8H,13H-6a,13a-Epidithio-1H,6H-pyrazino(1,2-a:4,5-a')diindole-1,6,8,13-tetrone, 4,4a,7,7a,11,11a,14,14a-octahydro-4,11-dihydroxy-, (4S-(4alpha,4aalpha,6abeta,7aalpha,11alpha,11aalpha,13abeta,14abeta))-