The standardised G115 Panax ginseng C.A. Meyer extract: a review of its properties and usage

Ginseng (Panax ginseng C.A. Meyer, ginseng) has been the most precious and renowned tonic drug in traditional Chinese medicine. Although the original discovery of its therapeutic efficacy has been lost in antiquity, believers in ginseng as a panacea have sought, cultivated, preserved and extracted its essences for the treatment of a wide range of ailments. Many patients have used aqueous and alcoholic extracts of ginseng during convalescence, particularly where previous health problem(s) resulted in some degree of debilitation, and a corresponding deficit in mental, physical or other functional capacities. An impressive body of information has been accumulated and scientific research has documented and reviewed the useful effects of P. ginseng C.A. Meyer. The high variability in composition of the marketed products clearly affects the results of clinical studies. The availability of the standardised ginseng extract G115® has made it possible to generate reproducible results in animal studies and human clinical research. Active constituents found in most ginseng species include ginsenosides, polysaccharides, peptides, polyacetylenic alcohols, fatty acids and trace elements. It is generally believed that ginsenosides and their metabolites are the most important components determining the pharmacological effects of ginseng. Ginsenosides are triterpene saponins of the dammaran series. They are divided into three groups, classified according to their chemical structures: 20(S)-protopanaxadiols, 20(S)-protopanaxatriols and the RO ginsenosides. The variability in the pharmacological activities of the various ginseng species may be related to the different composition of proportions of ginsenosides. One of the most common standardised extracts, used in many studies, is G115®, which contains 4% ginsenosides. In view of the wide variations, both qualitative and quantitative, standardisation must control the total amount of ginsenosides. Several clinical studies have been conducted with the standardised P. ginseng extract G115®. Here we briefly review only double-blind, placebo-controlled trials that are judged to be of scientific relevance for the clinical profile of the product. The efficacy of G115® on physical performance still needs to be confirmed in Good Clinical Practice (GCP) settings. Several clinical studies with ginseng have not shown any significant effect on the enhancement of physical performance. The ability of G115® to increase endurance and vitality, on the other hand, has been demonstrated in a number of non-GCP studies. The efficacy of G115® in relieving menopausal symptoms is supported by two studies, one of GCP quality. Efficacy in improving cognitive function has been extensively reviewed. Intake of G115® in acute and multiple doses is associated with improvements in cognitive function. A series of studies has assessed the effects of G115® in various volunteer populations using a widely validated and highly sensitive computerised cognitive test system, the Cognitive Drug Research (CDR) assessment system. Several preclinical studies have indicated that G115® may have immunomodulatory properties. These findings have been confirmed in two clinical studies. The efficacy and safety of G115® for potentiating vaccination against the common cold and/or influenza syndrome in a randomised, double-blind, placebo-controlled, parallel-group, multicentre study were determined. Moreover, the effects of G115® in reducing the bacterial count in the bronchial system of patients undergoing an acute attack of chronic bronchitis has been investigated in an open pilot study. The safety profile of G115® has been well established both from clinical studies in healthy volunteers and patients and from its use for over 30 years as a marketed medicinal product in many countries worldwide. Few clinical studies on G115® report adverse effects. In general, the lack of reported adverse effects suggests that they are few, and those present are very minor. On the other hand, a baseline level of adverse effects should be expected and is always present, even for placebo groups in clinical trials. A total of 1075 subjects have been treated with G115® to date in clinical trials. Seventy-one subjects experienced minor adverse effects but no serious events were reported. The most commonly reported adverse events were headache, itching, sore throat, skin rash, dry mouth, acne and diarrhoea, with no difference between placebo and G115®. In all trials, no changes in safety laboratory parameters were seen.