Effect of xylanase immobilisation conditions by combination of entrapment and covalent binding on alginate beads

The immobilisation of enzymes offer improvement in enzyme stability and characteristics as well as overcome the limitations of free enzyme systems for commercial purposes. In the current study, xylanase was immobilised using a combination technique of entrapment and covalent binding within and onto calcium alginate beads. The sodium alginate and calcium chloride (CaCl2) concentration used for the preparation of alginate beads which is the support matrix for xylanase immobilisation were fixed at 3% (w/v) and 0.3 M, respectively. The effect of immobilisation conditions (agitation rate, enzyme loading, and glutaraldehyde concentration) were studied using One-Factor-At-a-Time (OFAT) approach. The best condition for optimum immobilisation yield (83.93%) was found to be made up of the following parameter combination: agitation rate, 200 rpm; xylanase loading, 200 U; and glutaraldehyde concentration, 12% (w/w). The study shows the immobilisation conditions play a significant role towards the immobilisation yield of xylanase

Nephroprotective effects of Zingiber zerumbet Smith ethyl acetate extract against paracetamol-induced nephrotoxicity and oxidative stress in rats

Paracetamol (PCM) overdose can cause nephrotoxicity with oxidative stress as one of the possible mechanisms mediating the event. In this study, the effects of ethyl acetate extract of Zingiber zerumbet rhizome [200 mg per kg of body weight (mg/kg) and 400 mg/kg] on PCM-induced nephrotoxicity were examined. Rats were divided into five groups containing 10 rats each. The control group received distilled water while other groups were treated with extract alone (400 mg/kg), PCM alone (750 mg/kg), 750 mg/kg PCM+200 mg/kg extract (PCM+ 200-extract), and 750 mg/kg PCM+400 mg/kg extract (PCM+400-extract), respectively, for seven consecutive days. The Z. zerumbet extract was given intraperitoneally concurrent with oral administration of PCM. Treatment with Z. zerumbet extract at doses of 200 and 400 mg/kg prevented the PCM-induced nephrotoxicity and oxidative impairments of the kidney, as evidenced by a significantly reduced (P<0.05) level of plasma creatinine, plasma and renal malondialdehyde (MDA), plasma protein carbonyl, and renal advanced oxidation protein product (AOPP). Furthermore, both doses were also able to induce a significant increment (P<0.05) of plasma and renal levels of glutathione (GSH) and plasma superoxide dismutase (SOD) activity. The nephroprotective effects of Z. zerumbet extract were confirmed by a reduced intensity of renal cellular damage, as evidenced by histological findings. Moreover, Z. zerumbet extract administered at 400 mg/kg was found to show greater protective effects than that at 200 mg/kg. In conclusion, ethyl acetate extract of Z. zerumbet rhizome has a protective role against PCM-induced nephrotoxicity and the process is probably mediated through its antioxidant properties