| Author: | Poon, Pik-chi |
| Title: | Investigation of photoprotective effects of polysaccharide-rich extracts of Cordyceps (Cs-HK1) against UVA radiation-induced DNA damage in human skin cells |
| Degree: | M.Sc. |
| Year: | 2009 |
| Subject: | Hong Kong Polytechnic University -- Dissertations. Cordyceps. Skin. DNA -- Analysis. |
| Department: | Department of Health Technology and Informatics |
| Pages: | viii, 73 leaves : col. ill. ; 30 cm. |
| Language: | English |
| Abstract: | UVA radiation in sunlight is a significant photodamaging agent. The long wavelength of UVA (315-400nm) can penetrate skin deeply and generate free radicals, causing photoaging and DNA damage which may lead to skin cancers. Antioxidants in the skin may help prevent or lower UV-induced DNA damage. Polysaccharides in Cordyceps sinensis, a natural traditional Chinese medicine, were found to show free radical scavenging activities and trigger apoptosis in tumour cells. Cs-HKl is Cordyceps mycelial cultivate successfully fermented by researchers at The Hong Kong Polytechnic University. Cs-HKl is rich in polysaccharides. In this study, the effectiveness of photoprotective effect of Cs-HKl against UVA-induced DNA damage in human BJ fibroblasts was investigated using the comet assay. BJ cells were pre-incubated in four dosages (0, 50, 100 and 200 mg/L) of hot water extracts (HWE) or exopolysaccharide extracts (EPS) of Cs-HKl for 30 min and 24 hr before UVA irradiation. UVA-induced DNA lesions were revealed by T4EV treatment. Comet tail DNA % was scored as a measure of DNA damage and compared with control cells. Neither extracts showed direct UVA absorption effect. No significant (p > 0.05) improvement in UVA-induced T4EV specific DNA damage was recorded in cells pre-incubated in either extract. The photoprotective effect of Cs-HKl against UVA-induced DNA damage recognized by T4EV was not able to be demonstrated in the study. |
| Rights: | All rights reserved |
| Access: | restricted access |
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| File | Description | Size | Format | |
|---|---|---|---|---|
| b23228581.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 5.38 MB | Adobe PDF | View/Open |
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