Resolution and identification of scalemic caged xanthones from the leaf extract of Garcinia propinqua having potent cytotoxicities against colon cancer cells

Teerayut Sriyatep; Cholpisut Tantapakul; Raymond J Andersen; Brian O Patrick; Stephen G Pyne; Chatchai Muanprasat; Sawinee Seemakhan; Suparerk Borwornpinyo; Surat Laphookhieo

doi:10.1016/j.fitote.2017.10.009

Resolution and identification of scalemic caged xanthones from the leaf extract of Garcinia propinqua having potent cytotoxicities against colon cancer cells

Fitoterapia. 2018 Jan:124:34-41. doi: 10.1016/j.fitote.2017.10.009. Epub 2017 Oct 12.

Authors

Teerayut Sriyatep¹, Cholpisut Tantapakul², Raymond J Andersen³, Brian O Patrick⁴, Stephen G Pyne⁵, Chatchai Muanprasat⁶, Sawinee Seemakhan⁷, Suparerk Borwornpinyo⁸, Surat Laphookhieo⁹

Affiliations

¹ Center of Chemical Innovation for Sustainability (CIS), Mae Fah Luang University, Tasud, Muang, Chiang Rai 57100, Thailand; School of Science, Mae Fah Luang University, Tasud, Muang, Chiang Rai 57100, Thailand.
² School of Science, Mae Fah Luang University, Tasud, Muang, Chiang Rai 57100, Thailand.
³ Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada; Department of Earth, Ocean & Atmospheric Sciences, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
⁴ Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver, BC V6T 1Z1, Canada.
⁵ School of Chemistry, University of Wollongong, Wollongong, New South Wales 2522, Australia.
⁶ Department of Physiology, Faculty of Science, Mahidol University, Rajathevi, Bangkok 10400, Thailand.
⁷ Excellent Center for Drug Discovery, Faculty of Science, Mahidol University, Rajathevi, Bangkok 10400, Thailand.
⁸ Excellent Center for Drug Discovery, Faculty of Science, Mahidol University, Rajathevi, Bangkok 10400, Thailand; Department of Biotechnology, Faculty of Science, Mahidol University, Rajathevi, Bangkok 10400, Thailand.
⁹ Center of Chemical Innovation for Sustainability (CIS), Mae Fah Luang University, Tasud, Muang, Chiang Rai 57100, Thailand; School of Science, Mae Fah Luang University, Tasud, Muang, Chiang Rai 57100, Thailand. Electronic address: surat.lap@mfu.ac.th.

PMID: 29031558
DOI: 10.1016/j.fitote.2017.10.009

Abstract

A new scalemic 8,8a-dihydro caged xanthone (1) was isolated from the leaf extract of Garcinia propinqua. Five other known natural products, the three caged xanthones (2, 5 and 6) and the two neocaged xanthones, (3 and 4) were also isolated as scalemic mixtures. Their structures were characterized by spectroscopic methods. The enantiomeric ratios (er) of compounds 1-6 ranged from 1:0.7 to 1:0.9. These compounds were also resolved by semipreparative chiral HPLC. The absolute configurations of (+)-2 and (+)-3 were determined by single-crystal X-ray diffraction analysis using Cu Kα radiation while the absolute configurations of the other compounds were determined by comparisons of their ECD spectra. Compounds (-)-4, (+)-4, (-)-5, (+)-5, and (-)-6 showed potent cytotoxicities against a colon cancer cell line HCT116 with IC₅₀ values of 2.60, 7.02, 1.47, 3.37, and 4.14μM, respectively, which were better than the standard control doxorubicin (IC₅₀ 9.74μM).

Keywords: Cytotoxicity; Electronic circular dichroism; Garcinia propinqua; Scalemic caged xanthones.

MeSH terms

Antineoplastic Agents, Phytogenic / isolation & purification
Antineoplastic Agents, Phytogenic / pharmacology*
Cell Line, Tumor
Colonic Neoplasms / drug therapy
Garcinia / chemistry*
Humans
Molecular Structure
Plant Extracts / chemistry*
Plant Leaves / chemistry
Stereoisomerism
X-Ray Diffraction
Xanthones / isolation & purification
Xanthones / pharmacology*

Substances

Antineoplastic Agents, Phytogenic
Plant Extracts
Xanthones