Evaluation of the phytoestrogenic activity of Cyclopia genistoides (honeybush) methanol extracts and relevant polyphenols

Unfermented C. genistoides methanol extracts of different harvestings and selected polyphenols were evaluated for phytoestrogenic activity by comparing binding to both ER subtypes, transactivation of an ERE-containing promoter reporter, proliferation of MCF-7-BUS and MDA-MB-231 breast cancer cells, and binding to SHBG. The extracts from one harvesting of C. genistoides (P104) bound to both ER subtypes. All extracts transactivated ERE-containing promoter reporters via ERbeta but not via ERalpha. All extracts, except P122, caused proliferation of the estrogen-sensitive MCF-7-BUS cells. Proliferation of MCF-7-BUS cells was ER-dependent as ICI 182,780 reversed proliferation. Physiologically more relevant, extracts antagonized E2-induced MCF-7-BUS cell proliferation. Furthermore, all extracts, except P122, induced proliferation of the estrogen-insensitive MDA-MB-231 cells, suggesting that the extracts are able to induce ER-dependent and ER-independent cell proliferation. Binding to SHBG by extracts was also demonstrated. These results clearly show that C. genistoides methanol extracts display phytoestrogenic activity and act predominantly via ERbeta. HPLC and LC-MS analysis, however, suggests that the observed phytoestrogenic activity cannot be ascribed to polyphenols known to be present in other Cyclopia species.     

Capillary electrophoresis and high-performance liquid chromatography determination of polyglutamyl 5-methyltetrahydrofolate forms in citrus products

The 5-methyltetrahydrofolate (5mTHF) polyglutamates in citrus products were analyzed by capillary electrophoresis (CE) and high-performance liquid chromatography (HPLC). Folate species were purified from citrus products and concentrated from 2- to 100-fold using combined folate-affinity chromatography and C18 extraction. Seven polyglutamyl 5mTHFs were found in most not-from-concentrate (NFC) orange juices (OJ) in total amounts of approximately 1 nmol/mL, with varying distributions of individual polyglutamates. Folate amounts and distributions were also measured in orange fractions, single-strength OJ from concentrate, NFC grapefruit juice, and citrus peel molasses. Models containing ascorbic acid had folate thermal degradation rates one-seventh that of models without ascorbic acid. Pasteurization studies demonstrated that folate loss was <2% for commercial OJ pasteurization conditions (i.e., 93 degrees C for 5 s, 88 degrees C for 15 s, and 82 degrees C for 30 s). Both methods were precise, reproducible, and potentially faster than traditional analytical procedures requiring enzymatic deconjugation and microbial assays.     

Honeys from different floral sources as inhibitors of enzymatic browning in fruit and vegetable homogenates

Honeys from different floral sources were evaluated for their antioxidant content and for their ability to inhibit enzymatic browning in fruits and vegetables. Antioxidant contents of honeys vary widely from different floral sources, as do their abilities to protect against enzymatic browning. Polyphenol oxidase (PPO) activity was reduced over a range of approximately 2-45% in fruit and vegetable homogenates, corresponding to a reduction in browning index by 2.5-12 units. Soy honey was particularly effective when compared to clover honey, which had a similar antioxidant content. When compared to commercial inhibitors of browning, honeys were less effective; however, in combination they added to the effectiveness of metabisulfite and ascorbic acid. Honey has great potential to be used as a natural source of antioxidants to reduce the negative effects of PPO browning in fruit and vegetable processing.     

Crop germplasm conservation and developing countries

Loss of the genetic diversity of some of the world's crops has accelerated in recent decades, with many crops becoming increasingly susceptible to diseases, pests, and environmental stresses. A global network of gene banks has therefore been established to provide plant breeders with the genetic resources necessary for developing more resistant crops that will enable farmers to maintain high yields. Most of these gene banks now store the germplasm of only the major crops such as cereals, potatoes, and grain legumes. Cultivated varieties of these crops are conserved as well as wild species that might otherwise become extinct. Tropical cash crops such as bananas and coconuts are also important food crops in many Third World countries, and more effort needs to be made to conserve the germplasm of these crops as well as of other important plants such as plantation crops, medicinal herbs, and fruit and timber trees.     

Fluoride content of foods made with mechanically separated chicken

The goal of the present study was to determine the extent to which foods made with mechanically separated chicken can contribute to total fluoride intake. Fluoride content of each blended sample was determined with a fluoride combination electrode following perchloric-acid-facilitated diffusion of hydrogen fluoride. Infant foods had the highest fluoride content followed by chicken sticks, luncheon meats, and canned meats. A single serving of chicken sticks alone would provide about half of a child's upper limit of safety for fluoride. Fluoride content of foods made with mechanically separated chicken was significantly correlated with calcium content, which is consistent with the possibility that the mechanical separation process was the source of the extra fluoride. Foods made with mechanically separated turkey were not a major source of fluoride.     

The bioavailability and disposition kinetics of genistein in cats

The absorption and disposition kinetics of the soy isoflavone genistein were determined in cats (n = 6). An oral dose of 100 mg/kg was administered, which has previously been demonstrated to be the minimum oral estrogenic dose, and was administered intravenously at a dose of 20 mg/kg, being the largest practical dose that could be safely administered. Plasma free, and total (conjugated + free) genistein concentrations were determined by HPLC following organic extraction. Noncompartmental analysis revealed a half-life of 21.67 +/- 7.9 h (free) and 9.95 +/- 2.7 h (conjugated), volume of distribution 31.94 +/- 10.38 L/kg (free) and 11.82 +/- 3.96 L/kg (conjugated) following intravenous administration. Following oral administration the half-lives were determined to be 17 +/- 4.8 h (free) and 8.56 +/- 4.65 h (conjugated), with tmax = 4.4 +/- 0.6 h (free) and 4.42 +/- 0.99 h (conjugated), and Cmax = 0.276 +/- 0.1 microg/mL (free) and 6.24 +/- 6.58 microg/mL (conjugated). Oral bioavailabilities were 1.379 +/- 0.9% (free) and 29.85 +/- 22.61% (conjugated). The ratio of total:free genistein ranged from 25.9 to 5.5. Poor oral absorption and efficient conjugation explain the low bioavailability of free genistein. Accumulation of genistein in peripheral lipophilic compartments may occur.     

Relation of Geomagnetic Disturbances to Circulation Changes at 30,000-Foot Level

From analyses of waves in the circulation pattern at the jet-stream level of the atmosphere during the winters of 1956-57 and 1957-58, it was found that, in comparison with other waves, those which appeared in the Alaska-Aleutian area about 3 days after a magnetic disturbance subsequently developed into large-amplitude disturbances.