Structure, synthesis, biosynthesis, and activity of the characteristic compounds from Ginkgo biloba L

Covering: 1928-2021Ginkgo biloba L. is one of the most distinctive plants to have emerged on earth and has no close living relatives. Owing to its phylogenetic divergence from other plants, G. biloba contains many compounds with unique structures that have served to broaden the chemical diversity of herbal medicine. Examples of such compounds include terpene trilactones (ginkgolides), acylated flavonol glycosides (ginkgoghrelins), biflavones (ginkgetin), ginkgotides and ginkgolic acids. The extract of G. biloba leaf is used to prevent and/or treat cardiovascular diseases, while many ginkgo-derived compounds are currently at various stages of preclinical and clinical trials worldwide. The global annual sales of G. biloba products are estimated to total US$10 billion. However, the content and purity of the active compounds isolated by traditional methods are usually low and subject to varying environmental factors, making it difficult to meet the huge demand of the international market. This highlights the need to develop new strategies for the preparation of these characteristic compounds from G. biloba. In this review, we provide a detailed description of the structures and bioactivities of these compounds and summarize the recent research on the development of strategies for the synthesis, biosynthesis, and biotechnological production of the characteristic terpenoids, flavonoids, and alkylphenols/alkylphenolic acids of G. biloba. Our aim is to provide an important point of reference for all scientists who research ginkgo-related compounds for medicinal or other purposes.

Evaluation of the anti-inflammatory properties of the active constituents in Ginkgo biloba for the treatment of pulmonary diseases

Ginkgo biloba has long been used in ancient China for the treatment of cough, asthma, and other lung diseases. However, the active constituents in G. biloba for pulmonary disease treatment remain unclear. The objective of this study was to evaluate the anti-inflammatory active constituents in G. biloba and clarify their associated molecular mechanisms. The biological effects of different G. biloba extracts were evaluated in an ovalbumin-induced allergic mouse model. Anti-inflammatory compounds were present in the ethyl acetate phase of the extract, which were analysed by HPLC-MS. Biflavones were identified as the main compounds, which were further evaluated by docking calculations. Leukocyte elastase showed a high fit score with ginkgetin, one of the identified biflavones. The lowest binding free energy was -6.69 kcal mol-1. The effects of biflavones were investigated in vivo and in vitro. Ginkgetin markedly suppressed the abnormal expression of the Akt and p38 pathways in human neutrophil elastase (HNE)-stimulated A549 cells. Biflavones also decreased MUC5AC mRNA expression in HNE-stimulated A549 cells and the allergic mouse model. Inflammatory cells (neutrophils) and cytokines (IL-8) also decreased in mice treated with biflavones. The results suggest that G. biloba biflavones could inhibit the activity of leukocyte elastase. This in turn implicates G. biloba as a functional food for the treatment of airway inflammation.

Cultivar differentiation of Citri Reticulatae Pericarpium by a combination of hierarchical three-step filtering metabolomics analysis, DNA barcoding and electronic nose

The traditional Chinese medicine Citri Reticulatae Pericarpium (CRP) was mainly originated from the dried pericarp of Citrus reticulata 'Chachi' (Crc), Citrus reticulata 'Dahongpao' (Crd), Citrus reticulata 'Unshiu' (Cru) and Citrus reticulata 'Tangerina' (Crt) in China. Since these four cultivars have great similarities in morphology, reliable methods to differentiate CRP cultivars have rarely been reported. To discriminate the differences of these CRP cultivars, herein an efficient and reliable method by combining metabolomics, DNA barcoding and electronic nose was first established. The hierarchical three-step filtering metabolomics analysis based on liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) indicated that 9 species-specific chemical markers including 6 flavanone glycosides and 3 polymethoxyflavones could be considered as marker metabolites for discrimination of the geoherb Crc from other cultivars. A total of 19 single nucleotide polymorphism (SNP) sites were found in nuclear internal transcribed spacer 2 (ITS2) of CRP, and three stable SNP sites (33, 128 and 174) in the ITS2 region can distinguish the four CRP cultivars. The electronic nose coupled with chemometrics could also be used to effectively distinguish Crc from other CRP cultivars. Therefore, our results indicated that the integrated method will be an effective strategy for discrimination of similar herbal medicines.

Metabolic profiles of Cuibi-1 and Zhongyan-100 flue-cured tobacco leaves in different growing regions by gas chromatography/mass spectrometry

The metabolic profiles of tobacco leaves of two differential Chinese cultivars from different growing regions were analysed using gas chromatography-mass spectrometry (GC-MS). The results of principal component analysis, partial least-squares discriminant analysis and hierarchical cluster analysis showed significant differences in metabolome among three groups, identified 24 differential metabolites, and analysed the metabolic pathway in which the metabolites were involved. Among them, 13 metabolites were associated with geographical regions, including seven organic and fatty acids, four carbohydrates and two secondary metabolites. Four amino acids and two monosaccharides were associated with cultivars and the remaining five metabolites were associated with both. The relationships among the differential metabolites and the distinct characteristics of environment and cultivar were further discussed. In addition, correlation analysis indicated that most of the differential carbohydrates were negatively correlated with the differential amino acids and organic acids. Taken together, this study demonstrates the metabolite differences between two cultivars in different regions, and highlights the effect of environment and cultivar on tobacco leaf metabolism.