Anti-inflammatory and anti-oxidant activity-guided investigation of phytoconstituents from Lactuca indica L.

Vietnamese dandelion(Lactuca indica L.)presents various remedies to cure pustules and several derma-inflammatory diseases in terms of traditional medicine. In this study, the anti-inflammatory and antioxidant effects of several fractions from L. indica were screened by assessing the inhibitory capacity of nitric oxide production in RAW 264.7 cells and the DPPH scavenging activity. Through screening steps, the chloroform extract exhibited extraordinary inhibition on NO synthesis, whereas the ethyl acetate singly showed a remarkable capacity to neutralise the DPPH radical. Bioactivity-guided isolation led to the identification of six compounds from the chloroform and ethyl acetate extracts, including pentadecanoic acid (1), lupeol (2), vanillin (3), 5-hydroxy-3ʹ,4ʹ,7-trimethoxyflavone (4), luteolin-7-O-β-D-glucoside (5), acacetin-7-O-β-D-rutinoside (6). Only compound (5) exhibited notable interruption in NO synthesis (IC50=13.86±1.10 μM) and simultaneously neutralised DPPH radical (IC50=26.93±0.10 μM). This study suggests that compound (5) as well as the chloroform and ethyl acetate extracts could be potential in preventing inflammatory diseases mediated by excessive production of NO. Additionally, (5) and the ethyl acetate extract could potentially be natural anti-oxidants.