Free Flavonoids from Rhus retinorrhoea Steud, ex Olive

The isolation of persicogenin [1], velutin [2] and (2S) 5,3',4' trihydroxy-7-methoxyflavanone [3] and homoeriodictyol [4] from Rhus retinorrhoea (Anacardiaceae) is reported. The antimicrobial activity of the isolated compounds was studied. [1] and [2] were found devoid of any antimicrobial activity while [3] and [4] had weak activity (MIC; 200 µg/ml against Streptococcus faecalis and 300 µg/ml against Staphylococcus aureus. Furthermore, the LC 50 of the pure compounds were determined using the brine shrimp lethality assay, only velutin was significantly active.