Use of the antioxidant supplement Pycnogenol® to treat a variety of chronic disorders

Pycnogenol® is a herbal dietary supplement extracted from French maritime pine bark whose main ingredient is procyanidin. Procyanidin is a powerful antioxidant also found in food such as grapes, berries, pomegranates, red wine and various nuts. Supplements containing procyanidin are widely marketed worldwide for the promotion of health, and for the prevention and treatment of chronic disorders. The rationale for this is that antioxidants neutralise reactive oxygen species (ROS; frequently referred to as "free radicals") which, apart from performing important bodily functions, can cause damage to cells and tissues if present in excessive amounts. Available supplements vary in the source and quantity of procyanidin, as well as in number and type of other ingredients they contain. We chose to focus on Pycnogenol® as this supplement is a standardised product, many trials have been conducted, and it is extensively marketed internationally. Our review aimed to assess the efficacy and safety of Pycnogenol® as a treatment for chronic disorders. We identified 15 eligible randomised controlled trials with a total of 791 participants which addressed seven different chronic conditions: asthma (two studies); attention deficit hyperactivity disorder (one study), chronic venous insufficiency (two studies), diabetes (four studies), erectile dysfunction (one study), hypertension (two studies) and osteoarthritis (three studies). Due to small sample size, limited number of trials per condition, variation in outcomes evaluated and outcome measures used, as well as the risk of bias in the included studies, no definite conclusions regarding the efficacy and safety of Pycnogenol® are possible.

Authors' conclusions: 

Current evidence is insufficient to support Pycnogenol® use for the treatment of any chronic disorder. Well-designed, adequately powered trials are needed to establish the value of this treatment.

Read the full abstract...
Background: 

Oxidative stress has been implicated in the development of a number of conditions including cancer, arthritic disorders and cardiovascular disease. Pycnogenol®, a herbal dietary supplement derived from French maritime pine bark extract, is standardised to contain 70% procyanidin which is a powerful antioxidant. Pycnogenol® is marketed as a supplement for preventing or treating a wide range of chronic conditions.

Objectives: 

To assess the efficacy and safety of Pycnogenol® for the treatment of chronic disorders.

Search strategy: 

We searched CENTRAL (until 18 September 2010), MEDLINE (until 18 September 2010) and EMBASE (until 13 October 2010) as well as three trial registries. We also contacted the manufacturer of Pycnogenol® and hand-searched bibliographies of included studies.

Selection criteria: 

Randomised controlled trials evaluating the effectiveness of Pycnogenol® in adults or children with any chronic disorder were included. We assessed clinical outcomes directly related to the disorder (stratified as participant- and investigator-reported) and all-cause mortality as primary outcomes. We also assessed adverse events and biomarkers of oxidative stress.

Data collection and analysis: 

Two authors independently assessed trial eligibility, extracted all data and assessed risk of bias. A third author additionally extracted information on outcomes and results. With three exceptions, results for outcomes across studies could not be pooled.

Main results: 

This review includes 15 trials with a total of 791 participants that have evaluated Pycnogenol® for the treatment of seven different chronic disorders. These included asthma (two studies; N = 86), attention deficit hyperactivity disorder (one study; N = 61), chronic venous insufficiency (two studies; N = 60), diabetes mellitus (four studies; N = 201), erectile dysfunction (one study; N = 21), hypertension (two studies; N = 69) and osteoarthritis (three studies; N = 293). Two of the studies were conducted exclusively in children; the others involved adults.

Due to small sample size, limited numbers of trials per condition, variation in outcomes evaluated and outcome measures used, as well as the risk of bias in the included studies, no definitive conclusions regarding the efficacy or safety of Pycnogenol® are possible.