Antioxidant constituents from leaves of Engelhardtia roxburghiana

Antioxidant and In Vivo Hypoglycemic Activities of Ethanol Extract from the Leaves of Engelhardia roxburghiana Wall, a Comparative Study of the Extract and Astilbin

The leaves of Engelhardia roxburghiana Wall (LERW) has been used as sweet tea in China throughout history. In this study, the ethanol extract of LERW (E-LERW) was prepared and the compositions were identified by HPLC-MS/MS. It indicates that astilbin was the predominant component in E-LERW. In addition, E-LERW was abundant in polyphenols. Compared to astilbin, E-LERW presented much more powerful antioxidant activity. The E-LERW also had stronger affinity with α-glucosidase and exerted more vigorous inhibitory effect on the enzyme. Alloxan-induced diabetic mice had significantly elevated glucose and lipid levels. Treatment with E-LERW at the medium dose (M) of 300 mg/kg could reduce the levels of glucose, TG, TC, and LDL by 16.64%, 12.87%, 32.70%, and 22.99%, respectively. In addition, E-LERW (M) decreased food intake, water intake, and excretion by 27.29%, 36.15%, and 30.93%, respectively. Moreover, E-LERW (M) therapy increased the mouse weight and insulin secretion by 25.30% and 494.52%. With respect to the astilbin control, E-LERW was more efficient in reducing the food and drink consumption and protecting pancreatic islet and body organs from alloxan-induced damage. The study demonstrates that E-LERW may be a promising functional ingredient for the adjuvant therapy of diabetes.

Integrating Network Pharmacology and Component Analysis Study on Anti-Atherosclerotic Mechanisms of Total Flavonoids of Engelhardia roxburghiana Leaves in Mice

Engelhardia roxburghiana Wall. leaves are widely used to develop herbal teas in southeast of China due to medicinal use for diabetes mellitus and hyperlipidemia. Studies have demonstrated that the total flavonoids of E. roxburghiana leaves (TFER) exhibited regulatory effects on blood glucose and lipids. To clarify the active ingredients of TFER and their targets in treating atherosclerosis, the present study integrated chemical analysis, network pharmacology analysis and animal experimental studies. Firstly, high performance liquid chromatography-mass spectrometry/mass spectrometry (HPLC/MS/MS) was utilized to identify components of TFER. Then, active ingredients were screened by oral bioavailability (OB) and drug-likeness (DL) index. Thirdly, network was constructed to predict major targets of active ingredients against atherosclerosis. Finally, to verify parts of predicted signaling, Apoe^-/- mice were used to develop atherosclerosis. Atherosclerotic plaques in aorta were evaluated by echocardiography. Then, serum lipids, target genes expressions in thoracic aorta were determined by qRT-PCR and ELISA methods. Chemical analysis revealed 10 components in TFER sample, 7 of which acted as active ingredients, including naringenin, kaempferol, quercetin, isoengeletin, engeletin, astilbin and quercitrin. KEGG pathway analysis highly enriched in some inflammatory signalings, including NF-κB signaling, Toll-like receptor signaling and TNF signaling. The animal studies indicated that TFER reduced atherosclerotic plaques size in aorta and significantly decreased the serum lipids, down-regulated NF-κB signaling by decreasing mRNA level of NF-κB p65 subunit, TNF-α and VCAM-1, as well as IL-1β expressions in thoracic aorta, eventually alleviating atherosclerosis progression, which was in consistent with our prediction.

Characterization of the complete chloroplast genome of Engelhardia roxburghiana (Juglandaceae)

Engelhardia roxburghiana is a traditional Chinese medicine in the Juglandaceae family. In this study, the complete chloroplast (cp) genome sequence of E. roxburghiana was reported and characterized. The cp genome is 161,550 bp in length and contains a pair of inverted repeats (IRs, 25,862 bp) separated by a large (90,937 bp) and small (18,889 bp) single-copy regions. A total of 113 unique genes were predicted, including 79 protein-coding genes, 30 tRNA genes and 4 rRNA genes. The phylogenetic analysis suggested that E. roxburghiana is resolved as a sister group to the clade of subfam. Juglandoideae.