Isolation, characterization and biological evaluation of a phenoxazine, a natural dyestuff isolated from the leaves of Peristrophe bivalvis

Peristrophe bivalvis (L.) Merr. Is a wild growing and cultivated plant used for dyeing of foods by the ethnic minorities of Vietnam. The major component of the colour aqueour extract (CAE) of its leaves was identified as peritrophine by spectral analysis,especially the 2D NMR spectra (HSQC, HMBC and NOESY). Considering the widespread utilisation of the decoction of this plant for food dyeing, we evaluatet the acute oral toxicity of the CAE. Based on the results in an acute toxicity study in mice, the LD50 value of the CAE was determined as 9100±290 mg.kg-1 body weight. Additionally, in vitro cytotoxic assay showed an inhibition of peritrophine against Hepatocellular carcinoma (HepG2, IC503.90 μg mL-1). CAE and peritrophine (1) have also been tested for their ability to affect the cell number of the OCI acute myeloid leukaemia cell line. CAE and peritrophine significantly decreased the OCI cell number at different concentrations and times of treatment.