Curcuminoids, a group of phenolic compounds isolated from the roots of Curcuma longa (Zingiberaceae), exhibit a variety of beneficial effects on health and on events that help in preventing certain diseases. A vast majority of these studies were carried out with curcumin (diferuloyl methane), which is a major curcuminoid. The most detailed studies using curcumin include anti-inflammatory, antioxidant, anticarcinogenic, antiviral, and antiinfectious activities. In addition, the wound healing and detoxifying properties of curcumin have also received considerable attention. As a result of extensive research on the therapeutic properties of curcumin, some understanding on the cellular, molecular, and biochemical mechanism of action of curcumin is emerging. These findings are summarized in this review.

Consumption of n-3 polyunsaturated fatty acids (n-3 PUFAs) is associated with a reduced incidence of coronary arterial diseases. Dietary n-3 PUFAs act via several mechanisms. They depress plasma lipids, especially triglycerides (TGs), by inhibiting hepatic TGs and possibly apoprotein synthesis. They replace arachidonic acid (AA) in phospholipid pools with eicosapentaenoic acid (EPA) and docosahexaenoic acids (DHA). EPA and DHA, when released, inhibit cyclooxygenase and lipoxygenase and reduce eicosanoid synthesis, particularly thromboxane (TXA2) and leukotriene B4 (LTB4), by platelets and macrophages. Reduction of the proaggregatory, vasoconstrictive TXA2 decreases the thrombotic tendency of platelets. This is augmented by the limited depression of the vasoactive antiaggregatory prostacyclin (PGI2) and the generation of antiaggregatory prostaglandin I3 (PGI3) from EPA. The n-3 PUFAs also depress eicosanoid metabolism in platelets, monocytes, and macrophages, and thereby may retard the initiation and progress of atherogenesis. n-3 PUFAs reduce blood pressure and blood viscosity and modulate membrane fluidity and associated enzyme and receptor functions. The collective effects of n-3 PUFAs may account for the reduction in coronary arterial disease in populations consuming foods containing n-3 PUFAs.

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The spice principles curcumin (from turmeric) and eugenol (from cloves) are good inhibitors of lipid peroxidation. Lipid peroxidation is known to be initiated by reactive oxygen species. The effect of curcumin and eugenol on the generation of reactive oxygen species in model systems were investigated. Both curcumin and eugenol inhibited superoxide anion generation in xanthine-xanthine oxidase system to an extent of 40% and 50% at concentrations of 75 microM and 250 microM respectively. Curcumin and eugenol also inhibited the generation of hydroxyl radicals (.OH) to an extent of 76% and 70% as measured by deoxyribose degradation. The .OH-radical formation measured by the hydroxylation of salicylate to 2,3-dihydroxy benzoate was inhibited to an extent of 66% and 46%, respectively, by curcumin and eugenol at 50 microM and 250 microM. These spice principles also prevented the oxidation of Fe2+ in Fentons reaction which generates .OH radicals.

Garden cress (Lepidium sativum L.) is an edible, underutilised herb, grown mainly for its seeds in India. Physicochemical properties, minor components (unsaponifiable matter, tocopherols, carotenoids), fatty acid composition and storage stability of garden cress seed oil (GCO) were studied. Cold press, solvent and supercritical CO 2 extraction methods were employed to extract the oil. The total oil content of garden cress (GC) seeds was 21.54, 18.15 and 12.60% respectively by solvent, supercritical CO 2 and cold press methods. The physical properties of GCO extracted by the above methods were similar in terms of refractive index, specific gravity and viscosity. However, cold pressed oil showed low PV and FFA compared to the oil extracted by other methods. a-Linolenic acid (34%) was the major fatty acid in GCO followed by oleic (22%), linoleic (11.8%), eicosanoic (12%), palmitic (10.1%) erucic (4.4%), arachidic (3.4%) and stearic acids (2.9%). Oleic acid (39.9%) and a-linolenic acid (42.1%) were the predominant fatty acids at the sn-2 position. The total tocopherol and carotenoid content of GCO was 327.42 and 1.0 lmol/100 g oil, respectively. The oil was stable up to 4 months at 4°C. Tocopherol and BHT offered the least protection, while ascorbyl palmitate (200 ppm) offered the maximum protection to the oil, when subjected to the accelerated oxidative stability test. Thus GCO can be considered as a fairly stable oil with a high content of a-linolenic acid.