Chemical Science International Journal

Medicinal plants are valuable natural sources for the development of potentially safe drugs. The biological activities associated with these plants are due to the presence of certain phytochemicals that act individually or synergistically. Thus, this study examined the phytochemical components, antioxidant and antimicrobial activities of n-hexane, ethylacetate and methanolic extracts of Pennisetum purpureum (Schumach). Qualitative and quantitative phytochemical assays of P. purpureum showed the presence of alkaloids (0.004%), saponins (0.002%), flavonoids (0.021%), steroids, terpenoids and glycosides (0.008%). Methanol, n-hexane and ethylacetate extracts of P. purpureum were examined for antimicrobial activity using the disc diffusion method. Six microbial strains were exposed to six different concentrations of each extracts; 200 mg/ml, 100 mg/ml, 50 mg/ml, 25 mg/ml, 12.5 mg/ml and 6.25 mg/ml. The three extracts demonstrated varied concentration-dependent antimicrobial activities against the test organisms. The methanolic extract showed antibacterial activity against E. coli, S. aureus, B. cereus and antifungal activity against T. mentagrophyte and A. niger. Among all extracts, the methanolic extract of P. purpureum exhibited relatively strong antifungal activity against A. niger (10.3±0.12 mm) when compared to the standard antifungal agent, fluconazole (13.9±0.12 mm). Furthermore, antioxidant activities were spectrophotometrically studied using vitamin C as standard; methanol and ethylacetate extracts of P. purpureum showed pronounced scavenging activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH); and had a potent reductive ability on ferric ion and phosphomolybdate. However, only the non-polar extract of P. purpureum showed a non-significant correlation and significant differences when compared to vitamin C. Antioxidant activities of the plant extracts were observed in the order of methanol >ethylacetate> n-hexane extracts. The results showed that P. purpureum contains phytochemicals that significantly contributed to the observed antimicrobial and antioxidant abilities of the plant and could be used as a potential source for the development of novel therapeutic drugs.

In this work a new and simple polarographic method has been established for the determination of trace elements present in tea. After digestion with acids, tea samples were analyzed using various electrolytes such as acetate and ammonia at different pH values in the presence or absence of EDTA. Thus, it was possible tochoosethe best medium for the determination of6 trace elements in one tea sample. Polarographic peaks of copper and iron could be separated in HAc at about pH =7 in the presence of EDTA and their quantities were determined. Ni and Zn peaks could be separated and determined in ammonia buffer at about pH= 10. Lead could be determined at pH= 2HAc electrolyte. Selenite, was determined from its hydrogen catalytic peak in KCl, pH= 2 medium in the presence of Mo (VI). The LOD was found as 2.4x10^-7 for instead of (S/N=3).The trace element ranges in black tea were found as, Fe 35 μg/g, Cu 45 μg/g, Ni 19 μg/g, Zn  22 μg/g, Pb 28 μg/g and Se 77  μg/g.

Malaria continues to kill thousands of people worldwide. People South of the Sahara are paying the heaviest price for this epidemic. In addition, the resistance of Plasmodium falciparum which spreads to artemisinin derivatives becomes worrying. To respond to this emergency, the search for new molecules effective against the parasite is essential. Otherwise, chalcones have shown their potential as an effective pharmaceutical agent in numerous studies. However, despite their mainly antiparasitic efficacy, several compounds have been shown to be cytotoxic. This study aimed to assess the cytotoxic profile of chalcone derivatives. Cytotoxicity tests were carried out according to the method described by Taylor and collaborators on Vero cells. The 96-well plates were used in carrying out this study, 100 µl of the compounds were added with concentrations ranging from 7.5 to 1000 µg/ml in DMEM. The results obtained report three compounds derivatives (Chal_B14, Chal_B17 & Chal_SCA03) no-cytotoxic with LDH product values between 129 - 132.5 U/L and ATP ranging from 8.55 to 13.6 RLU. The IC_50s for no-cytotoxic compounds ranged from 102 to 236 µM. On the other hand, the cytotoxic compounds had IC_50s of less than 30 µM.

The results of this study show that the derivatives Chal_B14, Chal_B17 & Chal_SCA03 are candidate compounds with a view to finding new molecules.

Classical nucleation theory predicts the limit of superheat of liquids quite well. To come up with an equation for the limit of superheat of polymer solutions, the lattice model for polymer solutions was used to give the surface tension of polymer solutions. A formula for bubble nucleation in polymer solutions was derived by Jennings with the precursor equation dlnA/dK=1/(6K) where J=AexpK gives the nucleation rate for liquids. The aim of this paper was to show that the precursor equation holds for monomer in the polystyrene-cyclohexane system. Thus, the precursor equation is true for all molecular weight polymer. This happens because the surface tension of polystyrene is significantly more than cyclohexane and the influence of the surface tension dominates.

Aims: To determine the spatial distribution pattern of anthropogenic induced gaseous and particulate pollutants in air samples around major roads within Uyo Metropolis, Southern Nigeria. Also, to assess the response in terms of changes in concentrations of some non-enzymatic biochemical markers of Citrius sinesis leaves (orange) collected from these locations.

Study Design: Air samples from six major heavy traffic roads and a control site within Uyo Metropolis was collected. Citrius sinesis leaves were also collected from each major roads and Control to determine possible variations in concentrations of biochemical markers contents. 

Place and Duration of Study: Department of Chemistry, University of Uyo, Uyo, between September 2019 and January 2020.

Methodology: Absorption train techniques involving the adsorption of pollutant gases from air samples in a particular location into appropriate reagent solutions was adopted for this study. Estimation of the concentrations of SO_2, NO₂ and CO was done by calorimetric techniques. Concentrations of total phenolic, proline, malonialdehyde (MDA), cellulose, chlorophyll and ascorbic acid contents in Citrius sinesis leaves were determined using UV/Visible spectrophotometer.

Results: Air samples collected from major roads with heavy traffic and extraneous local automobile emissions recorded higher levels of all the gaseous and particulates pollutants analyzed than Control. Leaves of C. sinesis exposed to higher concentrations of these pollutants showed a higher accumulation of all the biochemical markers studied except chlorophyll, which was higher in leaves from the control site.

Conclusion: Anthropogenic activities directly increases the spatial distribution pattern and concentrations of gaseous and particulate pollutants (PM₁₀ and PM_2.5). Also, C. sinesis leaves from major roads within Uyo Metropolis showed different responses in terms of accumulation of these biochemical markers.