Table 1.

Natural products showing effect in respiratory disorders.

S.No.	Natural product	Nature	Chemical structure	Pharmacological/Mechanism of action	Ref.
1.	Apigenin	Flavonoid		•Anti-inflammatory via reducing the levels of interleukin (IL)-6, TNF- α and IL-17A •Anticarcinogenic •Antioxidant	[26]
2.	Asperuloside	Iridoid glycoside		•Anti-inflammatory via inhibition of MAPK and NF-κB signaling	[27]
3.	Eugenol	Terpenoid		•Ameliorate oxidative stress, •Anti-inflammatory via downregulation of TNF-α and IL-6 levels	[28]
4.	Curcumin	Alkaloid		•Ameliorates allergic airway inflammation and hyper-responsiveness by inhibiting the activation of NF-κB signalling pathway	[29]
5.	Berberine	Alkaloid		•Decrease in pro-inflammatory cytokine (TNF-α and IL-6) levels, •Inhibit NF-κB signalling pathway, •Increase the level of antioxidants in the body, •Reduces viability of cancerous cells	[30]
6.	Naringin	Flavanone glycoside		•Antioxidant, •Anti-inflammatory, Anti-apoptotic, •Anti-carcinogenic properties	[31]
7.	Naringenin	Flavonoid		•Anti-inflammatory via inhibition of pulmonary IkappaBalpha degradation and NF-kappa-B DNA-binding activity	[32]
8.	Luteolin	Flavone		•Inhibit MAPK and NF κB pathway •Reduces neutrophil inflammation •Inhibits LPS-induced TNF-α, interleukin-6. •Inhibits nitric oxide production in macrophages	[33]
9.	Quercetin	Flavonoid		•inhibits serum necrosis factor α, IL-1β, IL-6, nitric oxide (NO), IL-10 •Show anti-inflammatory and antioxidant properties	[34]
10.	Kaempferol glycoside	Flavonoid		•Suppress MAPKs and NF-κB signaling pathway	[35]
11.	Epicatechin	Flavonol		•Inhibits TNF-α expression •Inhibits proliferation of tumor cells and promotes cell death by apoptosis	[36]
12.	Picroside II	Iridoid glycoside		•Anti-inflammatory effect via suppressing neutrophilic lung inflammation	[37]
13.	Lactiflorin	Monoterpene glycoside		•Suppress the production of NO synthase and ROS	[38]
14.	Resveratrol	Polyphenolic compound		•Sensitize tumor cells to chemotherapeutic agents by modulating multiple cell signalling molecules	[39]