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Volume 9
Chemical Sciences Journal
Asia Chemistry 2018
September 12-13, 2018
11
th
Annual Congress on
September 12-13, 2018 Singapore
Chemistry
Cholestane rhamnosides from
Ornithogalum saundersiae
bulbs and their cytotoxic activity against
HL-60, A549 and TIG-3 cells
Tomoki Iguchi, Minpei Kuroda, Akihito Yokosuka and Yoshihiro Mimaki
Tokyo University of Pharmacy and Life Sciences, Japan
O
rnithogalum saundersiae
(Liliaceae) is native to South Africa and cultivated as an ornamental plant in the world.
Previously, we have reported a total of 29 cholestane glycosides, including OSW-1, isolated from the MeOH extract of
O. saundersiae
bulbs and their cytotoxic activity against several malignant tumor cells. In this presentation, we wish to report
focus on cholestane rhamnosides isolated from the MeOH extract of
O. saundersiae
bulbs. The concentrated MeOH extract
of O. saundersiae bulbs was passed through a Diaion HP-20 column eluted with 20% MeOH, EtOH, EtOAc, successively. The
EtOH eluate fraction was subjected to column chromatography on silica gel and ODS silica gel, as well as preparative HPLC
to give 19 Cholestane Rhamnosides including 12 new naturally occurring compounds. The structures of the new compounds
were determined by spectroscopic analysis mainly based on one and two-dimensional NMR and the results of hydrolysis.
Cholestane rhamnosides 3, 7-12, 15-17 and 19 exhibited cytotoxic activity against HL-60 human promyelocytic leukemia cells
and A549 human lung cancer cells with IC50 values ranging from 0.05 M to 7.72 M and 0.27 M to 2.41 M, respectively. HL-
60 cells treated with (22S)-3, 22-Dihydroxycholest-5, 24-dien-16-yl-L-Rhamnopyranoside (11), which had an IC50 value of
0.16 M, displayed the hallmark indicators of apoptosis, such as fragmented and condensed nuclear chromatins and activation
of caspase-3. In the HL-60 cells treated with 11, the accumulation of sub-G1 cells and G2/M phase cells was shown by flow
cytometry analysis. These results suggested that 11 arrests HL-60 cell proliferation in the G2/M phase induces apoptotic
cell death. Furthermore, the loss of the mitochondria membrane potential and release of cytochrome c to the cytosol were
not observed in the HL-60 cells treated with 11. In conclusion, 11 may induce apoptosis in HL-60 cells via a mitochondria-
independent pathway.
Biography
Tomoki Iguchi is a Doctoral student in Department of Medicinal Pharmacognosy, School of Pharmacy, Tokyo University of Pharmacy and Life Sciences, Japan. He
majors in Chemistry and Biochemistry of Natural Products.
y091015@toyaku.ac.jpTomoki Iguchi et al., Chem Sci J 2018, Volume 9
DOI: 10.4172/2150-3494-C5-030