1. INTRODUCTION. systems of medication such as Ayurvedic, Siddha and Unanic in India. Herbal medicine

Transcription

1 1. INTRODUCTION Medicinal plants (MPs) played a significant role in various ancient traditional systems of medication such as Ayurvedic, Siddha and Unanic in India. Herbal medicine is the oldest and still the most widely used system of medicine in the world today. It is used in all societies and is common to all cultures. According to World Health Organization (WHO), Herbal Medicine is defined as plant derived material or preparation, which contains raw or processed ingredients from one or more plants, with therapeutic values (Chapman and Chomchalow, 2004). The WHO estimates that a minimum of 20,000 plant taxa has recorded medicinal uses. It is estimated that up to 70,000 plants species are used in folk medicine and a majority of these species are found in the Asia-Pacific region (Batugal, 2004). Interest in the exploitation of medicinal and aromatic plants as pharmaceuticals, herbal remedies, flavourings, perfumes and cosmetics, and other natural products has greatly increased in the recent years (Anonymous 1994; Ayensu 1996; Salleh et al. 1997; Kumar et al. 2000). As with many other economic plants that are still being collected from the wild and exploited by humans unsustainably, threats to genetic diversity and species survival have also increased in the case of medicinal plants as a result of habitat destruction, overexploitation, land use changes and other pressures (Arora and Engels 1993). In India alone, less than 10 % of the medicinal plants traded in the country are cultivated, about 90% are collected from the wild, very often in a destructive and unsustainable manner (Natesh, 2000). Biological activities of Limonia crenulata (Roxb.) 1

2 The number of organizations conducting research and other activities related to the use of medicinal and aromatic plants is large and increasing (Ayensu 1996; Sharma et al., 2002). Botanic gardens are particularly well distributed network of institutions with experience and expertise in this area. Work on conservation of this resource, particularly at the level of intra-specific genetic diversity, has not kept pace with advances in other areas, such as pharmacognosy and documentation of indigenous knowledge (Leaman et al., 1999; Kshirsagar and Singh 2001). The medicinal plants have been used by humans from the pre-historical times. Studies have pointed out that many drugs that are used in commerce have come from folk-use and use of plants by indigenous cultures (Anonymous, 1994). Of the 2,50,000 higher plant species on earth, more than 80,000 are medicinal. India is one of the world s 12 biodiversity centres with the presence of over different plant species. India s diversity is unmatched due to the presence of 16 different agro-climatic zones, 10 vegetation zones, 25 biotic provinces and 426 biomes (habitats of specific species). Of these, about plants have good medicinal value. However, only species are used for their medicinal values by traditional communities. In India, drugs of herbal origin have been used in traditional systems of medicines such as Unani and Ayurveda since ancient times. The Ayurveda system of medicine uses about 700 species, Unani 700, Siddha 600, Amchi 600 and modern medicine around 30 species. The drugs are derived either from the whole plant or from different organs, like leaves, stem, bark, root, flower, seed, etc. Some drugs are prepared from excretory plant product such as gum, resins and latex. Even the Allopathic system Biological activities of Limonia crenulata (Roxb.) 2

3 of medicine has adopted a number of plant-derived drugs which form an important segment of the modern pharmacopoeia. Some important chemical intermediates needed for manufacturing the modern drugs are also obtained from plants (Eg. diosgenin, solasodine, and ionone). Not only, that plant-derived drug offers a stable market world wide, but also plants continue to be an important source for new drugs (Joy et al., 1998). Medicinal plants, as a group, comprise approximately 8000 species and account for about 50% of all the higher flowering plant species in India. A large number of the country's rural population depends on medicinal plants for treating various illnesses. About 1.5 million practitioners of the Indian Systems of Medicine and Homeopathy (ISM &H) use medicinal plants for preventive, promotive and curative applications. Furthermore, there are 7,843 registered ISM pharmacies and 851 of homoeopathy as well as a number of unlicensed small-scale units. Besides meeting national demands, India caters to 12% of the global herbal trade. In recent years, trade in herbal-based products has quantum leaped, particularly in the volume of plant material traded within and outside the country. Estimates by the EXIM (Export Import) Bank put medicinal plants related international trade at US$ 60 billion per year and still growing at a rate of 7% annually (Maiti, 2004). India is blessed with two mega centres of biodiversity such as the Hindustan Centre of Origin and the Central Asia Centre of Origin. This biodiversity is mainly distributed in Western Ghat, North Eastern India and the Himalayan Region. India has about 141 endemic genera of 5,150 species belonging to 47 families of higher plants. Among the different endemic species, 2,532 species are distributed in Himalayas, 1,788 Biological activities of Limonia crenulata (Roxb.) 3

4 species in the peninsular region and 185 species in the Andaman and Nicobar Islands. About 43,000 plant species are eferred to Indian folklore but only about 1,700 plant species have actually been documented in old literature (Maiti, 2004). Over three quarters of the world population relies mainly on plants and plant extracts for health care. More than 30% of the entire plant species, at one time or other, were used for medicinal purposes. It is estimated that world market for plant derived drugs may account for about Rs. 2,00,000 crores. Presently, Indian contribution is less than Rs crores. Indian export of raw drugs has steadily grown at 26% to Rs. 165 crores in from Rs. 130 crores in The annual production of medicinal and aromatic plant s raw material is worth about Rs.200 crores. This is likely to touch US $1150 by the year 2000 and US $5 trillion by 2050 (Joy et al., 1998). Over 7000 species belonging mainly to the families Fabaceae, Euphorbiaceae, Asteraceae, Poaceae, Cucurbitaceae, Apiaceae, Convolvulaceae, Malvaceae, Rutaceae and Solanaceae have been used from ancient times by various indigenous peoples in the country. This number corresponds to more than 25% of the world's known medicinal plants, estimated to be at around 30,000 species. Analyses of these plants show that they include all the major life forms (i.e., trees, shrubs, climbers and herbs), with the proportion of ferns and lichens being much smaller compared to flowering plants (Maiti, 2004). Biological activities of Limonia crenulata (Roxb.) 4

5 Nature has been a source of medicinal agents for thousands of years and an impressive number of modern drugs have been isolated from natural sources, many based on their use in traditional medicine. Plants produce a diverse range of bioactive molecules, making them a rich source of different types of medicines. For most of the developing world, the main issue of public health is still the acute need for basic health care, which is sadly lacking even at the most elementary level. This is true in both the rapidly growing cities and in the rural areas. The WHO indicates that more than half of the world's population does not have access to adequate health care services. This is due to the fact that poor people neither have access to nor could afford the present health care services. Therefore, innovative alternative approaches are needed to address this problem. The use of plants for treating various diseases predates human history and forms the origin of much of the modern medicine. Long before the advent of modern medicine, herbs were the mainstream remedies for nearly all ailments. People commonly diagnosed their own illness, prepared and prescribed their own herbal medicines, or bought them from the local apothecaries. Using plants as medicine provides significant advantages for treating many conditions. The therapeutic activity of a plant is due to its complex nature with different parts of the plant providing certain therapeutic effects. Today we are witnessing a great deal of public interest in the use of herbal remedies. The WHO estimated that 80% of the earth's inhabitants rely on traditional Biological activities of Limonia crenulata (Roxb.) 5

6 medicine for their primary health care needs and most of this therapy involves the use of plant extracts or their active components (Batugal, 2004). Herbal medicines are being used increasingly as dietary supplements to fight or prevent common maladies like cancer, heart attacks and depression. When added to foods as supplements, herbs have also been termed as neutraceuticals. Herbal remedies are unpurified plant extracts containing several constituents, which often work together synergistically. Health practices, approaches knowledge's and benefits incorporating plant, animal and mineral based medicines. Applied singularly or in combination to treat, diagnose and prevent illness or maintain well-being. In Africa upto 80% of the populations use traditional medicines for primary health care. In industrialized countries, adaptations of traditional medicine re-termed Complementary or Alternative Medicine (CAM). In United States, 158 millions of the adult population use complementary medicine, US$ 17 billion was spent on traditional remedies in In the United Kingdom, annual expenditure an alternative medicine was US $ 230 million. The global market for herbal medicines currently stands at over US $ 60 billion annual and is growing steadily 25% of modern medicines are made from plants first use traditionally. Over one third of the population in developing countries lack access to essential medicines. The provision of safe effective traditional medicine therapies could became a critical tool to increase access to health care. Biological activities of Limonia crenulata (Roxb.) 6

7 70 countries have a national regulation on herbal medicines but the legislative control of medicinal plants has not evolved around a structured model. This is because medicinal products or herbs are defined differently in different countries and diverse approaches have been adopted with regard to licensing, dispensing, manufacturing and trading (WHO, 2008). Indian sub continent is a rich source of plant and animal wealth, which is due to it's varied geographical and agroclimatic regions. Beside it is varied bio-diversity, it has a diverse cultural heritage too. Though at present Indian health care delivery consists of both modern system of medicines and traditional system of medicine like Ayurveda, Siddha, Unani and unorganized system like Folk-medicine have been flourishing well. Ayurveda and Siddha are of Indian origin and accounted for about 60% health care delivery in general and 75% of rural Indian population depends on these traditional systems. These two systems of medicine used plants, minerals, metals and animals as a source of drugs, plants being the major source. It is estimated that roughly 1,550 plant species in Ayurveda and 1,200 plant species in Siddha have been used for drug preparation (Jain, 1991; Krishnakumar and Sureshkumar, 1995). In Indian Folk medicine use of about 7,500 plant species are recorded as medical plants (Anonymous, 1996). Biological activities of Limonia crenulata (Roxb.) 7

8 Homeopathy system of medicine is a newer one which has been developed in 18th century by Samuel Hahnemann a German Physician and Chemist. These systems based on the concept of providing and prove (Treatment and Patient) that is the choice of drug for treatment depends on symptoms and the clinical condition of the patient (Kokate, 1994). Nowadays peoples are attracted towards modern system of medicine because of sudden relief from illness, availability etc. But the trend has been changing now, because of side effect, low cost and more efficacy than the modern medicine consequently does it has been a demand for herbs and their products. The major problem in quality control of herbal drug is lack of Pharmacological standards for all medicinal plants used in phyto drug making. Recently published Indian herbal pharmacopeias contain only a few (32) medicinal plants against about 500 drugs Indian medicine manufactures are used the plants by their products. It is ironical that even botanical identity of many herbs used in medicinal plant is known in different vernacular names in different parts of India. India is one of the 12 mega biodiversity centers of the world. The country is divided into 10 biogeography zones, and 25 hot spots representing all the major ecosystems. India is recognized as a country rich in biodiversity because of its tropical location, varied physical features and climate. These factors altogether have resulted in a diversity of ecological habitats like forests, grass land, wet lands, marine and desert ecosystems which harbors immense biodiversity. Indian biodiversity represents 7 percent Biological activities of Limonia crenulata (Roxb.) 8

9 of world flora and 6.5 percent of world fauna. In general, nearly 45,000 plant species and 81,000 animal species constitute India's biodiversity. The Indian flora Limonia crenulata (Roxb.) is a well known medicinal plant. All parts of this plant are medicinally useful. Literature in Indian traditional medicinal systems like Ayurveda, Siddha, Unani and Indian folk medicine has potential information on its therapeutic uses. Leaf, fruits and roots of this plant is used to treat dyspepsia, diarrhoea, fever and diabetes. Traditional medicines (TM) have been defined by WHO as "diverse health practices, approaches, knowledge and beliefs incorporating plant, animal and or mineral based medicines, spiritual therapies, manual techniques and exercises applied singularly or in combination to maintain well being, as well as to treat, diagnose or prevent illness". The advantages of traditional medicine include its widespread accessibility and relative cheapness, when most people in low income countries pay for medicines out of their own pockets. The government of China and India, amongst others, provides governmental support to strengthen training, research and the use of "traditional" medicine in their national health care strategies and a number of African countries are considering how to integrate traditional medicine into "main stream" health care. The possibilities for expanding such initiatives need to be examined. Apart from medical use, the production, sale and export of traditional medicine is an important component in some economies. China for instance, exports over 600 million dollars of traditional medicine products annually. Chinese health authorities have recently launched a nation wide program to build up Traditional Chinese Medicine (TCM) hospitals, each Biological activities of Limonia crenulata (Roxb.) 9

10 specializing in the treatment of a particular condition, such as different types of cancers, heart and vascular diseases and hepatitis (Hepeng, 2004.) Efficacy traditional medicine of is one of the most debated issues. There are philosophical, cultural, technical, methodological and practical aspects involved in efficacy or otherwise have been published in prestigious international scientific journals. For instance, the efficacy of acupuncture in relieving pain and nausea has been well demonstrated and is now acknowledge world wide. For herbal medicines, some of the best-known evidence of efficacy of an herbal product includes Artemisia annua for the treatment of malaria, St. John's wort for the management of mild to moderate depression. Patients usually experience fewer side effects than when treated with antidepressants such as amitriptyline. Such findings have inspired research worldwide to establish the efficacy of other extensively used TM. Many plant extracts have a variety of pharmacological effects, including anti inflammatory vasodilatory, antimicrobial, anticonvulsant, sedative and antipyretic effects. However, very few randomized controlled studies have been carried out to investigate the practice and treatment delivery of herbal practitioners in their every day work. Regarding no medication therapies, the 1999 British Medical Journal (BMJ) series on CAM commented that randomized controlled trials have provided good evidence that both hypnologic and relaxation techniques can reduce anxiety and prevent panic disorders and insomnia. It has also shown hypnosis to be of value in treating asthma and irritable bowel syndrome. Yoga is to be of benefit in asthma and in helping elderly people to reduce their fear of falls. Besides these limitations, there Biological activities of Limonia crenulata (Roxb.) 10

11 has been an enormous research that has been and is underway in many institutions globally. Many of the findings do substantiate the traditional claims (Patwardhan, 2005). The major advantage of herbal medicines over modern medicine is the substantial absence of serious side effects of herbs compared with pharmaceutical medicines. Herbs have traditionally been used in cooking as well as in the healing arts. Pharmaceutical medicines are their copies of herbal "active ingredient" are completely new molecules that do not occur in nature. People also tend to believe that natural products are inherently better than synthetic drugs. The natural drugs somehow contain the 'vital force' that is going to improve their health. The promise is of alternative and effective treatment for chronic disorders. The risk is borne out of the great-unknown effects of herbs on the human body. People who use herbal medicines for self-diagnosed ailments run potential health risks. The risks involve people of all ages (Litvinenko, et al., 1992). Nowadays traditional medicines and practices form an integral part of Complementary and Alternative Medicine (CAM). Although their efficacy and mechanisms of action have not been tested scientifically in most cases, these simple medicinal preparations often mediate beneficial responses due to their active chemical constituents (Park and Pezzuto, 2002). Biological activities of Limonia crenulata (Roxb.) 11

12 The use of plant compounds for pharmaceutical purposes has gradually increased in the world. Various medicinal plants have been used as a source of medicine for years in daily life to treat diseases. Over 50% of all modern clinical drugs are of natural product origin (Stuffness and Dourous, 1982). Ethnopharmacology provides an alternative approach for the discovery of antibacterial agents, namely the study of medicinal plants with a history of traditional use as a potential source of substances with significant pharmacological and biological activities (Pushpangadan, 1995). Phytoconstituents are the natural bioactive compounds found in plants. These phytoconstituents work with nutrients and fibers to form an integrated part of defense system against various diseases and stress conditions. Phytochemicals are basically divided into two groups, i.e. primary and secondary constituents; according to their functions in plant metabolism. Primary constituents comprises common sugars, amino acid, proteins and chlorophyll while secondary constituents consists of alkaloids, terpenoids, saponins, phenolic compounds, flavonoids, tannins, etc. Pharmacognosy means knowledge of drugs which is mainly concerned with naturally occurring substances this term was introduced by Seydler in 1815 in his work entitled Analecta pharmacognostica' (Evans, 1983). In other words it is an applied science that deals with biological, biochemical and economical features of natural drugs and their constituents (Tyler et al., 1981). Natural drugs are originated either from plant Biological activities of Limonia crenulata (Roxb.) 12

13 or animal origin. In the earlier days, only the morphological characters were used to identify the drugs. In the beginning of the present century, pharmacognosy had developed on the botanical side which is concerned with the description and identification of drugs both in whole and powdered states. Therapeutic efficacy of herbal drugs depends upon the quality and quantity of the active compounds that they contain. Pharmacognosy is the simultaneous application of various specific disciplines with the object of acquiring knowledge of drugs from every point of view. Many higher plants are major sources of natural products used as pharmaceutical agrochemicals, flavour and fragrance ingredients, food additives and pesticides. The search for new plant derived chemicals should be a priority in current and future efforts towards sustainable conservation and rational utilization of biodiversity. Secondary metabolism in a plant plays a major role in the survival of the plant in its environment. Attraction of pollinators, defense against predators and diseases are examples of the roles of secondary metabolites. Moreover, numerous plant secondary metabolites such as alkaloids, anthocyanins, flavonoids, tannins, fixed oil, resin, vitamin C, vitamin E, carbohydrate, protein and phytosterols have found commercial application as drug, dye, flavour, fragrance, insecticide etc. Such fine chemicals are extracted and purified from plant materials. The extraction is done by using different solvents. The crude extracts are further purified and the chemical structures of the purified material can then be analysed. Techniques for further chemical analysis include chromatography, bioautography, radioimmunino assay, various methods of structure identification and newer tools such as fast Atom Bombardment Mass Spectrometry (ABMS), Tandem Mass Spectroscopy Biological activities of Limonia crenulata (Roxb.) 13

14 (TMS), High Performance Liquid Chromatography (HPLC), Capillary Zone Electrophoresis (CZE), Nuclear Magnetic Resonance Spectroscopy (NMRS), and X-ray Crystallography (Cowan, 1999). It has been well known since ancient times that plants and spices have antimicrobial activity. There has been a considerable interest to use plants and spices for the elimination of microorganisms because of increasing antibiotic resistance of microorganisms. The phytochemical analysis can be carried out to determine the presence of carbohydrates, glycosides, proteins, amino acids, phytosterols, saponins, flavonoids, alkaloids and tannins using various solvents. These compounds are taken for characterization that can be done by different methods. Laboratories of the world have found literally thousands of phytochemicals which have inhibitory effects on all types of microorganisms in vitro. More of these compounds should be subject to animal and human studies to determine their effectiveness in whole-organism systems, including in particular toxicity studies as well as an examination of their effects on beneficial normal microbiota. It would be advantageous to standardize methods of extraction and in vitro testing so that the search could be more systematic and interpretation of results would be facilitated. Heterocyclic nitrogen compounds are called alkaloids. The first medically useful example of an alkaloid was morphine, isolated in 1805 from the Opium poppy, (Papaver somniferum). Solamargine, a glycoalkaloid from the berries of Solanum khasianum and other alkaloids may be useful against Human Immunodeficiency Virus (HIV) infection as Biological activities of Limonia crenulata (Roxb.) 14

15 well as intestinal infections associated with Acquired immune deficiency syndrome (AIDS). Berberine is an important representative of the alkaloid group. It is potentially effective against trypanosomes and plasmodia. The mechanism of action of highly aromatic plant quaternary alkaloids such as berberine and harmane is attributed to their ability to intercalate with DNA. Some of the simplest bioactive phytochemicals consist of a single substituted phenolic ring. Cinnamic and caffeic acids are common representatives of a wide group of phenyl propane derived compounds which are in the highest oxidation state. The common herbs Tarragon and Thyme both contain caffeic acid, which is effective against viruses, bacteria and fungi. Phenolic compounds possessing a C 3 side chain at a lower level of oxidation state and containing no oxygen are classified as essential oils and often cited as antimicrobial as well. Flavones are phenolic structures containing one carbonyl group. The addition of a 3-hydroxyl group yields a flavonol. Flavonoids are also hydroxylated phenolic substances but occur as a C 6 -C 3 unit linked to an aromatic ring. Since they are known to be synthesized by plants in response to microbial infection, it should not be surprising that they have been found in vitro to be effective antimicrobial substances against a wide array of microorganisms. Lipophilic flavonoids may also disrupt microbial membranes. Tannin is a general descriptive name for a group of polymeric phenolic substances capable of tanning leather or precipitating gelatin from solution, a property known as Biological activities of Limonia crenulata (Roxb.) 15

16 astringency. Their molecular weights range from 500 to 3,000 and they are found in almost every plant part bark, wood, leaves, fruits and roots. They are divided into two groups, hydrolyzable and condensed tannins. Many human physiological activities, such as stimulation of phagocytic cells, host mediated tumour activity and a wide range of anti-infective actions, have been assigned to tannins. Condensed tannins have been determined to bind cell walls of luminal bacteria, preventing growth and protease activity. The fragrance of plants is carried in the so called quinta essential, or essential oil fraction. These oils are secondary metabolites that are highly enriched in compounds based on an isoprene structure. They are called terpenes, their general chemical structure is C 10 S 16 and they occur as diterpenes, triterpenes and tetraterpenes as well as hemiterpenes and sesquiterpenes. When the compounds contain additional elements, usually oxygen, they are termed terpenoids. Terpenes or terpenoids are active against bacteria, fungi and virus. Papaya yields a milky sap, often called latex, which is a complex mixture of chemicals. Chief among them is papain, a well known proteolytic enzyme. An alkaloid, taparin, is also present. Terpenoids are also present and may contribute to its antimicrobial properties. Propolis is an extract of the balsam of various trees; it is often called bee glue, since honeybees gather it from the trees. Its chemical composition is very complex, like the latex, terpenoids are present as well as flavonoids, benzoic acids, substituted phenolic acids and esters (Amoros et al., 1992). Biological activities of Limonia crenulata (Roxb.) 16

17 Pharmacognosy is the study of medicines derived from natural sources, including plants. The American Society of Pharmacognosy (ASP) as "the study of the physical, chemical, biochemical and biological properties of drugs, drug substances or potential drugs or drug substances of natural origin as well as the search for new drugs from natural sources." It has been estimated that in developed countries such as United States, plant drugs constitute as much as 25% of the total drugs, while in fast developing countries such as China and India, the contribution is as much as 80%. Thus, the economic importance of medicinal plants is much more to countries such as India than to rest of the world. These countries provide two third of the plants used in modern system of medicine and the health care system of rural population depend on indigenous systems of medicine. Research interest has focused on various herbs that possess hypoglycemic, anti platelet, antitumor, or immune - stimulating properties that may by useful adjuncts in helping reduce the risk of various diseases. In different herbs a wide variety of active phytochemical, including the flavanoids, terpenoids, lignans, sulfides, polyphenolics, carotenoids, coumarins, saponins, plant sterols, curcumins, and phthalides have been identified (Tyler, 1981). Traditional knowledge of medicinal plants has always been a valuable guide in the quest for new medicines. In spite of the advent of modern high therapeutic drug Biological activities of Limonia crenulata (Roxb.) 17

18 discovery and screening techniques, traditional knowledge systems have given clues to the discovery of valuable drugs (Buenz et al., 2004). Traditional medicine offers distinct advantages even in modern times because they are often cheaper, locally available, and easily consumable as raw or simple medicinal preparations. Their role is still more predominant in developing countries. Nature can be considered as the ultimate chemist as natural products offer us with an abundant source of novel chemo-types, pharmocophores or lead structures, which could be directly used or derived into readymade drugs. Plants and microbes offer us with a lucrative diversity for screening of the novel bioactivities. Thus nature remains as the potential source of organic structures of unparalleled diversity. A number of enhancements can be made to the basic method of thin layer chromatography to automate the different steps, to increase the resolution achieved and to allow more accurate quantitative measurements. Gas chromatography-mass spectrometry (GC-MS) is a method that combines the features of gas-liquid chromatography and mass spectrometry to identify different substances within a test sample. Applications of GC-MS include drug detection, fire investigation, environmental analysis, explosives investigation, and identification of unknown samples. GC - MS can also be used in airport security to detect substances in luggage or on human beings. Additionally, it can identify trace elements in materials that were previously thought to have disintegrated beyond identification. Biological activities of Limonia crenulata (Roxb.) 18

19 High-performance liquid chromatography (or high-pressure liquid chromatography, HPLC) is a chromatographic technique that can separate a mixture of compounds and is used in biochemistry and analytical chemistry to identify, quantify and purify the individual components of the mixture. The pharmacological industries have produced a number of new antibiotics in the last three decades resistance to these drugs by microorganisms has increased. In general bacteria have the genetic ability to transmit and acquire resistance to drugs, which are utilized as therapeutic agents. Such a fact is cause for concern, because of the number of patients in hospitals who have suppressed immunity, and due to new bacterial strains which are multiresistant. The problem of microbial resistance is growing and the outlook for the use of antimicrobial drugs in the future is still uncertain. Therefore actions must be taken to reduce this problem, for example, to control the use of antibiotic, develop research to better understand the genetic mechanisms of resistance, and to continue studies to develop new drugs. The use of plant extracts and phytochemicals both with known antimicrobial properties can be of great significance in therapeutic treatments. In the last few years, a number of studies have been conducted in different countries to prove such efficiency. Many plants have been used because of their antimicrobial traits, which are due to compounds synthesized in the secondary metabolism of the plant. Plant generally produces many secondary metabolites which constitute an important source of microbicides, pesticides and many pharmaceutical drugs. Plant Biological activities of Limonia crenulata (Roxb.) 19

20 products still remain the principle source of pharmaceutical agent used in traditional medicine (Ibrahim, 1997; Ogundipe and Akinbiya, 1998). Since the introduction of antibiotics there has been tremendous increase in the resistance of diverse bacterial pathogens (Cohen, 1992; Gold and Moellering, 1996). Plant derived products have been used for medicinal purposes for centuries. Since ancient times, plants have been model source of medicines as they are a reservoir of chemical agents with therapeutic properties. The general population is increasingly using herbal medicines as dietary supplements to relieve and treat many different human disorders. It has been well known since ancient times that plants and spices have antimicrobial activity (Ayres et al., 1980; Zaika, 1988). Plants have been used as folk remedies and ethno botanical literature has described the usage of plant extracts, infusions and powders for centuries for diseases now known to be of bacterial origin. There is an increasing need for search of new compounds with antibacterial activity as the treatment of bacterial infections with the available antibacterial drugs is often unsatisfactory due to the problem of bacterial resistance coupled with the problem of bacterial latency and conflicting efficacy in recurrent infection in immunocompromised patients (Vlietinck and Vanden Berghe, 1991). A number of compounds extracted from various species of higher plants have shown antibacterial activity (Fukuchi, et al., 1989). There has been a considerable Biological activities of Limonia crenulata (Roxb.) 20

21 interest to use plants for the elimination of microorganisms because of increasing antibiotic resistance of microorganisms (Kunin, 1993; Finch, 1998; Smid and Gorris, 1999). The problem of microbial resistance is growing and the outlook for the use of antimicrobial drugs in the future is still uncertain. Therefore, there is a need for the development of new drugs to reduce this problem. In general bacteria and fungi have the genetic ability to transmit and acquire resistance to drugs, which are utilized as therapeutic agents (Cohen, 1992). Anti-inflammatory refers to the property of a substance or treatment that reduces inflammation. Anti-inflammatory drugs make up about half of analgesics, remedying pain by reducing inflammation as opposed to opioids which affect the central nervous system. A recent review of references indicates that the antiulcerogenic effects of many taxa of medicinal plants have been assessed worldwide (Yesilada and Gurbuz, 2003). It is also reported that many plant species have been used to alleviate gastric symptoms such as gastric pain, etc. Diarrhoeal diseases are one of the leading causes of morbidity and mortality in developing countries and are responsible for the death of millions of people each year.. Despite immense technological advancement in modern medicine, many people in the Biological activities of Limonia crenulata (Roxb.) 21

22 developing countries still rely on the healing practices and medicinal plants for their daily health care needs. Therefore, the WHO encouraged studies for the treatment and prevention of diarrhoeal diseases depending on traditional medical practices. Diarrhoea is an alteration in normal bowel movement and is characterized by an increase in the water content, volume, or frequency of stools. Plants have long been a very important source of new drugs. Many plant species have been screened for substances with therapeutic activity. Medicinal plants are a promising source of antidiarrhoeal drugs with this reason, international organizations including the studies and research on Diarrhoea. World Health Organization (WHO) has encouraged studies pertaining to the treatment and prevention of diarrhoeal diseases using traditional medical practices. In the development of medicine from plants, four important steps are involved: identification of suitable plants to investigate isolation and identification of single chemical entities from the chosen plant identification of the pharmacological actions of those entities conduct of controlled clinical trials Herbal medicine is increasingly being validated by scientific investigation which seeks to understand the active chemistry of the plant. Many modern pharmaceuticals have been modeled on, or derived from chemicals found in plants. Biological activities of Limonia crenulata (Roxb.) 22

23 The present need for development of new therapeutic agents from natural sources had made the researchers to refresh and uncoil the literatures. Development of suitable methods for effective isolation of bioactive compounds and reliable analytical techniques are research perspectives. In recent years, medicinal plants have attracted global interest as they constitute a rich treasure of improved cultural information and are sources of natural products, which provide health security to millions in rural communities. There is a growing tendency all over the world to shift from synthetic to natural based projects including medicinal plants. The first half of the twentieth century was a period of tremendous advancements in medicine as causes of diseases were uncovered and new miracle drugs were isolated and synthesized. Initially, many modern medicines were isolated products from traditional plant derived extracts. In the present scenario of emergence of multiple drug resistance to human pathogenic organism, search for now, safe and effective therapeutical agents from other source including plants are urgently needed. Anti-microbial agents from plants are plentiful in many countries, especially in India, where thousands of tribal communities still use medicinal plants today to cure. It is a necessity from the scientific point of view to establish a rational relationship between chemical, biological and therapeutical activities of medicinal plants. Biological activities of Limonia crenulata (Roxb.) 23

24 Realizing the benefit of herbal and medicinal plants and to improve the quality and knowledge on the medicinal plants, the pharmacognostical studies with pharmacological experimentations are essential. Nature has provided a complete storehouse of remedies to cure all ailments of mankind and the history herbal medicine is as old as human civilization., India has made tremendous progress in agro-technology, process technology, standardization, quality control, research and development etc. Screening of medicinal plant for antimicrobial, antioxidant, anti - inflammatory, antiulcer and antidiarrhoea for finding potential new compounds for therapeutic use. There is a lack of scientific studies on Limonia crenulata (Roxb.). Biological activities of Limonia crenulata (Roxb.) 24