The pharmacological action of Sho-saiko-to and Hange-koboku-to, components of Saiboku-to, as well as that of Sho-seiryu-to were compared with that of Saiboku-to and examined in intractable asthmatics with respect to both lymphocyte functions, including interleukin 2 (IL-2) production and IL-2 receptor expression in peripheral blood lymphocytes stimulated by Candida, and on neutrophil functions, including leukotriene C
4 (LTC
4) and superoxide (O
2-) production by peripheral blood neutrophils.
The results revealed, first, that, Sho-saiko-to, Hange-koboku-to, and Sho-seiryu-to did not have significant suppressive effects on IL-2 production and IL-2 receptor expression by Candia, though Saiboku-to caused significant suppression of these same parameters. Second, after 2 or 3 months oral administration to intractable asthmatics Saiboku-to (TJ-96) suppressed LTC
4 production by peripheral blood neutrophils in response to Candida and Ca-ionophore. Third, in vitro, Saiboku-to caused dose-dependent suppression of both LTC
4 and O
2- production by peripheral blood neutrophils. Sho-saiko-to and Sho-seiryu-to also had suppressive effects on both LTC
4 and O
2- production, with Sho-saiko-to causing the strongest suppression among these drugs.
These results indicate that Saiboku-to might be useful in the treatment of intractable asthma due to its suppressive effect on type IV allergy caused by lymphocyte activation by Candida. Moreover, its inhibitory effect of LTC
4 and O
2- production by neutrophils prevents prolonged broncho-constriction and irreversible changes in small airways.
View full abstract