Analyses of putative anti-cancer potential of three STAT3 signaling inhibitory compounds derived from Salvia officinalis oleh Maho Yanagimichi, Katsutoshi Nishino, Akiho Sakamoto, Ryusei Kurodai, Kenji Kojima, Nozomu Eto, Hiroko Isoda, Riadh Ksouri, Kazuhiro Irie, Taiho Kambe, Seiji Masuda, Toru Akita, Kazuhiro Maejima, Masaya Nagao