Age-related changes in the vasodilating actions of Ginkgo biloba extract and its main constituent, bilobalide, in rat aorta

Cardiovascular Activity of Ginkgo biloba-An Insight from Healthy Subjects

Ginkgo biloba is the oldest living tree species in the world. Despite less than encouraging clinical results, extracts from its leaves are among the most used herbal preparations in the prevention and treatment of cardiovascular diseases. Most data on the efficacy of Ginkgo biloba on cardiovascular disease is from clinical studies, with few results from healthy subjects. This paper aims to provide a comprehensive review of the mechanisms underlying the known beneficial cardiovascular activities of Ginkgo biloba. It displays myocardial suppressant and vasorelaxant activities ex vivo, potentiating endothelial-dependent and -independent pathways. It improves perfusion in different vascular beds, namely ocular, cochlear, cutaneous, cerebral, and coronary. Although scarce, evidence suggests that Ginkgo biloba displays a heterogeneous effect on tissue perfusion which is dependent on the individual elimination pathways. It displays an acceptable safety profile, with most reported adverse reactions constituting rare occurrences. Collectively, Ginkgo biloba positively impacts cardiovascular physiology, improving hemodynamics and organ perfusion. In the future, better controlled clinical studies should be performed in order to identify the target populations who may benefit the most from pharmacotherapeutic interventions involving Ginkgo biloba.

New Insight into the Mechanisms of Ginkgo Biloba Extract in Vascular Aging Prevention

BACKGROUND

Aging-associated vascular dysfunction promotes cardiovascular diseases. Recently, Ginkgo biloba extract (GBE) has attracted considerable attention in the prevention of aged vasculature.

METHODS

This review discusses the pathophysiological alterations in aged vasculature and the underlying mechanisms of GBE in vascular aging suppression.

RESULTS

Both arterial stiffening and endothelial dysfunction are critical aging-related vascular phenotypes that result in the progression of cardiovascular diseases in the general population. Consistent oxidative stress and inflammatory reaction lead to vascular dysfunction. GBE ameliorates aging-related vascular dysfunction, due to its antioxidant and anti-inflammatory properties. The main effects of GBE in aged vasculature might be associated with the longevity signaling pathways. GBE also attenuates the progression of vascular aging in diabetes mellitus via regulation of glucose and lipid metabolism.

CONCLUSION

GBE plays an important role in the prevention of vascular aging process. It is a promising therapeutic approach to ameliorate aging-related vascular dysfunction and cardiovascular diseases.

Pharmacological effectiveness of the active phytochemicals contained in foods and herbs

Food ingestions generally regulate many physiological functions to maintain a healthy life. Furthermore, herbal medicine is prescribed for the prevention and the treatment of various diseases. There are not a few herbal medicine-derived drugs (phytochemicals) clinically using now. The phytochemicals such as digitalis, curare, morphine, quinidine, atropine, and so on are so much important drugs for clinical treatments. Herbal medicine and foods are composed of many constituents. The pharmacological actions that contain phytochemicals are exerted each by each mediated through different receptors, ionic channels, and cellular signal transductions. Thus, they produce multiple pharmacological and pathophysiological functions mediated by the complex interactions with lots of the ingredients.

Pharmacological characteristics of Kampo medicine as a mixture of constituents and ingredients

Herbal medicine in Japan is termed as Kampo medicine, which is derived from traditional Chinese medicine. Shakuyakukanzoto (Shao-Yao-Gan-Cao-Tang) as a kind of Kampo formulations is composed of just two components; Paeoniae Radix and Glycyrrhizae Radix, which produced marked relaxation of intestinal tract. Mokuboito (Mu-Fang-Ji-Tang) inhibited cardiac ionic channel currents, and as a mixture also produced great vasodilatation. Sinomenine (a main ingredient of Mokuboito) as a single compound also caused the vasodilatation, but decreased it along with ageing. Gypsum containing in Mokuboito and Chotosan (Diao-Teng-San) caused more marked effects, as compared with those without Gypsum. On the other hand, Rokumigan (Liu-Wei-Wan), Hachimijiogan (Ba-Wei-Di-Huang-Wan) and Goshajinkigan (Niu-Che-Shen-Qi-Wan) increase in order the number of contained ingredients. The formulations with more herbs (ingredients) produced much more effective actions on rat aorta, presumably due to compensation of the decline of pharmacological sensitivity with ageing. Thus, there are some important differences between single chemical drugs and mixture drugs with many ingredients. The effects of Kampo medicine (mixture) are never just a sum of each effect induced by a lot of ingredients. For elder persons, furthermore, Kampo medicine exerts more effective actions.

Inhibitory effect of Ginkgo biloba extract on the tonus of the small intestine and the colon of rabbits

Ginkgo biloba is widely used in folk medicine. Patients very often use the plant preparation with no concern for purity. They also tend to increase the dosage by themselves and this may result in certain insufficiently researched acute effects. Due to this extremely widespread application, the aim of this work is an examination of the possible acute effects of Ginkgo bilobaon the motility of the small and the large intestine of rabbits. capital TE, Cyrilliche effects of Gingium - a standardized ginkgo biloba extract (GBE) [one milliliter preparation contained 8.8-10.8 mg ginkgo flavonol glycoside and 2.0-2.8 mg lactone ring-containing terpenes (ginkgolides and bilobalides)], on the tonus of isolated segments of the ileum and the colon of rabbits were examined. The experiments were carried out on isolated bowel incisions according to the Magnus method. Data was registered by physiography (Narco-Bio-System). Our results show that GBE (0.006 g/L, - 0.06 g/L) concentration-dependently reduces the tonus of the ileum and the colon of rabbits. Apart from that, GBE reduces the increase of the tonus of the ileum caused by acetylcholine (ACh), but does not change colon tonus intensified by ACh. This indicates that the effects of the used extract in the ileum are predominantly achieved through cholinergic mechanisms, while the relaxant effects in the colon are achieved in some other way.

Evaluation of the effect of Ginkgo biloba extract (EGb 761) on the myenteric plexus of the small intestine of Wistar rats

BACKGROUND

The aging process causes a reduction in the myenteric neuronal population, related to oxidative stress, resulting in malfunctioning of the digestive tract. The purpose of this study was to evaluate the action of Ginkgo biloba extract (EGb 761), an important antioxidant drug, on the myenteric plexus of the jejunum and ileum of rats after treatment for 120 days.

METHODS

Fragments of the jejunum and ileum were collected from three groups of rats: a 90-day-old group (group Y), a 210-day-old group (group A), and a 210-day-old group treated daily with the extract EGb 761 (50 mg/kg body weight) (group TA). The analysis was carried out by using the myosin-V immunohistochemical technique. Neuronal densities were estimated, and a study of the neuronal profile area of 500 neurons from each group was carried out.

RESULTS

In the jejunum, there was a significant neuronal population reduction of 17% only in group A compared with group Y. In the ileum, there was a significant neuronal reduction of 36% in group A compared with group Y, and a significant reduction in group TA of 20%. The difference in the reduction between groups A and TA in the ileum was also significant. In the jejunum, only group A showed a significant increase in neuronal profile area, but in the ileum, there was a significant increase in both groups A and TA.

CONCLUSIONS

A daily dose of 50 mg/kg body weight of Ginkgo biloba extract has a significant neuroprotector effect on the myenteric plexus of the ileum during the aging process in rats.