Use of Natural Products in Asthma Treatment

Table 1

List of natural compounds described in the literature reviewed.

Product	Product form	Product source	Active compound	Compound class/type	Mechanism of action	Reference
1,8-Cineol	Isolated compound	Essential oil of Eucalyptus globulus leaves	1,8-Cineol	Monoterpene	Reduces the expression of NF-κB target gene MUC2	Greiner et al. [62]
3-Methoxy-catalposide	Isolated compound	P. rotundum var. subintegrum extract	3-Methoxy-catalposide	Iridoid glycoside	Inhibits the expression of cyclooxygenase (COX)-2, nitric oxide synthase (iNOS), and proinflammatory genes (IL-6, IL-1β, and TNF-α)	Ryu et al. [63]
Achyranthes aspera L	Ethanolic extract	Roots	Not reported	Not reported	Bronchoprotective activity	Dey [64]
Ailanthus excelsa Roxb	Aqueous extract	Barks	Not reported	Not reported	Bronchodilator and mast cell stabilizing activities	Kumar [65]
Allium Cepa L. and quercetin	Extract and isolated compound	Methanolic extract and vegetable	Quercetin [2-(3, 4-dihydroxyphenyl)-3, 5, 7-trihydroxy-4H-1-benzopyran-4-one, 3, 3′, 4′, 5, 6-entahydroxyflavone]	Flavonoid	Reduce the production of proinflammatory cytokines (IL-4, IL-5, IL-13) and promote the relaxation of tracheal rings	Oliveira et al. [66]
Alstonia scholaris (L.) R. Br.	Extract	Leaves of Alstonia scholaris (L.) R. Br.	Scholaricine, 19-epi-scholaricine, vallesamine, picrinine	Alkaloid	Reduce the eosinophilia, the production of proinflammatory cytokine (IL-4) and the expression of serum IgE and eotaxin	Zhao et al. [67]
Amorphophallus konjac (konjac)	Gel extract	Not reported	Not reported	Plant	Not elucidated	Chua et al. [68]
Andropogon muricatus	Crude extract	Aerial parts	Vetivenes. vetivenol, vetivenic acid, and vetivenyl acetate	Sesquiterpenic compounds	Inhibit the Ca^2+ channels and phosphodiesterase activity	Shah and Gilani [69]
Anoectochilus formosanus Hayata	Aqueous extract	Whole plant	Kinsenoside	Plant	Reduce the IL-4 production by Tregs and enhance the production of IL-12 and IFN-γ by Th1 differentiation	Hsieh et al. [70]
Artemisia maritima	Essential oil	Leaves	1,8-Cineol, camphor, camphene, and β-caryophyllene	Terpenoid	Inhibit the Ca^2+ channels and phosphodiesterase activity	Shah et al. [71]
Aster tataricus L. f.	Extract	Rhizomes	Kaempferol, aurantiamide, and astin C	Flavonoid	Inhibit the expression of NF-κB and promote the activation of beta-2 adrenergic receptor	Chen and Zheng [72]
Aster yomena (Kitam.) Honda	Ethanolic extract	Leaves	Phenolic compounds not specified	Phenolic compounds	Attenuate the production of NO and IL-1β, and suppress the expression of NF-κB. In addition, suppress the activation of TLR4 and promote a reduction of intracellular ROS production	Kang et al. [73]
Baicalin	Isolated compound	Leaves and branch	7-Glucuronic acid-5,6-dihydroxyflavone	Flavonoid	Suppress the lipopolysaccharide-induced TNF-α expression and inhibit the cyclic adenosine monophosphate-specific phosphodiesterase 4 (PDE4)	Park et al. [74]
Baliospermum montanum Müll. Arg. (Euphorbiaceae)	Chloroformic and ethanolic extracts	Leaves	Alkaloids, triterpenoids, diterpenoids, and glycosides	Alkaloids, triterpenoids, diterpenoids, and glycosides	Stabilize the mast cell degranulation and decrease the histamine release	Venkatesh et al. [75]
Berry fruit	Polyphenolic extract	Not reported	Phenolic compounds not specified	Phenolic compounds not specified	Not reported	Power et al. [76]
Boswellia serrata, Boswellia carterii, and frankincense	Essential oil	Resinous part	Fl-boswellic acid, acetyl-fl-boswellic acid, 11-keto-fl-boswellic acid, and acetyl-11-keto-fl-boswellic acid	Boswellic acids	Inhibition of leukotriene biosynthesis	Hamidpour et al. [77] and Al-Yasiry and Kiczorowska [78]
Boswellia serrata, Glycyrrhiza glabra, and Curcuma longa	Essential oil extract and extract	Resinous part, licorice root and turmeric root, respectively	Curcumin and fl-boswellic acid	Polyphenol	Reduce the plasma level of the leukotriene C4, nitric oxide and malondialdehyde	Houssen et al. [79]
Buffalo spleen lipid and a bacterial polypeptide	Extract	Animal-derived and microorganism-derived, respectively	Not reported	Not reported	Reduce the tracheal responsiveness and the amount of white blood cells	Neamati et al. [80]
Bullfrog oil (Rana catesbiana shaw)	Oil	Bullfrog adipose tissue	Oleic, linolenic, stearic, palmitic, and myristic acids. Eicosapentaenoic acids and decosahexaenoic acid	Fatty acids	Not elucidated	Amaral-Machado et al. [81]
Bu-zhong-yi-qi-tang	Aqueous extract	Root of Astragalus mongholicus Bunge, Panax ginseng C.A.Mey, Angelica dah-rica Fisch. Ex Hoffm and Bupleurum chinense DC. Rhizome of Zingiber officinale Rosc, Atractylodes macrocephala Koidz, and Cimicifuga foetida L. Fruit of Ziziphus jujuba Mill. var. inermis Rehd. Pericarp of Citrus reticulata Blanco. Root and rhizome of Glycyrrhiza uralensis Fisch	Not reported	Not reported	Reduce the level of eotaxin, Th2-related cytokines (IL-4, IL-5, IL-13), IgE, and eosinophilia	Yang et al. [82]
Caenorhabditis elegans	Crude extract	Microorganism	Not reported	Not reported	Modulate the immunologic Th1/Th2 response	Huang et al. [83]
Camellia sinensis L.	Aqueous extract	Not reported	Polyphenois and flavonoids	Polyphenois and flavonoids	Not elucidated	Sharangi [84]
Carica papaya	Extract	Leaves	Tanins, alkaloids, steroids, and quinones	Tanins, alkaloids, steroids, and quinones	Reduce the expression of IL-4, IL-5, eotaxin, TNF-α, NF-κB, and iNOS	Elgadir et al. [85]
Carum roxburghianum	Crude extract	Seeds	Hydrocarbons, wax esters, sterol esters, triacylglycerols, free fatty acids, diacylglycerols, lysophosphatidylethanolamines, and phosphatidylinositols	Hydrocarbons, wax esters, sterol esters, triacylglycerols, free fatty acids, diacylglycerols, lysophosphatidylethanolamines, and phosphatidylinositols	Bronchodilator activity	Khan et al. [86]
Chitin	Isolated compound	Shrimp	Chitin	Polysaccharide	Not elucidated	Ozdemir et al. [87]
Chrysin	Isolated compound	Marketable synthetic compound	5,7-Dihydroxy-2-phenyl-1-4H-chromen-4-one	Flavonoid	Reduces the histamine release and decreases the gene expression of proinflammatory cytokines (IL-1β, IL-4, IL-6, TNF-α, NF-κB)	Yao et al. [88]; Yao et al. [89]; Bae et al. [90]
Cissampelos sympodialis Eichl	Extract	Leaves	Warifteine	Alkaloid	Reduce the expression of IL-3 and IL-5, increase the IL-10 level, and decrease the density of inflammatory cells	Cerqueira-lima et al. [91]
Citrus tachibana	Ethanolic extract	Leaves	Coumarins, carotenoids, and flavonoids	Coumarins, carotenoids, and flavonoids	Modulate the Th1/Th2 imbalance by inhibition of NF-κB signaling and histamine secretion	Bui et al. [92]
Conjugated linoleic acid	Conjugated compound	Fatty tissue from ruminants	Cis, cis-9,12-octadecadienoic acid	Polyunsaturated fatty acid	Modulate the PPARγ-dependent and PPARγ-independent inflammation signaling, the eicosanoid production, and humoral immune response	Macredmond and Dorscheid [93]
Coumarins	Isolated compound	Synthetic compounds	6,7-Dihydroxycoumarin, 7-hydroxycoumarin and 4-methyl-7-hydroxycoumarin	Coumarin	Not elucidated	Sanchez-Recillas et al. [94]
Crocetin	Isolated compound	Marketable synthetic compound	Crocetin	Carotenoid	Activates the FOXP3 signaling through TIPE2	Ding et al. [95]
Curcumin	Isolated compound	Curcuma longa	(1E, 6E)-1,7-Bis (4-hydroxy- 3-methoxyphenyl)-1,6- heptadiene-3,5-dione	Polyphenol	Inhibits the Notch1-GATA3 signaling pathway	Zheng et al. [96]; Chong et al. [97]
Cyclotheonamides	Isolated compound	Marine	Not reported	Cyclic pentapeptides	Inhibit the human ß-tryptase	Schaschke and Sommerhoff [98]
Diallyl-disulfide	Isolated compound	Garlic oil	Diallyl-disulfide	Organosulfur	Activates the NrF-2/HO-1 pathway and suppresses the NF-κB	Shin et al. [99]
Dietary plant stanol esters	Not reported	Fatty acid	Not reported	Stanol ester	Reduce the total plasma IgE, IL-1β, IL-13, and TNF-α	Brull et al. [100]
Dioscorea nipponica	Isolated compound	Not reported	Diosgenin	Steroidal saponin	Suppress the secretion of TNF-α, IL-1β, and IL-6	Junchao et al. [101]
D-α-tocopheryl acetate	Isolated compound	Natural source	D-α-tocopheryl acetate	Vitamin	Inhibits the oxidative stress. Modulates the allergic inflammation and the airway hyperresponsiveness	Hoskins et al. [102]
Echinodorus scaber	Hydroethanolic extract	Leaves	Vitexin, rutin, and gallic acid	Phenolic compounds	Decrease the migration of inflammatory cells and reduce the Th2 cytokines and IgE levels	Rosa et al. [103]
Eclipta prostrata (L.)L.	Methanolic extract	Whole plant	Wedelolactone and demethylwedelolactone	Coumestan	Reduce the bronchial hyperresponsiveness and the production of Th2 cytokines	De Freitas Morel et al. [104]
Ecklonia cava	Marine alga	Brown macroalgae	Fucodiphloroethol and phlorofucofuroeckol A	Phlorotannins	Downregulate the FcεRI expression and block the IgE-FcεRI binding	Vo et al. [105]
Ephedra intermedia	Crude extract	Aerial parts	Ephedrine and pseudoephedrine	Alkaloids	Not elucidated	Gul et al. [106]
Ellagic acid	Isolated compound	Marketable synthetic compound	Ellagic acid	Polyphenol	Inhibits the activation of the NF-κB	Zhou et al. [107]
Emodin	Isolated compound	Roots and barks of Rheum palmatum and Polygonum multiflorum	1,3,8-Trihydroxy-6-methylanthraquinone	Anthraquinone	Suppresses the characteristics of airway inflammation, mucin components, and chitinase protein expression. Inhibits the NF-κB signaling pathway	Shrimali et al. [108]
Euphorbia hirta	Aqueous extract	Not reported	Galloylquinic acid, phorbol acid, leucocyanidol, quercitol, camphol, quercetin, chlorophenolic acid, shikimic acid	Tanins, leucoanthocyanidins, flavonoids, and phenolic compounds	Not elucidated	Kunwar et al. [109]
Sesame	Fixed oil	Seeds	5,5′-(1S, 3aR, 4S, 6aR)-Tetrahydro-1H, 3H-furo [3,4-c]furan-1,4-diylbis-1,3-benzodioxole	Polyphenol	Decreases the levels of IL-4, Il-5, IL-13, and serum IgE. Reduces the amount of inflammatory cells and the eosinophil infiltration	Lin et al. [41]
Farnesol	Isolated compound	Fruits, leaves, flowers	3,7,11-Trimethyl-2,6,10-dodecatrien-1-ol	Sesquiterpene	Increases the level of IgG2a/IgE and reduces the total IgE, IgA, IgM, IgG	Ku and Lin [110]
Feverfew (Tanacetum parthenium L.)	Extract	Leaves and parts above the ground	Parthenolide	Sesquiterpene	Inhibit the IκB kinase complex and the histamine release	Pareek et al. [111]
Flavonoids	Isolated compound	Vegetables (capers, tomatoes, fennel, sweet potato leaves, etc.), fruits (apple, apricots, grapes, plums, and berries), cereals (green/yellow beans and buckwheat)	Not reported	Polyphenol	Prevent the IgE synthesis and the mast cell degranulation. Reduce the airway hyperresponsiveness and inhibit the human phospholipase A2	Castell et al. [112]; Lattig et al. [113]
Fumaria parviflora Linn	Aqueous methanolic extract	Aerial parts	Fumarophycine, cryptopine, sanactine, stylopine, bicuculline, adlumine, perfumidine, and dihydrosanguirine	Alkaloids	Block the muscarinic receptors and the Ca^2+ channels	Najeeb ur et al. [114]
Galangin	Synthetic compound	Alpinia officinarum	3,5,7-Trihydroxy-2-phenylchromen-4-one	Flavonol	Inhibits the TGF-β1 signaling by ROS generation and MAPK/Akt phosphorylation	Liu et al. [115]
Geastrum saccatum	Solid extract	Fruiting bodies of Geastrum saccatum	β-Glucose	Polysaccharide	Inhibit the NOS and COX	Guerra dore et al. [116]
Ginsenosides	Synthetic compound	Root of ginseng	Ginsenosides	Glycoside	Suppress the IL-4 level, increase the production of IFN-γ, and inhibit the mucus overproduction and recruitment of eosinophils	Chen et al. [117]
Grape seed	Extract	Seeds	Not reported	Not reported	Not elucidated.	Mahmoud [118]
Gymnema sylvestre R. Br.	Extract	Leaves	Not reported	Tanins and saponins	Not elucidated.	Tiwari et al. [119]; Di Fabio et al. [120]
Herba epimedii	Extract	Leaves	Icariin	Flavonoids, iridoid glycosides, and alkaloids	Inhibit the mRNA expression of TGF-β1 and TGF-β2. Modulate the TGF-β signaling	Tang et al. [121]
Higenamine	Isolated compound	Tinospora crispa, Nandina domestica THUNBERG, Gnetum parvifolium C.Y. Cheng, Asarum heterotropoides	1-[(4-Hydroxyphenyl)methyl]-1,2,3,4-tetrahydroisoquinoline-6,7-diol	Alkaloid	Not elucidated	Zhang et al. [122]
Homoegonol	Isolated compound	Styrax japonica	3-[2-(3,4-Dimethoxyphenyl)-7-methoxy-1-benzofuran-5-yl]propan-1-ol	Lignan	Reduces the inflammatory cells count and Th2 cytokines	Shin et al. [123]
Hypericum sampsonii	Isolated compound	Aerial parts	Not reported	Polycyclic polyprenylated acylphloroglucinols	Not elucidated	Zhang et al. [124]
Justicia pectoralis	Extract	Aerial parts	7-Hydroxycoumarin	Coumarin	Decrease the tracheal hyperresponsiveness and the IL-1β and TNF-α levels	Moura et al. [125]
Juniperus excelsa	Crude extract	Aerial parts	(+)-Cedrol, (+)-Sabinene, (+)-limonene, terpinolene, endo-fenchol, cis-pinene hydrate, α-campholena, camphor, borneol, triene cycloheptane 1,3,5-trimethylene, β-myrcene, o-allyl toluene	Anthraquinones, flavonoids, saponins, sterol, terpenoids, and tanins	Inhibit the Ca^2+ influx and the phosphodiesterase activity	Khan et al. [126]
Kaempferol	Isolated compound	Biotransformation of synthetic kaempferol by genetically engineered E. coli	Kaempferol-3-O-rhamnoside	Flavonoid	Reduces the inflammatory cells number, suppresses the production of Th2 cytokines and TNF-α	Chung et al. [127]
Kefir	Isolated compound	Kefir grains	Kefiran	Microorganism derived	Reduces the inflammatory cell number and decreases the level of IL-4, IL-13, IL-5, and IgE	Kwon et al. [128]; Lee et al. [129]
Laurus nobilis L.	Isolated compound	Leaves of Laurus nobilis L	Magnolialide	Sesquiterpene	Inhibit the mast cell degranulation and reduce the IL-4 and IL-5 production	Lee et al. [130]
Lepidium sativum	Crude extract	Seeds	Ascorbic acid, linoleic acid, oleic acid, palmitic acid, stearic acid	Vitamin and fatty acids	Promote a anticholinergic effect, inhibit the Ca^2+ influx, and inhibit the phosphodiesterase activity	Rehman et al. [131]
L-Theanine	Isolated compound	Green tea of Camellia sinensis	L-Theanine (N-ethyl-L-glutamine)	Amino acid	Reduces the ROS production and decreases the levels of NF-κB and MMP-9	Hwang et al. [132]
Luteolin	Isolated compound	Perilla frutescens	(2-(3,4-Dihydroxyphenyl)-5,7-dihydroxy-4-chromenone)	Flavonoid	Inhibits the mucus overproduction and the GABAergic system	Shen et al. [133]
Lysate bacterial (OM-85 Broncho-Vaxom)	Extract	H. influenzae, S. pneumoniae, Klebsiella pneumoniae, smelly nose Klebsiella, S. aureus, Streptococcus pyogenes, Streptococcus viridans, Neisseria catarrhalis	Not reported	Not reported	Increase the level of IL-4, IL-10, and IFN-γ	Lu et al. [134]
Mangifera indica L. extract (Vimang®)	Extract	Stem bark	Mangiferin (1,3,6,7-tetrahydroxyxanthone-c2-b-D-glucoside)	Xanthone	Inhibit the IgE production, the histamine release, and mast cell degranulation. Decrease the MMP-9 activity	Rivera et al. [135]
	Aqueous extract	Barks	Mangiferin (1,3,6,7-tetrahydroxyxanthone-c2-b-D-glucoside)	Xanthone	Reduce the inflammatory cells recruitment and the airway hyperresponsiveness. Increase the Th2 cytokines and attenuated the increase of the PIK3 activity	Alvarez et al. [136]
Mangosteen	Isolated compound	Garcinia mangostana Linn.	α- and γ-mangostin	Xanthone	Inhibits the histamine release and modulates the cytokine production	Jang et al. [137]
Marine bioactives	Isolated compound	Marine sponges Petrosia contignata and Xestospongia bergquisita	Contignasterol and xestobergsterol	Steroids	Upregulation of TNF-β and IL-10 expression	D’Orazio et al. [138]
Marshallagia marshalli	Isolated compound	Marshallagia marshalli	Secretory/excretory antigen	Microorganism derived	Prevent the release of TNF-α and IL-1β. Suppress the neutrophil migration	Jabbari et al. [139]
Mikania laevigata and M. glomerata	Extract	Leaves	Dihydrocoumarin, coumarin, spathulenol, hexadecanoic acid, 9, 12-octadecadienoic acid, 9,12,15-octadecatrineoic acid, cupressenic acid, kaurenol, kaurenoic acid, isopropyloxigrandifloric acid, isobutyloxy-grandifloric acid	Coumarins, terpenoids, steroids, and flavonoids	Not elucidated	Napimoga and Yatsuda [140]
Milk and colostrum	Conjugated compound	Bovine milk	Conjugated linoleic acid	Fatty acid	Modulate the cytokine and antibodies (IgE, IgM) production, interferon NO synthesis and iNOS activity. Modulate the mast cell degranulation	Kanwar et al. [141]
Monoterpenes	Isolated compound	Essential oil of several medicinal plants (Matricaria recutita, Boswellia carterii, Pelargonium graveolens, Lavandula angustifolia, Citrus limon, Melaleuca alternifolia, Melaleuca viridiflora, Santalum spicatum, Cedrus atlantica, and Thymus vulgaris)	Hydroxydihydrocarvone, fenchone, α-pinene, (S)-cis-verbenol, piperitenone oxide, α-terpinene, α-terpineol, terpinen-4-ol, α-carveol, menthone, pulegone, geraniol, citral, citronellol, perillyl alcohol, perillic acid, β-myrcene, carvone, limonene, thymol, carvacrol, linalool, linalyl acetate, borneol, l-borneol, bornyl acetate, terpineol, thymoquinone, thymohydroquinone, 1,8-cineol, l-menthol, menthone, and neomenthol	Terpenoids	Reduce the expression of NF-κB target gene MUC2	Cassia et al. [142]
Mandevilla longiflora	Hydroethanolic extract	Plant xylopodium	Ellagic acid, hesperidin, luteolin, naringin, naringenin, and rutin	Polyphenol and flavonoids	Decrease the eosinophils, neutrophils, and mononuclear cell migration in BALF and by histopathological analysis. Decrease the IL-4, IL-5, IL-13, IgE, and LTB4 levels	Almeida et al. [143]
Morus alba L.	Isolated compound	Root bark	Moracin M. (5-(6-hydroxy-1-benzofuran-2-yl)benzene-1,3-diol)	Not reported	Inhibit the PDE4	Chen et al. [144]
Haemanthus coccineus	Extract	Dried bulbs	Narciclasine	Alkaloid	Inhibit the edema formation, the leucocyte infiltration, and cytokine synthesis in vivo. Block the interaction between the leucocyte and endothelial cells, the activation of isolated leucocytes (cytokine synthesis and proliferation) and of primary endothelial cells (adhesion molecule expression) in vitro. Suppress the NF-κB-dependent gene transcription	Fuchs et al. [145]
Naringin	Isolated compound	Common grapefruit	Naringin	Flavone	Attenuates the bronchoconstriction by reduction of calcium influx	Wang et al. [146]
Nielumbo nucifera	Extract	Leaves	Nuiciferine and aporphine	Alkaloids	Attenuate the bronchoconstriction by reduction of calcium influx	Yang et al. [147]
Nigella sativa	Oil	Seeds	Thymoquinone (2-isopropyl-5-methyl-1,4-benzoquinone)	Quinone	Decrease the NO and IgE levels. Increase the IFN-γ	Salem et al. [148]; Koshak et al. [149]
NujiangexanthoneA	Isolated compound	Leaves of Garcinia nujiangensis	1,2,5,6-Tetrahydroxy-3-methoxy-4,7,8-tri(3-meth-ylbut-2-enyl)-xanthone	Xanthone	Suppresses the IgE/Ag activation and degranulation of mast cell. Suppresses the production of cytokines and eicosanoids, through inhibiting Src kinase activity and Syk-dependent pathways. Inhibits the release of histamine, PGD2 and leukotriene C4 generation. Inhibits the increase of IL-4, IL-5, IL-13, and IgE levels. Inhibits the cell infiltration and increases mucus production	Lu et al. [150]
Oleanolic acid	Synthetic compound	Forsythia viridissima	Oleanolic acid	Triterpenoid	Modulates the transcription factors T-bet, GATA-3, RORγt, and Foxp3	Kim et al. [151]
Omega 3	Isolated compound	Fish oil	n – 3 Polyunsaturated fatty acid	Fatty acid	Decreases the IL-17 and TNF-α levels	Hansen et al. [152]; Farjadian et al. [153]
Organic acids	Isolated compound	Berberis integerrima and B. vulgaris fruits	Malic, citric, tartaric, oxalic, and fumaric acids	Organic acids	Inhibits the Th2 cytokines	Ardestani et al. [154]; Shaik et al. [155]
Oroxylin A	Isolated compound	Scutellariae radix	5′7-Dihydroxy-6-methoxy-2phenyl-4H-1-benzopyran-4-one	Flavonoid	Reduces the airway hyperactivity. Decreases the levels of IL-4, IL-5, IL-13 and IgE in BALF	Lu et al. [156]; Zhou et al. [157]
Oxymatrine	Isolated compound	Root of the Sophora flavescens Aiton (Fabaceae)	Oxymatrine	Alkaloid	Inhibits the eosinophil migration, IL-4, IL-5, IgE, and IL-13 levels. Inhibits the expression of CD40 protein	Zhang et al. [158]
P. integerrima Gall and Pistacia integerrima stew. Ex brand	Methanolic and crude extract	Galls and whole plant	Not reported	Carotenoids, terpenoids, catechins, and flavonoids	Attenuate the TNF-α, IL-4, and IL-5 expression levels, and pulmonary edema by elevation of AQP1 and AQP5 expression levels	Rana et al. [159]; Bibi et al. [160]
Paeonia emodi royle	Extract	Rhizomes	1β, 3β, 5α, 23, 24-Pentahydroxy-30-nor-olean-12, 20(29)-dien-28-oic acid; 6α, 7α-epoxy-1α, 3β, 4β, 13β-tetrahydroxy-24, 30-dinor-olean-20-ene-28, 13β-olide; paeonin B; paeonin C; methyl grevillate; 4-hydroxy benzoic acid, and gallic acid	Terpenoids and phenolic compounds	Inhibits the lipoxygenase activity	Zargar et al. [161]
Petasites japonicus	Extract	Leaves	Petatewalide B	Not reported	Inhibit the degranulation of β-hexosaminidase in mast cells, the iNOS induction, and the NO production. Inhibits the accumulation of eosinophils, macrophages, and lymphocytes in BALF	Choi et al. [162]
Peucedanum praeruptorum dunn	Extract	Roots	Dihydropyranocoumarin, linear furocoumaris, and simple coumarin	Coumarins	Attenuate the airway hyperreactivity and Th2 responses	Xiong et al. [163]
Peucedani Radix	Extract	Roots	Nodakenin, nodakenetin, pteryxin, praeruptorin A, and praeruptorin B	Not reported	Inhibit the Th2 cell activation	Lee et al. [164]
Eryngium	Extract	Leaves, fruits, and roots	A1-barrigenol, R1-barrigenol, tiliroside, kaempferol 3-O-β-D-glucosyde-7-O-α-L-rhamnoside, rutin, agasyllin, grandivittin, aegelinol benzoate, aegelinol, R-(+)-rosmarinic (61), and R-(+)-3′-O-β-D-glucopyranosyl rosmarinic acid	Phenol, flavonoids, tannins, and saponins	Not elucidated	Erdem et al. [165]
Pericampylus glaucus	Extract	Stems, leaves, roots, and fruits	Periglaucine A-D and mangiferonic acid	Alkaloids, terpenoids, isoflavones, and sterols	Inhibit the COX enzymes activity	Shipton et al. [166]
Aquilaria malaccensis	Ethanolic extract	Seeds	Aquimavitalin	Phorbol ester	Inhibit the mast cell degranulation	Korinek et al. [167]
Phytochemicals	Isolated compound	Several medicinal plants	Luteolin, kaempferol, quercetin, eudesmin, magnolin, woorenoside, zerumbone, aucubin, triptolide, nitocine, berberine, and piperine	Flavonoids, lignans, terpenoids, and alkaloids	Suppress the TNF-α expression	Iqbal et al. [168]
Picrasma quassioides (D.Don) Benn	Alcoholic extract	Not reported	4-Methoxy-5- hydroxycanthin-6-one	Alkaloid	Decreases the inflammatory cell count in BALF. Reduces the IL-4, IL-5, IL-13, and IgE levels. Reduces the airway hyperresponsiveness. Attenuates the recruitment of inflammatory cells and the mucus production in the airways. Reduces the overexpression of inducible nitric oxide synthase (iNOS)	Shin et al. [169]
Pinus maritime (Pycnogenol®)	Extract	Barks	Procyanidin	Flavonoid	Decrease the NO production, the inflammatory cell count, and the levels of IL-4, IL-5, IL-13, and IgE in BALF or serum. Reduces the IL-1β and IL-6 levels, the expression of iNOS and MMP-9. Enhances the expression of heme oxygenase (HO)-1. Attenuates the airway inflammation and mucus hypersecretion	Shin et al. [170]
Ping chuan ke li					Not elucidated	Wang et al. [171]
Piperine	Isolated compound	Piper nigrum (black pepper) and Piper longum (long pepper)	Piperine	Alkaloid	Inhibits eosinophil infiltration and airway hyperresponsiveness by suppressing T cell activity and Th2 cytokine production	Chinta et al. [172]
Piperlongumine	Isolated compound	Piper longum	Piperlongumine (5,6-dihydro-1-[(2E)-1-oxo-3-(3,4,5-trimethoxyphenyl)-2-propenyl]-2(1H)-pyridinone)	Alkaloid	Inhibits the activity of inflammatory transcription factors, NF-κB, and signal transducer and activator of transcription (STAT)-3 as well as the expression of IL-6, IL-8, IL-17, IL-23, matrix metallopeptidase (MMP)-9, and intercellular adhesion molecule (ICAM)-1. Suppresses the permeability and leukocyte migration, the production of TNF-α, IL-6, and extracellular regulated kinases (ERK) 1/2 along with the activation of NF-κB	Prasad and Tyagi [173]
Piper nigrum	Ethanolic extract	Not reported	Piperine	Alkaloid	Inhibit the Th2/Th17 responses and mast cell activation	Bui et al. [174]; Khawas et al. [175]
Plectranthus amboinicus (Lour.) spreng.	Ethanol, methanol, and hexane extracts	Aerial parts	Rosmarinic acid, shimobashiric acid, salvianolic acid L, rutin, thymoquinone, and quercetin	Flavonoids	Not elucidated	Arumugam et al. [176]
Podocarpus sensu latissimo	Extract	Barks	3-Methoxyflavones and 3-O-glycosides	Flavonoids	Provinol and flavin-7	Abdillahi et al. [177]
Polyphenols and their compounds	Isolated compound	Provinol and flavin-7	Quercetin and resveratrol	Polyphenol	Decrease IL-4 and IL-5 levels, the airway hyperresponsiveness, and mucus overproduction	Joskova et al. [178]
Propolis	Isolated compound	Honey bees from several plants	Pinocembrin and caffeic acid phenethyl ester	Polyphenol and terpenoids	Inhibits TGF-β1	Kao et al. [179]
Psoralea corylifolia	Extract	Fruits	7-O-Methylcorylifol A, 7-O-isoprenylcorylifol A, and 7-O-isoprenylneobavaisoflavone	Flavonoids	Inhibit the N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP)-induced generation and/or elastase release	Chen et al. [180]
Quercetin	Isolated compound	Tea, fruits and vegetables	2-(3,4-Dihydroxyphenyl)-3,5,7-trihydroxy-4H-chromen-4-one	Flavonoid	Inhibits LOX and PDE4. Reduce leukotrienes and histamine release with a decrease in the IL-4 level. Inhibit prostaglandins release and the human mast cell activation by Ca2^+ influx	Townsend et al. [181]; Mlcek et al. [182]
Radix Rehmanniae Preparata	Extract	Not reported	Catalpol	Glycoside	Inhibit IgE secretion. Decrease IL-4 and IL-5. Inhibit eosinophil infiltration and suppress eotaxin and its receptor CCR3. Reduce IL-5Rα levels	Chen et al. [183]
Resveratrol	Isolated compound	Skin and barks of red fruits	Resveratrol (3,4,5-trihydroxystilbene)	Polyphenol	Decreases eosinophilia. Reduce neutrophil migration and inhibit PGD-2 release. Decrease IL-4 and IL-5 and also the hyperresponsiveness and mucus production	Lee et al. [184]; Hu et al. [185]; Chen et al. [186]
Schisandra chinensis	Extract	Dried fuits	α-Cubebenoate	Not reported	Suppress bronchiolar structural changes. Inhibit the accumulation of lymphocytes, eosinophils, and macrophages in BALF. Suppress IL-4, IL-13, and TGF-β1. Increase the intracellular Ca2^+	Lee et al. [187]
Sea cucumber (Holothurians)	Tonic	Marine animal (Sea cucumber)	Holothurin A3, pervicoside A, and fuscocinerosides A	Toxins	Reduce COX enzymatic activity	Guo et al. [188]
Selaginella uncinata (Desv.)	Extract	Dried herbs	Amentoflavone, hinokiflavone, and isocryptomerin	Flavonoids	Attenuate hyperresponsiveness and goblet cell hyperplasia. Decrease IL-4, IL-5, IL-13, and IgE levels in serum. Upregulation of T2R10 gene expression and downregulation of IP3R1 and Orai1 gene expression. Suppression of eotaxin, NFAT1, and c-Myc protein expression	Yu et al. [189]
Selaginella pulvinata	Isolated compound	Air-dried powder of the whole plant of S. pulvinata	Selaginpulvilin A, selaginpulvilin B, and selaginpulvilin C	Phenol	Inhibit the PDE4	Liu et al. [190]
Sideritis scardica	Extract	Leaves	Echinacoside, verbascoside, luteolin, apigenin, caffeic acid, vanillic acid	Glycosides, flavonoids, and phenolic acids	Not elucidated	Todorova and Trendafilova [191]
Siegesbeckia glabrescens	Extract	Aerial roots	3,40-O-Dimethylquercetin, 3,7-O-dimethylquercetin, 3-O-methylquercetin, and 3,7,40-O-trimethylquercetin	Flavonoids	Reduce inflammatory cell infiltration in BALF. Decrease IL-4, IL-5, IL-13, eotaxin, and IgE. Reduce airway inflammation and mucus overproduction. Decrease iNOS and COX-2 expression and reduce NO levels	Jeon et al. [192]
Sitostanol	Isolated compound	Marketable synthetic compound	Sitostanol	Steroid	Suppresses IL-4 and IL-13 release	Brüll et al. [193]
Soft coral	Isolated compound	Sarcophyton ehrenbergi	Not reported	Prostaglandins	Inhibits PDE4	Cheng et al. [194]
Solanum paniculatum L	Extract	Fruits	Stigmasterol and β-sitosterol	Steroid	Reduce IL-4 and NO levels. Decrease IFN-γ without changes in IL-10 levels. Reduce NF-κB, TBET, and GATA3 gene expression	Rios et al. [195]
Squill (Drimia maritima (L.) stearn) oxymel	Crude extract	Not reported	Scillaren A, scillirubroside, scilliroside, scillarenin, and proscillaridin A	Glycosides	Not elucidated	Nejatbakhsh et al. [196]
Sorbus commixta Hedl. (Rosaceae)	Methanolic extract	Fruits	Neosakuranin	Glycosides	Not elucidated	Bhatt et al. [197]
Thuja orientalis	Extract	Fruits	Cupressuflavone, amentoflavone, robustaflavone, afzelin, (+)-catechin, quercetin, hypolaetin 7-O-β-xylopyranoside, isoquercitrin, and myricitrin	Flavonoids	Reduce nitric oxide production and reduce the relative mRNA expression levels of inducible nitric oxide synthase (iNOS), IL6, cyclooxygenase-2, MMP-9, TNF-α in vitro. Decrease the inflammatory cell counts in BALF. Reduce IL-4, IL-5, IL-13, eotaxin, and IgE levels and reduce the airway hyperresponsiveness, in vivo. Attenuate mucus hypersecretion	Shin et al. [198]
Tonggyu-tang	Extract	Ledebouriella divaricata Hiroe, Angelica koreanum Kitagawa, Angelica tenuissima Nakai, Cimicifuga heracleifolia Kom., Pueraria thunbergiana Benth., Ligusticum wallichii var. officinale Yook., Atractylodes lancea DC., Thuja orientalisl., Ephedra sinica Stapf., Zanthoxylum schinifolium S.Z., Asarum sieboldii var. seoulense Nakai, Glycyrrhiza glabra, Astragalus membranaceus var. mongholicus Bung, Xanthium strumarium L., Magnolia denudate Desr., Mentha arvensis var. piperascens Makinv	Not reported	Plant	Inhibit inflammatory cytokines (IL-4, IL-6, IL-8, and TNF-α). Suppress mitogen activated protein kinase (MAPK) and NF-κB in mast cells and keratinocytes	Kim et al. [199]
Trigonella foenum-graecum	Extract	Seeds	Not reported	Flavonoids	Reduce IL-5, IL-6, IL-1β, and TNF-α. Reduce collagen deposition in goblet cells. Suppress inflammatory cells	Piao et al. [200]
Tropidurus hispidus	Oil	Fat of tropidurus hispidus	Croton oil, arachidonic acid, phenol, and capsaicin	Fatty acids and its derivated	Affect the arachidonic acid and their metabolites and reduce proinflammatory mediators	Santos et al. [201]
Urtica dioica L.	Extract	Leaves	Caffeic acid, gallic acid, quercetin, scopoletin, carotenoids, secoisolariciresinol, and anthocyanidins	Polyphenols, flavonoids, cumarin, and lignan	Reduce leucocytes and lymphocytes levels in serum. Inhibit the eosinophilia increase in BALF. Suppress inflammatory cells recruitment and attenuation of lipid peroxidation of lung tissues	Zemmouri et al. [202]
Verproside	Isolated compound	Pseudolysimachion	Verproside	Glycoside	Suppress the NF-κB and TNF-α expression	Lee et al. [203]
Vitamin D	Isolated compound	Not reported	Calcitriol	Vitamin	Inhibit lymphocytes (Th1 and Th2) and reduces cytokines production	Szekely and Pataki [204]
Vitamin E	Isolated compound	Plant lipids	α-, β-, γ-, and δ-Tocopherols and the α-, β-, γ-, and δ-tocotrienols	Vitamin	Reduce airway hyperresponsiveness, IL-4, IL-5, IL-13, OVA-specific IgE, eotaxin, TGF-β, 12/15-LOX, lipid peroxidation, and lung nitric oxide metabolites	Cook-Mills and McCary [205]; Abdala-Valencia et al. [206]
Vitex rotundifolia linn til (Verbenaceae)	Methanolic extract	Fruits	1H, 8H-Pyrano [3, 4-c]pyran-1,8-dione	Not reported	Inhibit eotaxin, IL-8, IL-16, and VCAM-1 mRNA	Lee et al. [207]
Viticis fructus	Extract	Dried fruit	Pyranopyran-1,8-dione	Not reported	Inhibit eosinophils and lymphocytes cell infiltration into the BAL fluid. Reduce to normal levels of IL-4, IL-5, IL-13 and eotaxin. Suppress IgE levels	Park et al. [208]
Yu ping feng san	Extract	Radix Saposhnikoviae (Fangfeng), Radix Astragali (Huangqi), and Rhizoma Atractylodis macrocephalae (Baizhu)	Calycosin-7-O-β-d-glucoside, calycosin, formonetin, atractylenolide III, II, and I; 5-O-methylvisammioside, 8-methoxypsoralen and bergapten	Flavonoids, terpenoids, saponins, and furocoumarins	Inhibit TNF-α, IFN-γ, and IL-1β	Stefanie et al. [209]
Zygophyllum simplex L	Extract	Aerial parts	Isorhamnetin-3-O-β-D-rutinoside, myricitrin, luteolin-7- O-β-D-glucoside, isorhamnetin-3-O-β-D-glucoside, and isorhamnetin	Phenol	Inhibit NF-κB, TNF-α, IL-1β, and IL-6	Abdallah and Esmat [210]
Ziziphus amole	Extract	Leaves, stems, barks, and roots	Alphitolic acid, sitosterol, ziziphus-lanostan-18-oico acid	Terpenoid and steroid	Inhibit myeloperoxidase activity	Romero-Castillo et al. [211]