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Terminalia calamansanai (Blanco) Rolf. (Combretaceae) is used medicinally as lithontriptic in Philippines. The 70% acetone extracts of T. calamansanai leaves inhibited the viability of human promyelocytic leukemia HL-60 cells. 1-Alpha-O-galloylpunicalagin, punicalagin, 2-O-galloylpunicalin, sanguiin H-4, and methyl gallate were the main components isolated from T. calamansanai with the IC(50) values of 65.2, 74.8, 42.2, 38.0 and >100 microM, respectively, for HL-60 cells. Apoptosis of HL-60 cells treated with 1-Alpha-O-galloylpunicalagin, punicalagin, 2-O-galloylpunicalin, and sanguiin H-4 was noted by the appearance of a sub-G(1) peak in flow cytometric analysis and DNA fragmentation by gel electrophoresis. 2-O-Galloylpunicalin and sanguiin H-4 induced a decrease of the human poly(ADP-ribose)polymerase (PARP) cleavage-related procaspase-3 and elevated activity of caspase-3 in HL-60 cells, but not normal human peripheral blood mononuclear cells (PBMCs), suggesting that both compounds may be new candidates for drug development in the prevention and treatment of cancer.

Cnidii monnieri Fructus [CmF; Cnidium monnieri (L.) Cusson] is used as a tonic agent in traditional Chinese medicine. In a previous Chinese herb-cytotoxicity screening test, the ethanol extract of CmF exhibited strong effects on human leukemia (HL-60), cervical carcinoma (HeLa) and colorectal carcinoma (CoLo 205) cells. Then, the CmF extract was subjected to silica gel column chromatography and recrystallization to give five coumarins: osthol, imperatorin, bergapten, isopimpinellin, and xanthotoxin. Among these compounds, osthol showed the strongest cytotoxic activity on tumor cell lines. The structure-activity relationship established from the results indicated that the prenyl group has an important role in the cytotoxic effects. However, imperatorin showed the highest sensitivity to HL-60 cells and the least cytotoxicity to normal PBMCs. Osthol and imperatorin both caused apoptotic bodies, DNA fragmentation, and enhanced PARP degradation in HL-60 cells by biochemical analysis. These results indicate that osthol and imperatorin can induce apoptosis in HL-60 cells. Therefore, osthol and imperatorin are cytotoxic marker substances in the fruits of Cnidium monnieri.

6-Gingerol, a naturally occurring plant phenol, is one of the major components of fresh ginger. In this paper, the antioxidative effects of 6-gingerol were detected by DPPH and DCFH assays and, as predicted, 6-gingerol as an antioxidant was shown to protect HL-60 cells from oxidative stress. Moreover, it induced cell death in promyelocytic leukemia HL-60 cells, caused DNA fragmentation and inhibited Bcl-2 expression in HL-60 cells. These results suggested that the inhibition of Bcl-2 expression in HL-60 cells might account for the mechanism of 6-gingerol-induced apoptosis. In the inhibitory assay, the cytotoxic effect of 6-gingerol could be prevented by catalase. We suggest that 6-gingerol induced cell death by mediating reactive oxygen species such as hydrogen peroxide and the superoxide anion. Therefore, the results showed that 6-gingerol induced apoptosis in HL-60 cells, not due to its antioxidative activity.

Vitis thunbergii var. taiwaniana (VTT) is an indigenous Taiwanese wild grape and is used as a folk medicine in Taiwan. VTT is rich in polyphenols, especially quercetin and resveratrol derivatives, which were demonstrated to exhibit inhibitory activities against carcinogenesis and prevent some neurodegenerative diseases. (-)-Vitisin B is one of the resveratrol tetramers extracted from VTT. In this study, we investigated the mechanisms of (-)-vitisin B on the induction of apoptosis in human HL-60 promyelocytic leukemia cells. First, (-)-vitisin B significantly inhibited cell proliferation through inducing cell apoptosis. This effect appeared to occur in a time- and dose-dependent manner. Cell-cycle distribution was also examined, and we found that (-)-vitisin B significantly induced a sub-G1 population in a dose-dependent manner. In addition, (-)-vitisin B exhibited stronger inhibitory effects on cell proliferation than resveratrol. Second, (-)-vitisin B dose dependently induced apoptosis-related protein expressions, such as the cleavage form of caspase-3, caspase-8, caspase-9, poly(ADP ribose) polymerase, and the proapoptotic Bax protein. Third, (-)-vitisin B treatment also resulted in increases in c-Jun N-terminal kinase (JNK) phosphorylation and Fas ligand (FasL) expression. Moreover, the (-)-vitisin B-induced FasL expression and caspase-3 activation could be reversed by a JNK inhibitor. These results suggest that (-)-vitisin B-induced apoptosis of leukemia cells might be mediated through activation of JNK and Fas death-signal transduction. [ABSTRACT FROM AUTHOR]

Abstract: To alter its hydrophobicity, a series of compounds bearing 9-O-alkyl- or 9-O-terpenyl- substituted berberine were synthesized and evaluated for anticancer activity against human cancer HepG2 and HT29 cell lines. We found that the lipophilic substitute of 9-O-alkyl- and 9-O-terpenyl berberine derivatives plays a role in inhibiting the human cancer cell growth and its activity could be maximized with the optimized substitute type and chain length. Most strikingly, nonetheless, of the six compounds prepared, sample 8, a farnesyl 9-O-substituted berberine, showed either comparable or better cytotoxic activity against human cancer HepG2 cell line than that of berberine. Compound 8 had also shown a 104-fold antiproliferation activity in compare with berberine against human hepatoma HepG2 cell lines after 48 incubation hours. Further, in Hoechst 33258 and annexin V-FITC/PI staining analyses it induced apoptosis in HepG2 cells at lower concentration than that of berberine for 24h. Take all; farnesyl 9-O-substituted berberine could be a potential candidate for new anticancer drug development. [Copyright &y& Elsevier]