Natural phenoxazine alkaloids from Peristrophe bivalvis (L.) Merr

Peritrophe, a genus of the Acanthaceae family, is distributed in Southern Asia and Afria. According to the literature there are four Peristrophe species in the Vietnamese flora. One of them Peristrophe bivalvis (L.) Merr. local name Cẩm, is growing wildly and cultivated for dying foods as sticky rice and other dishes by the ethnic minorities (Chi, 1999). This species appears in four forms, namely red, purple, purple- magenta and yellow according to the colours of aqueous extract. Besides the utilization as food dyestuff, this plant has been used in traditional medicine for the treatment of pulmonary tuberculosis, haemoptysis, congestion, bronchitis and wrench. We investigated the leaves of red and purple Peristrophe bivalvis, two common cultivated forms as a plant to dye food. The plant materials were collected in July 2009 in Moc Chau steppe of Vietnam and determined by Dr. Ninh Khac Ban of IEBR in VAST. Avoucher specimen No, HN35415 at the IEBR, VAST.