Safety and efficacy of a feed additive consisting of a dry extract obtained from the leaves of Ginkgo biloba L. (ginkgo extract) for horses, dogs, cats, rabbits and guinea pigs (FEFANA asbl)

Following a request from the European Commission, EFSA was asked to deliver a scientific opinion on the safety and efficacy of a feed additive obtained from the dried leaves of Ginkgo biloba L. (ginkgo extract) when used as a sensory additive in feed for horses, dogs, cats, rabbits and guinea pigs. Ginkgo extract contains ≥ 24% total flavonoids, ≥ 6% total terpene lactones and ≤ 1 mg/kg ginkgolic acids. The EFSA Panel on Additives and Products or Substances used in Animal Feed (FEEDAP) concluded that ginkgo extract is safe for the target species at the following concentrations in complete feed: 2.8 mg/kg for horses and cats, 1.1 mg/kg for rabbits and guinea pigs, and 3.3 mg/kg for dogs. No safety concern would arise for the consumers from the use of ginkgo extract up to the highest level in feed which is considered safe for food-producing species (horses and rabbits). The additive should be considered as irritant to skin and eyes, and as a dermal and respiratory sensitiser. The use of the additive at the proposed level in feed for the target species is not considered to be a risk to the environment. While the available data indicate that Ginkgo preparations have a distinctive flavour profile, there is no evidence that the ginkgo extract would impart flavour to a food or feed matrix. Therefore, the FEEDAP Panel cannot conclude on the efficacy of the additive.

Enhancing both oral bioavailability and anti-ischemic stroke efficacy of ginkgolide B by preparing nanocrystals self-stabilized Pickering nano-emulsion

Ginkgolide B (GB), which has been demonstrated as the most efficacious naturally occurring platelet-activating factor (PAF) antagonist, is extensively utilized for the management of cardiovascular and cerebrovascular ailments. Nevertheless, its limited oral bioavailability is hindered by its low solubility in gastric acid and inadequate stability in intestinal fluid, thereby constraining its practical application. This study aimed to develop GB nanocrystals (GB-NCs) and GB nanocrystals self-stabilized Pickering nano-emulsion (GB-NSSPNE) using a miniaturized wet bead milling method. Comparative evaluations were conducted in vivo and in vitro to assess their effectiveness. The findings revealed that GB-NSSPNE, with its intact nanoparticle slow release and absorption, was more effective in enhancing the oral bioavailability of GB compared to the rapid release and absorption of GB-NCs. This finding suggests a potential novel strategy for the oral delivery of GB.

Multiplex quantitation of 17 drug-derived components in human plasma after administration of a fixed herbal preparation of Sailuotong using combined online SPE-LC-MS/MS methods

ETHNOPHARMACOLOGICAL RELEVANCE

Sailuotong (SLT) is a standardized herbal medicine formula made from extracts of ginseng (the dried root and rhizome of Panax ginseng C. A. Meyer), ginkgo (the leaves of Ginkgo biloba L.), and saffron (the stigma of Crocus sativus L.). It is prescribed compatibly for the treatment of vascular dementia (VaD) following the TCM principle of Qi-invigorating and Blood-activating. Ginseng is widely used as a tonic for the restoration of strength in China. Ginkgo and saffron have been traditionally used for a long time as medicines with the main effect of promoting blood circulation and removing blood stasis.

AIM OF THE STUDY

SLT has been proven to be a promising medicine for VaD by existing pharmacological and clinical evidence. To understand how the formula herbs and their active ingredients cooperate to produce comprehensive effects, the present study aimed to establish a highly sensitive and accurate quantitative method to reveal the plasma exposure profile of SLT in humans.

MATERIAL AND METHODS

Multiplex quantitation of a total of 17 SLT-derived components in human plasma was fulfilled by using online SPE for sample extractions followed by LC-MS/MS determinations. Among them, 8 ginsenoside (Rg1, Re, F1, Rf, Rb1, Rb2, Rc and Rd) were determined in ESI+ mode, and ginkgo flavonoids of quercetin, kaempferol, isorhamnetin were in ESI- mode. Improved sensitivity was achieved through optimizing the condition of sample extraction and LC separation, as well as mass parameters. 4 ginkgolides, including ginkgolide A, B, C and bilobalide, and 2 crocins of crocin-1 and its metabolite crocetin, were analyzed concurrently in negative ion mode, and their stability was ensured by a series of protective solutions.

RESULTS

The lower limit of quantitation was achieved to be extremely sensitive at 0.078 ng/mL for all ginsenosides, 0.033 ‒ 0.2 ng/mL for ginkgo flavonoids, 0.75 or 1.5 ng/mL for ginkgolides and 3 ng/mL for crocins. The methods were fully validated to be accurate and precise, and applicability was demonstrated by the analysis of clinical samples from 2 healthy volunteers.

CONCLUSION

The developed methods should be useful in further detailed clinical pharmacokinetic research for clarifying the effect mechanism of SLT and formulating its rational therapeutic regimens.

Natural Product Co-Metabolism and the Microbiota-Gut-Brain Axis in Age-Related Diseases

Complementary alternative medicine approaches are growing treatments of diseases to standard medicine practice. Many of these concepts are being adopted into standard practice and orthomolecular medicine. Age-related diseases, in particular neurodegenerative disorders, are particularly difficult to treat and a cure is likely a distant expectation for many of them. Shifting attention from pharmaceuticals to phytoceuticals and "bugs as drugs" represents a paradigm shift and novel approaches to intervention and management of age-related diseases and downstream effects of aging. Although they have their own unique pathologies, a growing body of evidence suggests Alzheimer's disease (AD) and vascular dementia (VaD) share common pathology and features. Moreover, normal metabolic processes contribute to detrimental aging and age-related diseases such as AD. Recognizing the role that the cerebral and cardiovascular pathways play in AD and age-related diseases represents a common denominator in their pathobiology. Understanding how prosaic foods and medications are co-metabolized with the gut microbiota (GMB) would advance personalized medicine and represents a paradigm shift in our view of human physiology and biochemistry. Extending that advance to include a new physiology for the advanced age-related diseases would provide new treatment targets for mild cognitive impairment, dementia, and neurodegeneration and may speed up medical advancements for these particularly devastating and debilitating diseases. Here, we explore selected foods and their derivatives and suggest new dementia treatment approaches for age-related diseases that focus on reexamining the role of the GMB.

What dominates the changeable pharmacokinetics of natural sesquiterpene lactones and diterpene lactones: a review focusing on absorption and metabolism

Sesquiterpene lactones (STLs) and diterpene lactones (DTLs) are two groups of common phytochemicals with similar structures. It's frequently reported that both exhibit changeable pharmacokinetics (PK) in vivo, especially the unstable absorption and extensive metabolism. However, the recognition of their PK characteristics is still scattered. In this review, representative STLs (atractylenolides, alantolactone, costunolide, artemisinin, etc.) and DTLs (ginkgolides, andrographolide, diosbulbins, triptolide, etc.) as typical cases are discussed in detail. We show how the differences of treatment regimens and subjects alter the PK of STLs and DTLs, with emphasis on the effects from absorption and metabolism. These compounds tend to be quite permeable in intestinal epithelium, but gastrointestinal pH and efflux transporters (represented by P-glycoprotein) have great impact and result in the unstable absorption. As the only characteristic functional moiety, the metabolic behavior of lactone ring is not dominant. The α, β-unsaturated lactone moiety has the strongest metabolic activity. While with the increase of low-activity saturated lactone moieties, the metabolism is led by other groups more easily. The phase I (oxidation, reduction and hydrolysis reaction) and II metabolism (conjugation reaction) are both extensive. CYP450s, mainly CYP3A4, are largely involved in biotransformation. However, only UGTs (UGT1A3, UGT1A4, UGT2B4 and UGT2B7) has been mentioned in studies about phase II metabolic enzymes. Our work offers a beneficial reference for promoting the safety evaluation and maximizing the utilization of STLs and DTLs.

Therapeutic promises of ginkgolide A: A literature-based review

Ginkgolide A is a highly active platelet activating factor antagonist cage molecule which was isolated from the leaves of the Ginkgo biloba L. It is known for its inflammatory and immunological potentials. This review aims to sketch a current scenario on its therapeutic activities on the basis of scientific reports in the databases. A total 30 articles included in this review suggests that ginkgolide A has many important biological activities, including anti-inflammatory, anticancer, anxiolytic-like, anti-atherosclerosis and anti-atherombosis, neuro- and hepatoprotective effects. There is a lack of its toxicological (e.g. toxicity, cytotoxicity, genotoxicity and mutagenitcity) profile. In conclusion, ginkgolide A may be one of the potential therapeutic lead compounds, especially for the treatment of cardiovascular, hepatological, and neurological diseases and disorders. More studies are necessary on this hopeful therapeutic agent.

Effects of Gut Microbiota on the Bioavailability of Bioactive Compounds from Ginkgo Leaf Extracts

Ginkgo leaf extract (GLE) is a popular herbal medicine and dietary supplement for the treatment of various diseases, including cardiovascular disease. GLE contains a variety of secondary plant metabolites, such as flavonoids and terpenoids, as active components. Some of these phytochemicals have been known to be metabolized by gut microbial enzymes. The aim of this study was to investigate the effects of the gut microbiota on the pharmacokinetics of the main constituents of GLE using antibacterial-treated mice. The bilobalide, ginkgolide A, ginkgolide B, ginkgolide C, isorhamnetin, kaempferol, and quercetin pharmacokinetic profiles of orally administered GLE (600 mg/kg), with or without ciprofloxacin pretreatment (150 mg/kg/day for 3 days), were determined. In the antibacterial-treated mice, the maximum plasma concentration (C_max) and area under the curve (AUC) of isorhamnetin were significantly (p < 0.05) increased when compared with the control group. The C_max and AUC of kaempferol and quercetin (other flavonol glycosides) were slightly higher than those of the control group, but the difference was not statistically significant, while both parameters for terpenoids of GLE showed no significant difference between the antibacterial-treated and control groups. These results showed that antibacterial consumption may increase the bioavailability of isorhamnetin by suppressing gut microbial metabolic activities.

Ginkgolide A Prevents the Amyloid-β-Induced Depolarization of Cortical Neurons

Utilizing the N-methyl-d-aspartate (NMDA) receptor antagonist as a strategy, memantine is the only agent available for clinically treating mild to severe Alzheimer's disease (AD). Our aim was to develop novel similar herb-based drugs. Using a screening platform, ginkgolide A (GA), a pure compound extracted from Ginkgo biloba, was found to attenuate amyloid β (Aβ)-induced abnormal depolarization in mouse primary cortical neurons. Using receptor agonists, it was determined that GA inhibits both NMDA receptors and α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptors. Furthermore, the Aβ-induced increase in c-Jun N-terminal kinase phosphorylation in neurons was prevented by GA. Body weight, glutamate oxaloacetate transaminase, glutamic-pyruvic transaminase, liver histology, and kidney histology were similar when the wild-type/AD animal model mice with and without GA treatment were compared. This pure compound improves the memory of wild-type mice. Our findings indicate that GA has great potential clinically for the treatment of AD because it might target NMDA receptors just like memantine.