Bleaching of Palm Oil by Activated Local Bentonite and Kaolin Clay from Afashio, Edo-Nigeria

The bleaching potential of Afashio kaolin (AFK), from Edo state in Nigeria, for removal of pigments from palm oil was investigated in comparison with that of local bentonite (BN). Both AFK and BN were activated by acid treatment. Batch experiments were conducted to study the effects of adsorbent dosage (2 – 8 %), contact time (0 – 1.5 hr) and temperature (60 – 90oC) on pigment adsorption. Four adsorption isotherms were used to model the equilibrium data for both adsorbents (AFK and BN), namely Langmuir, Freundlich, Sips and Redlich-Peterson models. The Sips model provides the best correlation and adsorption occurred in monolayer. Kinetic adsorption data were analyzed using the pseudo-first order, pseudo-second order, and intraparticle diffusion models. The regression results showed that the adsorption kinetics was more accurately represented by the pseudo-first order kinetic model. Intraparticle diffusion studies reveals that pore diffusion is the controlling mechanism. Thermodynamic parameters, ?G, ?H and ?S, were calculated as a function of both temperature and adsorbent dosage. The values of enthalpy change were positive and greater than 40 kJ/mol in all cases, indicating that the bleaching process is endothermic and chemisorption in nature. The results suggest that AFK could be employed as low-cost alternative for removal of pigments from vegetable oil though BN is better. Keywords: Afashio kaolin, bentonite, bleaching, equilibrium isotherms, kinetic models

Coconut shell-based activated carbon as adsorbent for the removal of dye from aqueous solution: equilibrium, kinetics, and thermodynamic studies

The need to develop more efficient adsorbent, comparable to commercially available adsorbent, is attracting significant interest as promising adsorbent for waste water treatment. In this study, the potential of activated carbon prepared from waste coconut shell (CSAC) for the removal of methylene blue (Mb) from aqueous solution was reported. Batch experiments were conducted to determine the adsorption isotherm and kinetics of Mb on CSAC. Langmuir, Freundlich and Temkin isotherm models were employed to fit and analyze the adsorption equilibrium data. The result shows Langmuir isotherm model gave the best fit and an adsorption capacity of 320.5 mg/g was obtained for Mb at pH value of 7, 0.02 g adsorbent dosage and contact time of 4.5 hour. The experimental kinetic data at different initial Mb concentrations was also analyzed with pseudo-first order, pseudo-second order and intraparticle diffusion models. The obtained results showed that the pseudo-second order model fits the adsorption kinetic data with R2 range of0.9985-0.9996. Finally, the thermodynamic parameters show that the adsorption of Mb on CSAC was spontaneous and endothermic in nature. This therefore suggests that (CSAC) is a viable adsorbent for effective removal of dye from wastewater effluent. Keywords: Activated carbon, Adsorption isotherms, Coconut shells, Methylene blue, kinetics

Effect of Carica papaya (Linn) aqueous leaf extract on pharmacokinetic profile of ciprofloxacin in rabbits

Purpose: To investigate the fate of ciprofloxacin, after concomitant administration with the aqueous leaf extract of Carica papaya, which herbal practitioners in Nigeria have found helpful in the treatment of painful crisis in sickle cell anaemia (SCA) patients.Method: Thirteen rabbits were fasted for 12 h and given by oral route 20 mg/kg ciprofloxacin (control group); after a 3-week crossover period, the animals were given 500 mg/kg aqueous extract of Carica papaya followed by 20 mg/kg ciprofloxacin (treatment group). Blood samples were collected over a period of 0 - 24 h post-dosing, and pharmacokinetic profile of ciprofloxacin in plasma sample determined using a validated high performance liquid chromatography (HPLC) method.Results: Time to attain maximum plasma ciprofloxacin concentration (Tmax), lag time and clearance (CL/F) were higher in the treated group; all other pharmacokinetic parameters showed significant decrease in the treated group (p < 0.005) compared to the control group. The slow rate of elimination of ciprofloxacin in the control group (0.32 ± 0.11 h-1) compared to the treated group (0.21 ± 0.07 h-1) was not due to kidney impairment as plasma creatinine level indicated that kidney function was within normal range (0.68 ± 2.78 mg/dl).Conclusion: The results of the study show that there is interaction between ciprofloxacin and Carica papaya. This interaction can be avoided by taking ciprofloxacin at least 3 h prior to administration of the leaf extract of C. papaya.Keywords: Carica papaya, Ciprofloxacin, Sickle cell anaemia, Herb-drug interaction, Pharmacokinetic

A 5- month toxicity study of the ethanol extract of the leaves of Heliotropium indicum in Sprague Dawley rats after oral administration.

Background: Heliotropium indicum Linn. (Boraginaceae) is used in Nigerian traditional medicine to treat tuberculosis with treatment lasting for 3 months; however, information on its toxicity is scarce.Objective: This study investigated the safety of the leaves of Heliotropium indicum after a 5 month oral administration.Methods: The leaves of H. indicum were dried; extracted in 70 % ethanol and concentrated to dryness. Swiss mice were administered orally with single doses of the extract (0.5 to 12.0 g/kg b.wt /day); mortality was examined for up to 14 days. In another study, the plant material (0.5 to 2.0 g/kg b.wt /day) were administered daily by oral gavage to Sprague Dawley rats. Body weight was monitored weekly, hematological, biochemical and organ parameters were determined at the end of the 1st, 2nd and 5th months of extract administration.Results: The oral administration of the ethanol extract of H. indicum caused dose-dependent mortality. The LD was 50 9.78 g/kg b.wt for the Swiss mice; no harmful effect was observed on the liver and kidney except the testes which exhibited considerable inflammatory changes at the highest dose of 2.0 g/kg b.wt./day after the 5th month treatment. No significant difference (P>0.05) was shown in the enzyme study, marginal increase occurred in some haematological parameters. The increase in body weight of the treated rats after its initial reduction was consistent and significantly different (P<0.05) from their initial body weight.Conclusion: Prolonged administration of the crude leaf extract of H. indicum is considered to be safe and non-toxic at the doses studied. However, there is a probability of a negative effect on the testes at a higher dose of the extract.Keywords Heliotropium indicum, Liver enzymes, Histopathology, Animal toxicity, Traditional medicin