The effect of Ginkgo biloba on the activity of catalase and lipid peroxidation in experimental strangulation ileus

Neuroprotective and Antioxidant Effect of Ginkgo biloba Extract Against AD and Other Neurological Disorders

Alzheimer's disease (AD) is the most common progressive human neurodegenerative disorder affecting elderly population worldwide. Hence, prevention of AD has been a priority of AD research worldwide. Based on understanding of disease mechanism, different therapeutic strategies involving synthetic and herbal approaches are being used against AD. Among the herbal extract, Ginkgo biloba extract (GBE) is one of the most investigated herbal remedy for cognitive disorders and Alzheimer's disease (AD). Standardized extract of Ginkgo biloba is a popular dietary supplement taken by the elderly population to improve memory and age-related loss of cognitive function. Nevertheless, its efficacy in the prevention and treatment of dementia remains controversial. Specifically, the added effects of GBE in subjects already receiving "conventional" anti-dementia treatments have been to date very scarcely investigated. This review summarizes recent advancements in our understanding of the potential use of Ginkgo biloba extract in the prevention of AD including its antioxidant property. A better understanding of the mechanisms of action of GBE against AD will be important for designing therapeutic strategies, for basic understanding of the underlying neurodegenerative processes, and for a better understanding of the effectiveness and complexity of this herbal medicine.

Ginkgo extract EGb 761(®) shields from slowly accumulating neurodegenerative-like changes in a newly developed cell culture model induced by the combined action of low doses of antimycin A1 and 2-deoxy-D-glucose

Different cell culture models were already used to analyze the molecular base of the neuroprotective activities of the Ginkgo biloba extract EGb 761(®) after a single or short-term application. In these previous studies cells were severely injured with agents that promptly induce fatal cellular damage, like vast oxidative stress or mitochondrial dysfunction, and the protective effects of EGb 761(®) on such acute damage were evaluated. Our present study aimed to test EGb 761(®) action in cell cultures, where cellular functions are only moderately impaired by a longer lasting, but relatively modest oxidative stress, reduction of mitochondrial function and reduced intracellular energy levels, thereby causing only slow occurence of cellular damage over a time period of 2 weeks. To this end we used neuroblastoma cells (SK-N-MC) that were treated with low doses of a combination of antimycin A1 and 2-deoxy-D: -glucose. Addition of EGb 761(®) to the culture medium efficiently shielded the cells from progressing injury by reduced ATP-levels, oxidized redox state, lipid peroxidation damage and oxidative damage of mitochondrial DNA. As a result the cells were protected from apoptotic death that was observed in cultures without EGb 761(®) after 2 weeks of damage occurence. This cell culture system characterizing moderate cellular stress will be applied in future studies to further investigate the mode of action of single EGb 761(®) compounds.

Ginkgo biloba extract in Alzheimer's disease: from action mechanisms to medical practice

Standardized extract from the leaves of the Ginkgo biloba tree, labeled EGb761, is one of the most popular herbal supplements. Numerous preclinical studies have shown the neuroprotective effects of EGb761 and support the notion that it may be effective in the treatment and prevention of neurodegenerative disorders such as Alzheimer’s disease (AD). Despite the preclinical promise, the clinical efficacy of this drug remains elusive. In this review, possible mechanisms underlying neuroprotective actions of EGb761 are described in detail, together with a brief discussion of the problem of studying this herb clinically to verify its efficacy in the treatment and prevention of AD. Moreover, various parameters e.g., the dosage and the permeability of the blood brain barrier (BBB), impacting the outcome of the clinical effectiveness of the extract are also discussed. Overall, the findings summarized in this review suggest that, a better understanding of the neuroprotective mechanisms of EGb761 may contribute to better understanding of the effectiveness and complexity of this herb and may also be helpful for design of therapeutic strategies in future clinical practice. Therefore, in future clinical studies, different factors that could interfere with the effect of EGb761 should be considered.