**2. Major groups of antimicrobial compounds from plants**

Plants have an almost limitless ability to synthesize aromatic substances, most of which are phenols or their oxygen-substituted derivatives (Geissman 1963). Most are secondary metaboltes, of which at least 12,000 have been isolated, a number estimated to be less than 10% of the total (Schultes 178). In many cases, these substances serve as plant defense mechanisms against predation by microorganisms, insects, and herbivores. Some, such as terpenoids, give plants their odors; others (quinones and tannins) are responsible for plant pigment. Many compounds are responsible for plant flavor (e.g., the terpenoid capsaicin from chili peppers), and some of the same herbs and spices used by humans to season food yield useful medicinal compounds.

Simple phenols and phenolic acids, The mechanisms thought to be responsible for phenolic toxicity to microorganisms include enzyme inhibition by the oxidized compounds, possibly through reaction with sulfhydryl groups or through more nonspecific interactions with the proteins (Mason and Wasserman 1987).Phenolic compounds possessing a C3 side chain at a lower level of oxidation and containing no oxygen are classified as essential oils and often cited as antimicrobial as well. Eugenol is a well-characterized representative found in clove oil. Eugenol is considered bacteriostatic against both fungi (Duke 1985) and bacteria (Thomson 1978). Quinones are aromatic rings with two ketone substitutions. They are ubiquitous in nature and are characteristically highly reactive. Probable targets in the microbial cell are surface-exposed adhesins, cell wall polypeptides, and membrane-bound enzymes. Quinones may also render substrates unavailable to the microorganism. As with all plant-derived antimicrobials, the possible toxic effects of quinones must be thoroughly examined.Kazmi et al.

Flavones, flavonoids, and flavonols activity is probably due to their ability to complex with extracellular and soluble proteins and to complex with bacterial cell walls, as described above for quinones. More lipophilic flavonoids may also disrupt microbial membranes (Tsuchiya 1996). Tannins are found in almost every plant part: bark, wood, leaves, fruits, and roots (Scalbert 1991). This group of compounds has received a great deal of attention in recent years, since it was suggested that the consumption of tannin-containing beverages, especially green teas and red wines, can cure or prevent a variety of ills (Serafini et al 1994) their mode of antimicrobial action, may be related to their ability to inactivate microbial adhesins, enzymes, cell envelope transport proteins, etc. They also complex with

morphine, digoxin, quinine, ergometrine, reserpine, atropine, etc and all of which are

The inexplicable form of Traditional Medicine on the other hand, is the spiritual, supernatural, magical, occultic, mystical, or metaphysical form that cannot be easily investigated, rationalized or explained scientifically e.g. the use of incantations for healing purposes or oracular consultation in diagnosis and treatment of diseases. The explanation is beyond the ordinary scientific human intelligence or intellectual comprehension. Plants are reputed in the indigenous systems of medicine for the treatment of various diseases (Arise *et al*., 2009). Phyto-chemicals isolated from plant sources are used for the prevention and treatment of several medical problems including diabetes mellitus (Waltner- Law *et al*., 2002). There are more than 800 plant species showing a hypoglycemic activity. The World Health Organization (1980) has also recommended the evaluation of the effectiveness of

Plants have an almost limitless ability to synthesize aromatic substances, most of which are phenols or their oxygen-substituted derivatives (Geissman 1963). Most are secondary metaboltes, of which at least 12,000 have been isolated, a number estimated to be less than 10% of the total (Schultes 178). In many cases, these substances serve as plant defense mechanisms against predation by microorganisms, insects, and herbivores. Some, such as terpenoids, give plants their odors; others (quinones and tannins) are responsible for plant pigment. Many compounds are responsible for plant flavor (e.g., the terpenoid capsaicin from chili peppers), and some of the same herbs and spices used by humans to season food

Simple phenols and phenolic acids, The mechanisms thought to be responsible for phenolic toxicity to microorganisms include enzyme inhibition by the oxidized compounds, possibly through reaction with sulfhydryl groups or through more nonspecific interactions with the proteins (Mason and Wasserman 1987).Phenolic compounds possessing a C3 side chain at a lower level of oxidation and containing no oxygen are classified as essential oils and often cited as antimicrobial as well. Eugenol is a well-characterized representative found in clove oil. Eugenol is considered bacteriostatic against both fungi (Duke 1985) and bacteria (Thomson 1978). Quinones are aromatic rings with two ketone substitutions. They are ubiquitous in nature and are characteristically highly reactive. Probable targets in the microbial cell are surface-exposed adhesins, cell wall polypeptides, and membrane-bound enzymes. Quinones may also render substrates unavailable to the microorganism. As with all plant-derived antimicrobials, the possible toxic effects of quinones must be thoroughly

Flavones, flavonoids, and flavonols activity is probably due to their ability to complex with extracellular and soluble proteins and to complex with bacterial cell walls, as described above for quinones. More lipophilic flavonoids may also disrupt microbial membranes (Tsuchiya 1996). Tannins are found in almost every plant part: bark, wood, leaves, fruits, and roots (Scalbert 1991). This group of compounds has received a great deal of attention in recent years, since it was suggested that the consumption of tannin-containing beverages, especially green teas and red wines, can cure or prevent a variety of ills (Serafini et al 1994) their mode of antimicrobial action, may be related to their ability to inactivate microbial adhesins, enzymes, cell envelope transport proteins, etc. They also complex with

currently being used by orthodox medicine in modern hospitals all over the world.

plants in conditions where safe modern drugs are lacked.

yield useful medicinal compounds.

examined.Kazmi et al.

**2. Major groups of antimicrobial compounds from plants** 

polysaccharide (Ya et al 1988). The antimicrobial significance of this particular activity has not been explored. There is also evidence for direct inactivation of microorganisms: low tannin concentrations modify the morphology of germ tubes of *Crinipellis perniciosa* (Brownlee et al 1990). Tannins in plants inhibit insect growth (Schultz 1988) and disrupt digestive events in ruminal animals (Butler 1988).

Terpenoids and Essential Oils are secondary metabolites that are highly enriched in compounds based on an isoprene structure. They are called terpenes, their general chemical structure is C10H16, and they occur as diterpenes, triterpenes, and tetraterpenes (C20, C30, and C40), as well as hemiterpenes (C5) and sesquiterpenes (C15). When the compounds contain additional elements, usually oxygen, they are termed terpenoids. The mechanism of action of terpenes is not fully understood but is speculated to involve membrane disruption by the lipophilic compounds. Accordingly, Mendoza et al. (Mendoza et al 1997) found that increasing the hydrophilicity of kaurene diterpenoids by addition of a methyl group drastically reduced their antimicrobial activity.

Alkaloids are Heterocyclic nitrogen compounds. Alkaloids have been found to have microbiocidal effects (including against *Giardia* and *Entamoeba* species Ghosha et al 1996, the major antidiarrheal effect is probably due to their effects on transit time in the small intestine. Berberine is an important representative of the alkaloid group. It is potentially effective against trypanosomes (Freiburghaus et al 1996) and plasmodia Omulokoli et al 1997). The mechanism of action of highly aromatic planar quaternary alkaloids such as berberine and harmane (Hopp 1976) is attributed to their ability to intercalate with DNA (Phillipson and O'Neill 1987). The mechanism of lectins and polypeptides may be back to the formation of ion channels in the microbial membrane (Terras et al. 1993) or competitive inhibition of adhesion of microbial proteins to host polysaccharide receptors (Sharon and Ofek 1986). Recent interest has been focused mostly on studying anti-HIV peptides and lectins, but the inhibition of bacteria and fungi by these macromolecules, such as that from the herbaceous *Amaranthus*, has long been known (De Bolle et al 1996).

### **2.1 Ethnobotanical study**

Out of around 1076 species recorded so far from Semifinal Biosphere Reserve, more than 200 species are attributed with medicinal uses (Rout, 2004). This system of using herbs and different biological active ingredients in treating various diseases had become a part of their culture till recent years. Entrance of market economy gave rise to exploitation of natural resources and thereby depleting our resources base. The most affected part in this process was medicinal plants, which is most sensitive and delicate in the environment of forest. These medicinal plants gain further importance in the region where modern medical health facilities are either not available or not easily accessible. Although our ancient sages through hit and trial method developed herbal medicines, the reported uses of plant species do not certify efficacy.

The present preliminary report on the uses of some plant species need to pharmacologically screened, chemically analyzed and tested for bioactive activities. Pharmacological screening of plant extracts provides insight to both their therapeutic and toxic properties and helps in eliminating the medicinal plants or practices that may be harmful. The plant parts used for medical preparation were bark, flowers, rhizomes, roots, leaves, seeds, gum and whole plants. In some cases the whole plant including roots was utilized. The use of plant derived products containing high of dietary fiber and complex polysaccharide for the management of diabetes have been proposed (Jenkins et al., 1976). Natural products especially of plant origin have been found to be potential sources of novel molecules for the treatment of diabetes (Farnsworth, 1994; Marles and Farnsworth, 1995).

Considering the rate at which the vegetation is getting depleted in this part of the world, therefore it is needed to document the precious knowledge of these plants and to search for more plants with antidiabetic potential. The search for anti-diabetic agents has been focused on plants because of their ready availability, effectiveness, affordability and probably due to low side effects (Marles and Farnsworth, 1995). Ethnobotanical study has been the method often used to search for locally important plant species with low side effects especially for the discovery of crude drugs (Farnsworth, 1994). The present study therefore is a documentation of plants and plant parts used for the management of diabetes mellitus by traditional healers of the area (Table 1).


Table 1. Diagnosis methods of diabetes mellitus by the herbalists using herbal preparation
