1 ChapterI: Introduction
1.1 General introduction
1.2 History of medicinal plants
1.3 Significances of medicinal plants to human being
1.4 Biological background
1.5 Examples of plants used as medicine
1.6 Risks to health
1.8 Danger of extinction
1.9 Innovation of medicinal properties of plants
1.10 Existing status of medicinal plants
1.10.1 Dependency of medicinal plants and traditional practicize in Bangladesh
1.10.2 Medicinal plants in world context
1.10.3 Medicinal plants in world market
1.11 Drug development from medicinal plants
2 ChapterII : Literature review
2.1 General description of Lannea grandis Engl
2.1.1 The plant family: Anacardiaceae
2.1.2 The plant genus: Lannea
2.2 Botanical features of the Lannea grandis
2.2.1 Scientific classification
2.2.3 Common names
2.2.4 Regions of distribution
2.2.5 Countries of distribution
2.2.6 Description of the plant
2.2.7 Chemical constituents
2.2.8 Common uses
2.2.9 Distribution overview
2.2.10 Tree size
2.3 Literature review on plant family Anacardiaceae
2.4 Biological literature review on family Anacardiaceae
2.5 Literature review on species Lannea grandis & related genus
2.5.1 Chemical literature review on species Lannea grandis & related genus
2.5.2 Biological literature review on species Lannea grandis &related genus
Objective of the work
ChapterIII : Materials and method with result and discussion
3.1 Phytochemical investigation
3.1.2 General methods
22.214.171.124 Collection and identification
126.96.36.199 Drying and grinding
3.1.3 Different tests for chemical groups
3.1.4 Results and discussion of phytochemical investigation
3.2 Screening for antibacterial activity
3.2.1 Principle of the assay method
3.2.2 Principle of disc diffusion method
3.2.3 Procedure for antibacterial screening
3.2.4 Determination of the antibacterial activity
3.2.5 Results of antibacterial screening
3.3 Screening for antifungal activity
3.3.1 Preparation of the medium
3.3.2 Determination of the antifungal activity
3.3.3 Result of the antifungal screening
3.4. Screening of minimum inhibitory concentration (MIC)
3.4.1 Sterilization procedure
3.4.2 Culture media preparation
3.4.3 Preparation of test samples
3.4.4 Procedure for determination of MIC
3.4.5 Minimum inhibitory concentrations determination
3.4.6 MIC of different extracts of Lannea grandis (Engl.)
3.4.7 Results of minimum inhibitory concentration (MIC) test
3.5. Evaluation for antidepressant activity
3.5.1 Preparation of samples for test and control
3.5.2 Determination of antidepressant activity
3.5.3 Result of antidepressant activity
3.6 Screening for antidiarrhoeal activity on mice
3.6.1 Preparation of samples for the test, standard and control groups
3.6.2 Determination of invitro antidiarrhoeal activity
3.6.3 Result of the antidiarrhoeal screening
3.7 Screening for analgesic activity on mice
3.7.1 Sample preparation for test and control
3.7.2 Determination of the analgesic activity
3.7.3 Result of the analgesic activity
3.8 Screening for Invitro Antinflammatory activity
3.8.1 Sample preparation for test, standard and control groups
3.8.2 Preparation of samples for treatment groups
3.8.3 Preparation of aqueous albumin solution
3.8.4 Determination of the invitro antiinflammatory activity
3.8.5 Result of the invitro antiinflammatory activity
3.9 Screening for invitro membrane stabilization activity
3.9.1 Preparation of samples for treatment groups
3.9.2 Determination of invitro membrane stabilization activity
3.9.3 Result of membrane stabilization activity
3.10. Screening for antiatherothrombosis activity
3.10.1 Procedure of invitro thrombolytic activity test
3.10.2 Determination of anti atherothrombosis activity test
3.10.3 Result for anti atherothrombosis activity test
Chapter-IV : Conclusion
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Abbildung in dieser Leseprobe nicht enthalten
Plants had been used for medicinal purposes long before recorded history. Ancient Chinese and Egyptian papyrus writings describe medicinal uses for plants. Indigenous cultures (such as African and Native American) used herbs in their healing rituals, while others developed traditional medical systems (such as Ayurveda and Traditional Chinese Medicine) in which herbal therapies were used. Researchers found that people in different parts of the world tended to use the same or similar plants for the same purposes.
In the early 19th century, when chemical analysis first became available, scientists began to extract and modify the active ingredients from plants. Later, chemists, pharmacists began making their own version of plant compounds, and over time, the use of herbal medicines declined in favor of drugs.1
Many plants synthesize substances that are useful to the maintenance of health in humans and other animals. These include aromatic substances, most of which are phenols or their oxygen-substituted derivatives such as tannins. Many are secondary metabolites, of which at least 12,000 have been isolated — a number estimated to be less than 10% of the total. In many cases, these substances (particularly the alkaloids) serve as plant defense mechanisms against predation by microorganisms, insects, and herbivores. Many of the herbs and pices used by humans to season food yield useful medicinal compounds.2
The theories and concepts of prevention, diagnosis, improvement and treatment of illness in traditional medicine historically rely on a holistic approach towards the sick individual, and disturbances are treated on the physical, emotional, mental, spiritual and environmental levels simultaneously. As a result, most systems of traditional medicine may use herbal medicines or traditional procedure-based therapies along with certain behavioural rules promoting healthy diets and habits. Holism is a key element of all systems of traditional medicine. Therefore, when reviewing the literature on traditional medicine (both herbal medicines and traditional procedure based therapies), the theories and concepts of the individual practice of traditional medicine, as well as the cultural background of those involved, must be taken into account.3
Medicinal plants, herbs, spices and herbal remedies are known to Ayurveda in India since long times. The value of medicinal plants, herbs and spices as herbal remedies is being lost due to lack of awareness, and deforestation. The result is many valuable medicinal herbs are becoming rare and precious information is lost. Less pollution we make, more ecological balance we maintain, will add to happiness of humankind. Preserve the knowledge of medicinal plants, herbs, spices and herbal remedies, which humankind has received from the past generations, for posterity.
History of herbal remedies is very old. Since old times before modern medicine, people became ill and suffered from various ailments. In absent of modern medicinal remedies people relied on herbal remedies derived from herbs and spices. There are many medicinal herbs and spices, which find place in day-to-day uses, many of these, are used as herbal remedies. Many cooked foods contain spices. Some minor ailments like common cold, cough, etc. may be cured by herbal remedies with use of medicinal properties of spices. Herbal remedies can be taken in many forms. Infusions are steeping herbs or spices, with parts like leaves and flowers with boiling water for some time. Filtered or unfiltered use this water extracts of spices as herbal remedies. Decoction is boiling roots, bark and hard parts of herbs and spices with water for along time. Infusion and decoction both are known as herbal teas. Some times essential oil of herbs and spices are also used as herbal remedies. Action of herbal remedies may vary from human to human and care should be observed in using it. Always inform your healthcare professional while taking any of the herbal remedies or consuming large quantity of medicinal herbs or spices as medicinal product.4
Compared with the precision of modern diagnosis and prescription medicine, herbal remedies can seem out of place today. But herbal preparations were once the only medications available. Modern physicians argue that synthetic medicines are superior because they are free of impurities, are of known strength and effects, and are more stable.
Herbal practitioners believe that when used appropriately, herbal remedies have an important role today. In many countries, herbal remedies remain the only readily available treatment. And, of course, many of today’s medicines are derived from naturally occurring plants.5
In most cultures around the world, the earliest forms of healing were based on herbs. People built up a wealth of knowledge based on experimentation within their environments, and they handed that knowledge on to the next generation. The arrival of written language provided us with records of the use of herbs as medicine as early as 3000 BC in Egypt, Babylon, China and India.
Examples abound of the importance herbs played in the health and well-being of ancient peoples. In 300 BC, a medical school was set up in Alexandria, where research was conducted into the uses of herbs in treating illnesses. This led to the creation of a document listing more than 600 herbs, with a prescription for how to prepare each as a treatment for specific diseases. This book was considered the most important source of information on herbal medicine for the next 1,500 years.
Native Americans used many different herbal medicines. From willow bark they extracted a pain-relieving ingredient used in today’s aspirin. Iris roots ground with suet, lard and beeswax made an ointment for cuts and grazes. Coca leaves were used as a local anesthetic. Juice of lady’s slipper roots eased pain, soothed hysterics and relieved cold and flu symptoms.
Traditional Chinese medicine attaches a great deal of importance to the harmony of the human body and the relationship of the body with nature. Chinese people have been using natural herbs to treat a wide variety of diseases for over 3,000 years.
While much has been added to the basic philosophy of this ancient healing system, very little has been taken out. Herbal medicines comprise roots, bark, flowers, seeds, fruits, leaves and branches. In China today, there are up to 5,000 different herbs in use in traditional medicine. It is wise to use only Chinese herbs that have been prescribed by a professional.5
1. Many of the modern medicines are produced indirectly from medicinal plants, for example aspirin.
2. Plants are directly used as medicines by a majority of cultures around the world, for example Chinese medicine and Indian medicine.
3. Many food crops have medicinal effects, for example garlic.
4. Medicinal plants are resources of new drugs. It is estimated there are more than 250, 000 flower plant species.
5. Studying medicinal plants helps to understand plant toxicity and protect human and animals from natural poisons.
6. Cultivation and preservation of medicinal plants protect biological diversity, for example metabolic engineering of plants.6
All plants produce chemical compounds as part of their normal metabolic activities. These include primary metabolites, such as sugars and fats, found in all plants, and secondary metabolites found in a smaller range of plants, some useful ones found only in a particular genus or species. Pigments harvest light, protect the organism from radiation and display colors to attract pollinators. Many common weeds have medicinal properties. The functions of secondary metabolites are varied. For example, some secondary metabolites are toxins used to deter predation, and others are pheromones used to attract insects for pollination. Phytoalexins protect against bacterial and fungal attacks. Allelochemicals inhibit rival plants that are competing for soil and light.
Plants upregulate and downregulate their biochemical paths in response to the local mix of herbivores, pollinators and microorganisms. The chemical profile of a single plant may vary over time as it reacts to changing conditions. It is the secondary metabolites and pigments that can have therapeutic actions in humans and which can be refined to produce drugs.
Plants synthesize a bewildering variety of phytochemicals but most are derivatives of a few biochemical motifs.
- Alkaloids contain a ring with nitrogen. Many alkaloids have dramatic effects on the central nervous system. Caffeine is an alkaloid that provides a mild lift but the alkaloids in datura cause severe intoxication and even death.
- Phenolics contain phenol rings. The anthocyanins that give grapes their purple color, the isoflavones, the phytoestrogens from soy and the tannins that give tea its astringency are phenolics.
- Terpenoids are built up from terpene building blocks. Each terpene consists of two paired isoprenes. The names monoterpenes, sesquiterpenes, diterpenes and triterpenes are based on the number of isoprene units. The fragrance of rose and lavender is due to monoterpenes. The carotenoids produce the reds, yellows and oranges of pumpkin, corn and tomatoes.
- Glycosides consist of a glucose moiety attached to an aglycone. The aglycone is a molecule that is bioactive in its free form but inert until the glycoside bond is broken by water or enzymes. This mechanism allows the plant to defer the availability of the molecule to an appropriate time, similar to a safety lock on a gun. An example is the cyanoglycosides in cherry pits that release toxins only when bitten by a herbivore.
The word drug itself comes from the Dutch word "druug" (via the French word Drogue), which means 'dried plant'. Some examples are inulin from the roots of dahlias, quinine from the cinchona, morphine and codeine from the poppy, and digoxin from the foxglove.
The active ingredient in willow bark, once prescribed by Hippocrates, is salicin, which is converted in the body into salicylic acid. The discovery of salicylic acid would eventually lead to the development of the acetylated form acetylsalicylic acid, also known as "aspirin", when it was isolated from a plant known as meadowsweet. The word aspirin comes from an abbreviation of meadowsweet's Latin genus Spiraea, with an additional "A" at the beginning to acknowledge acetylation, and "in" was added at the end for easier pronunciation. "Aspirin" was originally a brand name, and is still a protected trademark in some countries. This medication was patented by Bayer AG.7
Few herbal remedies have conclusively demonstrated any positive effect on humans, mainly because of inadequate testing. Many of the studies cited refer to animal model investigations or in-vitro assays and therefore cannot provide more than weak supportive evidence.
- Aloe vera has traditionally been used for the healing of burns and wounds. A systematic review (from 1999) states that the efficacy of aloe vera in promoting wound healing is unclear, while a later review (from 2007) concludes that the cumulative evidence supports the use of aloe vera for the healing of first to second degree burns.
- Agaricus blazei mushrooms may prevent some types of cancer.
- Artichoke (Cynara cardunculus) may reduce production cholesterol levels according to in vitro studies and a small clinical study.
- Blackberry (Rubus fruticosus) leaf has drawn the attention of the cosmetology community because it interferes with the metalloproteinases that contribute to skin wrinkling.
- Black raspberry (Rubus occidentalis) may have a role in preventing oral cancer.
- Butterbur (Petasites hybridus)
- Calendula (Calendula officinalis) has been used traditionally for abdominal cramps and constipation. In animal research an aqueous-ethanol extract of Calendula officinalis flowers was shown to have both spasmolytic and spasmogenic effects, thus providing a scientific rationale for this traditional use.
There is "limited evidence" that calendula cream or ointment is effective in treating radiation dermatitis.
- Cranberry (Vaccinium oxycoccos) may be effective in treating urinary tract infections in women with recurrent symptoms.
- Echinacea (Echinacea angustifolia, Echinacea pallida, Echinacea purpurea) extracts may limit the length and severity of rhinovirus colds; however, the appropriate dosage levels, which might be higher than is available over-the- counter, require further research.
- Elderberry (Sambucus nigra) may speed the recovery from type A and B influenza. However it is possibly risky in the case of avian influenza because the immunostimulatory effects may aggravate the cytokine cascade.
- Feverfew (Chrysanthemum parthenium) is sometimes used to treat migraine headaches. Although many reviews of Feverfew studies show no or unclear efficacy, a more recent RTC showed favorable results Feverfew is not recommended for pregnant women as it may be dangerous to the fetus.
- Gawo (Faidherbia albida), a traditional herbal medicine in West Africa, has shown promise in animal tests
- Garlic (Allium sativum) may lower total cholesterol levels
- German Chamomile (Matricaria chamomilla) has demonstrated antispasmodic, anxiolytic, antiinflammatory and some antimutagenic and cholesterol-lowering effects in animal research. In vitro chamomile has demonstrated moderate antimicrobial and antioxidant properties and significant antiplatelet activity, as well as preliminary results against cancer. Essential oil of chamomile was shown to be a promising antiviral agent against herpes simplex virus type 2 (HSV-2) in vitro.
- Ginger (Zingiber officinale), administered in 250 mg capsules for four days, effectively decreased nausea and vomiting of pregancy in a human clinical trial.
- Green tea (Camelia sinensis) components may inhibit growth of breast cancer cells and may heal scars faster.
- Honey may reduce cholesterol. May be useful in wound healing.
- Purified extracts of the seeds of Hibiscus sabdariffa may have some antihypertensive, antifungal and antibacterial effect. Toxicity tested low except for an isolated case of damage to the testes of a rat after prolonged and excessive consumption.
- Lemon grass (Cymbopogon citratus), administered daily as an aqueous extract of the fresh leaf, has lowered total cholesterol and fasting plasma glucose levels in rats, as well as increasing HDL cholesterol levels. Lemon grass administration had no effect on triglyceride levels.
- Milk thistle extracts have been recognized for many centuries as "liver tonics.".
Research suggests that milk thistle extracts both prevent and repair damage to the liver from toxic chemicals and medications.
- Nigella sativa (Black cumin) has demonstrated analgesic properties in mice. The mechanism for this effect, however, is unclear. In vitro studies support antibacterial, antifungal, anticancer, anti-inflammatory and immune modulating effects. However few randomized double blind studies have been published.
- Ocimum gratissimum and tea tree oil can be used to treat acne.
- Oregano may be effective against multi-drug resistant bacteria.
- Pawpaw can be used as insecticide (killing lice, worms).
- Peppermint oil may have benefits for individuals with irritable bowel syndrome.
- Phytolacca or Pokeweed is used as a homeopathic remedy to treat many ailments.
It can be applied topically or taken internally. Topical treatments have been used for acne and other ailments. It is used to treatment tonsilitis, swollen glands and weight loss.
- Pomegranate contains the highest percentage of ellagitannins of any commonly consumed juice. Punicalagin, an ellagitannin unique to pomegranate, is the highest molecular weight polyphenol known. Ellagitannins are metabolized into urolithins by gut flora, and have been shown to inhibit cancer cell growth in mice.
- Rauvolfia serpentina, high risk of toxicity if improperly used, used extensively in India for sleeplessness, anxiety, and high blood pressure.
- Rose hips - Small scale studies indicate that hips from Rosa canina may provide benefits in the treatment of osteoarthritis. Rose hips show anti COX activity.
- Salvia lavandulaefolia may improve memory.
- Rooibos (Aspalathus linearis) contains a number of phenolic compounds, including flavanols, flavones, flavanones, flavonols, and dihydrochalcones. Rooibos has traditionally been used for skin ailments, allergies, asthma and colic in infants. In an animal study with diabetic mice, aspalathin, a rooibos constituent improved glucose homeostasis by stimulating insulin secretion in pancreatic beta cells and glucose uptake in muscle tissue.
- Saw Palmetto can be used for BPH. Supported in some studies, failed to confirm in others.
- Shiitake mushrooms (Lentinus edodes) are edible mushrooms that have been reported to have health benefits, including cancer-preventing properties. In laboratory research a shiitake extract has inhibited the growth of tumor cells through induction of apoptosis. Both a water extract and fresh juice of shiitake have demonstrated antimicrobial activity against pathogenic bacteria and fungi in vitro.
- Soy and other plants that contain phytoestrogens (plant molecules with estrogen activity) (black cohosh probably has serotonin activity) have some benefits for treatment of symptoms resulting from menopause.
- St. John's wort, has yielded positive results, proving more effective than a placebo for the treatment of mild to moderate depression in some clinical trials A subsequent, large, controlled trial, however, found St. John's wort to be no better than a placebo in treating depression However, more recent trials have shown positive results or positive trends that failed significance. A 2004 meta-analysis concluded that the positive results can be explained by publication bias but later analyses have been more favorable. The Cochrane Database cautions that the data on St. John's wort for depression are conflicting and ambiguous.
- Stinging nettle In some clinical studies effective for enign prostatic hyperplasia and the pain associated with osteoarthritis. In-vitro tests show antiinflammatory action. In a rodent model, stinging nettle reduced LDL cholesterol and total cholesterol. In another rodent study it reduced platelet aggregation.
- Valerian root can be used to treat insomnia. Clinical studies show mixed results and researchers note that many trials are of poor quality.8
In some cases, herbal medicines offer an inexpensive and safe alternative to pharmaceuticals. In the U.S., which has just 4% of the world's population, 106,000 patients died from and 2.2 million were seriously injured by adverse effects of pharmaceuticals in the year 1994 (Journal of the American Medical Association). Proper double-blind clinical trials are needed to determine the safety and efficacy of each plant before they can be recommended for medical use. In addition, many consumers believe that herbal medicines are safe because they are natural. Herbal medicines may interact with synthetic drugs causing toxicity to the patient, herbal products may have contamination that is a safety consideration, and herbal medicines, without proven efficacy, may be used to replace medicines that have a proven efficacy. Standardization of purity and dosage is not mandated in the United States, but even products made to the same specification may differ as a result of biochemical variations within a species of plant. Plants have chemical defense mechanisms against predators that can have adverse or lethal effects on humans. Examples of highly toxic herbs include poison hemlock and nightshade. They are not marketed to the public as herbs, because the risks are well known, partly due to a long and colorful history in Europe, associated with "sorcery", "magic" and intrigue. Although not frequent, adverse reactions have been reported for herbs in widespread use. On occasion serious untoward outcomes have been linked to herb consumption. A case of major potassium depletion has been attributed to chronic licorice ingestion. Black cohosh has been implicated in a case of liver failure. Few studies are available on the safety of herbs for pregnant women. Herb drug interactions are a concern. In consultation with a physician, usage of herbal remedies should be clarified, as some herbal remedies have the potential to cause adverse drug interactions when used in combination with various prescription and over-the- counter(OTC) pharmaceuticals.
Dangerously low blood pressure may result from the combination of an herbal remedy that lowers blood pressure together with prescription medicine that has the same effect. Some herbs may amplify the effects of anticoagulants. Certain herbs as well as common fruit interfere with cytochrome P450, an enzyme critical to drug metabolism.9
The gold standard for pharmaceutical testing is repeated, large-scale, randomized, double-blind tests. Some plant products or pharmaceutical drugs derived from them are incorporated into medicine. To recoup the considerable costs of testing to the regulatory standards, the substances are patented and marketed by pharmaceutical companies.10 Many herbs have shown positive results in-vitro, animal model or small-scale clinical tests but many studies on herbal treatments have also found negative results. The quality of the trials on herbal remedies is highly variable and many trials of herbal treatments have been found to be of poor quality, with many trials lacking an intention to treat analysis or a comment on whether blinding was successful. The few randomized, double- blind tests that receive attention in medical publications are often questioned on methodological grounds or interpretation. Likewise, studies published in peer-reviewed medical journals such as Journal of the American Medical Association receive more consideration than those published in specialized herbal journals. This preference may be due to the possibility of location bias for such trials. One study found that non-impact factor alternative medicine journals published more studies with positive results than negative results and that trials finding positive results were of lower quality than trials finding negative results. High impact factor mainstream medical journals, on the other hand, published equal numbers of trials with positive and negative results. In high impact journals, trials finding positive results were also found to have lower quality scores than trials finding negative results. Another study reported that some clinical studies of herbal medicines were not inferior to similar medical studies. However, this study used a matched pair design and excluded all herbal trials that were not controlled, did not use a placebo or did not use random or quasi random assignment.
Herbalists criticize mainstream studies on the grounds that they make insufficient use of historical usage, which has no relevance to the medical efficacy of a product's usage. They maintain that tradition can guide the selection of factors such as optimal dose, species, time of harvesting and target population.
Dosage is in general an outstanding issue for herbal treatments: while most medicines are heavily tested to determine the most effective and safest dosages (especially in relation to things like body weight, drug interactions, etc.), there are fewer varieties of dosages for various herbal treatments on the market. Furthermore, herbal medicines taken in whole form cannot generally guarantee a consistent dosage or drug quality, since certain samples may contain more or less of a given active ingredient.
Several methods of standardization may be applied to herbs. One is the ratio of raw materials to solvent. However different specimens of even the same plant species may vary in chemical content. Another method is standardization on a signal chemical.11
On January 18, 2008, the Botanic Gardens Conservation International (representing botanic gardens in 120 countries) stated that "400 medicinal plants are at risk of extinction, from over-collection and deforestation, threatening the discovery of future cures for disease." These included Yew trees (the bark is used for cancer drugs, paclitaxel); Hoodia (from Namibia, source of weight loss drugs); half of Magnolias (used as Chinese medicine for 5,000 years to fight cancer, dementia and heart disease); and Autumn crocus (for gout). The group also found that 5 billion people benefit from traditional plant-based medicine for health care.12
The innovation of medicinal properties of plants was not certainly based on any scientific data or on the knowledge of chemical constitutes of plants. On the contrary, the exploration of medicinal properties of plants throughout the ages was accomplished principally through careful observation, trial or error and accidental discovery. Curiosity and search of early man for food had contributed considerably to his knowledge about the plants and their virtues. Superficial resemblance between a specific plant part and the affected organ or some symptoms of the ailment has also guided ancient man in his selection of medicinal plants. Observation of the animal’s instinctive discrimination between toxic and palatable plants might also have helped primitive man in choosing those plants which were beneficial from nutritive and medicinal standpoint.13
About 500 medicinal plants have been reported to occur in Bangladesh.
Almost 80% of rural populations are dependent on medicinal plants for their primary health care.
The local people conserve traditional knowledge through their experiences and practices, which is handed down orally without any documentation. The over exploitation of wild medicinal plants has become a threat to its extinction.
In Bangladesh there are no systematic cultivation processes of conservation strategies about medicinal plants.
There is no government policy or rules and regulations about the medicinal plants cultivation conservation and marketing.
There are almost 422 herbal medicinal companies using medicinal plants as raw materials mostly by importing from abroad.14
An enumeration of the WHO from the late 1970s listed 21,000 medicinal species (Penso 1980).However, in China alone 4941 of 26,092 native species are used as drugs in Chinese traditional medicine (duke and Ayensu 1985), an astonishing 18.9%.If this proportion is calculated for other well-known medicinal floras and then applied to the global total of 422,000 flowering plant species (Govaert 2001; Bramwell 2002), it can be estimated that the number of plant species used for medicinal purposes is more than 50,000.15
The largest global markets for MAPs China, France, Germany, Italy, Japan, Spain, the UK and the US. Japan has the highest per capita consumption of botanical medicines in the world (Laird 1999).
The International Council for Medicinal and Aromatic Plants accepts world growth during 2001 and 2002 to be approximately 8-10 percent a year (Srivastava 2000). In 1999, the world market for herbal remedies was US$19.4 billion, with Europe in the lead (US$6.7 billion), followed by Asia (US$5.1 billion) and the rest of the world (US$1.4 billion) (Laird and Pierce 2002).
India is the major exporter of raw MAPs and processed plant-based drugs. Exports of crude drugs from India in 1994-1995 were valued at US$ 53,219million and of essential oil US$13,250million (Lambert et al. 1997:31).
Over all sales of botanical medicine products in China in 1995 were estimated at US$5 billion (Laird 1999). The botanical medicine market in Japan in 1996 was estimated at US$2.4billion.14
Efforts of development of new drugs from medicinal plants are still continuing all over the world new drugs are discovered and developed everyday. Out of the 104 new drug developed in China between the years 1949 and 1981, 60 originated directly or indirectly from the medicinal plants.16
Development of drugs from medicinal plants is often an elaborate, laborious, time consuming and expensive exercise. Drug discovery from plants involves a multi-disciplinary approach combining botanical, ethno botanical, phytochemical and biological techniques. Plants continue to provide us new chemical entities (lead molecules) for the development of drugs against various pharmacological targets.
Current research in drug discovery from medicinal plants involves a multifaceted approach combining botanical, phytochemical, biological, and molecular techniques. Medicinal plant drug discovery continues to provide new and important leads against various pharmacological targets including cancer, HIV/AIDS, Alzheimer's, malaria, and pain. Several natural product drugs of plant origin have either recently been introduced to the United States market, including arteether, galantamine, nitisinone, and tiotropium, or are currently involved in late-phase clinical trials. As part of our National Cooperative Drug Discovery Group (NCDDG) research project, numerous compounds from tropical rainforest plant species with potential anticancer activity have been identified. Our group has also isolated several compounds, mainly from edible plant species or plants used as dietary supplements that may act as chemopreventive agents. Although drug discovery from medicinal plants continues to provide an important source of new drug leads, numerous challenges are encountered including the procurement of plant materials, the selection and implementation of appropriate high-throughput screening bioassays, and the scale-up of active compounds.17
The stages involved in the development exercise may be summarized in the following way:
- Selection and proper identification of the medicinal plants.
- Extraction with the suitable solvents.
- Detection of biological activity of crude extracts and establishment of a bioassay system to permit the identification of the active fraction and rejection of the inactive one.
- Fractionation of crude extracts by using the most appropriate chromatographic procedures.
- Biological evaluation of all fractions and separation of the active fractions.
- Repeated fractionation of active fractions to isolate the pure or lead compounds.
- Elucidation of chemical structure of pure compounds by using spectroscopic methods.
- Evaluation of biological activities of pure compounds.
- Investigation of other pharmacological properties of the active agents.
- Toxicological tests with pure compounds.
- Production or development of drug in appropriate dosage forms.
Since plants are the natural reservoir of many antimicrobials and anticancer agents. Bangladeshi people have traditional medicinal practice as an integral part of their culture. A lot of medicinal plants are available for the treatment of various diseases.18 The indigenous knowledge of the use of plant resources for the cure of various human ailments being used since immemorial times is still believed to be persisted among the Bangladeshi people especially in rural areas. They use medicinal plants for their primary health treatment.19
The ethanol extract of the selected plant possesses glycosides, tannins, alkaloids, flavonoids type’s valuable chemical groups and biologically cytotoxic as well as significant anti-microbial activity on some pathogenic bacterial and fungal species, which may play an important role in the modern drug discovery program.
Anacardiaceae (the cashew family or the sumac family) is a family of flowering plants bearing fruits that are drupes and in some cases producing urushiol, an irritant. Its numerous genera include several of economic importance. Notable plants in this family include cashew (in the type genus Anacardium), mango, poison ivy, sumac, smoke tree, and marula. The genus Pistacia (which includes the pistachio and mastic tree) usually is now included, but has sometimes been placed in its own family, Pistaciaceae.20
2.1.2 The plant genus: Lannea
Trees, shrubs or suffrutices , with the young parts and inflorescences stellately tomentose . Milky latex intermittently present in a few species . Leaves alternate, imparipinnate or 3- foliolate, rarely 1-foliolate (and thus appearing simple), entire. Panicles terminal or axillary, ± branched and pyramidal or spike-like. Male flowers: calyx 4-partite; petals 4; stamens 8. Female flowers: calyx and petals similar to males; staminodes present; ovary 4-locular; styles 3-4. Drupe obovoid or ovoid.
The genus Lannea is in the family Anacardiaceae in the major group Angiosperms (Flowering plants).21
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