ImmunoProtective Role of Medicinal Herbs as Phytotherapeutic Drugs in Ayurveda – A Prospective Approach for Defending COVID19

Cinnamomum zeylanicum Garcin ex Blume

Cinnamomum zeylanicum of the family Lauraceae is commonly known as cinnamon (Figure 1). It is native to Sri Lanka and wildly grown in Western ghats, and adjoining hills of west India. The plant is also found in Java, Sumatra, and South America, Mauritius and is a bushy evergreen tropical tree. Cinnamon is the dried inner brown bark of the tree having 0.5% to 1% of aromatic essential oil. These plants possess amazing therapeutic properties like antioxidant, antifungal, antibacterial, lowering cholesterol level, maintaining sugar level in the body, controlling vomiting in the body, and its regular intake will reduce breathlessness, strengthen heart muscles and vascular system. The biochemical constituents are cinnamaldehyde, eugenol, phellandrene, benzaldehyde, etc.

Different immunomodulatory phytoconstituents present in the plant are Cinnamaldehyde, Eugenol [8]. Niphade, et al. reported that 100 mg/kg bodyweight of cinnamon high dose (CHD) showed immunostimulant activity in Swiss Albino. It was reported to increase the phagocytic index in the carbon clearance test, increased serum immunoglobulin levels, and also increased the antibody titer in the indirect hemagglutination test. He also reported that cinnamon at a high dose increases both cell-mediated and humoral immunity.

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The bark of the plant contains cinnamaldehyde, benzaldehyde, cumin aldehyde, and terpenes [8, 9, 10]. Cinnamaldehyde is reported to inhibit lymphocyte proliferation and NF-kB stimulation. Polyphenols and volatile phenols are the two chemical classes that are isolated from C. zeylanicum. The essential oil extracted from the bark contains cinnamaldehyde with a range of 90% to 62% and is the most signified substance. Eugenol has a higher concentration >80% and cinnamyl acetate and caryophyllene is the main component of cinnamon leaf oil and cinnamon flowers and fruit [11].

Glycyrrhiza glabra L.

It is commonly known as Liquorice or sweet wood or Mulaithi of family Fabaceae (Figure 2) is native to parts of Asia and Europe. Hong, et al. (2009) reported from their preclinical study that co-administration of polysaccharides isolated from G. glabra to mice feeding on a high-fat diet enhances the immune response and increases the activities of various antioxidant enzymes. It is a flowering herbaceous perennial legume plant native to Western Asia, North Africa, and Southern Europe. With sweet aromatic flavoring extract obtained from the root is having high medicinal value [12, 13].

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Liquorice root has been widely used around the world to treat cough since ancient times. It contains. Glycyrrhizin and glycyrrhetinic acid are considered to be the main active components and are potent inhibitors of cortisol metabolism, due to their steroid-like structures. Glycyrrhizin, also called glycyrrhizic acid (GLR), a major active constituent, is a triterpene glycoside/triterpenoid saponin mainly isolated from the roots of the plant’s Glycyrrhiza glabra [14]. It contains a lot of phytochemicals including more than 300 flavonoids (of them 42 chalcones) and 20 triterpenoids [15]. So, the root of this plant has been used for the treatment of coughs, colds, and asthma. Glycyrrhizin alleviated allergic asthma in an ovalbumin-induced experimental mouse model of asthma as evidenced by increased IFNγ level, while it decreased IL-4, IL-5 levels, and eosinophil count in bronchoalveolar lavage (BAL) [16, 17, 18]. Owing to its therapeutic potential, the plant was used from ancient times as alternative natural medicine in Ayurveda. Besides its use as food additives, such as flavors and sweetening agents, it has high potential in the treatment of many diseases [19]. Glycyrrhizin and Liquorice extract are present in most traditional Chinese medicine formulas used against SARS- CoV-2 in China. Significant data are showing that glycyrrhizin and liquorice extract have multiple beneficial activities in combating most features of SARS-CoV-2 [15]. Several review articles concluded that the antiviral activity of liquorice extract and glycyrrhizin has been reported against various viruses including SARS-CoV and SARS-CoV2 [14, 19, 20, 21].

Several bioactive compounds viz. polysaccharides, triterpenes, and flavonoids found in glycyrrhizin enhance immunity through the activation of different targets such as increase of interferon-gamma production, enhances the lymphocytic proliferation in response to viral infection, dose- dependent cell-mediated and humeral immunomodulatory activity, significantly increase leukocyte count and phagocytic index, reduced the duration of viral antigen shedding and increases the serum antibody titers [14, 15, 19]. It causes an increase in chemokine and chemokine receptor genes expression that modulates B and T cell recruitment to lymphoid follicles. Glycyrrhizin promotes the release of immune factors and its two components viz. isoliquiritigenin, and naringenin, promote regulatory T cells induction. They are useful against inflammatory and autoimmune diseases as they enhance immune suppression of Regulatory T cells [15].Polysaccharides show immunostimulatory activity and promote dendritic cell maturation [14, 15].

Adhatoda vasica L

Adhatoda vasica (L.) Nees commonly known as Vasaka is a well-known medicinal plant widely used in the Unani and Ayurvedic system of medicine [22].The plant grows throughout the Indian peninsula up to an altitude of 1300m in the sub-Himalayan tract, also found in Nepal, Pakistan, Myanmar, Sri Lanka, and Germany (Figure 3). It usually grows in waste places frequently near villages and often as an escape from cultivation as a hedge plant.

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The principal constituents of Vasaka are its several alkaloids, the chief one being vasicine. The leaves contain two major alkaloids called vasicine and vasicinone2, 3. The leaves of Vasaka are rich in vitamin C, carotene, and essential oil. Vaccine also exhibits strong respiratory stimulant activity [22]. Adhatoda vasica has been used in traditional Indian medicine for thousands of years to treat respiratory disorders like bronchitis, tuberculosis, and other lung and bronchiole disorders [23]. This could be an advantage to fight the COVID-19 symptoms. A decoction of the leaves can be used as an herbal treatment for cough and other symptoms of colds. The soothing action helps irritation in the throat and the expectorant will help loosen phlegm deposits in the airway which makes Adhatoda a good remedy for sore throat [23]. The leaves, roots, and flowers are extensively used in indigenous medicine as a remedy for cold, cough, bronchitis, and asthma as prescribed in Ayurvedic medicine. In acute stages of bronchitis where the sputum is thick and sticky, which is a case in post Covid impact; this plant gives unfailing relief by liquefying tilt sputum. The dried leaves should be smoked for relief in asthma [23]. Kumar, et al. [23] also reported that leaf decoction (7 leaves of the plant are boiled in water, strained, and mixed with 24 grams of honey), a confection of vasaka (mixture of 60 grams of flowers and 180 grams of jaggery in doses of 12 grams twice daily) relieves cough. It has vasicine, vasicinone and vasicolone as major chemical constituents. These primary alkaloids are well established as therapeutical r. Previous experimental and clinical trials demonstrated that Vasaka has antiviral action. It has shown antiviral action against different viruses indicating that it could be a therapeutic option for the management of COVID19 related symptoms [22, 24, 25].

Cinnamomom Respiratory Agent zeylanica

• English: Cinnamon
• Hindi: Dalchini
• Properties Taste: Bitter, Pungent, sweet Qualities: Light, unctuous Penetrating Potency: Hot Final Test: pungent
• Chemical Constituent: Cinnamaldehyde, Eugenol.
• Actions: It subsides Kapha and Vata It elevates Pitta. It is digestive and increases appetite. It enhances internal immunity and is a blood purifier. It is expectorant.
• Uses: Dyspepsia, Loss of appetite, cough, Infection, etc.
• Parts Used: Bark oil, Leaf.
• Dose: Bark powder 3-6 gm, oil- 2-5 drops.
• Medicine: Sitopaladi Powder.

Glycyrrhiza glabra

• English: Liquorice
• Hindi: Mulethi
• Properties Taste: sweet (50 times sweeter than sugar) Qualities: Heavy, unctuous Potency: Cold Final test: sweet
• Chemical Constituent: Glycyrrhizin, isoliquiritin, etc.
• Actions: It subsides Vata & Pitta. It is a potent acid neutralizer. Expectosant, Health Booster.
• Uses: Hyperacidity, cough, and general debility
• Parts Used: Root
• Dose: 3-5 gm.
• Medicine: Yastimadhu Powder

Adhatoda Vasica

• English: Malabar nut.
• Hindi: Adusa
• Properties Taste: Bitter, Astringent Qualities: Unctuous, Light Potency: Cold Final test: Pungent
• Chemical Constituent: Vasicine Adhatodic acid.
• Actions: It Kapha and Pitta. It liquefies cough and expectorant. It increases the surface area of Bronchial tree.
• Uses: Cough, Epistaxis
• Parts Used: Root, Leaf & Flower
• Dose: Root Decoction of 20-50 ml.
• Medicine: Vasavaleha, vasarista etc.