Comparative Study on Chemical Composition and Antimicrobial Activity of Brassica oleracea Varieties (Broccoli and Cabbage)

Abstract

1. Introduction and Literature Review 1.1.Introduction: Natural products are chemical compounds or substance produced by a living organism or found in nature that have pharmacological or biological activity. Living organisms produce manifold primary and secondary metabolites(1) . Primary metabolites have essential function in the organism whereas secondary metabolites may have important functions for their producers or they could simply be waste products. However, secondary metabolites may also have properties that are beneficial to humans. In many cases they can be used as drugs against human diseases such as cancer, bacterial infections, inflammation, and many other diseases(1) . However, a number of these secondary metabolites have been noted for their antimicrobial activity. Secondary metabolites with antimicrobial activity can be found in most organisms including: plants such as fruits, vegetables, seeds, herb, and spices(2), animal sources such as milk, eggs, and tissues, and microorganisms such as bacteria and fungi(3) . Natural antimicrobials are been given more attention due to the increase concerns on chemical preservatives among consumer. Even though chemical preservatives are approved for human consumption by government agencies, many of these preservatives still threaten our health. Thus, the scientific communities have given more attention towards the potential antimicrobial activities of natural products. On the other hand, the increasing antibiotic resistance against chemical preservatives of some pathogens associated with foodborne illness is in increasing rates(4,5) . Natural antimicrobials seems to be the most promising answer to many of the increasing concerns regarding antibiotic resistance and could yield better results than antimicrobials from combinatorial chemistry and other synthetic procedures(6) . Therefore, novel types of effective and healthy antimicrobial compounds that could protect food against contamination and consumer against infection is highly demanded(6) . 2 Plants have been the primary source of medicines for early drug discovery. In developing countries, due to economic factors, nearly 80% of the population still depends on plant extracts as a source of medicine. Due to increasing risk of chronic illness worldwide, World Health Organization (WHO) is encouraging developing countries to use traditional herbal medicines for the treatment of various chronic ailments(7). American Cancer Society, (1984) and National Research Council, (1982) have been advised to include more cruciferous vegetables, such as cabbage, broccoli, brussel sprouts, kohlrabi, and cauliflower, in their diets. Vegetables form an important part of our daily diet; the market is crammed with varieties of vegetables. Veggies are naturally good and contain lots of minerals and vitamins. They help in protecting our body against cancers, diabetes and heart diseases. Almost all the vegetables are low in fat and calories, none have cholesterol and many of them are great sources of fiber (8) . The high levels of fiber in vegetables keep the digestive system healthier; allowing you to avoid issues with constipation. Since veggies are low on calories, it enables us to eat lots of vegetables without consuming excess energy. The presence of many vitamins and other substance in vegetables provide nutrients to the body. Vegetables provide essential amino acids which are required by the body for survival. A simple meal of spinach, beans, and whole grain rice is a great way to treat your body right. This gives us the energy to become more active and helps us produce more energy each day. There are numerous types and varieties of vegetables, all of them being the powerhouse of nutrients, minerals and vitamins(8) . Plants are a resource for a variety of drugs such as emetics, anti-cancer, antimicrobials etc. Phytochemicals play a vital role as they exhibit these properties 3 . Cruciferae family which is one of the largest families in the plant kingdom is rich in medicinal plants. It includes 338 genera and 3350 species that are distributed worldwide. 3 Various studies indicate that consumption of large number of cruciferous vegetables (e.g., broccoli, cabbage, kale, and Brussels sprouts) are associated with a reduced incidence of cancer. These contain various primary and secondary metabolites(8) . A high intake of cruciferous vegetables is associated with a reduced risk of cancer, particularly lung and those of the gastrointestinal tract(9)