(1) H-NMR analysis of terpene trilactones (TTLs) in Ginkgo biloba: green female leaves contain the most TTLs

Ginkgo biloba leaf extract EGb 761® as a paragon of the product by process concept

It is an often-neglected fact that extracts derived from the very same plant can differ significantly in their phytochemical composition, and thus also in their pharmacokinetic and pharmacodynamic properties which are the basis for their clinical efficacy and safety. The Ginkgo biloba L. [Ginkgoaceae] special extract EGb 761® is one of the best-studied plant extracts in the world. In the present review, using that extract as a paradigm, we describe insights how climate, the harvest region, processing of the plant material, the drying process, the extraction solvents, and the details of the subsequent process steps substantially impact the quality and uniformity of the final extract. We highlight the importance of regulating active constituent levels and consistent reduction of undesired substances in herbal extracts. This is accomplished by a controlled production process and corresponding analytical specifications. In conclusion, since extracts derived from the same plant can have very different phytochemical compositions, results from pharmacological, toxicological and clinical studies gained with one specific extract cannot be extrapolated to other extracts that were generated using different production processes. We propose that the heterogenous nature of extracts should be meticulously considered when evaluating the efficacy and safety of plant-derived remedies.

Antioxidant Phenylpropanoid Glycosides from Ginkgo biloba Fruit and Identification of a New Phenylpropanoid Glycoside, Ginkgopanoside

Ginkgo biloba (Ginkgoaceae), well-known as the oldest living plant species and often referred to as a "living fossil," is a famous medicinal plant that has been used in multiple countries to improve numerous illnesses, including anxiety, dementia, peripheral artery disease, and eye problems. We conducted a phytochemical exploration of G. biloba fruit, commonly consumed as a functional food as part of an ongoing natural product chemical research for the discovery of bioactive phytochemicals with novel structures. The natural product chemical analysis of the methanol extract of G. biloba fruit using column chromatography and high-performance liquid chromatography separation under the guidance of a liquid chromatography-mass spectrometry (LC/MS)-based analysis identified six phenylpropanoid glycosides (1-6), including one new compound, ginkgopanoside (1). The structures of the isolated compounds were elucidated by nuclear magnetic resonance spectroscopic data and LC/MS analysis, and the absolute configuration of compound 1 was established by chemical reactions followed by the application of Snatzke's method. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activities of the isolated compounds 1-6 and the aglycone 1a of 1 were evaluated, and we found that compounds 1-5 exhibited antioxidant activities with IC₅₀ values in the range 32.75-48.20 μM, while the aglycone 1a exhibited greater radical scavenging activity (IC₅₀ = 5.23 μM) comparable to that of ascorbic acid (IC₅₀ = 2.54 μM), a positive control, implying that the present of glucose may decrease the DPPH scavenging activity. These findings provide experimental information that the active phenylpropanoid glycosides could represent natural antioxidants for use in pharmaceuticals and functional foods.

Ginkgonitroside, a new nitrophenyl glycoside and bioactive compounds from Ginkgo biloba leaves controlling adipocyte and osteoblast differentiation

Eight compounds (1-8) including one novel nitrophenyl glycoside, ginkgonitroside (1) were isolated from the leaves of Ginkgo biloba, a popular medicinal plant. The structure of the new compound was characterized using extensive spectroscopic analyses via 1D and 2D NMR data interpretations, HR-ESIMS, and chemical transformation. To the best of our knowledge, the present study is the first to report the presence of nitrophenyl glycosides, which are relatively unique phytochemicals in natural products, in G. biloba. The isolated compounds (1-8) were examined for their effects on the regulation of mesenchymal stem cell (MSC) differentiation. Compounds 1-3 and 8 were able to suppress MSC differentiation toward adipocytes. In contrast, compounds 5 and 8 showed activity promoting osteogenic differentiation of MSCs. These findings demonstrate that the active compounds showed regulatory activity on MSC differentiation between adipocytes and osteocytes.

Ginkwanghols A and B, osteogenic coumaric acid-aliphatic alcohol hybrids from the leaves of Ginkgo biloba

Ginkgo biloba (Ginkgoaceae), commonly known as "ginkgo", is called a living fossil, and it has been cultivated early in human history for various uses in traditional medicine and as a source of food. As part of ongoing research to explore the chemical diversity and biologically active compounds from natural resources, two new coumaric acid-aliphatic alcohol hybrids, ginkwanghols A (1) and B (2) were isolated from the leaves of G. biloba. The coumaric acid-aliphatic alcohol hybrids of natural products have rarely been reported. The structures of the new compounds were determined by extensive NMR spectroscopic analysis, HRESI-MS, and quantum chemical ECD calculations, and by comparing the experimental HRESI-MS/MS spectrum of chemically transformed compound 1a with the predicted HRESI-MS/MS spectra proposed from CFM-ID 3.0, a software tool for MS/MS spectral prediction and MS-based compound identification. Ginkwanghols A (1) and B (2) increased alkaline phosphatase (ALP) production in C3H10T1/2, a mouse mesenchymal stem cell line, in a dose-dependent manner. In addition, ginkwanghols A and B mediated the promotion of osteogenic differentiation as indicated by the induction of the mRNA expression of the osteogenic markers ALP and osteopontin (OPN).