Phytochemical analysis of traditional herb

Review Article

Title: Phytochemical analysis of traditional herb: Dill (Anethum graveolens)

WAQAS AHMAD

Institute of Horticultural Sciences,

University of Agriculture Faisalabad

Faisalabad-38000, Punjab, Pakistan

[email protected], +92 336 4950217

Abstract: Anethum graveolens locally known as Dill or Sowa is a commonly used traditional medicinal plant. This herb is considered important because of its anti-resistance potential in microbes and as an alternative to antibiotics. It acts as preventive medicinal plant against lipid per-oxidation, digestion problems, liver damage, colic, diabetes, and abdominal pain. The review gives the information of its phytochemistry and active constituents for specific ailments. Flavonoids and phenolic compounds act as anti-oxidant; alkaloids, tannins and saponins as anti-bacterial; and essential oil in the management of diabetes. So, it covers the brief detail of bio-active constituents of Anethum graveolens that are responsible for its anti-oxidative potential, anti-microbial activity and for the management of diabetes mellitus.

Key-words: Anethum graveolens, phytochemistry, active constituents, anti-oxidant, anti-microbial, diabetes mellitus.

1. Introduction

Medicinal plants have been used for the treatment of various diseases from the beginning of life on earth. These plants are mostly used in Indian health system called Ayurveda and in Chinese herbal medicines. Almost 2000 plant species have been used in Ayurveda and 7500 Chinese medicines are of plant origin. About 80 % of world population still dependent on traditional medicines even in the presence of modern health system. Anethum graveolens is one of the most important medicinal plants commonly used in Ayurveda and herbal medicines in treatment of many diseases ^[1].

1.1       Origin and Classification

Anethum graveolens/dill is originated from Mediterranean region and West Asia. It grows wild in the rich earth and sunny region of Ouezzane. Anethum graveolens belong to family Umbelliferae. Many spices and herbal plants belong to this family. Umbelliferae is sub-divided into three sub-families Hydrocotyloideae, Saniculoideae and Apieideae. Anethum graveolens belong to Apieideae like many other medicinal plants. It belongs from genus Anethum which derived from Greek word Aneeson or Aneeton which means “Strong smelling”. Anethum graveolens is known as DILL in English and SOWA in Hindi and also by many other names according to the parts of plant used in medicines. We call dill seed when seeds are being used and dill herb when leaves are being used for extracting essential oils and active constituents. Common method used for extraction is distillation for Anethum graveolens extracts.

It is an annual sometime biennial herb of 1.5 m height. Leaves are used as salad and tea while seed is used in tea, bread, soup, salad and preservatives. Leaves and seed are mostly used for medicinal purpose or sometime fruit or inflorescence but roots are not yet seen in literature as medicinal treatment ^{[1, 3, 16].}

1.2       Curative Role

Discovery of herbs that are anti-oxidants, anti-microbial and have anti-inflammatory activities are considered very important in medicine. Anethum graveolens is an Indian traditional medicinal herb. It is used in abdominal discomfort, colic and promotes digestion. It is diuretic, anti-spasmodic, stimulant and has anti-microbial activity against Saccharomyces cervices and Cisteria monocytogenes. Dill herb is anti-oxidant, anti-stress, cardio protective and anti-cancer ^[4]. It is used as Iranian folk medicine as an anti-hypercholesterolemic plant. Dill is a most significant spice in food industry and has anti-hyperlipidemic, hypertensive, anti-emetic and laxative effects. It helps during bad breathe and lactation problems. It increase milk production for mothers who breastfeed and prevent menstrual pains. Volatile seed oil with bitter taste is stomachic, anti-pyretic, carminative and anti-ulcer. It also helps in abdominal pain and used for preparation of gripe water. Essential oil has hypolipidemic activity and could be used as cardio protective agent. Major constituents are carvone, limonene, and monoterpenes. Dill herb has a specific odor which is due to α-phellandrene, dill ether and myristicin ^{[6, 9].} Anethum graveolens has also been used in management of diabetes as traditional Asian medicine ^[19].

1.3       Antibiotics and Current issues

With the discovery of antibiotics, a new revolution came in the field of medicine. But due to the development of resistance in microorganisms against specific antibiotic drugs, medical doctors have to face a lot of problems. Antibiotic resistance is an emerging global issue which makes difficult the pattern of treatment of many diseases. Multidrug resistance strains called “superbug” are emerging which increasing the rate of morbidity and mortality. All these issues of resistance are due to overuse and misuse of synthetic drugs and antibiotics. Upon observing all these problems, Scientists are again moving toward the discovery of new medicinal plants and active constituents in them and revival of medicinal plants used in past. Many medicinal plants are being used for their Phytochemical constituents and bioactive compounds to cure many aliments. Crude extract of medicinal plants are considered more effective as compares to isolated components. In India, essential oils have been used for treatment and their side effects are noticed. But research has cleared that phytochemicals as secondary metabolites are responsible for the bioactivity of medicinal plants ^{[11, 16, 18].}

The main reason of this review paper is to find out all those bio-active constituents of Anethum graveolens that are responsible for its anti-oxidant potential, anti-microbial activity and for management of diabetes. So, the public can have full awareness about such a valuable, cheaper, and easily available medicinal plant.

2. Phytochemical screening and analysis of Anethum graveolens

2.1       Bio-active constituents

Bio-active constituents are those chemicals that work against specific ailments. Almost each herb has large range of such bio-active compounds. So, scientists are working on the biochemistry of medicinal plants. Anethum graveolens is a very commonly used medicinal plant with a range of active ingredients. These ingredients are alkaloids, tannins, flavonoids, anthocyanins, anthracene derivatives, glycosides, saponins, sterols, terpenes, carotenoids, mucilage, quionens, cumarins, volatile oil, lipoids and iridoids ^[3].

Because of resistance developing character of microbes, synthetic medicines fail in treatment of many microbial diseases but many medicinal plants are successful and cheaper comparatively ^[4]. Dill has also some nutritional values and is used as salad. It contains essential oil, fatty acids, moisture, protein, carbohydrates, fibers, ash, mineral elements such as calcium, potassium, magnesium, phosphorous, sodium, vitamin A, niacin ^[5].

2.2       Anti-oxidative characteristic

Mainly two parts of Dill are used for medicinal purpose, leaves and seed. Its leaves are called dill herb dried, crushed and powdered and then the active constituents are extracted by different methods of extraction. Many chemicals are present in leaf extract. Carbohydrates, glycosides, flavonoids and tannins are present in higher amount as compared to alkaloids, proteins and saponins. Most important anti-oxidant from these chemicals is flavonoid and other phenolic compounds. These both acts as potent water soluble anti-oxidant phenolics are extracted from leaves of Anethum graveolens, so, this is a natural anti-oxidant. The anti-oxidative activity of phenolics is due to their redox phenomena. It acts as reducing agent, hydrogen donator and has metal chelating ability. Flavonoids another chemical having anti-oxidative potential is an important secondary metabolite. It modulates lipid per-oxidation which is the major cause of atherogenesis, thrombosis and carcinogenesis. Carbohydrates and glycosides act on immune system and tannins as anti-ulcer and prevent the stomach cancer. So, Anethum graveolens leaf extract has therapeutic efficacy with anti-oxidative potential because of hydrogen donating ability of its active ingredients ^{[6, 7].}

The other part used for medicinal purpose is dill seed which is important because of its essential oil. Essential oil has 29 components but carvone is in highest amount almost 40-60 %.While limonene, cis-dihydrocarvone, trans-dihydrocarvone and other chemicals are in a very low amount. Essential oil of dill seed is a good alternative to dill as spice because it is a good anti-oxidant and also protect from free radical damage. From components of essential oil that is carvone responsible for its anti-oxidative activity ^[8]. Liver damage by CCl₄ is also protected by essential oil of dill seed. So, anti-oxidant potential of Anethum graveolens is due to polyphenolics present in both parts leaves and seed ^{[9, 10].}

2.3       Anti-microbial screening

Dry seed and leaves of dill are powdered; their aqueous and organic extracts are used in the treatment of various ailments. Among the large list of bio-active constituents of Anethum graveolens alkaloids, flavonoids, tannins, saponins, and cardiac glycosides are considered useful against microbial activity ^[11]. Dill extracts are very useful as anti-bacterial and antifungal agents. It may kill or weaken the bacteria without developing any resistance in it. Aqueous extract of Anethum graveolens kills microbial activity of E. faecalis, S. aureus, E. coli, P. aeruginosa II, S. typhimurium and S. flexneri ^[12]. It has been noticed that the gram positive bacteria are affected much as compared to gram negative bacteria. This difference is because of the outer peptidoglycan layer of gram positive bacteria that is not a good protective barrier ^[11].

Different types of dill extracts are useful against different microbes because of variation in their composition. Organic extract of Anethum graveolens protects liver damaging activity of Helicobacter pylori, so, it is used as anti-cancer ^[13]. Aqueous extract of dill seed is a better anti-bacterial as compared to some anti-bionics. Alkaloids and flavonoids are used as analgesic, anti-spasmodic and bactericidal. Chemically, these compounds make complexes with extracellular, soluble protein and bacterial cell wall ^{[14, 15].} Essential oil of Anethum graveolens has a very high anti-bacterial potential against Exterococcus spp., E. coli, Salmonella typhi, Bacillus subtillis and S. aureus ^{[16, 17].}

Tannins are important compounds for inhibiting the damage by P. aeruginosa, S. flexneri ^[11]. While testing against microbial activity, aqueous extract of seed is more effective than leaf and root extract. It also affects Staphylococcus aureus, Bacillus cereus, pseudomonas aeruginosa, Ghigella flexneri and Salmonella thphium. So, dill active constituents act as anti-microbial against all these microbes causing many diseases and it is important that every chemical is responsible for effecting different microbes ^[18].

2.4       Diabetes management

Diabetes mellitus is a metabolic disorder that causes a large number of morbidity and mortality. It is as dangerous as cancer and is differentiated into two types:

• Type 1 Diabetes
• Type 2 Diabetes

552 million diabetic patients have been estimated in 2030 as compared to 336 million people in 2011 ^[20]. The symptoms of this fatal disease are hyperglycemia, frequent urination, excessive thirst, weight loss, extreme hunger, sudden vision changes, tiredness, very dry skin, nausea and vomiting. It is also one of the major sources of heart diseases. The treatment of diabetes mellitus by synthetic chemicals is expensive, less effective and problem causing as compared to herbal treatment. The problems of weight gain, risk of fractures, gastrointestinal diseases and edema are commonly observed by the use of synthetic medicines. So, the herbal medicines are considered the best way of its management and treatment.

One of the major causes of this disease is blood lipid per-oxidation that increases defects of insulin secretion by pancreatic β-cells. Such defects can cause low level of high density lipoprotein cholesterol and oxidation stress. These problems are fixed by flavonoids of Anethum graveolens that modulates lipid per-oxidation. Dill essential oil reduces triglycerides total cholesterol, low density lipoprotein cholesterol, glucose level and increase high density lipoprotein cholesterol level. So, Anethum graveolens is a good herb in management of diabetes mellitus ^[19].

3. Conclusion

Ultimately, Medicinal plants are more effective, useful and cheaper as compared to synthetic medicines. The study of Anethum graveolens reveals that it is very effective in the treatment of many diseases and can also be used as preventive medicine against many ailments without any side-effect. Use of such plants is economically very important for any country because of the potential of decreasing the costs of expensive synthetic medicines that are manufactured within the country or imported. So, the cultivation of medicinal plants like Anethum graveolens should be increased and awareness programs should be run by each country’s government for the welfare of their public. Conclusively, Scientists should also continuously work on medicinal plants to explore their chemistry.

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