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Abstracts

Life Extension Magazine July 2012
Abstracts

Broccoli sprout

Physiological and biochemical metabolism of germinating broccoli seeds and sprouts.

Changes in physiological and biochemical metabolism as well as glucoraphanin and sulforaphane contents of germinating broccoli seeds and sprouts were investigated in this study. Sprout length, root length, and fresh weight increased with germination time. Dry weight varied from 2.5 to 3.0 mg per sprout. A rapid increase in respiratory rate of sprouts occurred between 24 and 36 h of germination and then stayed at a high level. HPLC analysis found that glucoraphanin content increased at the early stage (0-12 h) of germination, decreased to a low value of 3.02 mg/g at 48 h, and then reached the highest value of 6.30 mg/g at 72 h of germination. Sulforaphane content decreased dramatically during the first day of germination, then increased slowly, and reached a high value of 3.38 mg/g at 48 h before declining again.

J Agric Food Chem. 2012 Jan 11;60(1):209-13

Broccoli sprouts: an exceptionally rich source of inducers of enzymes that protect against chemical carcinogens.

Induction of phase 2 detoxication enzymes [e.g., glutathione transferases, epoxide hydrolase, NAD(P)H: quinone reductase, and glucuronosyltransferases] is a powerful strategy for achieving protection against carcinogenesis, mutagenesis, and other forms of toxicity of electrophiles and reactive forms of oxygen. Since consumption of large quantities of fruit and vegetables is associated with a striking reduction in the risk of developing a variety of malignancies, it is of interest that a number of edible plants contain substantial quantities of compounds that regulate mammalian enzymes of xenobiotic metabolism. Thus, edible plants belonging to the family Cruciferae and genus Brassica (e.g., broccoli and cauliflower) contain substantial quantities of isothiocyanates (mostly in the form of their glucosinolate precursors) some of which (e.g., sulforaphane or 4-methylsulfinylbutyl isothiocyanate) are very potent inducers of phase 2 enzymes. Unexpectedly, 3-day-old sprouts of cultivars of certain crucifers including broccoli and cauliflower contain 10-100 times higher levels of glucoraphanin (the glucosinolate of sulforaphane) than do the corresponding mature plants. Glucosinolates and isothiocyanates can be efficiently extracted from plants, without hydrolysis of glucosinolates by myrosinase, by homogenization in a mixture of equal volumes of dimethyl sulfoxide, dimethylformamide, and acetonitrile at -50 degrees C. Extracts of 3-day-old broccoli sprouts (containing either glucoraphanin or sulforaphane as the principal enzyme inducer) were highly effective in reducing the incidence, multiplicity, and rate of development of mammary tumors in dimethylbenz(a)anthracene-treated rats. Notably, sprouts of many broccoli cultivars contain negligible quantities of indole glucosinolates, which predominate in the mature vegetable and may give rise to degradation products (e.g., indole-3-carbinol) that can enhance tumorigenesis. Hence, small quantities of crucifer sprouts may protect against the risk of cancer as effectively as much larger quantities of mature vegetables of the same variety.

Proc Natl Acad Sci USA. 1997 Sep 16;94(19):10367-72

Protection against UV-light-induced skin carcinogenesis in SKH-1 high-risk mice by sulforaphane-containing broccoli sprout extracts.

Aerobic life, UV solar radiation, genetic susceptibility, and immune status contribute collectively to the development of human skin cancers. In addition to direct DNA damage, UV radiation promotes the generation of reactive oxygen intermediates that can cause oxidative damage and inflammation, and ultimately lead to tumor formation. Treatment of murine and human keratinocytes with the isothiocyanate sulforaphane elevated phase 2 enzymes and glutathione and protected against oxidant toxicity. Topical application of sulforaphane-containing broccoli sprouts extracts induced the phase 2 response in mouse skin in vivo. Sulforaphane inhibited cytokine-dependent (gamma-interferon or lipopolysaccharide) induction of iNOS in RAW 264.7 macrophages. The UV-radiation-induced skin carcinogenesis in “initiated high-risk mice” was substantially inhibited by broccoli sprout extracts containing sulforaphane. After completion of the UV irradiation schedule (30 mJ/cm(2)/session twice a week for 20 weeks), groups of approximately 30 mice were treated topically on their backs (5 days a week for 11 weeks) with broccoli sprout extract containing either the equivalent to 0.3 micromol (low dose) or 1.0 micromol (high dose) sulforaphane, respectively. At this time point, the tumor incidence had reached 100% in the control mice. Tumor burden, incidence, and multiplicity were reduced by 50% in the animals that received the high dose of protector. Tumor incidence and multiplicity did not differ between the low dose-treated and the control groups, but the low dose treatment resulted in a substantial reduction of the overall tumor burden. Thus, topical application of sulforaphane-containing broccoli sprout extracts is a promising strategy for protecting against skin tumor formation after exposure to UV radiation.

Cancer Lett. 2006 Aug 28;240(2):243-52

Induction of the phase 2 response in mouse and human skin by sulforaphane-containing broccoli sprout extracts.

The isothiocyanate sulforaphane was isolated from broccoli extracts in a bioactivity-guided fractionation as the principal and very potent inducer of cytoprotective phase 2 enzymes and subsequently shown to inhibit tumor development in animal models that involve various carcinogens and target organs. Because broccoli and broccoli sprouts are widely consumed, extracts obtained from them are viewed as convenient vehicles for sulforaphane delivery to humans. In relation to our current interest in devising strategies for protection against UV light-induced skin cancer, it was necessary to examine the safety and efficacy of topical application of sulforaphane-containing broccoli sprout extracts as single and multiple doses in both mice and humans. Topical application of an extract delivering 100 nmol sulforaphane/cm(2) increased the protein levels of NAD(P)H:quinone oxidoreductase 1 (NQO1), glutathione S-transferase A1, and heme oxygenase 1, three representative phase 2 enzymes, in mouse skin epidermis. Quantitative assessment of the activity of NQO1 24 h after dosing showed increases of 1.5- and 2.7-fold after application of single and multiple (thrice, every 24 h) doses, respectively. A dose-escalation safety study in healthy human subjects revealed no adverse reactions when doses as high as 340 nmol of sulforaphane in the form of broccoli sprout extracts were applied topically to the center of a 1-cm-diameter circle drawn on the volar forearm. A subsequent efficacy study showed that despite the interindividual differences in basal levels, the enzyme activity of NQO1 in homogenates of 3-mm full thickness skin punch biopsies increased in a dose-dependent manner, with maximum increases of 1.5- and 4.5-fold after application of 150 nmol doses, once or three times (at 24 h-intervals), respectively, thus providing direct evidence for induction of the phase 2 response in humans.

Cancer Epidemiol Biomarkers Prev. 2007 Apr;16(4):847-51

Sulforaphane mobilizes cellular defenses that protect skin against damage by UV radiation.

UV radiation (UVR) is a complete carcinogen that elicits a constellation of pathological events, including direct DNA damage, generation of reactive oxidants that peroxidize lipids and damage other cellular components, initiation of inflammation, and suppression of the immune response. Recent dramatic increases in the incidence of nonmelanoma skin cancers are largely attributable to higher exposure of an aging population to UVR. Therefore, the development of cellular strategies for intrinsic protection of the skin against the deleterious effects of UVR is imperative. Here we show that erythema resulting from UVR is a comprehensive and noninvasive biomarker for assessing UVR damage and can be precisely and easily quantified in human skin. Topical application of sulforaphane-rich extracts of 3-day-old broccoli sprouts up-regulated phase 2 enzymes in the mouse and human skin, protected against UVR-induced inflammation and edema in mice, and reduced susceptibility to erythema arising from narrow-band 311-nm UVR in humans. In six human subjects (three males and three females, 28-53 years of age), the mean reduction in erythema across six doses of UVR (300-800 mJ/cm(2) in 100 mJ/cm(2) increments) was 37.7% (range 8.37-78.1%; P = 0.025). This protection against a carcinogen in humans is catalytic and long lasting.

Proc Natl Acad Sci U S A. 2007 Oct 30;104(44):17500-5

Topical beta-carotene is converted to retinyl esters in human skin ex vivo and mouse skin in vivo.

Human epidermis contains endogenous retinoids (retinol and retinyl esters) and carotenoids (mostly beta-carotene). Previous studies have shown that the enzymes involved in retinoid metabolism are present in human epidermis. There is still a controversy about the presence in the skin of the enzymes able to convert beta-carotene into vitamin A (retinol), although a recent study demonstrated the conversion of beta-carotene into retinol in human cultured epidermal cells. In this study, we addressed the question of the possible bioconversion of topical beta-carotene into vitamin A or derivatives by human and mouse skin. Surgically excised human abdominal skin was mounted on Franz perfusion chambers to assess the cutaneous penetration of topical beta-carotene as well as its metabolism, after a 24-h incubation period, whereas hairless mice received topical beta-carotene 24 h before assaying epidermal beta-carotene and retinoid concentrations. Epidermal retinoid and beta-carotene concentrations were determined by high-pressure liquid chromatography. Topical beta-carotene penetrated well into human and mouse epidermis and induced a 10-fold (human) and a threefold (mouse) increase of epidermal retinyl esters, which demonstrates that topical beta-carotene is converted into retinyl esters by human and mouse epidermis and thus appears as a precursor of epidermal vitamin A.

Exp Dermatol. 2004 Sep;13(9):558-61

Interventions for photodamaged skin.

BACKGROUND: Photodamage describes skin changes such as fine and coarse wrinkles, roughness, freckles and pigmentation changes that occur as a result of prolonged exposure to the sun. Many treatments are available to reverse the damage, but it is unclear which work and at what cost in terms of unwanted side effects. OBJECTIVES: To assess the effects of topically applied treatments, tablet treatments, laser and surgical procedures for photodamaged skin. SEARCH STRATEGY: We searched the Cochrane Central Register of Controlled Trials (CENTRAL) in The Cochrane Library, Issue 1 2002, MEDLINE (1966-June 2002), EMBASE (1974-June 2002), Health Periodicals (1976-June 2002). We checked references of articles and communicated with authors and the pharmaceutical industry. SELECTION CRITERIA: Randomised controlled trials which compared drug or surgical interventions with no treatment, placebo or another drug, in adults with mild, moderate or severe photodamage of the face or forearms. DATA COLLECTION AND ANALYSIS: Two reviewers independently extracted data and assessed trial quality. MAIN RESULTS: Thirty studies of variable quality were included. Eight trials showed that topical tretinoin cream, in concentrations of 0.02% or higher, was superior to placebo for participants with mild to severe photodamage on the face and forearms (although losses to follow-up were relatively high in most studies). For example, the relative risk of improvement for 0.05% tretinoin cream, compared to placebo (three studies), at 24 weeks, was 1.73 (95% confidence interval 1.39 to 2.14). This effect was not seen for 0.001% topical tretinoin (one study) or 0.01% (three studies). A dose-response relationship was evident for both effectiveness and skin irritation. One small within-patient study showed benefit from topical ascorbic acid compared with placebo. Tazarotene (0.01% to 0.1%) and isotretinoin (0.1%) both showed significant improvement over placebo for moderate photodamage (one study each). There is limited evidence (one trial), to show that the effectiveness of 0.05% tretinoin, is equivalent to the effects of 0.05% and 0.1% tazarotene. One small study showed greater improvement in upper lip wrinkles with CO2 laser technique compared to Baker’s phenol chemical peel, at 6 months. Three small RCTs comparing CO2 laser with dermabrasion found no difference in wrinkle score at 4 to 6 months, suggesting that both methods are equally efficacious, but more erythema was reported with the laser. The effectiveness of other interventions such as hydroxy acids and natural polysaccharides was not clear. AUTHORS’ CONCLUSIONS: There is conclusive evidence that topical tretinoin improves the appearance of mild to moderate photodamage on the face and forearms, in the short term. However erythema, scaling/dryness, burning/stinging and irritation may be experienced initially. There is limited evidence that tazarotene and isotretinoin benefit patients with moderate photodamage on the face: both are associated with skin irritation and erythema. The effectiveness of other interventions remains uncertain.

Cochrane Database Syst Rev. 2005 Jan 25;(1):CD001782

Modern approach to topical treatment of aging skin.

The main processes involved in skin aging are intrinsic and extrinsic. Apart from them, so called stochastic aging connotes cell damage caused by metabolic processes, free radicals and cosmic irradiation. The clinical expression of intrinsic aging include smooth, dry, and thinned skin with accentuated expression lines. It is inevitable and time dependent. Extrinsically aged skin shows signs of photodamage which include appearance of wrinkles, pigmented lesions, actinic keratoses and patchy hypopigmentations. Therapeutic modalities imply photoprotection with sunscreens that prevent sunburns and block ultraviolet irradiation. Other modalities include use of retinoids which regulate gene transcription with subsequent cellular differentiation and proliferation. The topical and peroral administration of network antioxidants, such as vitamin E and C, coenzyme Q10, alpha-lipoic acid and glutathione, enhance antiaging effect. The other antioxidants such as green tea, dehydroepiandrosterone, melatonin, selenium and resveratrol, have also antiaging and anti-inflammatory effects. Topical bleaching agents such as hydroquinone, kojic acid and azelaic acid can reduce signs of aging. Studies confirm the efficacy of these topical agents in combination with superficial and/or medium depth or deep peeling agents for photodamaged skin treatment. Indications for type of chemical peels according to various clinical diagnosis are done, as well as advantages and disadvantages of different types of chemical peels.

Coll Antropol. 2010 Sep;34(3):1145-53

Chitosan green tea polyphenol complex as a released control compound for wound healing.

OBJECTIVE: In recent years, oxidative stress has been implicated in a variety of degenerative process and diseases, including acute and chronic inflammatory conditions such as wound healing. Green tea polyphenols have shown anti-oxidant property. The present study discussed the application of chitosan green tea polyphenol complex on the wound healing. METHODS: The wound healing effect of chitosan green tea polyphenol complex was studied in ten-week-old healthy male Sherman rats weighing 150-180 g by two wound models. The rats were randomly chosen and divided into four groups (n=5), administered with distilled water in Group A as control group, epigallocatechin-3-gallate (EGCG) in Group B, chitosan-EGCG complex in Group C and chitosan-green tea polyphenols complex in Group D, respectively. In rats’incision wound model, two straight paravertebral incisions were made and skin tensile strength was measured using continuous water flow technology on the 10th day. In rats’excision wound model, wound contraction and period of epithelization were measured. The polyphenols release from the complex was continuously monitored by an elution technique in aqueous solution at different pH values (pH=4, 5, 6, 7). RESULTS: The treatment groups showed significantly enhanced the breaking strength in incision wound (328+/-14.5) g and (421+/-18.5) g compared with control (264+/-16.7) g. In the excision wound model, the wound contraction percentage in treatment groups was relatively increased during the recovery period. Respectively, the percentage of wound contraction ranged from 47.60%+/-2.15% on day 4 to 107.98% +/-1.26% on day 16 compared with control group (8.46%+/-5.42% to 59.80%+/-4.47%). The complex demonstrated a gradual increase in the release rate from the initial stage and slow increase at different pH values. The release rate approximated 0.6-0.7 in the complex and remained stable 6 hours after injury, which may be the end of the release process. CONCLUSIONS: In our study, chitosan polyphenol complex has enhanced the healing of incision wounds by increasing the breaking strength of the wounds. In excision wound model, the complex hastens the period of epithelialization. The study on the optimal release of complex among various pH values could be applied in the wound test, which can lead to a gradually active substance(polyphenols) release and efficient coverage of epithelial layers found in the healing of incision and excision wound.

Chin J Traumatol. 2010 Apr 1;13(2):91-5

Anti-angiogenic effects of epigallocatechin-3-gallate in human skin.

Epigallocatechin-3-gallate (EGCG) is the main polyphenol component of green tea. This compound exhibits antioxidant, immunomodulatory, photoprotective, anti-angiogenic, and anti-inflammatory properties. We conducted a small randomized, double blind, split face trial using a cream containing 2.5% w/w of EGCG. Four healthy volunteers with significant erythema and telangiectasia on the face applied EGCG cream to one side of the face, and vehicle control cream to the other, twice daily for six weeks. After six weeks, biopsies were taken from EGCG and vehicle treated sites. Immunohistochemistry was used to measure VEGF and HIF-1 α. HIF-1 α expression was decreased in EGCG treated sites, such that 28.4% of the epidermis showed positive staining in vehicle treated vs. 13.8% in EGCG treated sites (p<0.001). A similar decrease in VEGF expression was found (6.7% in EGCG vs. 11.0%in in vehicle-treated skin (p<0.005). EGCG topical treatments influence HIF-1 α induction and VEGF expression and may serve as a potential agent in the prevention of telangiectasias.

Int J Clin Exp Pathol. 2010 Aug 5;3(7):705-9