Oxalate content of eleven indigenous Thai plants

The total, soluble and insoluble oxalate contents of eleven indigenous fruits and vegetables commonly consumed in Surin Province in the northeast of Thailand were determined using high-performance chromatography. The fresh food samples were purchased in local markets and harvested growing wild in the local district. Four of the studied vegetables contained no detectable levels of oxalate. The remaining seven plant foods had total oxalate contents ranging from 4.6 to 2056.4 mg oxalate/100 g fresh weight (FW) while soluble oxalate content ranged from 51.3 to 1238.1 mg oxalate/100 g FW. Four of these foods contained no detectable levels of soluble oxalate. As all of these foods are consumed raw or only lightly cooked so there is little scope to reduce the intake of soluble oxalates in the three of the other foods, two of which, the fruits of Phyllanthus emblica Linn and flowers of Musa sapientum Linn., contain very high levels of soluble oxalates (1238.1 +/- 31.4, 230.6 +/- 1.6 mg/100 g FW, respectively). A juice prepared by extracting Indian gooseberry fruits produced a tart drink, which contained 1160.6 mg +/- 18.4 soluble oxalate/100 ml.