Immunology: Current Research
Open Access

CB: Cannabinoid; CTL: Clerodendron trichotomum Tunberg Leaves; COX: Cyclooxygenase; IL: Inter Leukin; LOX: Lipoxygenase; NF- Necrosis Factor; PG: Pprostaglandin; TNF: Tissue Necrosis Factor; TwHF: Tripterygium wilfordii hook

Human body immune system plays important role to protect the body from the attack of pathogenic microorganisms. Immune system is categorized into two types such as cell mediated immunity and humoral or antibody mediated immunity. Similarly, immunosuppressive activity refers to the reduction in the activation of the immunity system [1]. The imbalance in immune system leads to a various diseases in humanbeings. So, the immune-suppressants are applied to monitor the symptoms of allergic, autoimmune and organ transplantation related disorders. Autoimmune diseases includes psoriasis, celiac disease, rheumatoid arthritis, myasthenia gravis, systemic lupus erythematosus, Crohn's disease, and ulcerative colitis whereas organ transplantation involves body organs such as bone marrow, heart, kidney, lungs and liver [2]. The activity of medicinal plants as immunosuppressive agents is due to their inhibitory cellular and humoral immune responses on immune system [3].

Cannabis suppresses the hyperactivity of immune system by acting on cannabinoid receptors such as cannabinoid receptor 1 (CB1) and cannabinoid receptor 2 (CB2). CB1 receptors are mostly present in the brain whereas CB2 receptors are abundant in immune cells. So, the cannabinoids are used for the treatment of cancer and inflammatory disorders [4] Structure 1.

Structure 1

Brasilicardin-A is isolated from the cultured broth of Nocardia brasiliensis IFM0406 and exhibit immunosuppressive activity. It contains the active chemical constituents such as amino acid and perhydro-phenanthrene moiety with a sugar rhamnose [5] Structure 2.

Structure 2

Green tea is a product of the dried leaves of Camellia sinensis of family Theaceae and is used for treatment of autoimmune arthritis. The polyphenolic compound (catechin) present in green tea possesses antiinflammatory properties [6] Structure 3.

Structure 3

PArtemisia annua has been extensively used for the treatment of autoimmune diseases such as systemic lupus erythematoses and rheumatoid arthritis. Artemesinin as well as its derivatives artesunate and artemether possess immune-modulatory effect [7] Structure 4.

Structure 4

Sarsaparilla plant contains steroids such as sarsasapogenin, smilagenin, sitosterol, stigmasterol and saponins like sarsasaponin, smilasaponin. Sarsaparilla is beneficial for the treatment arthritis due to its ability to inhibit TNF-α induced NFk-β activation [8] Structure 5.

Structure 5

Turmeric (Curcuma longa) of Zingiberace family is widely utilized for treatment of infections and inflammatory diseases. Curcumin is a yellow colored pigment which is extracted from the rhizome of Curcuma longa. This constituent of Curcuma regulates immune system by cellular and humoral mediated immunity [9] Structure 6.

Structure 6

Ashwagandha (Withania somnifera) is widely used in the treatment of psoriasis, arthritis and rheumatism. The chemical constituents present in Ashwagandha are alkaloids (isopelletierineanaferine), steroidal lactones (withanolides, withaferins), saponins (sitoindoside VII and VIII) and withanolides. These constituents produce immunosuppressive action on B and T cell activity in hyper-immune states [10] Structure 7.

Structure 7

Ginger (Zingiber officinale) is used to decrease pain in arthritis. The chemical constituent zingiberene is mainly responsible to reduce pain and inflammation by inhibiting cyclooxygenase (COX) and lipoxygenase (LOX) pathways [11] Structure 8.

Structure 8

Stephania tetrandra is used for the treatment of autoimmune disease and rheumatic arthritis. Tetrandrine is the active constituent which produces immunemodulating effects by inhibiting TNF-α [12] Structure 9.

Structure 9

Tripterygium wilfordii is widely known to treat autoimmune diseases such as systemic lupus erythematosus and rheumatoid arthritis. Its active constituent triptolide exhibits anti-inflammatory and immunosuppressive activities by producing inhibitory effect on T-cells [13] Structure 10.

Structure 10

Salvia miltiorrhiza of Labiatae family is recognized for the treatment of immunological disorders. The chief active constituent of Salvia miltiorrhiza is Tanshione IIA (TSN). TSN produces its action by reducing inflammatory cytokines such as IL-2, IL-4 and TNF-α [14] Structure 11.

Structure 11

Liquorice (Glycyrrhiza glabra) belongs to Fabaceae family which exhibits immune-modulatory properties. Glycyrrhizin and glycyhrritinic acid are the active constituents which have antiinflammatory effects by inhibition of calcineurin activity and T-cell proliferation [15] Structure 12.

Structure 12

Parthenolide is a major sesquiterpene lactone present in extracts of Tanacetum parthenium of Asteraceae family and used for the treatment for rheumatoid arthritis. It inhibits the release of pro-inflammatory mediators such as nitric oxide, prostaglandin (PG) E2 and TNF-α [16] Structure 13.

Structure 13

Berberis vulgaris of Berberidaceae family has immunosuppressive action. Berbamine is the active constituent which has selective inhibitory effect on STAT-4 expression and production of IFN-γ in cells [17,18] Structure 14.

Structure 14

Andrographis paniculata of family Acanthaceae is recommended for the relief of rheumatoid arthritis and autoimmune disease. The main constituent Andrographis paniculata is andrographolide. It produces inhibitory effects on NF-κB trans-activation activity [19,20] Structure 15.

Structure 15

Alliin is chemically a sulfoxide which is the natural constituent of garlic (Allium sativum). It is a derivative of the amino acid cysteine. Alliin is capable of suppressing LPS inflammatory signals by generating an anti-inflammatory gene expression and prevented the increase in expression of pro-inflammatory cytokines IL-6 and MCP-1[21] Structure 16.

Structure 16

The active constituent Clerodinin-A is isolated from Clerodendron trichotomum Tunberg Leaves (CTL) which inhibits the pro-inflammatory gene expression in LPS-stimulated RAW 264.7 macrophages by suppressing NF-kappa-B activation [22] Structure 17.

Structure 17

The geranylated flavonoids (5,7,4'-trihydroxy-3'-[7-hydroxy- 3,7-dimethyl-2(E)-octenyl]isoflavone) isolated from the roots of Campylotropis hirtella exhibits immunosuppressive activities [23] Structure 18.

Structure 18

Triptolide is an active ingredient present in the Chinese herb Tripterygium wilfordii hook (TwHF). Chemically, it is a diterpene triepoxide and act as potent immunosuppressant and anti-inflammatory agent [24] Structure 19.

Structure 19

Various experiments are carried out to find out the immunosuppressive effects of medicinal plants growing in different parts of the world [25]. The following plants are studied for their immunosuppressive effects which are presented in Table 1.

Table 1: List of Medicinal plants as immunosuppressive agents.

Various medicinal plants have been used for the treatment of different immunological disorders. There are extensive studies carried out for determining the mode of action plant constituents as immunosuppressive agents. So, the pharmacological properties lend themselves to further confirmatory testing and expanded to other immuno-suppresive uses. The active ingredients present in various medicinal plants used as immunosuppressive agents includes Withania somnifera, Glycyrrhiza glabra, Andrographis paniculata, Salvia miltiorrhiza, Zingiber officinale, Berberis vulgaris, Curcuma longa etc. These plants have been extensively studied for their active constituents and their mechanism of action towards immunosuppressant activities.

We declare that we have no conflict of interest.