Traditional Medicinal Plants (Dar Es Salaam University Press - Ministry of Health - Tanzania, 1991, 391 p.): PART I: USE AND PROMOTION OF TRADITIONAL MEDICINAL PLANTS IN THE AFRICAN REGION: Effect of nitrogen and phosphorus on the essential oil yield and quality of chamomile (Matricaria chamomilla L.) flowers

Traditional Medicinal Plants (Dar Es Salaam University Press - Ministry of Health - Tanzania, 1991, 391 p.)

PART I: USE AND PROMOTION OF TRADITIONAL MEDICINAL PLANTS IN THE AFRICAN REGION

		Registration and utilization of herbal remedies in some countries of Eastearn, Central and Southern Africa
		A report on the development of a traditional medicine for bronchial asthma
		Resume of current research in medicinal plants in Botswana
		The use of data from traditional medicine: Tunisian experience
		Chemical and pharmacological studies of marketed traditional drugs
		Research into medicinal plants: The Somali experience
		Effect of nitrogen and phosphorus on the essential oil yield and quality of chamomile (Matricaria chamomilla L.) flowers
		Chemical characterization of pharmacologically active compounds from Synadenium pereskiifolium
		Abietane diterpene quinones from lepechinia bullata
		Antimicrobial activity of Tanzanian traditional medicinal plants
		Identification of clovanediol: A rare sesquiterpene from the stem bark of canella winterana L. (Canellaceae), using spectrophotometric methods
		A comparative study of the traditional remedy ''Suma-kala'' and chloroquine as treatment for malaria in the rural areas
		Ethnobotany and conservation of medicinal plants
		Biotransformation of hydroxyanthraquinone glycosides in Cassia species
		Le m�dicament indig�ne Africaine: Sa standardisation et son �valuation dans le cadre de la politique des soins de sant� primaires
		Chemical Evaluation of Tanzanian medicinal plants for the active constituents as a basis for the medicinal usefulness of the plants
		Ethnobotany and the medicinal plants of the Korup rainforest project area, Cameroon
		Seaweeds in medicine and pharmacy: A global perspective
		Biotechnology and medicinal plants
		Phytochemical investigations of four medicinal plants of Malawi: What next?
		The chemistry and pharmacology of the essential oil from the leaves of Hyptis suaveolens (L) Point
		Some CNS effects of Datura stramonium L (Solanaceae) in mice
		Discovery and development of drugs from natural sources
		A Survey of medicinal plants in Tabora region, Tanzania
		Int�r�t pharmacognosique des plantes de la flore m�dicinale Rwandaise: valeur chimiotherapeutique de quelques plantes Rwandaise
		A note on the utilization and commercialisation of traditional medicine
		Experience on the use of Tanzanian medicinal plants for the last decade (1979-1989)
		A comparison of the status of medicinal plants development in Africa with selected parts of the world
		Exp�rience du Burkina Faso en mati�re de pharmacope� traditionnelle
		The role and use of ethnomedical data in the research on traditional medicines and medicinal plants
		Traditional medicinal plants: Our cultural heritage
		The use of traditional medicinal plants: The cultural context

Effect of nitrogen and phosphorus on the essential oil yield and quality of chamomile (Matricaria chamomilla L.) flowers

V.E. EMONGOR*, J.A. CHWEYA*, S.O KEYA* and R.M. MUNAVU**

*Crop Science Department, University of Nairobi
P.O. Box 29053, Nairobi, Kenya

** Department of Chemistry, University of Nairobi
P.O. Box 30197, Nairobi, Kenya

ABSTRACT

Field experiments were carried out to determine the effect of nitrogen (0, 50, 100, and 150kg N/ha) and phosphorus (0, 17.47, 34.93, and 52.41 kg P/ha) and their interactions on the essential oil yield and composition of chamomile. Nitrogen significantly increased essential oil yield and influenced its composition. Phosphorus did not significantly influence essential oil yield and composition, but low phosphorus rates (17.47 kg P/ha) tended to increase essential oil yield. High phosphorus rates decreased essential oil yield. Application of 17.47 kg P/ha at transplanting and top-dressing later with 50 kg N/ha gave the best results.

Introduction

Chamomile flowers contain an essential oil which is used in the manufacture of drugs for the treatment of such diseases as convulsions in children, diarrhoea, colic and acidity, hysteria, allergy, inflammation of body tissues, sleeplessness and stomach ulcers induced by chemical stress or heat coagulation (Martindale, 1977; Sticher, 1977 and Isaac, 1980). The essential oil also promotes epithelization and granulation, and shows antibacterial and antimycotic effects, through the activity of (-)-a-bisabolol and chamazulene (Isaac, 1979). The oil can also be used for flavouring liquors, colouring foods and making cosmetics (Bailey, 1949 and Kirk and Othmer, 1952). The essential oil content of chamomile flowers is in the range of 0.2-2.0% per unit dry flower weight (Martindale, 1977 and Franz, 1980). The composition and yield of essential oil may be affected by many factors, including plant nutrition (Franz et al., 1978 and Franz. 1982).

Work done elsewhere, and not in Kenya, has shown that nitrogen and phosphorus fertilization increases the yield and essential oil content of the flowers (El-Hamidi et al., 1965; Franz 1981; Singh, 1977 and Meawad et al. 1984). The authors further reported that nitrogen and phosphorus influenced oil composition. Although nitrogen and phosphorus increased chamazulene content in the essential oil, excess nitrogen decreased it. Franz (1983) reported that nitrogen increased the concentration of (-)-a-bisabolol but decreased that of bisabololoxide B. No work on chamomile has been conducted in Kenya.

The importance and usefulness of chamomile essential oil in the pharmaceutical, food, and cosmetics industries and the fact that Kenya is importing a lot of the essential oil, has led to the initiation of studies on chamomile. The objective of this study was to show the effect of nitrogen and phosphorus and their interactions on the essential oil yield and composition of chamomile flowers.

Materials and methods

Field experiments were carried out between August, 1985 and March, 1987 at the Field Station, Faculty of Agriculture, University of Nairobi. Chamomile seeds (variety max et oljea) were sown in the nursery and seedlings were transplanted four weeks after germination, when they had attained 6-7 true leaves. The treatments consisted of 4 levels each of phosphorus (0, 17, 47, 34.93 and 52.41 kg P/ha) and nitrogen (0, 50, 100, and 150 kg N/ha). These were combined factorially to give 16 treatment combinations which were laid down in a split-plot design with three replicates. Phosphorus and nitrogen treatments were allocated to main plots and sub-plots, respectively. Phosphorus and nitrogen were applied at transplanting time and two weeks after transplanting, respectively.

Harvesting of flowers started when 50% of the plants had flowered and continued for 98 days. At every harvest, only flower heads with more than 40% open tubular florets were harvested. The fresh flowers were dried to constant weight in an air-ventilated oven, at 35° C for 5 days and their dry weights were then determined and cumulated. The cumulated dry flowers were then used for extraction in order to determine the quantity and quality of the essential oil.

Determination of the quantity of the essential oil in the dried flowers was based on steam distillation. Clevinger apparatus were used for the extraction using the method described by Trease and Evans (1978) and Kornhauser (1986).

The qualitative analysis of the essential oil was done using gas liquid chromatography (GLC) as outlined by Kirk and Othmer (1952), Trease and Evans (1978) and Kornhauser (1986), with slight modifications on the conditions of the GLC. The conditions of the GLC used were as follows: Apparatus: Gow-mac series 69-750; column: 2.5 m long, 0.25 cm internal diameter; Packing: OV-1 on chromosorb W/HP (100-120); Temperature linear programming, 85- 175°C, 2.5°C per minute; Detector: Flame ionization; Injector temperature: 220°C; Detector temperature: 220°C; Column temperature: 170°C; Carrier gas: Nitrogen (flow rate 25 cm³ per minute); Attenuation: 16; Chart speed: 1 cm per minute; and Range: 10^-11. The results presented are means of two trials.

Results discussions

Essential oil yield

Nitrogen fertilization significantly increased essential oil yield per both unit dry flower weight and hectare (Table 1). Increasing nitrogen from 0 to 100 kg N/ha increased essential oil yield per both unit dry flower weight and hectare from 0.627 to 1.036% (65% increase), and 5.85 to 16.64 kg (184% increase), respectively. Nitrogen rate above 100 kg N/ha decreased oil yield. Similar results were reported by El-Hamidi et at., (1965), Franz (1981), Agena (1974), Meawad, (1981) and Meawad et al. (1984); that is nitrogen increased chamomile essential oil content and yield. The increase of essential oil yield due to nitrogen fertilization could be accounted for by the fact that nitrogen played an active role in the development and division of new essential oil cells, cavities, secretory ducts and glandular hairs (Meawad 1981; Meawad et al, 1984 and Agena, 1974). Nitrogen may have increased the essential oil yield because of increased carbohydrate accumulation, gibberellins and auxins concentration in chamomile plants. These were then utilised in the formation of more essential oil cells in the secretory ducts, cavities or glandular hairs (Sacks and Kofranek, 1963; Moore, 1979; Agena, 1974 and Abou-Zeid and El-Sherbeeny, 1974).

Table 1: Effect of nitrogen on essential oil yield of chamomile plants

N rates kg N/ha	Essential oil yield per unit dry flower weight*	Essential oil yield per plant (Kg/ha)
0	0.627^a	5.85^a
50	0.869^c	13.08^b
100	1.036^d	16.64^b
150	0.811^b	13.16^b

* These values are ratios and hence they have no units

Effects of phosphorus and nitrogen and phosphorus interactions on essential oil yield per both unit dry flower weight and hectare were not significant.

Essential oil composition

Nitrogen fertilization significantly increased chamazulene, (-)-a-bisabolol and farnesene concentrations in the essential oil of the flowers (Table 2). Increasing nitrogen from 0 to 50 kg N/ha increased chamazulene, bisabolol, farnesene and cis-spiroether contents by 25, 13, 11 and 15%, respectively. Application of nitrogen above 50 kg N/ha led to a decrease in the contents of these constituents. However, bisabolol content increased throughout with increase in nitrogen. Similar results have been reported by Agena (1974), Franz (1981) and Franz (1983). The increase of chamazulene (matricine), bisabolol, farnesene, and cis-spiroether concentrations in the essential oil of chamomile flowers with increase in nitrogen application could be due to the decrease in the contents of bisabololoxides A and B with increasing nitrogen application. Amino acid metabolism in nitrogen-rich chamomile plants leads to the biosynthesis of chamazulene (matricine), bisabolol, farnesene and cis-spiroether at the expense of bisabololoxides A and B and vice versa (Franz, 1981 and 1983). This implies that the biosynthesis of basic hydrocarbon terpenes (matricine, farnesene and bisabolol) of chamomile are antagonistic to that of the oxygenated terpenes (bisabololoxides and bisabolonoxides).

Nitrogen application significantly decreased the concentrations of both bisabololoxides A and B in the essential oil of the flower (Table 2). Increasing nitrogen from 0 to 150 kg N/ha resulted in a decrease of 27 and 39% in bisabololoxides A and B concentrations, respectively. Franz (1981 and 1983) reported similar results.

Bisabololoxides (A + B) were predominant in the essential oil of the flowers, as they constituted on the average, 54.21% of the total constituents. Other constituents included bisabolol 6.02%, chamazulene 7.76% farnesene, 13.65% and cis-spiroether 7.97%. Mr-lianova and Felklova (1983) reported similar results. They reported that bisabololoxides (A + B) contents in essential oil of chamomile flowers were over 50%. This can be attributed to the fact that the biosynthesis of bisabololoxide A and B, and bisabolol are controlled by dominant and recessive genes, respectively (Franz, 1982).

Phosphorus application and the interaction between nitrogen and phosphorus did not significantly influence essential oil composition of chamomile flowers.

Table 2: Effect of nitrogen on essential oil composition of chamomile flowers

N rates kg N/ha	% chamazulene	% bisabolol	% farnesene	% cis-spiro ether	% bisabololoxide A	% bisabololoxide B
0	6.89^a	5.17^a	12.93^a	7.38^a	43.55^d	22.69^d
50	8.60^c	5.84^b	14.31^b	8.46^a	38.68^c	18.11^c
100	8.02^bc	6.51^c	13.84^ab	8.13^a	34.82^b	15.09^b
150	7.45^ab	6.54^c	13.90^ab	7.90^a	31.58^a	13.20^a

Figures followed by same letter(s) down the columns are not significantly different according to Duncan's multiple range test at 5% probability level.

Conclusion and recommendation

The study showed that application of 17.47 kg P/ha (40 Kg phosphorus pentoxide, P₂O₅/ha) during transplanting and two weeks later top-dressing with 50 kg N/ha, would ensure high essential oil yield which has good quality. The study also showed that nitrogen was important in the biosynthesis of essential oil and its components. However, it is recommended that more research should be done in the field of plant breeding, agronomy (varietal evaluation, plant nutrition, ecological zones), plant biochemistry and economic evaluation of chamomile growing in Kenya.

Acknowledgements

The authors are grateful to the University of Nairobi for financial assistance during the period of this study. They also wish to record their thanks to Dr. B.O. Mochoge of the Department of Soil Science for his assistance during the laboratory work.

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