Table 2.

Clinical studies on the use of polyphenols against respiratory diseases.

Polyphenols	Diseases	Model/Method	Outcomes	Ref.
CYSTUS052	Upper respiratory tract infection (Bacterial infection and influenza)	A randomized, placebo-controlled clinical study with 160 patients, including 56 men and 104 women aged between 7 and 81 years, suffered from an upper respiratory tract infection by medical signs. Throat Swabs were collected and placed in an appropriate bacterial culture medium to determine the infection's pathogen	129 patients finished the study out of 160 participants After four days of treatment, a significant decrease in the symptoms with inflammatory markers, including CRP and FVIII, was seen	148
Gallic acid, Catechin, Epigallocatechin gallate; Epicatechin; Epicatechin gallate	Common cold	A prospective, randomized, placebo-controlled, double-blinded, multi-centric clinical study with 100 patients (age 20 -65 years): Patients were told to intake 2 to 250 mL of the test beverage or placebo beverage twice per day for ten days	41.9 percent of patients receiving test beverages reported being complaint-free on the evening of research day 7, compared to 5 percent of patients in the placebo group	180
Quercetin	Lung cancer	A case-control study with a large population (EAGLE) was conducted in Italy. An investigation was done with 1822 incident lung cancer cases and 1991 frequency-matched controls from the Environment and Genetics in Lung cancer Etiology study.	Consumption of combination fruits and vegetables, alone fruits, and only vegetables were related to a 30, 21, and 24% decreased risk of lung cancer, respectively, in a large population-based case-control research from Northern Italy. A diet high in quercetin-rich foods was associated with a 53% decreased incidence of lung cancer. Women and men, ever smokers, showed the inverse association with quercetin-rich diets, which were highest among the heaviest smokers	9
Quercetin and Naringin	Lung cancer	Five hundred eighty-two individuals with incident lung cancer were subjected to a population-based, case-control study. Patients were diagnosed with primary lung cancer at all major medical centers of the study region between January 1, 1992, and January 1, 1997	Inverse associations between lung cancer and polyphenol food sources were shown to be statistically significant, with a 40%-50% decreased risk of lung cancer, with the patients having the highest intake of polyphenols compared with the lowest category.	162
Resveratrol and genistein	COPD	Lymphocytes were extracted for NF‑κB immunocytochemical staining and analysis of TNF‑α and MMP‑9 concentration levels from 30 healthy people and 34 COPD patients, then placed into four study groups with dexamethasone, resveratrol, and genistein.	The translocation of NF‑κB was inhibited by resveratrol and genistein, and they also reduced TNF‑α and MMP‑9 concentration levels.	58
Naringenin	Bronchial pneumonia in children	One hundred eighty patients were randomly allocated to one of two groups: naringenin (NAR) and azithromycin (AZI). During the clinical intervention, all individuals were advised to follow a five-day oral dosing protocol, and their blood cytokine levels were analyzed.	Naringenin was able to minimize the frequencies of bronchial pneumonia complications and related adverse responses, as well as enhance the health of the patients, by inhibiting inflammation and shortening the time it took for clinical signs to vanish.	189
Cranberry polyphenols	Colds and influenza	A randomized, double-blinded, placebo-controlled intervention study to see if cranberry polyphenols might affect immunity, particularly γδ -T cell proliferation. For this purpose, a total number of 54 healthy individuals, including 17 men and 37 women, aged between 21 to 50 years old and with BMI between 18 to 30 kg/m^2, were studied. 45 subjects (83%) out of 54 completed the study	After ten weeks of cranberry beverage intake, the levels of γδ-T cell proliferation were nearly five times higher, with reducing number of symptoms related to colds and influenza.	179
Catechin	Influenza	A study with 124 individuals (age limit- at least 65 years) was conducted in which 76 out of 124 subjects, including 24 men and 52 women, gargled with tea catechin extract, whereas 48 subjects gargled without tea catechin extracts and were divided into catechin group and control group consecutively.	The incidence of influenza infection decreased significantly from 1.3 percent in the catechin group to 10 percent in the control group.	150
Theanine and green Tea catechins.	Influenza	During a 5-month randomized, placebo-controlled, double-blinded experiment of 200 healthcare professionals, 98 were given green tea and theanine capsules, and 99 were given a placebo	When compared to the placebo group, the catechin/theanine group had a significantly lower incidence of both clinically and laboratory-confirmed influenza infection	149
Carvacrol	Asthma	Forty individuals with mild to severe asthma for two months	Improvements in respiratory symptoms and PFT readings were seen as a consequence of the study	199
Pomegranate juice (Ellagitannins)	COPD	30 patients for five weeks	Adding pomegranate juice to existing COPD treatment does not improve outcomes	200
EGCG, EGC, ECG, EC, and catechin gallate	Influenza infection	76 adult persons for three months	They had a reduced rate of influenza infection in the catechin-treated group compared to the control group	150
EGCG	Esophagus Cancer	51 patients	EGCG solution may be effective in treating ARIE in esophageal cancer patients receiving radiation therapy, potentially acting as an ARIE-reliever without compromising radiation therapy efficacy.	163