Determination of polycyclic aromatic hydrocarbons in dry tea.

Twenty-eight different tea samples sold in the United States were evaluated using high-performance liquid chromatography (HPLC) with fluorescence detection (FLD) for their contamination with polycyclic aromatic hydrocarbons (PAHs). Many PAHs exhibit carcinogenic, mutagenic, and teratogenic properties and have been related to several kinds of cancer in man and experimental animals. The presence of PAHs in environmental samples such as water, sediments, and particulate air has been extensively studied, but food samples have received little attention. Eighteen PAHs congeners were analyzed, with percentage recovery higher than 85%. Contamination expressed as the sum of the 18 analyzed PAHs was between 101 and 1337 µg/kg on dry mass and the average contents in all of the 28 examined samples was 300 µg/kg on dry mass. Seven of the congeners were found in all samples with wide ranges of concentrations as follows: fluorene (7-48 µg/kg), anthracene (1-31 µg/kg), pyrene (1-970 µg/kg), benzo(a)anthracene (1-18 µg/kg) chrysene (17-365 µg/kg), benzo(a)pyrene (1-29 µg/kg), and indeno(1,2,3-cd)pyrene (4-119 µg/kg). The two most toxic congeners benzo(a)pyrene and dibenzo(a,h)anthracene were found at high concentrations only in Earl Grey Twinnings, Earl Grey Harney& Sons Fine Teas, and Chai Ultra Spice Black Tea Twinnings. Six PAH congeners are considered as suspected carcinogens (U.S.EPA), formed the basis of the estimation of the toxic equivalent (TEQ), Chai Ultra-Spice Black Tea Twinnings had the highest TEQ (110.9) followed by two grey tea samples, Earl Grey Harney & Sons Fine Tea (57.7) and Earl Grey Twinnings (54.5). Decaffeinated grey teas had the lowest TEQs, decaffeinated Earl Grey Bigelow (9.4) and Green Tea Honey Lemon Decaffeinated Lipton (9.6).

Antioxidant and Anti-Hepatitis C Viral Activities of Commercial Milk Thistle Food Supplements.

Milk thistle dietary supplements that contain silymarin are widely marketed and used in the USA and other countries for liver enhancement and recovery. More recently, silymarin has also been identified as a possible antiviral for the treatment of hepatitis C virus (HCV) infection. To assess different brands of commercially sold silymarin, 45 products were collected from local stores and analyzed for their silymarin content, antioxidant activities, and antiviral activity against HCV. Antioxidant activity was measured as radical scavenging activity using DPPH and by estimating their antioxidant capacity as trolox equivalent. Anti-HCV activity was measured in an HCV genotype 1b replication inhibition assay. Samples were found to vary widely in their silymarin content, with some samples having none or very low concentrations while silymarin represented higher than 80% of other samples. Both antioxidant and anti-HCV activity correlated with the overall level of silymarin.

Comprehensive assessment of antioxidant activity of essential oils.

UNLABELLED: Essential oils have been studied for their unique ability to act as antioxidants. Antioxidant activities of 423 essential oils of 48 different botanical families were evaluated for their antioxidant activities as free radical scavenging agents using the 1,1-diphenyl-2-picrylhydrazyl method. Seventy-three oils showed 50% or more inhibition at a concentration of 1.25 mg/mL. The 73 most active oil samples were further evaluated for their scavenging activities using series of dilutions to estimate their EC(50) . The EC(50) of the 73 most active oils ranged from 4 to 2000 µg/mL. Oils having an EC(50) of less than 300 µg/mL (20 selected samples) were subjected to ß-carotene bleaching antioxidant activity test and more detailed analysis including thin layer chromatography, gas chromatography/mass spectrometry, high performance liquid chromatography and bioautography. Essential oils of the botanical families Lamiaceae and Myrtaceae were the most effective antioxidants. Thymol and carvacrol were the major constituents in most of the essential oils of the family Lamiaceae and eugenol was the major terpene in all of the essential oils of the family Myrtaceae. PRACTICAL APPLICATIONS: Supplementation of food with spices containing essential oils may counteract and retard the process of oxidative damage, lipid oxidation and elevate antioxidant activity of the final product.