Mitsumasa Haruna

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Three neolignans, known as magnolol [1], honokiol [2] and the new monoterpenylmagnolol [3], were isolated from the bark of Magnolia officinalis as inhibitors of Epstein-Barr virus early antigen (EBV-EA) activation induced by 12-O-tetradecanoylphorbol-13-acetate (TPA). The structure of 3 was determined from 2D nmr spectral data and difference nOe(More)
The extract of the roots of Euphorbia kansui, which has been widely used in Chinese folk medicine for the treatment of cancer, demonstrated antileukemic activity against the P-388 lymphocytic leukemia in mice. Bioassay-directed fractionation of the active extract led to the isolation and characterization of two novel antileukemic diterpene esters,(More)
A chloroform extract of the whole plant of Anaphalis morrisonicola HAY, showed significant antitumor activity against Ehrlich ascites carcinoma, Walker 256 carcinosarcoma, and P-388 lymphocytic leukemia. Systematic fractionation of the extract led to isolation and characterization of helenalin, a pseudoguaianolide, as the major active principle.
We recently reported that PL-AG, a Schiff base of pyridoxal and aminoguanidine, was more effective than aminoguanidine (AG), a well-known anti-diabetic-complication compound, in preventing nephropathy in diabetic mice and presented brief data indicating the antioxidant activity of the adduct. In the present study, we additionally investigated the inhibitory(More)
Evidence is presented that a number of sesquiterpene lactones isolated from plants and synthesized pyrimidines containing the alpha-methylene-gamma-lactone moiety are potent inhibitors of Walker 256 carcinosarcoma and Ehrlich ascites tumor growth and marginal inhibitors of P-388 lymphocytic leukemia and Lewis lung tumor growth. In vitro aerobic basal(More)
Bioassay-directed isolation of the antitumor extract of Wikstroemia indica (Thymelaeaceae) has led to the characterization of tricin, kaempferol-3-O-beta-D-glucopyranoside, and (+)-nortrachelogenin as the major antileukemic constituents. In addition, daphnoretin was identified as the potent antitumor principle in vivo against the Ehrlich ascites carcinoma(More)
A series of analogues of etoposide, the C-4 amino- and alkylamino-substituted 4'-demethyl-epipodophyllotoxins, have been synthesized and studied for their activity to inhibit type II human DNA topoisomerase as well as their activity in causing cellular protein-linked DNA breakage. Substitution of the glycosidic moiety of 1 by a 2"-hydroxyethylamino or(More)
Several derivatives of podophyllotoxin with modifications at the C-4 position of ring C, in addition to demethylation at the C-4' position of ring E, were examined for inhibitory activity against DNA topoisomerase II and tubulin polymerization, generation of protein-linked DNA breaks, and cytotoxicity against KB cells and VP-16-resistant KB variants.(More)
A new sesquiterpene pyridine alkaloid, emarginatine B [2] has been isolated, along with maytansine [3], from Maytenus emarginata. Emarginatine B showed potent cytotoxicity against human KB cells (ED50 = 0.4 micrograms/ml). Spectral correlations established its structure as a 9-benzoate and C-8 epimer of emarginatine A [1]. The conformational aspect of the(More)