Chromatographic analysis of organic acids in artichoke, milk thistle and borututu using UFLC-PDA

Cynara scolymus L. (artichoke), Silybum marianum (L.) Gaertn (milk thistle) and Cochlospermum angolensis Welw. (borututu) are three plants widely used for medicinal purposes due to their richness in bioactive compounds that provide antioxidant and hepatoprotective effects. Among these compounds are organic acids, that are involved in various fundamental pathways, as intermediate or end products, in plant metabolism and catabolism !21• Some of them, like malic, citric and oxalic acids, seems to be related to processes operating in the rhizosphere, including nutrient acquisition, metal detoxification, alleviation of anaerobic stress in roots, mineral weathering and microbial attraction[31• In this study, ultra fast liquid chromatography and photodiode array detection (UFLC-PDA) was used to analyse organic acids in the mentioned plants. The species presented oxalic, quinic, malic, shikinic, citric and fumaric acids with the exception of quinic and shikinic acids for artichoke and borututu, respectively. The higher values of total organic acids (53 mg/g dw) and quinic acid (27 mg/g dw) were found in milk thistle; artichoke showed the highest content of oxalic and malic acids, being the most abudant oxalic acid (20 mg/g dw); and borututu revealed higher contents of shikinic, citric and fumaric acids when compared whit the other plants but its main acid was oxalic (7 mg/g dw). Thus, in addition to their capacity to prevent oxidative stress and liver diseases, these plants could also be included in food formulations as acidulants, given the presence of citric and malic acids in the plants composition.