Lettuce (Lactuca sativa L.) belongs to Asteraceae family and is a widely grown and a popularly consumed vegetable worldwide cause leafy vegetables are common items in a well-balanced diet. Lettuce is low in calories, fat and sodium. It is a good source of fiber, iron, folate, vitamin C and various bioactive compounds. Lettuce is consumed in salad mixes and, as its consumption is increasing, is becoming one of most 'healthy' food. Moreover, since lettuce is generally eaten raw, more nutrients and bioactive compounds are retained compared to other vegetables that are cooked or processed, avoiding in this way the degradation of the thermolabile phytochemicals with potential nutraceutical interest.

In vitro and in vivo studies have shown anti-inflammatory, cholesterol-lowering, anti-diabetic, and antioxidant activities attributed to the bioactive compounds in lettuce. The healthy properties are attributed to a large supply of antioxidant compounds mainly polyphenols. As they act as free radical scavengers, both these secondary plant metabolites are fundamental to counter oxidative stress, inflammation, cancer, diabetes, age-related neurodegeneration and cardiovascular disease. Further, various studies have investigated the effects of the polyphenolic compounds present in green lettuce, in reducing oxidative and anti-inflammatory stresses.

This work aims to assess polyphenolic content, as well as related antioxidant capacity of 16 lettuce types, belonging to butterhead (var. capitata) and crisphead (var. crispa) varieties, in order to know their potential correlation between phenolic content and antioxidant activity. Results have shown lattuce an interesting and cheap source of antioxidant phenolics useful to functionalise various products.