1.       Background of the Study

Cinnamic acid is an organic acid occurring naturally in plants which has low toxicity and a broad spectrum of biology activities. It is an aromatic fatty acid. In the search for novel pharmacologically active compounds, cinnamic acid derivatives are important and promising compounds with high potential for development into drugs. Many cinnamic acid derivatives, especially those with the phenolic hydroxyl group, are well-known antioxidants and are supposed to have several health benefits due to their strong free radical scavenging properties. It is also well-known that cinnamic acid has antimicrobial activity. Research studies have revealed the importance of reactive oxygen species in diseases associated with oxidative stress (e.g. atherosclerosis, inflammatory injury, cancer and cardiovascular diseases). In the above diseases, reactive oxygen species (ROS) such as superoxide anion, hydroxyl radical and hydrogen peroxide can attack lipids, proteins and DNA and cause proliferation, genetic instability, chemoresistance, angiogenesis, radio resistance and invasion. Cinnamic acid and its several derivatives have been considered attractive potential antioxidants and anti-inflammatory agents by many research groups due to the multifunctional activities they present. Furthermore, they have been found to present anti-microbial, anti-inflammatory, anti-cancer, anti-oxidative and cardiovascular protective properties. Especially, P-coumaric acid or 4-hydroxyl-trans-cinnamic acid presents antioxidant activity involving direct scavenging of ROS by minimizing the oxidation of low-density lipoprotein (Leietal., 1995, Lobo etal., 2010, Sova, 2012).

1.2   Statement of Research Problems

Endogenous dietary antioxidants currently available are not in sufficient quantity and also the therapeutic potency to eliminate the number of free radicals present in the system and put an end to several diseases they cause. Additionally, the antioxidant drugs being sold in the market are somewhat expensive and toxic. Hence, there is a high demand for a novel pharmacologically active antioxidant compound with high potency, less toxicity and easily affordable. Thus need for obtaining acetylated derivative of cinnamic acid.

1.3   Justification of Study

Free radicals adversely alter lipids, proteins and DNA creating a condition known as oxidative stress which leads to a number of human diseases including cancer, atherosclerosis, Alzheimer’s disease, Parkinson’s disease. This occurs when the free radicals overwhelm the body’s ability to regulate them. A balance between free radicals and antioxidant is necessary for proper physiological function. Hence the application of external source of antioxidants can assist in copping this oxidative stress. Thus the search for effective, non-toxic, natural compounds with antioxidant activity from cinnamic acid.

1.4       Aim of Study

To evaluate the antioxidant activity of the acetylated derivative of cinnamic acid.

1.5       Objectives of Study

  1. To carry out some monographic determinations of cinnamic acid viz; melting point.
  2. To determine its refractive index.
  3. To determine its optical rotation.
  4. To synthesize the acetylated derivative of the acid.
  5. To evaluate the antioxidant activity of the acid and its acetylated derivative.
  6. To determine the refractive index of the derivative.
  7. To determine optical rotation of the derivative.
  8. To obtain the IR spectral characteristics of the acid and its derivative.

1.6       Statement of Research Hypothesis

               Cinnamic acid has an antioxidant activity. Therefore, whatever derivative obtained will probably be expected to be more active than cinnamic acid.

1.7       Review of Related Literature

 Antioxidants are artificial or natural substances that may prevent or delay some types of cell damage. Antioxidants are believed to play a very important role in the body defence system against reactive oxygen species. In other term, antioxidant is any substance that when present at low concentration compared with that of an oxidizablesubstrate significantly delays or inhibits oxidation of the substrate. Regular consumption of anti-oxidative vegetables and fruits has been recognized as reducing the risk of oxidative damage.

1.7.1    Various Types of Antioxidants

In present time various antioxidant found include natural anti-oxidants, synthetic anti-oxidants, dietary anti-oxidant, endogenous anti-oxidants and exogenous anti-oxidant. Natural Anti-Oxidants: Natural anti-oxidants are constituents of many fruits and vegetables.  Natural anti-oxidants occur in all parts of plants, food tissues, because they are living and are under constant oxidative stress from free radicals, ROS and pro-oxidants generated both exogenously (heat and light) and endogenously (H2O2 and transition metals). For this reason, many of these tissues have developed anti-oxidant systems to control free radicals, lipid oxidation catalysts, oxidation intermediates and secondary breakdown products. These compounds include flavonoids, phenolic acids, carotenoids and tocopherols. There are several common natural anti-oxidants which are found in everyday foods, the most common of which being vitamin C (ascorbic acid), vitamin E(tocopherols), vitamin A (carotenoids), various polyphenols including flavonoids, anthocyanins (a type of flavonoid), lycopene (a type of carotenoid), and coenzyme Q 10, also known as ubiquitin, which is a type of protein (Anujetal., 2016).