Allergic rhinitis, also known as hay fever, is an inflammatory disorder of the nasal mucosa that affects more than 400 million people worldwide, with a high prevalence in industrialized nations.1 Approximately 80% of individuals with a diagnosis of allergic rhinitis develop symptoms before the age of 20 years.2 Allergic rhinitis occurs when an allergen, such as pollen, is inhaled by an individual with a sensitized immune system. In sensitized individuals, the allergen initiates a cascade of events that lead to the production of the allergic antibody immunoglobulin E (IgE), which binds to mast cells and basophils that result in the release of histamine and other mediators of the allergic reaction. Common symptoms include sneezing, pruritus, rhinorrhea, and nasal congestion-hypersensitivity responses to indoor and outdoor environmental allergens, which are similar to those symptoms found in allergic asthma.3,4 Upon initial exposure to an allergen, symptoms of allergic rhinitis occur within minutes and can remain for 1 to 2 hours before noticeable improvement. Late-phase nasal symptoms may include nasal obstruction, postnasal mucous discharge, hyposmia, and nasal hyperreactivity.3
Pycnogenol provides potent antioxidant and anti-inflammatory properties.16
Epidemiologic studies indicate that allergic rhinitis is part of a systemic inflammatory process and is associated with other inflammatory diseases affecting respiratory mucous membranes such as asthma, allergic conjunctivitis, and rhinosinusitis. Allergic conjunctivitis occurs in 50% to 70% of individuals with allergic rhinitis, is characterized by intense eye itching, watering, and, occasionally, periorbital edema, and is a symptom that differentiates allergic rhinitis from other forms rhinitis.4
Although allergic rhinitis is commonly regarded as a seasonal disorder, it can involve persistent inflammation of mucosa, which synergizes with infective inflammation that precipitates viral colds in those individuals with allergic rhinitis.5,6 The combination of rhinoviral infection, allergic sensitization, and allergen exposure increases the rate for hospital admission of children for asthma.7 Evidence has repeatedly and consistently shown the coexistence of rhinitis and asthma, since most individuals with allergic and nonallergic asthma have rhinitis.1 This association is of critical importance for early diagnosis and preventive measures through the avoidance of high-risk factors known to stimulate allergic rhinitis such as cyclic pollens or year-round allergens that include specific foods, animal dander, and molds.
Further evidence supports a link between sinus disease and allergic rhinitis. It has been found that 25% to 30% of individuals with a diagnosis of acute sinusitis have allergic rhinitis, whereas 40% to 60% of those with unilateral chronic sinusitis and up to 80% of individuals with chronic bilateral sinusitis have coexisting allergic rhinitis.8 Acute nasal inflammation caused by allergic rhinitis predisposes to sinusitis, resulting in nasal congestion and obstruction of sinus ostia. A decrease in sinus ventilation leads to ciliary dysfunction, discharge of fluids, and stagnation of mucus, culminating in the promotion of bacterial pathogens.8-10
Although allergic rhinitis is considered a common disorder, it is clearly evident that it holds significant clinical relevance because it underlies numerous complications, has the potential to negatively impact an individual's quality of life, as well as productivity in both work and school environments,11,12 and is a major risk factor for asthma.13 The guiding principle for management of allergic rhinitis is reducing exposure to allergens and the incorporation of therapeutic agents that are safe and effective in ameliorating associated symptoms. Although pharmaceutical drugs are the mainstay treatment of allergic rhinitis within conventional medicine, they are not without side effects. For those individuals who seek a safe and effective natural approach to addressing allergic rhinitis, a proprietary extract of French maritime pine bark (Pycnogenol) has been shown to improve symptoms associated with allergic rhinitis.
PHYTOMEDICINE PROFILE
French maritime pine (Pycnogenol)
Pycnogenol is the registered trade name for a special standardized extract from the bark of the French maritime pine (Pinus pinaster Ait. subsp atlantica L. [Fam. Pinacea]). It is cultivated in large monocultures in southwestern France and is distinguished from other species by its thick, deeply fissured, reddish bark that represents a characteristic adaptation to a harsh climate and sandy soil. The traditional use of pine bark was in the treatment of scurvy and wound healing.14 Currently, Pycnogenol is used to restore capillary integrity in cases of retinopathy, or edema formation.
Phytochemistry
Pycnogenol represents a concentrate of phenolic compounds, consisting of flavonoids, including the bioflavonoids catechin and taxifolin, as well as phenol-carbonic acids.15 The primary constituents of Pycnogenol are procyanidins, biopolymers consisting of catechin and epicatechin subunits.
Pycnogenol extract is prepared from fresh crushed bark. The patented extraction process uses ethanol and water as the menstruum in a multistep chemical extraction procedure. The purified aqueous extract is then spray dried into a fine, brownish powder with an aromatic scent and astringent taste. It requires 1000 kg of bark to produce 1 kg of Pycnogenol. The standardized extract, Pycnogenol, which corresponds to the "maritime pine extract" of the National Formulary of the US Pharmacopoeia in terms of identity and purity. The content of Pycnogenol procyanidins is between 65% and 75% and is quantified colorimetrically.
Phytopharmacology
Antioxidant and anti-inflammatory activities
Pycnogenol has potent antioxidant and anti-inflammatory activity. Studies have shown that Pycnogenol can scavenge both superoxide anions and hydroxyl radicals.16 The active constituents of Pycnogenol can increase both the antioxidant function of vitamin C and the activity of other internal antioxidant systems such as superoxide dismutase and glutathione peroxidase.17,18 Pycnogenol has also been shown to inhibit the process of inflammation by inhibiting nitric oxide synthase, which leads to excess nitric oxide production. Furthermore, Pycnogenol is known to inhibit expression of proinflammatory cytokine IL-1.19 In addition to Pycnogenol's potent antioxidant and anti-inflammatory actions, it improves endothelial function (produces vasodilation), reduces platelet aggregation, and promotes wound healing.
RESEARCH IN REVIEW
Wilson D, Evans M, Gutherie N, et al. A randomized, double-blind, placebo-controlled exploratory study to evaluate the potential of Pycnogenol for improving allergic rhinitis symptoms. Phyto Res. 2010;24(8):1115-1119.20
OBJECTIVE
This single-center, randomized, double-blind, placebo-controlled study assessed the effectiveness of a standardized extract of French maritime pine bark (Pinus pinaster Ait.) for improving the symptoms associated with allergic rhinitis in adults allergic to birch pollen.
PHYTOMEDICINE TEST AGENT
The test agent consisted of a proprietary extract of French maritime pine bark (Pinus pinaster Ait. subsp atlantica), trade name Pycnogenol, http://www.pycnogenol.com (United States); Pycnogenol, patented powdered bark extract, Horphag Research, Geneva, Switzerland.
STUDY DESIGN
This randomized, double-blind, placebo-controlled exploratory study took place at a single center and involved 39 healthy patients (n = 39), male and female, with an age distribution between 18 and 65 years. Appropriate screening, anthropologic measurements, blood tests, physical examination, and a skin test for birch pollen (Betula spp) allergy confirmation were conducted. Skin prick tests for other tree pollen, such as oak (Quercus spp), Maple (Acer spp), Elm (Ulmus spp), etc, were determined as negative to rule out crossover allergens. All patients met the inclusion and exclusion criteria.
Procedure
Patients (n = 39) were randomized into 2 groups, the Pycnogenol test group (n = 19) (Manhattan Drug Company, Hillside, New Jersey) or the placebo group (n = 20). Subjects in each respective group were supplied with either 50.0 mg of Pycnogenol tablets or 50.0 mg of placebo tablets and instructed to take a total of 2 tablets per day, 1 tablet in the morning and 1 tablet in the evening with meals. It was hypothesized that a lag time between the start of Pycnogenol treatment and the onset of action may be required on the basis of a previously held exploratory study. Therefore, patients (n = 39) were randomized at baseline, with treatment administration 5 to 8 weeks prior to the onset of the (birch) pollen season. Blood samples were collected at 5 screenings, at 2- to 4-week intervals, to measure the total IgE and birch pollen IgE determination.
Study subjects were instructed to evaluate nasal symptoms (sneezing, congestion, nasal discharge, pruritus) and eye symptoms (eye itching, watery or tearing eyes, redness) through a self-assessment questionnaire each day and to record these observations in a treatment journal. All nasal and eye symptoms were scored with values ranging from 0 to 3, with 0 indicating absence of symptoms, 1 as mild (with tolerated symptoms), 2 as moderate (with symptoms that impaired life activities), and 3 indicating severe symptoms that prevented normal activity. The local pollen forecast was recorded daily for the duration of the study.
Comparative changes in nasal and eye symptom assessment scores between the Pycnogenol and placebo groups underwent a statistical evaluation using analysis of variance and unpaired t tests. Comparisons of frequencies were applied using the [chi]2 test. Comparisons of birch pollen IgE between groups were made using unpaired t tests and analysis of covariance. Probability values less than .05 were considered to be statistically significant.
SUMMARY OF RESULTS
The total average nasal symptom score for the allergy season was lower in the Pycnogenol group (n = 19; 0.31 +/- 0.30) than in the placebo group (n = 20; 0.39 +/- 0.33). The corresponding average total eye symptom score was lower in the Pycnogenol group (0.13 +/- 0.18) than in the placebo group (0.20 +/- 0.21); however, the results did not reach statistical significance. There was no significant difference between groups in the number of adverse events. In conclusion, this preliminary study demonstrated that the Pycnogenol test agent has the ability to decrease both nasal and ocular symptoms in patients with allergic rhinitis with sensitivity toward birch tree pollen allergens.
AUTHOR COMMENTS
Although the results of this study did not meet statistical significance due, in part, to limitations in sample size, further studies are warranted that will include a larger patient population, with a more refined inclusion criteria, and standardization of study guidelines.
REFERENCES