Anti-oxidant activity and effect of Pinus morrisonicola Hay. on the survival of leukemia cell line U937.

The free radical scavenging and anti-cancer activites of Pinus morrisonicola Hay. were studied using different parts of the pine, namely, needle, bark and cone. Results showed that pine needle water extract has the highest scavenging superoxide anion activity and the lowest IC50 value in inhibiting superoxide anion formation; however, the bark water extract showed the best anti-lipid peroxidation activity. Additionally, needle water extract displayed the highest inhibition of leukemia cell line U937 growth. The results indicated that P. morrisonicola Hay. possesses potential chemopreventative and therapeutic properties.

Substrate-velocity relationships for the Trichoderma viride cellulase-catalyzed hydrolysis of cellulose.

The influence of substrate and enzyme concentrations on the rate of saccharification of two defined insoluble cellulose substrates, Avicel (FMC Corp., Philadelphia, Pa.) and Solka-Floc (James River Co., Berlin, N.H.), by the cellulase enzyme system of Trichoderma viride was evaluated. In the assays, enzyme concentrations ranging from 0.004 to 0.016 IU/ml and substrate concentrations up to 10% (wt/vol) were used. Analysis by initial velocity methods found the maximum velocity of saccharification to be nearly equivalent for the two substrates and the Km for the two substrates to be of a similar magnitude, i.e., 0.20% (wt/vol) for Solka-Floc and 0.63% (wt/vol) for Avicel. Studies in which relatively high substrate concentrations (greater than 15 times the Km) were used demonstrated that the enzyme exhibited very different apparent substrate inhibition properties for the two substrates. The rate of saccharification of Avicel at relatively high substrate concentrations was up to 35% lower than the maximum rate which was observed at lower substrate concentrations. The Avicel concentration corresponding to the maximum rate of saccharification was dependent on the enzyme concentration. In contrast to the results with Avicel, the enzyme did not exhibit substrate inhibition with the Solka-Floc substrate. Potential differences in the degree of substrate inhibition with different substrates, as reported here, are particularly relevant to the experimental design of comparative studies.

Utilization of purified cellulose in fiber studies.

Purified cellulose-type fiber products are widely used in experimental nutrition. Their use in a broad spectrum of studies may potentially lead to the acceptance of the misconception that the various commercially available cellulose products are equivalent. In this paper we have attempted to show that this is not the case. The comparative structural data of Table 2 and the compositional data of Olsen et al provide examples which indicate that purified cellulose preparations should not necessarily be considered equivalent. Unfortunately, our current lack of understanding of how fibers are metabolized and how they may affect specific physiological parameters makes it difficult to determine which, if any, of the measurable structural and chemical properties will be of relevance for a given in vivo study. At present, it appears that researchers utilizing/evaluating the consequences of consuming a purified cellulose-type fiber would be prudent to provide at least a limited amount of data on the properties of the cellulose preparation used in their studies. The characterization of the cellulose product may be done by a variety of methods depending on the expertise of the laboratory. The methods and results discussed in this paper provide an example of the type of information which may be obtained from an in vitro characterization of cellulose products.