Hippophae rhamnoides L. leaf extracts alleviate diabetic nephropathy via attenuation of advanced glycation end product-induced oxidative stress in db/db mice

Quality differences in sea buckthorn (Hippophaë rhamnoides L.) berries of major varieties in China based on key components and antioxidant activity

Sea buckthorn is rich in active ingredients, widespread, and has both medicinal and nutritional value. The present comparative study of wild and cultivated species remains insufficient, which is not conducive to their quality control. Therefore, this study aimed to compare the differences of 21 sea buckthorn samples in total phenolic content (TPC), total flavonoid content (TFC), phenolic components content, secondary metabolites, and antioxidant capacity and the fatty acid, to investigate the quality differences of different varieties. The TPC, TFC and antioxidant activity of wild varieties were higher than those of the cultivated. Multivariate statistical analysis revealed large differences in phenolic content, with higher levels of gallic acid and isorhamnetin-3-O-neohesperidin in the wild, whereas the cultivated were characterized by narcissin and kaempferol. These findings provided the scientific basis for the improvement of quality evaluation standards for different varieties and offered new insights for the further development of sea buckthorn resources.

Research progress of sea buckthorn (Hippophae rhamnoides L.) in prevention and treatment of cardiovascular disease

Sea buckthorn (Hippophae rhamnoides L.) contains a variety of biologically active compounds, including flavonoids, terpenoids, polysaccharides, organic acids, volatile oils, and vitamins. It has been demonstrated to be effective in the treatment of cardiovascular disorders. In this paper, we evaluated the pharmacological effects of sea buckthorn in cardiovascular diseases through preclinical studies, and revealed the mechanism of action of the active components in sea buckthorn in cardiovascular diseases, including anti-inflammatory, lipid oxidation regulation, antioxidant, vascular function modulation, anti-platelet aggregation, autophagy, intestinal microorganism regulation, and cell apoptosis reduction. In clinical trials, sea buckthorn was proven to be effective in managing lipid metabolism, blood pressure, and blood glucose levels in patients. We also extensively reviewed the safety of sea buckthorn medicine and its toxicity to numerous organs. To summarize, sea buckthorn has a beneficial effect on cardiovascular disease and may give a novel strategy for clinical intervention and therapy. This paper summarizes the phytochemistry, pharmacology, clinical applications, safety, and toxicity of sea buckthorn in order to better understand the mechanism of action of the various bioactive components in sea buckthorn, investigate its medicinal potential, and provide more options for the treatment of cardiovascular diseases.

Antioxidant and Stress Resistance Properties of Flavonoids from Chinese Sea Buckthorn Leaves from the Qinghai-Tibet Plateau

The unique ecological environment of the Qinghai-Tibetan Plateau has endowed Chinese sea buckthorn leaves with rich bioactivities. In this study, we investigated the bioactivity and stress resistance mechanisms of flavonoids derived from Chinese sea buckthorn leaves (FCL) native to the Qinghai-Tibet Plateau. Our analysis identified a total of 57 flavonoids, mainly flavonol glycosides, from FCL, of which 6 were novel flavonoids. Isorhamnetin glycosides, quercetin glycosides and kaempferol glycosides were the three most dominant classes of compounds in FCL. In particular, isorhamnetin-3-O-glucoside-7-O-rhamnoside emerged as the most abundant compound. Our results showed that FCL possesses potent antioxidant properties, as evidenced by its ability to effectively scavenge DPPH free radicals and demonstrate ferric reducing antioxidant power (FRAP) and oxygen radical absorbance capacity (ORAC) levels comparable to Trolox, a well-known antioxidant standard. Furthermore, FCL showed remarkable efficacy in reducing reactive oxygen species (ROS) levels and malondialdehyde (MDA) levels while enhancing the activities of key antioxidant enzymes, namely superoxide dismutase (SOD) and catalase (CAT), in Caenorhabditis elegans, a widely used model organism. Mechanistically, we elucidated that FCL exerts its stress resistance effects by modulating of transcription factors DAF-16 and HSF-1 within the insulin/insulin-like growth factor-1 signaling pathway (IIS). Activation of these transcription factors orchestrates the expression of downstream target genes including sod-3, ctl-1, hsp16.2, and hsp12.6, thus enhancing the organism's ability to cope with stressors. Overall, our study highlights the rich reservoir of flavonoids in Chinese sea buckthorn leaves as promising candidates for natural medicines, due to their robust antioxidant properties and ability to enhance stress resistance.

Effect of advanced glycation end-products in a wide range of medical problems including COVID-19

Glycation is a physiological process that determines the aging of the organism, while in states of metabolic disorders it is significantly intensified. High concentrations of compounds such as reducing sugars or reactive aldehydes derived from lipid oxidation, occurring for example in diabetes, atherosclerosis, dyslipidemia, obesity or metabolic syndrome, lead to increased glycation of proteins, lipids and nucleic acids. The level of advanced glycation end-products (AGEs) in the body depends on rapidity of their production and the rate of their removal by the urinary system. AGEs, accumulated in the extracellular matrix of the blood vessels and other organs, cause irreversible changes in the biochemical and biomechanical properties of tissues. As a consequence, micro- and macroangiopathies appear in the system, and may contribute to the organ failure, like kidneys and heart. Elevated levels of AGEs also increase the risk of Alzheimer's disease and various cancers. In this paper, we propose a new classification due to modified amino acid residues: arginyl-AGEs, monolysyl-AGEs and lysyl-arginyl-AGEs and dilysyl-AGEs. Furthermore, we describe in detail the effect of AGEs on the pathogenesis of metabolic and old age diseases, such as diabetic complications, atherosclerosis and neurodegenerative diseases. We summarize the currently available data on the diagnostic value of AGEs and present the AGEs as a therapeutic goal in a wide range of medical problems, including SARS-CoV-2 infection and so-called long COVID.