Therapeutic Efficacy of Flavonoids in Allergies: A Systematic Review of Randomized Controlled Trials

Table 1

Baseline characteristics of the randomized controlled trials included in the systematic review.

Author, year	Country	Study design	Sample size (interv./placebo)	Sex (♂/♀)	Range age (mean years)	Allergic disease	Intervention	Dose/day	Study duration (wk)
Lau et al., 2004	USA	Parallel	28/26	NA	6-18 (14)	Asthma	Pycnogenol®	105 mg	13 wk
Kishi et al., 2005	Japan	Parallel	18/18	36/0	20-64 (NA)	Cedar pollinosis	Apple polyphenol	500 mg	12 wk
Enomoto et al., 2006	Japan	Parallel	22/11	9/24	15-65 (35)	Allergic rhinitis	Apple polyphenol	50 mg; 200 mg	4 wk
Yoshimura et al., 2007	Japan	Parallel	17/16	14/19	18-56 (35)	Allergic rhinitis	Tomato extract	360 mg	8 wk
Watson et al., 2008	Iran	Parallel	22/21	16/27	18-60 (36)	Asthma	Purple passion fruit peel extract	150 mg	4 wk
Corren et al., 2008	USA	Crossover	16	NA	18-65 (38)	Allergic rhinitis	ClearGuard™	1350 mg	3 d
Kawai et al., 2009	Japan	Parallel	10/10	16/4	NA (39)	Cedar pollinosis	Enzymatically modified isoquercitrin	100 mg	8 wk
Hirano et al., 2009	Japan	Parallel	12/12	19/5	NA (36)	Cedar pollinosis	Enzymatically modified isoquercitrin	100 mg	8 wk
Wilson et al., 2010	Canada	Parallel	30/30	21/39	18-65 (44)	Allergic rhinitis	Pycnogenol®	100 mg	3-8 wk
Bakhshaee et al., 2011	Iran	Parallel	30/30	23/37	NA (29)	Allergic rhinitis	Silymarin	420 mg	4.3 wk
Smith et al., 2015	USA	Parallel	193/193	132/254	17-49 (34)	Asthma	Soy isoflavone	100 mg	24 wk
Mehrbani et al., 2015	Iran	Parallel	24/18	6/36	NA (28)	Atopic dermatitis	Whey+dodder seed extract	2000 mg	4.28 wk
Patrizi et al., 2016	Italy	Parallel	20/19	13/26	6-69 (27)	Atopic dermatitis	Vitamin E, EGCG, and grape seed procyanidins (MD2011001)	NA	4 wk
Marseglia et al., 2019	Italy	Parallel	64/64	NA	6-12 (9)	Allergic rhinitis	Lertal®	150 mg	4-12 wk
Arpornchayanon et al., 2019	Thailand	Parallel	8/8	5/11	18-65 (43)	Allergic rhinitis	Shallot extract	3 g	4 wk

Abbreviations: wk: week; d: day; NA: not available or unclear; USA: United States of America; ♂: male; ♀: female; PEF: peak expiratory flow; Pycnogenol®: mixture of water-soluble bioflavonoids extracted from the bark of French maritime pine (Pinus pinaster Aiton); ClearGuard™ combination botanical product: cinnamon (Cinnamomum zeylanicum) bark extract, acerola (Malpighia glabra) fruit concentrate, and Spanish needles (Bidens pilosa); EGCG: epigallocatechin gallate; Lertal®: quercetin 150 mg, Perilla frutescens 80 mg (as dry extract of the seeds containing rosmarinic acid, luteolin, apigenin, and chrysoeriol), and vitamin D3 5 mcg (200 IU). Dose considering the average weight of a teen (47.6 kg).