.90±41.40 and 23.26±0.82 μM, while H2O2 showed no inhibition on β-glucuronidase. It was further revealed that the inhibition of hypochlorite on both arylsulfatase and β-glucuronidase was irreversible. On the contrary, the inhibition by H2O2 and PAA was reversible. Moreover, it was found that the inhibitions of arylsulfatase and/or β-glucuronidase by these three chemicals were pH-dependent, among which the inhibition by H2O2 was competitive and non-competitive for PAA. In general, H2O2 and hypochlorite can be endogenously produced in human, which suggested that the two compounds are potential endocrine disruption compounds (EDCs) as they can cause endocrine disruption via inhibition of arylsulfatase and β-glucuronidase. This work further indicated that any agent that can induce production of H2O2 or hypochlorite in human is potential EDC, which explains why some EDCs with very weak or no estrogenic potency can cause endocrine disruption that confirmed in epidemiological studies.

Pharmacological investigations of Litsea lancifolia (Roxb.) Hook. F.

The petroleum ether, chloroform and ethyl acetate soluble fractions of methanolic extract of Litsea lancifolia Roxb. leaves were subjected to different pharmacological screenings to explore its potential as anti-oxidant, antimicrobial, peripheral analgesic, hypoglycemic and CNS depressing agent. The ethyl acetate soluble fraction showed highest total phenolic content and free radical scavenging activity compared to the standard, acetyl salicylic acid. Potential antimicrobial activity was shown against P. aeruginosa (23.50 mm), E. coli (22.33 mm), B. cereus (18 mm) and S. paratyphi (18 mm). The crude extract demonstrated significant peripheral analgesic (p < 0.01) activity with 69.45 and 77.96% inhibition of acetic acid-induced writhing at 100 and 200 mg/kg b.w., respectively. The crude methanolic extract also showed significant hypoglycemic activity (p < 0.01) at a dose of 500 mg/kg/day on the 7th day of treatment. All the organic soluble fractions exhibited noteworthy (p < 0.001) CNS depressant activity. Taken together, the plant can be considered as a good material for further chemical investigation to isolate the bioactive constituents.

BIOCHAR FOR THE IMPROVEMENT OF SOIL AND ROCK WITH ACID POTENTIAL

Biochar is a carbonaceous material generated by the heating of organic matter under limited access to oxygen (called pyrolysis). While pyrolysis is applied to dry feed, hydrothermal carbonization can be used for wet materials such as sludge. Application of biochar to soil is considered inherent climate friendly since biochar remain stable in the soil for a long time, and thus removing carbon from the short-term carbon cycle. Biochar has the ability to adsorb trace elements and raise pH, when added to soil or/and water. Geomaterials, both soil and rock, containing sulphur in the form of sulphide minerals have the potential to harm the environment. Lowering groundwater in sulphide rich soils and disposal of excavated sulphide rich soil and rock in piles are example of situations where measures have to be taken to mitigate the formation of acid leachate. This presentation aims at presenting the results from two studies where biochar’s capacity to adsorb trace elements is investigated. In the first study, the adsorption capacity of several biochars was compared with leachate generated from the oxidation of sulphide soil, showing a significant decrease of the concentration of elements such as copper and zinc. In the second study, the ability of waste timber biochar to stabilize the leaching from sulphide rich gneisses containing readily soluble, oxidized secondary mineral crusts was investigated. Preliminary results show that the acidity of the oxidized gneisses exceeds the buffer capacity of the biochars, resulting in an acidic, metal rich leachate. Rather reducing metal leaching through sorption and pH control, metals from the biochar matrix are released, resulting in an increased release of metals compared to the control.