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Exp Biol Med (Maywood). 2016 Jan;241(2):166-76. doi: 10.1177/1535370215600102. Epub 2015 Aug 19.

In vitro and in vivo characterization of the anticancer activity of Thai stingless bee (Tetragonula laeviceps) cerumen.

Author information

1
Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.
2
Institute of Biotechnology and Genetic Engineering, Chulalongkorn University, Bangkok 10330, Thailand.
3
National Nanotechnology Center, National Science and Technology Development Agency, Thanon Phahonyothin, Tambon Khlong Nueng, Amphoe Khlong Luang, Pathum Thani 12120, Thailand.
4
Research Centre for Bioorganic Chemistry, Department of Chemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand chanpen@sc.chula.ac.th.
5
Department of Biology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand.

Abstract

Tetragonula laeviceps cerumen was sequentially extracted with 80% (v/v) methanol, dichloromethane, and hexane and also in the reverse order. By the MTT assay and the respective 50% inhibition concentration value, the most active fraction was further purified to apparent homogeneity by bioassay-guided silica gel column chromatography. α-Mangostin was identified by high-resolution electrospray ionization mass spectrometry and nuclear magnetic resonance analyses. It had a potent cytotoxicity against the BT474, Chago, Hep-G2, KATO-III, and SW620 cell lines (IC50 values of 1.22 ± 0.03, 2.25 ± 0.20, 0.94 ± 0.01, 0.88 ± 0.16, and 1.50 ± 0.39 µmol/L, respectively). The in vitro cytotoxicity of α-mangostin against the five human cancer cell lines and primary fibroblasts was further characterized by real-time impedance-based analysis. Interestingly, α-mangostin was more cytotoxic against the cancer-derived cell lines than against the primary fibroblasts. Later, the migration assay was performed by continuously measuring the attachment of cells to the plate electrodes at the bottom of the transwell membrane. The combined caspase-3 and -7 activities were assayed by the Caspase-Glo® 3/7 kit. It showed that the cytotoxic mechanism involved caspase-independent apoptosis, while at low (non-toxic) concentrations α-mangostin did not significantly alter cell migration. Furthermore, the in vivo cytotoxicity and angiogenesis were determined by alkaline phosphatase staining in zebrafish embryos along with monitoring changes in the transcript expression level of two genes involved in angiogenesis (vegfaa and vegfr2) by quantitative real-time reverse transcriptase- polymerase chain reaction. It was found that the in vivo cytotoxicity of α-mangostin against zebrafish embryos had a 50% lethal concentration of 9.4 µM, but no anti-angiogenic properties were observed in zebrafish embryos at 9 and 12 µM even though it downregulated the expression of vegfaa and vegfr2 transcripts. Thus, α-mangostin is a major active compound with a potential anticancer activity in T. laeviceps cerumen in Thailand.

KEYWORDS:

Tetragonula laeviceps; cancer; cerumen; cytotoxicity; α-mangostin

PMID:
26290139
PMCID:
PMC4935392
DOI:
10.1177/1535370215600102
[Indexed for MEDLINE]
Free PMC Article

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