Cytotoxic constituents from the seeds of Vietnamese Caesalpinia sappan

Abstract

Context: Caesalpinia sappan Linn. (Leguminosae) has been used in folk medicines for the treatment of many diseases. The heartwood of this plant contains various phenolic components with interesting biological applications; however, the chemical and biological potentials of the seed of this plant have not been fully explored.

Objective: This study identified the cytotoxic activity of compounds from the seeds of C. sappan.

Materials and methods: The methanol extract of the seed of C. sappan was suspended in H₂O and then partitioned with CH₂Cl₂, EtOAc, and n-BuOH, successively. Diterpenoid compounds were isolated from the CH₂Cl₂-soluble fraction by silica gel column chromatography methods using organic solvents. The compound structures were determined by detailed analysis of NMR and MS spectral data. Cytotoxic activity was measured using a modified MTT assay against HL-60, HeLa, MCF-7, and LLC cancer cells. The activation of caspase-3 enzyme and western blotting assay were performed to confirm inhibitory mechanism of active compound.

Results: Five cassane-type diterpenoids were isolated and identified as phanginin I (1), phaginin A (2), phanginin D (3), phanginin H (4), and phanginin J (5). Compounds 1–4 showed effective inhibition against HL-60 cells with the IC₅₀ values of 16.4 ± 1.5, 19.2 ± 2.0, 11.7 ± 1.6, and 22.5 ± 5.1 μM. Compounds 1–3 exhibited cytotoxic activity against HeLa cells with the IC₅₀ values of 28.1 ± 3.6, 37.2 ± 3.4, and 22.7 ± 2.8 μM. Treatment of HL-60 cell lines with various concentrations of 3 (0–30 μM) resulted in the growth inhibition and induction of apoptosis.

Conclusion: These findings demonstrate that compound 3 (phanginin D) is one of the main active components of the seed of C. sappan activating caspases-3 which contribute to apoptotic cell death.

• Cassane-type diterpene
• cytotoxicity
• human promyelocytic leukemia
• leguminosae

Declaration of interest

The authors have declared that there is no conflict of interest. This research is funded by Vietnam National Foundation for Science and Technology Development (NAFOSTED) under Grant number 106.05-2011.52.