MSeA treatment significantly reduced the microvessel density of the xenograft tumor. A. Control. IHC staining for CD31 (brown) showed that the microvessel density was much higher in xenograft tumors from the nude mice received no oral administration of MSeA. B. MSeA treatment. Single dose oral administration of the nude mice with MSeA at 3 mg/kg/day x 18 days resulted in significant reduction in microvessel density, as indicated by CD31 IHC staining. Scale bar = 100 μm. C. Statistical summary of the microvessel density in the treatment and the control groups. A reduction of 38% in microvessel density was observed in the MSeA-treated nude mice (p < 0.05), with mean density for the control and MSeA-treatment group being 87±19 and 54±4, respectively (student-t test).