Niwat Keawpradub, Sukanya Dej-adisai, and Supreeya Yuenyongsawad

pp. 455 - 467

Abstract

The stems of Arcangelisia flava, Coscinium blumeanum and Fibraurea tinctoria, collectively known
in southern Thailand as Khaminkhruea, were sequentially extracted with petroleum ether, chloroform,
methanol, and boiling water to afford 12 crude extracts. All extracts have been assessed for antioxidant
activity against DPPH (1,1-diphenyl-2-picrylhydrazyl) radical and cytotoxic activity against brine shrimp
and human cancer cell line MCF-7 (breast adenocarcinoma). Methanol extract of A. flava (AFM), and methanol
and chloroform extracts of C. blumeanum (CBM and CBC) exhibited moderate antioxidant activity with
EC₅₀ values of 25-55 µg/ml. Chloroform extracts of A. flava (AFC) and F. tinctoria (FTC), AFM, CBC and
CBM showed pronounced cytotoxic activity against brine shrimp and MCF-7 cells with LC₅₀ and IC₅₀ values
of 210-278 and 8-12 µg/ml, respectively. Bioassay-guided chemical investigation led to the isolation of
berberine as a main compound of AFC, AFM, CBC and CBM. Palmatine and jatrorrhizine were found to be
main alkaloids of FTC, and minor alkaloids of AFC, AFM, CBC and CBM. In addition, an ester triacontanyl
caffeate was isolated for the first time from C. blumeanum (CBC). Chemical structures of the isolated compounds were determined by spectroscopic methods particularly NMR and mass spectrometry.
Triacontanyl caffeate was mainly responsible for antioxidant activity of C. blumeanum with an EC₅₀ value of
6.8 µg/ml. Jatrorrhizine possessed moderate antioxidant activity with an EC₅₀ value of 98.0 µg/ml, whereas
palmatine and berberine were found to be considerably less active (EC₅₀ >100 µg/ml). The LC₅₀ values of the
four isolated compounds on brine shrimp were ranging from 37-206 µg/ml. The IC₅₀ values of berberine,
palmatine and jatrorrhizine against MCF-7 cells were in the range of 1-4 µg/ml. Triacontanyl caffeate was
considerably less cytotoxic than the alkaloids with an IC₅₀ value of 15.5 µg/ml.