title: Triterpenoids from the leaves of Diospyros kaki (persimmon) and their inhibitory effects on protein tyrosine phosphatase 1B.
abstract: Phytochemical study on a methanol-soluble extract of the leaves of persimmon (Diospyros kaki) resulted in the isolation of two new ursane-type triterpenoids, 3alpha,19alpha-dihydroxyurs-12,20(30)-dien-24,28-dioic acid (1) and 3alpha,19alpha-dihydroxyurs-12-en-24,28-dioic acid (2), together with 12 known ursane- and oleanane-type triterpenoids (3-14). Triterpenoids with a 3beta-hydroxy group were found to inhibit protein tyrosine phosphatase 1B (PTP1B) activity, with IC50 values ranging from 3.1+/-0.2 to 18.8+/-1.3 microM, whereas those with a 3alpha-hydroxy moiety were not active.
authors.affiliation: College of Pharmacy, Chosun University, 375 Seosuk-dong, Dong-gu, Gwangju 501-759, Korea.
authors.forename: Phuong Thien
authors.initials: PT
authors.lastname: Thuong
authors.forename: Chul Ho
authors.initials: CH
authors.lastname: Lee
authors.forename: Trong Tuan
authors.initials: TT
authors.lastname: Dao
authors.forename: Phi Hung
authors.initials: PH
authors.lastname: Nguyen
authors.forename: Wan Gi
authors.initials: WG
authors.lastname: Kim
authors.forename: Sang Jun
authors.initials: SJ
authors.lastname: Lee
authors.forename: Won Keun
authors.initials: WK
authors.lastname: Oh
mesh_terms: D029788:Diospyros / Q000737:chemistry*; D006801:Humans; D007723:Korea; D015394:Molecular Structure; D018515:Plant Leaves / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry*; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1 / Q000037:antagonists & inhibitors*; D014315:Triterpenes / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology
chemical_list: C532941:3alpha,19alpha-dihydroxyurs-12,20(30)-dien-24,28-dioic acid; C532940:3alpha,19alpha-dihydroxyurs-12-en-24,28-dioic acid; D014315:Triterpenes; D054562:Protein Tyrosine Phosphatase, Non-Receptor Type 1