Gossypin　is　a　flavone　that　was　originally　isolated　from　Hibiscus　vitifolius　and　has　traditionally　been　used　for　the　treatment　of　diabetes,　jaundice,　and　inflammation.　Recently,　gossypin　was　found　to　have　potent　anticancer　properties;　however,　its　effect　on　human　gliomas　still　remain　unknown.　To　investigate　the　potential　anticancer　effects　of　gossypin　on　malignant　gliomas　and　analyze　the　associated　molecular　mechanisms,　we　treated　human　glioma　U251　cells　with　gossypin.　Our　study　showed　that　the　treatment　of　U251　cells　with　gossypin　inhibited　cell　proliferation　in　a　dose-　and　time-dependent　manner　and　was　observed　to　be　minimally　toxic　to　normal　human　astrocytes.　Gossypin＇s　effect　on　cell　cycle　distribution　was　observed,　and　we　found　that　it　induced　G2/M-phase　arrest　in　U251　cells.　An　analysis　of　cell-cycle　regulatory　proteins　indicated　that　the　arresting　effect　of　gossypin　on　the　cell　cycle　at　G2/M　phase　was　involved　in　the　phosphorylation　of　cell　division　cycle　25C　(Cdc25C)　tyrosine　phosphatase　via　the　activation　of　checkpoint　kinase　1　(Chk1).　These　findings　indicate　that　gossypin　is　a　potential　treatment　of　gliomas　because　of　gossypin＇s　potential　to　regulate　the　proliferation　of　U251　cells　via　the　cell-cycle　regulatory　proteins　Chk1　and　Cdc25C.