Various compounds of EGb have anti-aging effect. Quercetin, luteolin, kaempferol and beta-sitosterol might play vital role in the anti-aging network of EGb based on the prediction method of network pharmacology. Quercetin, a polyphenol widely present in nature, has received the most attention in anti-aging. Studies have shown that quercetin exert neuroprotective actions in the aging nervous system via stimulating cellular defenses against oxidative stress, activating sirtuins1 (SIRT1), inducing autophagy. Quercetin played an anti-aging role via enhancement of cell proliferation and restoration of heterochromatin architecture . In addition, several evidence-based studies suggest quercetin has significant research prospect in the prevention and treatment of vascular aging related diseases [27, 28]. Luteolin is found to possess the potential for antioxidative activity. Luteolin, as an anti-inflammatory and neuroprotective agent, can inhibit the generation of reactive oxygen species (ROS) via modulation of the AMPK-SIRT1 pathway to reduce age-related disorders . The study also found that luteolin may improve cognitive performance in older mice by inhibiting microglia and neuroinflammation. Luteolin may have the potentially useful in the prevention skin aging by inhibiting uva-induced production of collagen mmp-1. A prospective study shows that vegetables and foods rich in kaempferol, lutein, folate, and etc may slow cognitive decline with aging. Kaempferol is an antioxidant and anti-inflammatory by regulating NF-kappaB signaling cascade and inhibiting NADPH oxidase activation, hence kaempferol is considered as a potential anti-aging agent . Beta-sitosterol may increased the proliferation and stimulated the differentiation of embryonic neural stem cells (eNSCs) to prevent neurodevelopmental syndromes, cognitive decline during aging . Beta-sitosterol can extend lifespan of adult flies, possibly by activating AMP-activated protein kinase (AMPK) .
These eight targets, including DPP4, GSK3B, CCNA2, AR, ESR1, PTGS2, PPARG, MAPK14, might play a crucial role in the anti-aging network of EGb. DPP4 and GLP-1 had been found to play important roles in oxidative stress, lipid metabolism, insulin resistance and inflammation. Recently, the balance between DPP4 and GLP-1 might be a therapeutic target for the management of vascular aging and atherosclerosis in animals . Studies have shown that GSK3B, which acted as egative regulator in the hormonal control of glucose homeostasis, Wnt signaling and regulation of transcription factors and microtubules, was closely related to Healthy Aging Index . Silencing of CCNA2, which controled both the G1/S and the G2/M transition phases of the cell cycle, emarkably triggered the cellular aging, while CCNA2 overexpression delayed cellular aging . The expression of PTGS with a particular role in the inflammatory response was up-regulated in diseases related to brain aging . PPARG, key regulator of adipocyte differentiation and glucose homeostasis, was associated with inflammation . MAPK14 played important roles in cell proliferation, differentiation, migration, transformation and programmed cell death .
In the GO enrichment analysis, the targets were closely related to positive regulation of transcription from RNA polymerase II promoter, nitric oxide biosynthetic process, smooth muscle cell proliferation, negative regulation of apoptotic process. Cell components involve nucleoplasm nucleus. Molecular functions involve the binding of enzymes, proteins and transcription factors.
KEGG pathway enrichment analyses demonstrated EGb to be involved with regulation of multiple pathways. Elevated oxidative stress and inflammation including HIF1 signaling pathway and TNF signaling pathway plays significant role in aging, especially vascular aging. Neurotrophin signaling pathway plays an important role in higher order activities such as neural development and learning and memory and several genes in the pathway are closely related to brain aging . Insulin resistance is strongly associated with type II diabetes and Non-alcoholic fatty liver disease, the elderly often develop insulin resistance. Oxidative stress, mitochondrial dysfunction, accumulation of intracellular lipid derivatives, and inflammation (via IL-6 and TNFα) contribute to decreased activation of signaling molecules including PI3K and AKT leading to insulin resistance[45–47].The absence of sphingomyelin, a second messenger functions in a variety of cellular signaling pathways, leads to a shortened lifespan in animals and it suggests that sphingolipid signaling may play a role in neuronal function and animal stress response during aging. The focal adhesion, mitogen-activated protein kinase (MAPK) signaling pathway and ErbB signaling pathway is module that is involved in cell proliferation, differentiation and migration [49–51].Focal adhesion, a signaling molecule associated with cell survival, relies on the interaction between integrins and actin to connect cells to the extracellular matrix . Studies have shown that extracellular matrix proteins–cell interactions gives rise to target organ damage, and inflammatory pathways leading to calcification or atherosclerosis [1, 52]. MAPK signaling pathway, including extracellular signal-regulated kinase 1 and 2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38, is closely related to the biological process of aging and the progression of the inflammatory process leads to dysregulation of MAPK that accelerates cell aging . Inactivation of the ErbB signaling pathway leads to a loss of myocardial protective function during cardiac hypertrophy and to the onset of early failure .T cell receptor (TCR) signaling pathway, Toll-like receptor (TLR) signaling pathway and NOD-like receptor (NLR) signaling pathway are responsible for generating innate immune responses and playing a critical role in inflammation. Toll-like receptors play a significant role in promoting aging adipose tissue inflammation, and the study shows that old TLR4-deficient mice have improved glucose tolerance compared to age-matched wild type mice. A different set of NOD-like receptors induces caspase-1 activation and the activated of caspase-1 regulates maturation of the pro-inflammatory cytokines IL-1B, IL-18 and drives pyroptosis. The forkhead box O (FOXO) family regulates the expression of genes in apoptosis, cell-cycle control, glucose metabolism, oxidative stress resistance, and longevity. Recent evidence indicates that the FOXO family plays a key role in the self-renewal of adult and embryonic stem cells, which could contribute to tissue regeneration . Vascular endothelial growth factor (VEGF) can stimulate endothelial cell growth, promote angiogenesis and increase vascular permeability. The decreased angiogenesis associated with the aging of the body is related to the decreased expression of VEGF, and the proliferation ability of vascular endothelial cells in elderly animals is weakened. The addition of VEGF can help restore the proliferation ability of vascular endothelial cells leading delay vascular aging . Wnt proteins are secreted morphogens that are required for basic developmental processes. The overactivation of Wnt/β-catenin signaling pathway is closely related to stem cell aging.