ABSTRACT
The need for new compounds active against malaria parasites is made more urgent by the rapid spread of drug-resistance to available antimalarial drugs. The crude methanolic leaf extract of Crateva adansonii was investigated for its antimalarial activity against Plasmodium berghei (NK65) infected mice. A total of 15 mice were intraperitoneally infected with chloroquine sensitive P. berghei strain and divided into 5 equal groups, group 1 served as negative control (untreated), groups 2,3 and 4 were given 200, 400 and 600 mg/kg Crateva adansonii methanolic leaves extract respectively while group 5 served as positive control and was given 5 mg\kg chloroquine for five days. The phytochemical constituents of the plant extract were evaluated to elucidate the possibilities of their antimalarial effects. The extract produced a significant dose dependent decrease in the level of parasitaemia when compared to infected untreated group. Also, the extract at dose of 400 mg/kg and 600 mg/kg produced significant increase in body weight and PCV of the infected mice as compare to mice treated with 200 mg/kg of extract and infected untreated group. Phytochemical screening showed that the leaves extract contains alkaloids, anthraquinones, tannins, flavonoids, saponins cardiac glycosides and steroids. It is concluded that Crateva adansonii could serve as a possible source of antimalarial compounds.
ABSTRACT
Aim: To identify isolates for industrial production of pectinase. Methodology: The isolates were screened for pectinolytic activity using pectin as substrate. Enzyme activity was expressed as mg of glucose equivalent released per ml of crude enzyme solution per second. The kinetic parameters of the enzyme were determined to obtain the optimum pH, temperature, Km and Vmax. Pectinase produced from Bacillus subtillis was immobilized on chitosan and its activity was compared with that of free enzyme. Results: Pectinase from Bacillus subtilis was screened to have the highest enzymatic activity among bacterial isolates while pectinase from Aspergillus niger had the highest enzymatic activity among fungal isolates. High yield of pectinase enzyme was obtained from B. subtilis after 24hrs with activity of 4.01×10-4 mg/ml/sec while high yield of pectinase was obtained from A. niger on the 5th day with activity of 2.07×10-4 mg/ml/sec. The optimum pH for pectinase produced from B. subtilis and A. niger were 8 and 6, respectively. The optimum temperature for pectinase from B. subtilis and A. niger were at 50ºC and 40ºC, respectively. The Vmax and Km of pectinase from B. subtilis and A. niger were 16.88×10-4 (mg/ml/sec) and 10 (mg/ml); 9.29×10-4 (mg/ml/sec) and 30 (mg/ml), respectively. Optimum temperature and pH of immobilized pectinase were 70ºC and 4.0, respectively. Residual activity of immobilized enzyme was 92% after storage at 4ºC for 14 days. Conclusion: This study revealed that Bacillus subtilis from snail gut may be considered as a good candidate for industrial production of pectinase.