Chios Mastic gum is derived from Pistacia lentiscus var. Chia cv. Anacardiaceae, a plant which is mainly met on the greek island of Chios. The beneficial, healing properties of mastic gum have been known since antiquity . From Dioscurides and Galenus to the 'Jerusalem Balsam', Pistacia lentiscus has been traditionally considered as a medical agent and is incorporated in Mediterranean cuisine, as a therapeutic means for hepatic inflammation, for disorders of the stomach and intestine, and beneficial for the teeth . Nowadays, food products (apart from the well-established chewing gum) and cosmetics based on mastic have been created. Chios mastic gum is consumed as chewing gum and also in other culinary art usage, especially in Greek, Turkish and Arabic kitchens, i.e. in the powder form as food additive, in the form of sugar containing gel as a sweetener and as mastic oil as a sweet additive in drinks. It has been referred to over centuries as having medicinal properties to treat a variety of diseases. It has been proven as a therapeutic agent against various gastric malfunctions, such as gastralgia, dyspepsia and gastric ulcer [3, 4].
Clinical studies have emphasized anti-inflammatory activity of Chios mastic gum [5, 6]. This biological activity can be attributed to a variety of compounds. It contains triterpenes of the oleanane, euphane and lupine type [7, 8]; alpha-tocopherol and polyphenols; the latter have been associated with a hypotensive effect of mastic . Chios mastic possesses anti-bacterial activity [10, 11], for which verbenone, alpha-terpineol, and linalool seem to be responsible.
Pistacia lentiscus has been traditionally regarded also as an anti-cancer agent, especially on tumours of breast, liver, stomach, spleen, and uterus. Surprisingly enough, these traditional beliefs are in line with recent studies demonstrating that Chios mastic induces apoptosis and possesses antiproliferative activity in colon cancer cells . Pistacia lentiscus has already been associated with cardiovascular protection and hepatoprotection . It inhibits human LDL oxidation and acts on peripheral blood mononuclear cells to elicit an antiatherogenic effect . The aqueous extract from the leaves of Pistacia lentiscus demonstrated hepatoprotective effect in rats intoxicated with carbon tetrachloride , which is well-known for induction of oxidative stress. The antiatherogenic activity and protection from carbon tetrachloride toxicity are likely to be associated with antioxidant properties of mastic gum. However, free radical scavenging properties and antioxidant activity of mastic gum has not been investigated.
Inflammation is strongly associated with oxidative stress induced by TNF-α and angiotensin II . Pro-inflammatory cytokine TNF-α stimulates of superoxide production by NADPH oxidases  which provides feed-forward activation of inflammatory pathways . We have hypothesized that anti-inflammatory activity of Chios mastic gum is associated with its potential antioxidant activity. In this work, we have evaluated the free radical scavenging and antioxidant activity of Chios mastic gum on TNF-α and angiotensin II - induced superoxide production. We found that mastic gum inhibited superoxide production induced by both TNF-α and angiotensin II, which may have direct implications for its physiological activity.