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General feature: These are aromatic leaves used in the cooking of exotic foods. The leaves are intended to add fragrances in the cooked items. In practice, leaves are never been eaten with the cooked meals so taken away before any serving. Usually, fresh cut leaves are dried for few weeks and afterward used in the event of cooking because the fresh ones are inefficient to provide adequate quantity of fragrances. Until dried, they do not develop to offer the full flavoring capacity. The leaves are not eaten not because it has the harmful effect but it has least delicate taste to offer. As per texture they are harsh and distasteful. So its use is confined to the purpose of flavoring the cooked items. The tree normally grows about 15 – 20 feet height from the ground if not frequently pruned. The leaves are approximately 3 – 4 inches long shiny dark green elliptical shape. It often bears star shaped flowers or grows small berries which are also used for the flavoring of food. There are diverse groups of bay leaves: California laurel (Bay laurel) which has strong flavor similar to Mediterranean variety and belongs to the Lauraceae family; Indian bay leaf (Cinnamon tamala or Malabathrum) has cinnamon like flavor and is commonly called Tejpata in Hindi. It also belongs to the Lauraceae family. It is a native of India and grows taller in size (~ 60 feet) with bigger leaves. The name Malabathrum comes from the place named Malabar in the spice state of India, Kerala. Indonesian bay leaf belongs to the Myrtaceae family. It is suitable for adding to the meat but not so compatible with vegetables. It is also unfounded outside the Indonesia. West Indian bay leaf belongs to Myrtaceae family also. It is used either for the culinary purposes or in preparing cologne. Indian bay leaf grows in India, Bangladesh, Nepal, and Bhutan and also in parts of China. The leaves are widely used in making North Indian or Mughlai cuisine like Biriyani and also in delicious rice pudding. Characteristically, Cinnamon tamala of Lauraceae family possesses high level of essential oil and it also signposts its primeval existence during the splitting era of Gondwana supercontinent. Many aromatics are common in the most kind of bay leaves. But the higher level of β – caryophyllene, Caryophyllene oxide, Eugenol and Linalool are seen mostly within the Indian bay leaves.
History of Bay leaves: Due to soothing fragrance, Bay leaves / Bay laurel are appreciated from the very ancient times. Romans used to make wreaths to crown their commanders to celebrate the victory. Those wreaths are still offered to the winners of Olympic game. It stands for the cultural celebrations of Greek or Roman society. The legend says that Greek God Apollo who is Sun God and also the sign of truth and prophecy was extremely fond of the Bay tree. He introduced it as a sacred plant and asked everyone to wear its wreath. The other story says that Apollo was in obsessive love with a nymph named Daphne. To avoid Apollo, Daphne turned herself into a Bay Laurel. So the Greeks often use the name Daphne tree. The legend also says that before making any prophecy Oracle, the Goddess of prophecy at Delphi used to eat foods with bay leaves to enter into trans. Greeks always consulted with her through Apollo regarding any difficult or large decision, like getting involved in the wars etc. No such mythical stories are ever recorded regarding the use of Tejpata / Indian bay leaves.
Uses: The bay leaves are used primarily for adding fragrances to the cooked meals. Many European, Asian and Mediterranean cuisines use the leaves as flavoring agent. In Indian cuisines it is often added in making rice dishes like Biriyani. It is an essential ingredient of Garam masala (mixture of flavorful spices). The leaves are eventually removed from the cooked food before the eating thus normally used as intact. Obviously crushing would add more flavor. Occasionally the crushed leaves are added in a muslin bag for its easy removal from the food stuff. Environmentally, the presence of dry leaves in food storage discourages molds to grow. The vapor emitted from leaves can kill many insects and its larva. So bugs tend to stay away from it although large beetles are somewhat immune to that. It is speculated that members of the laurel family possess cyano-glycosides. But it is not true always. Traces of no such compounds are ever detected in any variety of bay leaves or Indian Tejpata. So, the insect repelling actions are due to the presence of other natural ingredients. In recent days, essential oils from the bay leaves are used in cosmetics, perfumery and food flavoring purposes even in the liquors and confectioneries. Considering its medicinal actions, the boiled leaf extract in water is often introduced for preventing flatulency and diuretic reasons which is also employed in treating minor chronic cardiac problems. In early days it was frequently used in the case of colic pain and diarrhea and even for controlling the rheumatism. But the extract finds its major application in removing the bad mouth odor. On the other hand the extract of bark is used in the treatment of gonorrheal infection.
Chemical components: The flavoring agents of any bay leaves are various terpenes as shown in case of Indian variety, Tejpata. Its average composition of major components in essential oil of Indian Tejpata are: β – Caryophyllene ~ 26 %, Caryophyllene oxide ~ 11%, Linalool ~ 14 % and Eugenol ~ 12 %. In addition to those there are several others and they are: Pinenes α & β, Phellandrene, Terpineol, Geraniol, Myrcene etc. Their compositions vary from place to place and for the species also. The average composition of essential oil of Bay Laurel / Laurus nobilis is: Eucalyptol (1, 8 Cineol) ~ 45 %, Terpenyl acetate ~ 8 – 12 %, Sesquiterpenes ~ 3 – 4 %, Methyl eugenol ~ 3 %, trans – β – Ocimene ~ 9 %, and other terpenes ~ 12 % (various Pinenes, Phellandrene, Terpineol, Linalool, Geraniol, Sabinene).
Besides flavoring agents, the leaves contain many vitamins and minerals. For example, on the average, 100 g of leaves have folate (~ 200 µg), Niacin (~ 2 mg), Pyridoxine (~ 1.8 mg), Riboflavin (~ 0.5 mg), Vitamin C (~ 47 mg) and Vitamin A (6200 IU). As per mineral content in similar amount, it has Ca (850 mg), Mg (120 mg), Mn (8.2 mg), P (113 mg), Zn (8 mg), Fe (50 mg), Cu (0.5 mg), Se (4.0 µg). The leaves are excellent source of Folate, Vitamin A, Vitamin C and others. It is a noble source of minerals also. Evidently, the leaves are good source of vitamins. The components of B Vitamins help synthesize numerous enzymes, regular functioning of nervous system and sustaining metabolism. Considering the role of delicate minerals, Mn and Cu act as a cofactor of antioxidant enzymes eg, super oxide dismutases whereas Fe is needed for red cell formation and cofactor for cytochrome oxidases. The leaves contain high level of K which helps regulate heart rate, blood pressure and other cellular functions.
Pharmacological actions: The ordinary extract or essential oils distilled out of the leaves have numerous terpenoids which are widely known for their immense pharmacological roles. The common and major terpenoid found in most varieties of bay leaves is β – Caryophyllene, a sesquiterpene which is structurally unique for its annexation of a cyclobutane ring displaying numerous pharmacological actions that includes its potent anti-cancer ability also. The uniqueness of Caryophyllene is owing to its duality while acting as terpene and also behaving as a dietary cannabinoid, efficient to bind with the CB2 receptors triggering many physiological actions. These receptors have role in peripheral immune system, peripheral nervous system, gastrointestinal system and brain while acting as anti-oxidants, anti-cancers, and anti-inflammatory also as local anesthetics or analgesics. The other second major item is Linalool, a monoterpene that exist naturally in both S – and R- enantiomers. The R – enantiomer is predominant in bay leaf and responsible for spreading the aroma of lavender. It is a good sleep aid offering relaxation and lowering anxiety in the nervous system in brain. It is also highly needed for the synthesis of Vitamin E and normally acts as an anti-inflammatory agent. Eugenol is although not a terpenoid but it is a good flavoring agent expressing the floral scent of gardenia. It is synthesized in many spices, flowers and leaves. As per chemical nature it has a Guaiacol ring attached to an allyl chain. The compound shows strong anti-inflammatory, analgesic, antiseptic and anti-oxidant properties. The analgesia is primarily due to the blocking of ion channels. The anti-inflammatory action exerted is due to the inhibition of PGE2 and IL-1β synthesis. Further it acts as an agonist to GABA whereas antagonist to the NMDA receptor which bears important role during pain transmission. Its neuroprotective action can prevent the progression of Alzheimer’s disease. The compound is very effective against many parasitic and viral infections and also a potent anti-depressant in human.
Eucalyptol / Cineole is a cyclic mono-terpene having camphor like smell. Most of the essential oils in nature have good proportion of eucalyptol. It is commercially used in cough suppressants and mouth washes. Medicinally, it has strong anti-cancer and anti-inflammatory roles enabling to block the cancer cell division and preventing any inflammation by blocking the metabolism of arachidonic acid. In addition, it also has anti-fungal effects. α – Terpineol occurs as a major isomer in comparison to the others. It is a potential anticancer compounds acting by blocking NF – κβ signaling. It also induces vaso-relaxation and creates hypotension by releasing NO thus subsequently activating the NO-cGMP pathway. The Ocimene exists as cis and trans isomers. It is a monoterpene and each variety exists also in α – and β – forms. In bay leaf mostly trans – β category is the predominant one. It has pleasant odor and generally used in the perfumery but the compound also defends the plant from fungus. It is a good fungicide. α – Phellandrene is also a monoterpene that bears sweet smell. Physiologically it has significant anti-nociceptive role.
Medicinal effects: The components of bay leaf / Tejpata have various medicinal actions whether used as an extract after boiling in the water or its essential oil. In Indian folk medicine (Pachhon) where a concoction of five spices are made by boiling in water along with the palm sugar crystal, one of its ingredient is bay leaf. The concoction is sweet tasting highly aromatic syrup intended to act as expectorant also reducing the body temperature during fever and preventing body ache. Anyway the bay leaf has many other medicinal advantages.
- It is diuretic and appetite stimulant.
- It reduces ulcer formation within stomach also provide relief from flatulence and colic pain of children.
- The essential oil can be used in treating arthritis, muscle pain and bronchitis.
- It is a good insect repellant.
- It acts as a good fungicide.