Control 1 10 100
Aloe barbadensis Gel (ng/ml)
Figure 12.5 Activation of macrophage cultures by incubation with crude, A. barbadensis Process A gel processed in the absence of exogenous 'cellulase' or processed with various concentrations (2.5 g per 215 liters or 5 g per 215 liters) of T. reesei cellulase. Data of Lewis Sheffield from Sheet 3 (Figure 3) of Strickland etal. (1998).
(Table 12.12, 'None' column; '6 Weeks', 5 ± 10%). However, the statistical significance of this effect was weak (Strickland etal, 1998, Table 2, Significance of Treatment Effect, p = 0.026, p = 0.06, p not significant). However, at the same time, we were studying the process of concentrating A. barbadensis gel extracts by a rising-falling thin-film evaporation process that required the addition of 'cellulase' for mechanical efficiency. We noticed that 'cellulase' altered the biological effect in that system (Strickland etal., 1998, Example 1). Therefore we set up specific experiments to determine the effects of cellulase upon activation and decay or CHS protective activity (Table 12.12 above). The use of cellulase accelerated the activation and the decay process in a dose-related fashion. There was now (Strickland etal., 1998, Table 2) a strong statistical therapeutic effect (Prep A, p = 0.001 to p = 0.0001; Prep B, p = 0.005 to p = 0.0001; Prep C, p = 0.003).
This activation of biological activity was accompanied by physico-chemical changes in the gel polysaccharide. Native Process A gel, prior to being activated, has significant psuedoplasticity, that is, physically it is a gel and its polysaccharide is entirely in a very high molecular weight form (Figure 12.4 above). The process of activation is associated with loss of psuedoplasticity, cleavage of the polysaccharide and a shift in the size exclusion chromatograph to a lower molecular weight profile (Figure 12.6).
Finally, excessive use of cellulase results in the destruction of biological activity. In the parallel experiments with Dr Sheffield referred to above (Figure 12.5), there was also a 'cellulase' effect in his in vitro phagocyte activation system. Thus we began to think in terms of a 'cellulase-sensitive' factor that protected the skin immune system against UV injury. We need to stress that this 'cellulase-sensitive' UV-protective activity is not the only epithelial protective activity encountered. There are other, 'cellulase-insensitive' factors with different physico-chemical properties and different mechanisms
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