Antimicrobial activities observed inthis study might be due to the presence of flavonoid Compounds. Extracts ofvarious medicinal plants containing phenolic and flavonoids possessantimicrobial activity investigated the properties of Gallic, caffeic, vanillicacid, rutin, and quercetin of different wine against pathogenic microorganisms. (Higdon et al., 1996). Escherichia coli were the most sensitive bacteriumand Flavo bacterium sp.
was resistant against all phenolic compounds tested. Theflavonoid revealed the presence ofkaempferol, myricetin, naringin, quercetin and rutin in P. macrocarpa fruit. .(cook et al.,1996). The presence ofthese compounds might contribute to antimicrobial activity of P. macrocarpafruit since Cushnieand Lamb reported that kaempferol, myricetin, naringin,quercetin and rutin have antimicrobial activity against human pathogenicmicroorganisms with some mechanisms of action such as inhibition Of nucleicacid synthesis, cytoplasmic membrane function and energy metabolisms.
(Pandey et al., 2012).Inflammation is a normal biologicalprocess in response to tissue injury, microbial pathogen infection, andchemical irritation. Inflammation is started by transfer of immune cells fromblood vessels and release of mediators at the site of injury.(Neussely et al.,2000). This process isfollowed by call of inflammatory cells, release of ROS, RNS, and inflammatorycytokines to release foreign pathogens, and repairing injured tissues.
Ingeneral, normal inflammation is rapid and self-limiting, but normal typeresolution and very long inflammation cause many lethal defects. Introdution ofantimicrobials has long paved the way for human health. However, futureeffectiveness of antibiotics is somewhat doubtful, because microorganisms are developingpotential in an unavoidable manner to these antimicrobial agents. .(Nishidaet al (1985).
Flavonoids are known to be produce byplants in response to microbial infection; thus it should not be surprisingthat they have been found in vitro to be effective antimicrobial substancesagainst a wide range of microorganisms. Flavonoid rich plant extracts fromdifferent species have been reported to possess antibacterial activity.(Iqbal et al.
,(2003) Several flavonoidsincluding apigenin, galangin, flavone and flavonols glycosides, isoflavones,flavanones, and Chalcones have been shown to possess potent antibacterialactivity Antibacterial flavonoids might be having various cellular targets,rather than one specific site of action.(Ohsugiet al.,1985) One of their molecular actions is to form complex withproteins through hydrogen bonding and hydrophobic effects, as well as bycovalent bond formation. Thus, their mode of antimicrobial action may berelated to their ability to inactivate microbial adhesins, enzymes, cellenvelope transport proteins, and so forth.(Dixonet al (1983).
Lipophilic flavonoids may also disrupt microbial membranes. Catechins, the most reduced form ofthe C3 unit in flavonoid compounds, have been extensively researched due totheir antimicrobial activity. These compounds are reported for their in vitroantibacterial activity against Vibrio cholerae, Streptococcus mutans, Shigella,and other bacteria..
(cook et al.,1996)Flavonoidsare present in photosynthesising cells and are commonly found in fruit,vegetables, nuts, seeds, stems, flowers, tea, wine, propolis and honey. For centuries,preparations having these compounds as the principal physiologically activeconstituents have been used to treat human diseases.(Berrel et al (1999) Increasingly, this class of natural productsis becoming the subject of anti-infective research, and many groups have separatedand identified the structures of flavonoids having antifungal, antiviral andantibacterial activity.
(Bolwel etal.,(1995). Moreover, several groups have demonstrated synergy betweenactive flavonoids as well as between flavonoids and existing chemotherapeutics.
Reports of activity in the field of antibacterial flavonoid research having widelyclash, probably owing to inter- and intra-assay variation in susceptibilitytesting.(simmonds et al.,2003)However, several high-quality investigations have observe the relationshipbetween flavonoid structure and antibacterial activity and these are in closeagreement. In addition, numerous research groups have sought to clear theantibacterial mechanisms of action of selected flavonoids.(cotelle et al.,(1996) The activity of quercetin, for example, hasbeen at least partially attributed to inhibition of DNA gyrase. It has alsobeen proposed that sophora flavone G and (-)-epigallocatechin gallate inhibitcytoplasmic membrane function, and that licochalcones A and C inhibit energymetabolism.
(Abrosca et al.,(1988)Other flavonoids whose mechanisms of action have been investigated includerobinetin, myricetin, apigenin, rutin, galangin,2,4,2′-trihydroxy-5′-methylchalcone and lonchocarpol A. These compoundsrepresent novel leads, and future studies may allow the development of apharmacologically acceptable antimicrobial agent or class of agents.(feeny et al., (1998).Naturalproducts of higher plants may contain a new source of antimicrobial agents withpossibly novel mechanisms of action. They are effective in the treatment ofinfectious diseases while simultaneously contain many of the side effects thatare often associated with conventional antimicrobials.
(Stewart et al.,(2000) A method using scanning electron microscope(SEM) to study the morphology of the bacterial and fungal microbes and thusdetermining antimicrobial activity.(Nishidaet al.,(1997).