Medicinal Plants of Bangladesh

Plants and man are inseparable. Plants existed on the earth in the geological past form the early history of the earth. The use of plants to alleviate human suffering is as old as the evolution of human civilization itself. From the early stages of human civilization, plants, especially medicinal plants have played a pioneering role for the welfare of human beings. Recently, dramatic changes have taken place in the primary health care system of world population through the development of science, technology and medical science, but till to day 400 cores of people of the world are totally dependent on herbal medicine. It is revealed that even in the developed countries 25%, of the prescribed drugs come from plant sources and herbal medicines are used by about 75-80% of the world’s population for primary health care because of their better cultural acceptability, better compatibility with human body and lesser side effects.. WHO consultative body of medicinal plants has formulated a definition of medicinal plants in the following way “A medicinal plant is any plant which in one or more of its organs, contains substances that can be used for therapeutic purposes or which is a precursor for synthesis of useful drugs” (Sofowora,1982).

Statement of the Problem

Bangladesh has very rich in Bio-diversity. It has more than 500 medicinal plants species (Yusuf et al., 1994). An alarmingly populous, but size-wise a very small country is rather unique in having diversified genetic resources in a wide range of habitats. Increasing population pressure and multifarious anthropogenic activities on the natural ecosystems are posing severe and serious threats to once dense and rich genetically diversified plant communities of this country. Loss of habitats from the wild forests as well as from the village groves, cultivated plains and wild lands are quite common in this country. A broad genetic base has been replaced by a narrow one, and the old genetic diversity is disappearing both inside and outside of the ancient gene centers. This trend is inevitable with the need for highly efficient and uniform cultivars in advanced and sophisticated farming systems. At present, we have no real protected area for natural genetic resources and also have no specific practical policy on conservation of biodiversity. Although there are several gene banks having limited facilities to preserve some economic crops like rice, jute, wheat, pulses etc in Bangladesh, but there is no centralized organization to maintain germplasms of the wild relatives for agriculture, horticulture, medicinal and economically less important forest species. Bangladesh Agricultural Research Council (BARC) is very worried about this. However, the rich and diverse heritage of traditional medicinal system in the Indian sub-continent including Bangladesh is increasingly threatened by the interplay of a number of factors such as rapid deforestation and habitat destruction, indiscriminate collection and exploitative trade network.

In Bangladesh there are about 297 Unani, 204 Ayurvedic and 77 Homeopatheic drug manufacturing industries where the medicinal plants are extensively used in both raw and semi– processed forms of medicine in various pharmaceutical dose formulations. These plants also serve as important raw materials for many modern medicinal preparations. The market value of drugs produced by these industries from medicinal plants is about Tk. 300 crores. (The Daily Jugantor, 21 June, 2003).

Besides, village Kobiraj, street Vendors and Tribal people also use a large number of medicinal plants for the treatment of various diseases. There is no actual figure how many medicinal plants are used in Bangladesh. Chowdhury at SAARC workshop (held on 16-18 June, 2002) gave a brief idea about the amount of medicinal plants used annually in Bangladesh. A few of them are mentioned here: Ashwagondha (Withania somnifera)- 56,000 kg, Anantamul (Hemidesmus indicus)- 50,000 kg, Kurchi (Holarrhena antidysenterica)-1,00,000 kg, Gulancha (Tinospora cordifolia)- 127,000 kg. According to Hamdard Laboratories (WAQF), in Bangladesh the annual demand for a few medicinal plants are- Satomuli (Asparagas racemosus)– 800 tons, Sarpagondha (Rauvolfia serpentina)– 1,000 tons, Ghritokumari (Aloe vera)– 24,000 tons, Kalomegh (Andrographis paniculata)– 1,000 tons (Hassan, 2003).  Every year Bangladesh imports a large quantity raw materials belonging to of medicinal plants mostly under the banner of spices and spends more than 64 crores Taka annually for this purpose. Ironically, 70% of this imported raw materials can be met from the indigenous sources from Bangladesh (Begum, 2003).

Table 1. Medicinal plant species listed by WHO which can be grown in Bangladesh commercially.

Source: (Islam, 2003).

Significant and Rationale of the Study

Cultivation of medicinal plants is a potential resource for uplifting state economy so, we should know about growth and productivity of some commercially important medicinal plants .A large number of people in Bangladesh are solely dependent on Ayurvedic treatment for maintaining their health. The medicinal plants as a whole occupy an important position in modern medicine since the industry is showing special interest in synthesizing natural substances as they are found to be more effective in particular applications. It provides a complete system of healing and prevention of diseases. Herbal drugs are becoming popular because they are holistic in nature, able to look beyond the symptoms to the underlying systemic imbalance. When applied by the trained practitioners, herbal medicine offers very real and permanent solution to very real problems. In fact, century old nature friendly medicare system has stood the test of time and holds promise for the present and the future.Cultivation of medicinal plants gives scope to improve the quality of the drugs. There is a growing demand today for plant-based medicines and health products, pharmaceuticals, food supplements, cosmetics etc. in the international market.

Objectives of the Study

The objective of this research as follows:

1. Know about growth and productivity of the selected medicinal plants
2. Development of cultivation prescriptions
3. Transfer of cultivation technologies to homestead growers, cultivators through training, workshops, pamphlets, brochures, seminars etc.

 Scope of the study

The term paper, which I have given, is Growth and Productivity of Some Commercially Important Medicinal Plants Of Bangladesh. It is very important topic now a day. In this topic I tried to know about the cultivation process specially growth and productivity of these commercially important medicinal plants, those are losing from our wild habitat.

REVIEW OF LITERATURE 

A few works on the commercially important medicinal plants were performed by many workers viz., Pavitra et al. (1991); Mamatha et al.(1993), Supari et al. (1993), Le Roux and Robbertse (1994), Kumaraswamy et al. (1994), Swarmapriya et al. (1996), Alagesaboopathi and Ramachandran (2000),  Supratik et al. (1998),  Dhar (1999), Kattimani et al. (1999), (1999),  Maheshwari et al. (2000), Shah et al.(2000), Raina  et al (2000),  Kumar et al. (2001)

These works mainly dealt with seed germination, method/s of propagation, effect of pre-sowing seed treatment on growth and yield as well as the alkaloid content and effect of environmental conditions on growth, carbon allocation, the concentrations of organic solutes, including soluble carbohydrates and water requirements of some medicinal plants.

Medicinal plants of Bangladesh has drawn the attention of Botanists as well as the Environmentalists during the recent years. In an initiative led by the Ministry of Health, medicinal plants have been planted for the first time in Govt. hospitals and clinics throughout Bangladesh as a part of National Tree Planting Programme. Sporadic and diverse researches were done on various aspects of medicinal plants by Hassan and Khan (1996), Mia and Huq (1998), Yusuf et al. (1994), Alam (1992), Ghani (1998), Uddin et al. (2001), Khan et al. (2001, 2002), Partha and Hossain (2002). M.S. Rahman etal. (2006)

The medicinal plants are often traditionally collected from the forests or wild lands and no systematic effort was made in the past for developing the cultivation practices for these plants. Therefore, for a large number of these plant species, the best way of propagating them is not known.

METHODOLOGY

The Plant materials which has been selected for this research work are Ashwagandha (Withania sominfera Dunal) family Solanaceae, Ulatchandal (Gloriosa superba) Linn. family Liliaceae and Chita (Plumbago zeylanica Linn.) family Plumbaginaceae sunny shaddy and partially shaddy condition. For this research work data has been collected from secondary sources. This secondary source are different books, journals, different website. Here those are state as follows:

 List of Books:

I. Name          : Medicinal plants of Bangladesh : Chemical constituents and uses.

Author        : Prof. Abul Ghani

Publisher   : Asiatic Society of Bangladesh, Dhaka, Bangladesh

Published date : 1998

II.      Name     : Red data book of vascular plants of Bangladesh. (eds).

Auther   : M. Salar, Rahman Khan,, M. Matiur, M. Arshad Ali.

Publisher: Bangladesh National Herbarium, Dhaka, Bangladesh

Published date: 2001

III.    Name     : Medicinal plants of Bangladesh.

Auther   : M Yusuf,., J. Chowdhury,.., M.A. Wahab,

Publisher: Bangladesh council of Scientific and Industrial Research

Published date: 1994

List of Journals:

I.  Name: Bangladesh Journal of Life Sciences

Publisher: Faculty of life sciences, Jahangirnagar university, Savar, Dhaka

II.  Name     : Bangladesh Journal of Plant Taxonomy

Publisher: Bangladesh Botanical Society

List of Websites:

1. http:// www.holistic-herbalist.com
2. http:// www.ics.trieste.it/MAPs/MedicinalPlants_Plant.aspx
3. www.spicesmedicinalherbs.com/ashwagandha-withania–somnifera.ht
4. www.agricultureinformation.com www.openlibrary.org
5. www.tnsmpb.tn.gov.in/images/www.en.wikipedia.com
6. www.ambikamedico.com › authentic ayurvedic products

By collected all data, first I have organized in two separate parts. One is about general information about the selected plants and another is about their growth and productivity specially cultivation technique for home cultivation. All of the textbook I have collected from My University teacher and from my personal collection. Some are Collected from research journal and from internet surfing.

PRESENTATION AND ANALYSIS OF DATA

Withania somnifera Dunal

 Introduction

Ashwagandha (Withania somnifera Dunal) known as Indian Ginseng (Tripathi et al., 1996) is not found in wild condition in Bangladesh (Hassan, 2003). Due to higher demand in traditional medicine as well as an adjuvant in cancer therapy and for its threatened status, this species needs to be conserved. To save this species from further extinction and to meet the growing demands for its medicinal application, there is an urgent need to develop a suitable cultivation method. This is dealt with basic knowledge about the cultivation method including its reproductive biology, such as seed germination, seed dormancy  and sowing time, habitat requirements, multiplication method, harvesting time, phonological data such as pollination pattern, anthesis, budding, flowering, fruit ripening and to obtain a comprehensive knowledge about growth parameters such as plant height, branches per plant, nodes per plant, number of fruits per plant, number of seeds per fruit, root length, fresh weight of leaves, stem and root and total alkaloid content in leaves, stem and root as well as in the whole plant grown under different environmental conditions .

Growth and Productivity Parameters (GPP)

 Seed germination and seed sowing

July to August is the appropriate time for seed sowing. During this period seed germination rate was maximum (74-70%), followed by 28-38% during January to March and dormancy period was minimum (7-24 days) during July to August and maximum (18-46 days) during January to March (Table 4).

 Mode of germination: Epigeal.

Seed dormancy

Seeds of W. somnifera germinate throughout the year but its dormancy period varied form month to month. Seeds have dormancy period of about 7-46 days (Table 1).

 Propagation

Propagates only through seeds. Vegetative propagation trials by means of stem cuttings failed to produce plantings.

Growing distance

Seeds can be directly sown in the field or in the seed bed or earthen pots. Seedlings has to be transplanted in the August-September after 4-6 weeks of growth. In sunny condition, seedlings were planted at a distance of 10 cm in rows which are 30-40 cm apart. Individual seedling was transplanted to each earthen pot in shady and partially shady conditions.

 Irrigation

Withania somnifera is a rain fed crop which required little irrigation after the crop got established and irrigation was done at regular (after 3 days) intervals with a proper drainage system for better root growth.

Fertilizer schedule

No chemical fertilizer was used, because it may lead to a much branched and fibrous roots which are not good for commercial purpose.

 Weed management

In the early stages of crop establishment, regular weeding was required, but once the crop picked up growth, the weeds were suppressed and weeding was done as and when required.

Flowering and Fruiting

Flowers opened early in the morning, anthesis was accomplished at 8:30–11 a.m. Anthers were at the same level with the stigma, so self pollination is the only means of pollination in this species. Bagging experiment also proved this contention. Fruit development was accomplished within 3-4 days after anthesis and the fruits ripened after 25-28 days of fruit development. Flowering and fruiting took place throughout the year.

Harvesting

The plant was harvested after six months of sowing the crop (February-March). Harvesting was done by digging up the roots. Roots were lifted up, washed and dried up to 10-12 % moisture content.

Problem of cultivation

Damping off disease at seedling stage resulted in heavy seedling mortality which was identified as the main problem for the cultivation of Withania somnifera.

Data on different growth parameters

Plant height, Branch per plant, Number of fruits per plant, Number of seeds per fruit, Root length, Fresh weight of leaves, Fresh weight of stem, Fresh weight of root will be highest if plant grown in sunny environment condition supplemented with 50% cow dung and 50% soil.

 Gloriosa superba Linn.

Family- Liliaceae

 Introduction

Gloriosa superba Linn, commonly called Glory Lily, is an important medicinal plant and has been used to cure various aliments in the traditional Ayurvedic system of medicine since ancient times. Due to expanding human population, increasing agriculture, rapid urbanization, unchecked extraction of plants or  plants parts for various uses from their natural habitat have led to many species, specially medicinal plants either becoming extinct or rare (Nayar and Sastry, 1987). This situation is causing concern not only for the loss of species diversity, but also because the availability of raw materials for uses in various medicines are becoming scarce day by day. G. superba is one of such species. Earlier, the medicinal properties were thought to be present only in its tubers (Anonymous, 1956) and these were ruthlessly extracted without any concerted attempt to re-grow these plants. However, the seeds also possess the same medicinal properties and contain colchicines (Bhakuni & Suda, 1995). The seeds contain up to 0.75 percent colchicines as compared to only 0.30 percent in its tuber (Gupta, 1997),   but the seed yield in nature is quite low and variable. Hence, the species has been listed under threatened plant category.

The seed yield of Gloriosa superba L. is variable and decreasing in nature. Moreover, the extensive collections of tubers and seeds from its natural population for widespread medicinal uses have made this species threatened in Bangladesh. Therefore, in order to understand the reasons for variable as well as less seed yield, the reproductive biology of this species needs to be studied in detail. Knowledge of reproductive biology of a desired species is necessary in order to find out the causes of low production of its propagules and to develop the convenient method and technique for its cultivation for the increase of propagules production through which its sustainable use can be facilitated.

 Here, seed germination of Gloriosa superba has been recordee  in different periods of the year to know the basic knowledge about dormancy period of seeds and germination percentage. Data on Seed germination has been recorded done in the moist blotting paper to reduce the dormancy period and seeds were pre-treated with various chemicals to know their effect or effects on plant growth and tuber size. Tuber of about 50 g weights was planted in partially shady and sunny condition with (50:50) soil-cow dung mixture. Phenological data, germination of pollen grain in sucrose solution, and comparative growth performance of this plant species under sunny and partially shady condition were recorded and presented in the following paragraphs. Data recorded for the effect of pre-sowing seed treatment on seedling growth and tuber size also presented.

Growth and productivity parameters

. Seed germination and seed sowing

From seed germination experiment conducted in earthen pots and open field condition, it was revealed that the months of April and May are suitable for seed germination. During this time, the rate of germination was maximum (34%, 30%) and the dormancy period was minimum (23-40, 28-43 days) in earthen pots and in the open field,  (Table) respectively  and this result was partially in conformity with the findings of previous work (Anonymous, 2002).

In moist blotting chamber, the percentage of seed germination was increased to some extent (28%) and dormancy period was reduced to a greater extent (14-38 days) by incubating the seeds in moist blotting camber, compared to those that were sown in earthen pot and in the field condition on the same date

Table 3. Seed germination of Gloriosa superba in earthen pot under shady condition and open field condition.

Seed germination conducted in open field  condition.

Table 4. Seed germination of Gloriosa superba in moist blotting chamber

Table 5. Effect of 1% NaOCl and Thiourea (4000 ppm and 5000 ppm) on seed germination of Gloriosa superba.

 The result was in partial agreement with the findings of Kozolowski et al. (1994) who reported that Platycodon grandiflorum seeds germinated well in the laboratory conditions.

From the seeds those were pre-treated with different chemicals; it was revealed that the maximum seed germination percentage (60%) and the minimum time required for germination (19-32 days) could be achieved from the seeds pre-treated with 1% NaOCl followed by soaking in distilled water for 24 hours (Table 19.3). The germination percentage of seeds was also high (40%) in the seeds pre-treated with 4000 ppm Thiourea which was in conformity with the results obtained by Supari et al. (1993).

In the field conditions seeds that fall on ground were found to germinate from the last of April to the middle of May. This period was recorded as the optimum time for seed germination of G. superba. It was also found to vary owing to the effect of the first rainfall. Plants that were developed from germinated seeds were found to be dried up within 5-7 months without developing any flower. In the following year, new seedlings were observed to grow from the one-year old underground tuber.

Propagation

It was propagated through seeds or by the sprouting of under ground tuber. Plants propagated from the seeds do not flower in the same year.

Growing distance

The crops were raised using large sized (above 50 g) tubers spaced at 60 cm × 45 cm in sunny and partially shady condition. Seedlings of about 30 days old were transplanted to polythene bags filled with soil: crow dung (50:50) mixture.

Sprouting of tubers

Tubers were sown in both sunny and partially shady conditions on the same date (14.04.2003) which were sprouted on the 12^thday after planting in partially shady condition, but on the 15^th day in sunny condition. This observation agrees well with the findings of Mamatha et al. (1993).

 Problems of cultivation

Natural regeneration of Gloriosa superba is hampered by the low seed germination percentage.

Effect of pre-germination seed treatment on initial growth parameters

 It is recorded that initial growth parameters were significantly influenced by different seed treating chemicals. Significantly highest value was obtained for most of the parameters   (Table 3) from the plants grown with 4000 ppm Thiourea treated seeds

 Table-6. Effect of pre-germination seed treatments on initial growth parameters of Gloriosa superba seedlings.

In the field conditions, the existence or survival period of different phenological parameters (PP) of Gloriosa superba have been presented in Table 21.

 Table 7. The existence or survival period of different phonological parameters of Gloriosa superba.

In Gloriosa superba, when non-emasculated flowers were covered completely with polythene bags from the period of budding stage and allowed for pollination after anthesis of the stamens of same the flower, pollination occurred successfully. This observation indicated that G. superba is self-pollinated. At maturity, the flowers of G. superba also develop a special mechanism of stigmatic movement for ensuring the natural self-pollination. Fruit formation was not recorded from the emasculated flowers, which indicate the absence of apomictic fruit formation in this species. Moths, butterflies and ants were found as visitors for the red-coloured flowers of G. superba which exhibit noticeable colour change from the young (yellow) to the mature (red)   stage.

Growth performance in different environmental condition

 Plant height (cm) at flower initiation

In sunny condition, the average plant height was recorded to be as 57-90 cm, but in the partially shady condition, the average plant height was recorded to be 155-180 cm. This indicated that the plant under investigation is a shade-loving one.

Number of leaves at flower initiation

Number of average fully open leaves at flowering stage ranged from 52 to 80 in the sunny condition and 57-180 in the partially shady condition. This was also indicated of the shade-loving nature of Glory Lily plant.

 Average seed output of Gloriosa superba L.

The average seed out put of this species is assumed to be moderately high in partially shady condition (204.27) than that of the sunny condition (171.15) that might be due the formation of good number of seeds per fruit in partially shady condition (Table 24).

Table 8. Average seed output of Gloriosa superba L.

Plumbago zeylanica Linn.

Family- Plumbaginaceae

Intrduction

Plumbago zeylanica L., common name- Chita, English name- Ceylon Leadwort, is an important plant species in Ayurveda and also cultivated in gardens for its profuse white flowers. In the present study, several experiments have been conducted (field experiment and pot experiment) to know about its growing condition and growth performance in different environmental conditions with the application of different treatments. Data obtained from the growth parameters and phonological parameters are presented.

Growth and productivity parameters

 Seed germination and seed sowing

June is the appropriate time for seed sowing. During this period, seed germination rate was maximum (50 %), followed by 42 % during November and minimum (36-28 %) during March to April. Time required for seed germination was minimum (6-15 days), followed by maximum (17-30 days) during March to April (Table-40.1). Seed germination rate can be increased and the time required for germination can be minimized many fold times by incubating the seeds in moist blotting chamber (Table-41.2)

 Mode of germination: Hypogeal

Seed dormancy: Seeds have a dormancy period of about 6-31 days.

 Propagation

This plant is propagated through seeds and can also be propagated easily by means of stem cuttings.

Table 9. Seed germination experiments of Plumbago zeylanica in earthen pots.

 Table 10. Seed germination experiments of Plumbago zeylanica in moist blotting chamber.

 Irrigation

Irrigation was done as and when required.

Fertilizer schedule

No chemical fertilizer was used.

Flowering and fruiting

In this plant, flowering and fruiting took place from November to April. Anthesis was accomplished at 9-11:30 a.m. and when the non-emasculated flowers were covered completely with polythene bags from the period of budding stage and allowed for pollination after anthesis of the stamens of the same flower, then pollination occurred successfully. The plants produced fruits after the bagging, which indicated that it is a self pollinated plant. Fruit development was accomplished within 5-6 days after anthesis and the fruits ripened after 15-17 days of fruit set.

 Harvesting

Plants were harvested during March-April after the ripening of fruits. The plants were lifted up along with the roots washed and dried up in shade.

Data on different growth parameters

Plant height, Branches per plant, Number of fruits per plant, Root length, Fresh weight of stem, Fresh weight of root will be highest if plants are grown in sunny conditions supplemented with 50% soil and 50% cow-dung which is supported by Supratik et al.(1998) who reported that cow dung along with bone meal and Neem seed cake gave the best vegetative growth, root yield and alkaloid contents in roots

DISCUSSION

Medicinal plants are important natural wealth of our country. They play a significant role in providing primary health care services to most of the indigenous people as well as the major bulk of the rural population. The quality and growth of indigenous medicinal plants can be substantially improved by bringing them under planned cultivation process.

In the present research it was found from the data  of Withania somnifera Dunal grown under sunny condition with 50% soil and 50% cow-dung mixture performed better results in terms of plant height, number of nodes per plant, number of fruits per plant, number of seeds per fruit, fresh weight of leaves, stem and root, and higher root length. Similar findings are found  in case of Plumbago zeylanica Linn. This result is in partial agreement with the findings of Supratik et al. (1998) who reported that cow dung along with bone meal and Neem seed cake gave the best vegetative growth, root yield and alkaloid contents in roots.

From the data of  Gloriosa superba Linn. it was revealed that seeds those were pre-treated with different chemicals showed maximum seed germination percentage (60%) and the minimum time required for germination (19-32 days) could be achieved from the seeds pre-treated with 1% NaOCl followed by soaking in distilled water for 24 hours. The germination percentage of seeds was also high (40%) in the seeds pre-treated with 4000 ppm Thiourea which was in conformity with the results obtained by Supari et al. (1993). Tuber sprouting time was recorded 12 days both in partially shady and sunny environmental  condition and this observation agrees well with the findings of Mamatha et al. (1993). In sunny condition, the average plant height was recorded to be as 57-90 cm, but in the partially shady condition, the average plant height was recorded to be 155-180 cm. This indicated that the plant under investigation is a shade-loving one. The average seed out put of this species is assumed to be moderately high in partially shady condition (204.27) than that of the sunny condition (171.15) that might be due the formation of good number of seeds per fruit in partially shady condition.

RESEARCH FINDINGS

In this research work the following concern have found.

 1.      For Withania somnifera Dunal.

i. appropriate seed sowing time is July to August

ii. Seed has dormancy period of 7-46 days

iii. Propagates through seeds

iv. Plants can be harvested after six months of seed sown

v. Growth and productivity will highest if plant is grown in sunny condition supplemented with 50% soil and 50% cow-dung.

 2.      Incase of Gloriosa superba Linn

i. appropriate seed sowing time is April to May

ii. Seed has dormancy period of 28-43 days, Seed germination rate is 30-34% but it may be increased up to 60% after treated with 1% NaOCl.

iii. Propagates through seeds and tuber

iv. Plants produced from the seed will not provide flowering in the next year but produced from tuber arise flower and fruit in the following year.

v. Growth and productivity will highest if plant is grown in partially shady condition.

 3.      For Plumbago zeylanica Linn.

i. appropriate seed sowing time is June to November

ii. Seed has dormancy period of 6-31days

iii. Propagates through seeds and stem cuttings

iv. Plants can be harvested after five months of seed sown

v. Growth and productivity will highest if plant is grown in sunny condition supplemented with 50% soil and 50% cow-dung.

RECOMMENDATIONS

Bangladesh falls within one of the World’s Biodiversity Centres, encompassing 8 vegetation zones having different habitats of specific species. It has been estimated that about 5,000 plant species (nearly 2.2% of the global species) occurs in Bangladesh. About 2,500 species of both higher and lower plant groups are of medicinal value, among them, more than 500 plants are identified as medicinal plants (Yusuf et al., 1994). But indiscriminate exploitation, overpopulation and deforestation have led to 106 plant species being listed as threatened by the Bangladesh Agricultural Research Council and the Bangladesh National Herbarium (Khan et al., 2001). Here some suggestion and recommendation is given to reverse this situation:

i. Appropriate steps must therefore be taken immediately in order to cope up with this situation with regard to growth, conservation and supply of medicinal plants in this country

ii. We should stop the indiscriminate and extensive collection of rare and commercially important medicinal plant from the wild.

iii. We should aware people by transferring cultivation technologies to homestead growers, cultivators through training, workshops, pamphlets, brochures, seminars etc.

iv. We need Sporadic and diverse researches on various aspects of medicinal plants

v. We should develop standardized cultivation practice of all commercially important medicinal plant gradually

vi. If required the threatened plant species may be multiplied through appropriate technique/s and bulk production of seeds/propagules for preservation, distribution to homestead growers and also for commercial purposes.

vii. Necessary steps should be taken for ex situ conservation of endangered and commercially important medicinal plants

CONCLUSION

Medicinal plants of Bangladesh has drawn the attention of Botanists as well as the environmentalists during the recent years. These plants are important natural wealth of our country. They play a significant role in providing primary health care services to most of the indigenous people as well as the major bulk of the rural population. They serve as an important therapeutic agents as well as important raw materials for the manufacture of traditional and modern medicines. Substantial amount of foreign exchange can be earned by exporting medicinal plants. Cultivation of medicinal plants has several advantages. Firstly this would ease the stress on the natural populations and also can assure a constant supply of the required medicinal plants to the user industries. Consequently, medicinal plants are important for a better daily life and better national economic condition.

Market value of a number of highly priced medicinal plant species used in Bangladesh are given as. Many countries of the world for example India, Kenya, Nepal, Japan, Germany, and England have taken systematic conservation and cultivation programmes of medicinal plants as a result of which they are also earning significant amount of valuable foreign exchange. It is also possible for Bangladesh by developing  sustainable improved and planed cultivation process of commercially important medicinal plants

REFERENCES

Alagesaboopathi, C. and Ramachandran, V.S. 2000. Methods of mass-multiplication of Indian Andrographis Wallich ex, Ness and its chemical analysis. J. Econ. Taxon. Bot. 24(3): 659-662.

Alam, M.K. 1992. Medicinal ethnobotany of Marma Tribe of Bangladesh. Economic Botany, 46(3):330-335.

Bhakuni, D.S. and Sudha, J. 1995. Chemistry of cultivated medicinal plants. Advances in Horticulture. Malhotra Publishing House, Delhi. 11: 41-45.

Dhar, A.K. 1999. Propagation in Plumbago zeylanica. J. Med. Aromat. Pl. Sci. 21(2): 304-307.

Gupta, L.M. 1997. Studies on reproductive biology and colchicine content in Gloriosa superba L. M.Sc. thesis. Dr. YS Pramar University of Horticulture and Forestry, Nauni-Solan 173 230 (HP) India, P.57.

Ghani, A. 1998. Medicinal plants of Bangladesh : Chemical constituents and uses. Asiatic Society of Bangladesh, Dhaka, Banglaesh.

Hassan, M.A. 2003. ‘Shaystha O Shoundarja Paricharjai Vesoz Udvid’(in Bengali). Al Hakim. 13(2): 11-16.

Hassan, M.A. and Khan, M.S. 1996. Ethnobotanical records in Bangladesh-2. Plants used for healing cuts and wounds. Bangladesh J. Plant Taxon, 3(2): 49-52.

Islam, R. 2003. ‘Chikitshar Upakaran O Oushad Shilper Kachamal Hishabey Oushidhi Udvidaer Avvantorien Baybohar Ebong Raptaner Somvabona O Shamosshya.’ Oushodi Udvidaer.  Baybohar: Somvabona O Shamosshya Bishayak Kormashala (in Bengali),pp. 21-30.

Khan, M. Salar, Rahman, M. Matiur, Ali, M. Arshad. 2001. Red data book of vascular plants of Bangladesh. (eds). B.N.H, Dhaka, Bangladesh.

Khan, M.S., Hassan, M.A. and Uddin, M.Z. 2002. Ethonobotanical survey in Rema-Kelenga wildlife sanctuary (Habiganj) in Bangladesh.  Bangladesh J. Plant Taxon. 9(1): 51-60.

Kumar, A., Kaul, B.L. and Verma, H.K. 2001. Phenological observations on root yield and chemical composition in different morphotypes of Withania somnifera. J. Med. Aromat. Pl. Sci. 23(2): 21-23.

Le Roux, L.G. and Robbertse, P.J. 1994. Tuber ontogeny, morphology and vegetative reproduction of Gloriosa superba L. S.  Afr. J. Bot. 60(6):  321-324.

Maheshwari, S.K., Sharma, R.K. and Gangrade, S.K. 2000. Ashwagandha (Withania somnifera) to organic manures and fertilizers in a shallow black soil under rainfed condition. Indian J. Agronomy. 45 (1): 214-216.

Mamatha, M., Farooqi, A.A., Prasad, T.G., Palevitch, D., Simon, J.E. and Mathe, A. 1993. Studies on growth, development and relationship between vegetative growth and yield in Gloriosa superba Linn. Acta-Horticulturae. 331: 365-370.

Mia, M.K. and Huq, M.A. 1998. A preliminary ethnobotanical survey in the Jointiapur, Tamabil and Jaflong area, Sylhet, Bull. 3. Bangladesh National herbarium, Dhaka. P. 10.

M.S. Rahman, G.M. Hossain and A.B.M. Enayet Hossain, 2010. Seed germination, growth, productivity and alkaloid content of Withania somnifera Dunal.,  cultivated  under different levels of cow-dung, and soil and light  condition..Bangladesh J. Life Sci.  22 (1): 11-16.

Partha, P. and Hossain, A.B.M.E. 2002. Ethnoconservational practices by 14 ethinic communities in Bangladesh. Bangladesh Environment. (eds.), Bangladesh Poribesh Andolon, Dhaka. pp. 523-530.

Nayar, M.P. and Sastry, A.R.K. (Eds.). 1987. Red data book of Indian plants. Botanical survey of India. Calcutta, 1-3.

Pavitra, M., Farooqi, A.A. and Prasanna, K.T. 1991. Influence of seed tuber size on sprouting, growth and productivity in Gloriosa superba Linn. My forest. 27(4): 351-354.

Shah, P., Tiwari, G. and Tiwari, J.P. 2000. Influence of harvesting dates on plant growth and root productivity of Plumbago zeylanica. J. Med. Aromat. Pl. Sci. 22(Suppl.1): 86.

Sofowora, A. 1982. Medicinal plants and traditional Medicine in Africa. John Wiley & Sons Limited, New York.

Supari, M.R., Farooqi, A.A. and Prasad, T.G. 1993. Influence of various pre-sowing treatments and growth regulators on seed germination in Gloriosa superba L. Indian J. Forestry. 16(2): 123-126.

Supratik, M., Jana, B.K., Subrata, D., Maitra, S. and Debnath, S. 1998. Response of plant nutrients on growth and alkaloid content of aswagandha (Withania somnifera Dunal.). J. Interacademicia.  2(4): 243-246.

Swarmapriya, R., Doraipandian, A., Arumugam, T. and Radha, N.S. 1996. Floral biology of Gloriosa superba L. South Indian Horticulture. 43(1&2):    40-44.

Tripathi, A.K., Shukla, Y.N. and Kumar, S. 1996. Ashwagandha (Withania somnifera Dunal, Solanaceae): A status report. J. Med. Aromat. Pl. Sci. 18(1): 46-62.

Yusuf, M., Chowdhury, J.U., Wahab, M.A. and Begum, J. 1994. Medicinal plants of Bangladesh. Bangladesh council of Scientific and Industrial Research, Dhaka-1205, Bangladesh, pp. 340.

Uddin, M. Z., Khan, M.S., and Hassan, M. A. 2001. Ethnobotanical  plant records of Kalenga forest range (Habiganj) Bangladesh for Malaria, jaundice, diarrhoea and dysentery. J. Plant Taxon., 8(1): 101-104.