Assignment 2: Writing Introduction

Assignment 2: Writing Introduction

Stage 1:

Medicinal plants have been used to treat sickness throughout human history. The various chemical compounds synthesized from plant are used to support biological function and to prevent from fungi, insects, and herbivorous animals. 

Stage 2:

Cotton plant (Gossypium hirsute, Malvaceae) is an interesting plant which has plenty benefits.  Fiber and seed oil are by-product from cotton industrial process. The mainly active substance from the cotton plant, a yellow flavonoid-liked pigment,  is the polyphenolic compound called “gossypol” (1,1’,6,6’,7,7’-hexahydroxy-5,5’diisopropyl-3.3’dimethyl-[2,2’]binaphthalenyl-[8,8’]dicarbaldehyde). Gossypol has various biological activities such as antiviral, antiprotozoal, anticancer (Dowd et al., 2008). Moreover, Wang et al. (1987) discovered that gossypol showed significant male contraceptive activity via inhibited maturation of human sperm. Qian et al. (1984) and Colin-Negrete et al. (1996) found that gossypol absorption was toxic to animal and human health. In addition, Gilbert et al. (1995) reported that gossypol and gossypolone showed the potent activity of decrease in the number of carcinoma cell in in vivo study. Furthermore, Ford et al. (1991) stated that the (-)-enantiomer was more active in anticancer activity than (+)-enantiomer. Thus, scientists attempted to separate these two isomers. Development of methods to quantitate the gossypol component in cotton has been suggested in various publications. A range of high-performance liquid chromatography (HPLC) methods for separating gossypol enantiomers have been developed since 1968. Cass et al. (1991) analyzed the gossypol isomer ratios in cottonseed samples that were collected from different places. They neither quantitated their results nor demonstrate the validity of the method. However, (R)-(-)-2-amino-1-propanol was used in the method performed by Wu et al. (1988) and Kim et al. (1996). (R)-(-)-2-amino-1-propanol was used to convert gossypol to imine product and developed to analyze samples from plasma and tissue. Nevertheless, their methods were suitable for pharmacokinetic investigation but were not proper for determination of gossypol isomers in cottonseed samples. According to Hron et al. (1999), the (+)- and (-)-gossypol enantiomers separation by high performance liquid chromatography was successful using R-(-)-2-amino-1-propanol as derivatizing substance. This technique becomes a recommended method by the American Oil Chemists’ Society (Ba 8a-99). 

Stage 3:

Although gossypol was first found in cottonseed, but it could be extracted from several genera: Cienfuegosia, Gossypoides, Hampea, Kokia, Lebronnecia, Montezuma, and Thespesia (Jaroszewski J.W., 1991). Hibiscus tiliaceus has long been used in traditional medicines and its genus is close to the Gossypium. However, an investigation of gossypol enantiomers in leaves of H. tiliaceus has not been studied.  

Stage 4 & 5:

The present research aimed at developing a method for quantitation of the gossypol enantiomers and total gossypol content in leaves of Hibiscus tiliaceus collected from different sources throughout Thailand.  The validated HPLC method could be served the purpose of high throughput screening of gossypol enantiomers and the accurate identification given quality control of the plant material is an essential prerequisite for ensuring the quality, safety, and efficacy of herbal materials.

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