Yan Zhang

Document Type

Thesis - University Access Only

Award Date

1996

Degree Name

Master of Science (MS)

Department / School

Pharmaceutical Sciences

First Advisor

Chandradhar Dwivedi

Abstract

Cancer is a group of diseases characterized by uncontrolled growth and spread of abnormal cells. It is estimated that over 10 million Americans alive today have a history of cancer and over 500,000 will die in 1996 because of this disease. One of every four deaths in the United States is from cancer. Among all the types of cancer, the occurrence of skin cancer is the highest one. About 800,000 cases of skin cancer occur in U.S. each year. Chemoprevention is the promising approach to reduce the occurrence of cancer. Chemopreventive agents may slow, block, suppress, or reverse the effects of cancer-causing factors. A large variety of chemopreventive agents, both naturally occurring and synthetic, have been investigated. Sandalwood oil (SW oil) is an essential oil obtained from the small chips and billets cut out of the heart wood of Sandalwood (Santa/um Album Linn). The oil is extremely viscid, of a light yellow color and possesses a characteristically pleasant odor. It has been used for the treatment of inflammatory and eruptive skin diseases in India for several centuries. Preliminary results have indicated the chemopreventive effects of SW oil on CD1 mice skin tumor development. The purpose of the present investigation is to study the dose-response and time-response of SW oil on 7,12-dimethylbenz(a)anthracene (DMBA)-initiated and 12-0-tetradecanoylphorbol-13-acetate (TPA)-promoted skin tumor formation in female CD1 mice. In order to elucidate the possible mechanism of action, effects of SW oil pretreatment on TPA-induced ornithine decarboxylase (ODC) activity was studied. A total of four hundred seventy-eight female CD1 mice (5-6 weeks old) were used. In the skin tumorigenesis protocol, the mice were divided into thirteen groups having thirty mice in each group, and a weight control group (no treatment) having twenty mice. One week after topical application of DMBA alone or with SW oil, the mice were treated with TPA alone or SW oil at different concentrations (e.g., 1.25%, 2.5%, 3.75%, or 5% SW oil in acetone, w/v) at different times (e.g., 0.5hr, 1hr, or 2hrs) before TP A application twice weekly for twenty weeks. The mice were weighed and papillomas were counted weekly. The results from this experiment indicates that SW oil inhibits papilloma incidence and multiplicity (mean number of papilloma per animal) in a dose-, and time-dependent manner. Among all of these fourteen groups, the topical application of 5% SW oil 1hr before TPA treatment had the maximum chemopreventive effect. To study the effect of SW oil pretreatment on ODC activity, the mice were divided into seventeen groups having four mice in each group. The mice were treated with topical application of accetone, TPA or SW oil (5%) alone, or treated with TPA and SW oil at different concentrations (e.g., 1.25%, 2.5%, 3.75%, or 5% SW oil) and at different time (e.g., 0.5hr, 1hr, or 2hrs before TPA application). The mice were sacrificed at appropriate times. The ODC activity was assayed using the radiometric method of measuring the formation of 14CO2 from 14C-ornithine. The mice which were pretreated with SW oil (regardless of the concentration) before TPA had significantly (P

Library of Congress Subject Headings

Sandalwood oil
Skin -- Cancer -- Chemoprevention
Skin -- Cancer -- Animal models
Mice -- Diseases

Format

application/pdf

Publisher

South Dakota State University

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Rights Statement

In Copyright