PhotosensitizersPhotosensitizers Bergamot oilBergamot oil

IntroductionIntroductionPhotosensitive reactions have been recognized for

thousands of years. In ancient Egypt, India, and Greece psoralen-containing plants extracts were combined with exposure to sunlight to treat skin diseases.

In 1897, reports of dermatitis following contact with parsnips and angelica came from both the United States and England, and in 1916, E. Freund observed characteristic hyperpigmented lesions that he attributed to eau de cologne containing bergamot oil. Unfortunately, none of the authors recognized the necessity of ultraviolet radiation (UVR) for the reaction.

In 1938, H. Kuske showed that plant furocoumarins caused photosensitization, and shortly thereafter, T.Jensen and K. G. Hansen reported that UVR between 320 and 380 nm caused the reaction maximum..

In 1967, British researchers discovered that sandalwood oil in sunscreens and cosmetics caused photoallergies. Shortly thereafter, French scientists demonstrated that bergamot oil in sunscreens caused photosensitivity disorders, and German researchers isolated photoreactive agents from colognes, perfumes, and oral contraceptives

Photosensitivity is an adverse cutaneous reaction that results when a certain chemical or drug is applied topically or taken systemically at the same time when a person is exposed to UVR or visible light . Photosensitivity reactions may be more specifically categorized as phototoxic or photoallergic in nature. Phototoxicity is much more common than photoallergy

Photosensitivity reactionsPhotosensitivity reactions

photosensitizers are chemicals that induce a photoreaction. The chemicals may be therapeutic, cosmetic, industrial, or agricultural. Photosensitivity reactions can be caused by injected, oral, or topically applied chemical photosensitizers. In most cases, the mechanism is phototoxicity like a bergamot oil, but some agents cause photoallergy.

PhotosensitizersPhotosensitizers

Bergamot oilBergamot oil

Scientific Name: Citrus bergamiaCommon Name: Bergamot Oil

Bergamot oil is cold-pressed from the peel of the nearly ripe fruit. The aroma of bergamot oil is fresh, lively, fruity and sweet. It is an excellent deodorizer. Aromatherapy benefits: uplifting, inspiring, confidence. Avoid using bergamot on the skin when there is a possibility of exposure to sunlight because it can cause phototoxicity.

Composition of Bergamot oil

Bergapten Linalyl acetate Linalool

Limonene alpha-Pinene Myrcene

How to evaluate the phototoxicityHow to evaluate the phototoxicity In vivo experiment

Test Sample (bergamot oil)

The test sample was inject into the patch tests (diameter of 10 mm) and was applied on the back skin areas.

It was exposed with irradiation (at a dose of 5 J/cm2,as measured in the

UVA rang)

It was exposed with irradiation (as controlled)

Observed and recored every 24 h,48h,72h after exposure

How to evaluate the phototoxicityHow to evaluate the phototoxicityIn vitro experiment

3D skin model tissues

It was pre-incubated in fresh medium for 1 h (37 o C,5%CO2) were applied with test sample overnight ( 16-20 h )

It was exposed with UV light(at a dose of 6 J/cm2,as measured in the UVA rang)

It was not exposed with UV light

It was detected by spectrophotometer (at 540 nm)

Statistical analysis by the mean photo effect (MPE)

The MPE & MEDThe MPE & MED

The MPE (Mean Photo Effect )

MPE is a statistical comparison of the dose–response curves obtained with and without UV and a test substance is predicted as phototoxic

• if MPE is higher than 0.1 is predicted as ‘‘probably phototoxic’’ (OECD, 2004)

The MED (Minimal Erythema Dose )

MED is amount of sunlight needed to cause a minimally perceptible erythema sunburn.

• MED quantifies the subject’ s actinic sensitivity is depend on subject’s phototypes

Phototoxic in Bergamot oilPhototoxic in Bergamot oil

Hyperpigmented on streak on the dorsa of hand of a patient with bergapten phototoxicity

Skin irritation

Application of Cosmetic

ReferenceReference- Rūta Dubakienė, Miglė Kuprienė. Scientific problems of photosensitivity. Medicina (Kaunas) 2006; 42(8)- emedicine.medscape.com/article/1119063-media

- www.elsevier.com/locate/toxinvit

-http://www.sunadvise.com/?page_id=32

-http://books.google.co.th/books?id=2iCr7Xglyi4C&pg=PA192&lpg=PA192&dq=definition+of+Minimal+erythema+dose&source=bl&ots=sz3at_cEx9&sig=LXHEiyoLRS57qcXULNMWuM47hhA&hl=th&ei=v1SzSuPgII_y6gOBzYz_CQ&sa=X&oi=book_result&ct=result&resnum=10#v=onepage&q=definition%20of%20Minimal%20erythema%20dose&f=false-สำ��นั�กวิ�ทย�ศ�สำตร์�เคร์��องสำ��อ�ง.เอกสำ�ร์ปร์ะกอบก�ร์สำอนัเร์��อง photosensitive reaction & phototoxicity.