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Life Extension Magazine

LE Magazine June 2007
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What’s Missing from Your Sunscreen?


By Dale Kiefer

Green Tea Extract

Green tea is possibly one of the world’s oldest sun-protective agents, having been consumed as a “functional food” for at least 4,000 years.27-29 Studies have shown that green tea and green tea extract prevent photoaging both from within (taken orally) and without (when applied topically).30-35

Numerous studies have shown that topically applied green tea extract (or applications of the main bioactive green tea polyphenol, epigallocatechin-3-gallate or EGCG) can prevent the development of skin cancers in lab rodents specially bred for these types of investigations. Mechanisms of action appear to include enhanced DNA repair and retention of robust immune function. Unprotected skin exposed to excessive UV radiation invariably suffers a significant suppression of immune function, a deficit believed to play a role in UV-induced cancers. Furthermore, topical EGCG interferes with tumors’ ability to supply themselves with blood, and stimulates immune system T cells, which function to destroy aberrant cells. Thus, green tea acts to thwart cancer at several stages in its development and spread.36-38

Rosemary

Rosemary, a perennial herb used as both a culinary and medicinal plant for thousands of years, is packed with a broad array of beneficial compounds, including cancer-fighting chemicals, antioxidants, and anti-inflammatories.39-41 Italian scientists recently identified several rosemary compounds that exhibit potent anti-inflammatory action.41 Two of these compounds—carnosic and ursolic acids—have been shown to be of particular benefit to skin.42-44

Rutgers University researchers showed that topical application of both carnosic and ursolic acids significantly inhibits tumor growth in a mouse model of human skin cancer. Tumor inhibition was as high as 99%, depending on the concentration of the rosemary extract.42 More recently, Indian scientists studied the effects of feeding rosemary extract to specialized lab mice, which serve as surrogate models for human skin cancer. “[The] . . . extract could prolong the latency period of tumor occurrence [and] decrease tumor incidence, tumor burden, and tumor yield,” the researchers concluded.45

Milk Thistle Extract

Milk thistle contains silibinin and silymarin, two flavonoid compounds used for many years to treat liver disease in Europe and Asia. These unique compounds have recently come under increased scrutiny by scientists due to their well-documented antioxidant, anti-inflammatory, and immune-enhancing properties. Numerous studies have shown that these extracts combat skin cancer through a variety of mechanisms, including protecting DNA against damage, decreasing oxidative stress, and lessening inflammation.46-61

Researchers at the University of Michigan noted recently, “Melanoma is one of the few tumors that have increased in incidence over the last few decades.”49 They suggested that silymarin and green tea are among “several promising agents” that could be harnessed to “significantly decrease the morbidity and mortality from this deadly cancer.”49

“Silymarin possesses exceptionally high protective effects against [skin] tumor promotion,” concluded investigators at Case Western Reserve University.53 As such, silymarin is a superb choice for inclusion in sun protection products. It is exceptionally well tolerated and protects against skin cancers through diverse mechanisms. “Silymarin may favorably supplement sunscreen protection and provide additional anti-photocarcinogenic protection,” wrote Dr. Katiyar, in the International Journal of Oncology.46

Licorice Root Extract

Licorice root has been used medicinally since prehistoric times.62 In Chinese medicine, it is one of the oldest and most frequently employed botanicals, with recognized anti-inflammatory, anti-viral, anti-ulcer, and cancer-preventive properties.63 Japanese researchers showed that licorice constituents inhibit the growth of melanoma cancer cells growing in culture. More recently, Japanese scientists demonstrated that a licorice constituent induces a variety of cancer cell types (from liver and stomach cancer to leukemia cells) to undergo apoptosis, or cellular suicide.64

Today, scientists are interested in licorice extract’s ability to promote skin health and avert cancer. Middle Eastern scientists conducted a double-blind study of licorice gel as a treatment for atopic dermatitis, a chronic inflammatory disease of the skin. They concluded, “Licorice extract could be considered as an effective agent for treatment of atopic dermatitis.”65 Italian researchers studying the licorice constituent glycyrrhizin concluded, “Glycyrrhizin treatment might offer protection from the damage induced in humans by UVB radiation.”66

Conclusion

Maintaining youthful-looking skin and protecting against cancer require a multipronged approach, one that incorporates both UV blockers and bioactive botanicals for protection from the sun’s aging effects. Simple sunscreens may be inadequate to achieve this level of defense. For total protection and restoration of skin, consider daily use of products that provide scientifically substantiated, natural skin-rejuvenating agents.

References

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4. Gray-Schopfer V, Wellbrock C, Marais R. Melanoma biology and new targeted therapy. Nature. 2007 Feb 22;445(7130):851-7.

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14. Wei D, Williams D, Browder W. Activation of AP-1 and SP1 correlates with wound growth factor gene expression in glucan-treated human fibroblasts. Int Immunopharmacol 2002 Jul;2(8):1163-72.

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16. Kougias P, Wei D, Rice PJ, et al. Normal human fibroblasts express pattern recognition receptors for fungal (1-->3)-beta-D-glucans. Infect Immun. 2001 Jun;69(6):3933-8.

17. Lowe EP, Wei D, Rice PJ, et al. Human vascular endothelial cells express pattern recognition receptors for fungal glucans which stimulates nuclear factor kappaB activation and interleukin 8 production. Winner of the Best Paper Award from the Gold Medal Forum. Am Surg. 2002 Jun;68(6):508-17.

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22. Khanna S, Venojarvi M, Roy S, et al. Dermal wound healing properties of redox-active grape seed proanthocyanidins. Free Radic Biol Med. 2002 Oct 15;33(8):1089-96.

23. Sen CK, Bagchi D. Regulation of inducible adhesion molecule expression in human endothelial cells by grape seed proanthocyanidin extract. Mol Cell Biochem. 2001 Jan;216(1-2):1-7.

24. Khanna S, Roy S, Bagchi D, Bagchi M, Sen CK. Upregulation of oxidant-induced VEGF expression in cultured keratinocytes by a grape seed proanthocyanidin extract. Free Radic Biol Med. 2001 Jul 1;31(1):38-42.

25. Sharma SD, Meeran SM, Katiyar SK. Dietary grape seed proanthocyanidins inhibit UVB-induced oxidative stress and activation of mitogen-activated protein kinases and nuclear factor-{kappa}B signaling in in vivo SKH-1 hairless mice. Mol Cancer Ther. 2007 Mar;6(3):995-1005.

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29. Yang CS, Prabhu S, Landau J. Prevention of carcinogenesis by tea polyphenols. Drug Metab Rev. 2001 Aug;33(3-4):237-53.

30. Katiyar S, Elmets CA, Katiyar SK. Green tea and skin cancer: photoimmunology, angiogenesis and DNA repair. J Nutr Biochem. 2006 Oct 16.

31. Elmets CA, Singh D, Tubesing K, et al. Cutaneous photoprotection from ultraviolet injury by green tea polyphenols. J Am Acad Dermatol. 2001 Mar;44(3):425-32.

32. Rees JR, Stukel TA, Perry AE, et al. Tea consumption and basal cell and squamous cell skin cancer: Results of a case-control study. J Am Acad Dermatol. 2007 Jan 26.

33. Chiu AE, Chan JL, Kern DG, et al. Double-blinded, placebo-controlled trial of green tea extracts in the clinical and histologic appearance of photoaging skin. Dermatol Surg. 2005 Jul;31(7 Pt 2):855-60.

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36. Vayalil PK, Elmets CA, Katiyar SK. Treatment of green tea polyphenols in hydrophilic cream prevents UVB-induced oxidation of lipids and proteins, depletion of antioxidant enzymes and phosphorylation of MAPK proteins in SKH-1 hairless mouse skin. Carcinogenesis. 2003 May;24(5):927-36.

37. Chung JH, Han JH, Hwang EJ, et al. Dual mechanisms of green tea extract (EGCG)-induced cell survival in human epidermal keratinocytes. FASEB J. 2003 Oct;17(13):1913-5.

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39. Ho CT, Wang M, Wei GJ, Huang TC, Huang MT. Chemistry and antioxidative factors in rosemary and sage. Biofactors. 2000;13(1-4):161-6.

40. Calabrese V, Scapagnini G, Catalano C, et al. Biochemical studies of a natural antioxidant isolated from rosemary and its application in cosmetic dermatology. Int J Tissue React. 2000;22(1):5-13.

41. Altinier G, Sosa S, Aquino RP, et al. Characterization of topical antiinflammatory compounds in Rosmarinus officinalis L. J Agric Food Chem. 2007 Mar 7;55(5):1718-23.

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43. Offord EA, Gautier JC, Avanti O, et al. Photoprotective potential of lycopene, beta-carotene, vitamin E, vitamin C and carnosic acid in UVA-irradiated human skin fibroblasts. Free Radic Biol Med. 2002 Jun 15;32(12):1293-303.

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49. Lao CD, Demierre MF, Sondak VK. Targeting events in melanoma carcinogenesis for the prevention of melanoma. Expert Rev Anticancer Ther. 2006 Nov;6(11):1559-68.

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55. Singh RP, Dhanalakshmi S, Agarwal C, Agarwal R. Silibinin strongly inhibits growth and survival of human endothelial cells via cell cycle arrest and downregulation of survivin, Akt and NF-kappaB: implications for angioprevention and antiangiogenic therapy. Oncogene. 2005 Feb 10;24(7):1188-202.

56. Mallikarjuna G, Dhanalakshmi S, Singh RP, Agarwal C, Agarwal R. Silibinin protects against photocarcinogenesis via modulation of cell cycle regulators, mitogen-activated protein kinases, and Akt signaling. Cancer Res. 2004 Sep 1;64(17):6349-56.

57. Li LH, Wu LJ, Zhou B, et al. Silymarin prevents UV irradiation-induced A375-S2 cell apoptosis. Biol Pharm Bull. 2004 Jul;27(7):1031-6.

58. Dhanalakshmi S, Mallikarjuna GU, Singh RP, Agarwal R. Dual efficacy of silibinin in protecting or enhancing ultraviolet B radiation-caused apoptosis in HaCaT human immortalized keratinocytes. Carcinogenesis. 2004 Jan;25(1):99-106.

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60. Singh RP, Tyagi AK, Zhao J, Agarwal R. Silymarin inhibits growth and causes regression of established skin tumors in SENCAR mice via modulation of mitogen-activated protein kinases and induction of apoptosis. Carcinogenesis. 2002 Mar;23(3):499-510.

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64. Hibasami H, Iwase H, Yoshioka K, Takahashi H. Glycyrrhetic acid (a metabolic substance and aglycon of glycyrrhizin) induces apoptosis in human hepatoma, promyelotic leukemia and stomach cancer cells. Int J Mol Med. 2006 Feb;17(2):215-9.

65. Saeedi M, Morteza-Semnani K, Ghoreishi MR. The treatment of atopic dermatitis with licorice gel. J Dermatolog Treat. 2003 Sep;14(3):153-7.

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