Pericarpium Citri Reticulatae (PCR, Citrus reticulata ‘Chachi’, Guangchenpi in Chinese) is one of the most famous Chinese citrus herbal medicines. The in vivo anti-asthmatic activity of ‘Chachi’ PCR was investigated using a histamine-induced experimental asthma model in Guinea pigs. Two alkaloid-type compounds, synephrine and stachydrine, were analyzed and identified in the ‘Chachi’ PCR alkaloid fraction. The alkaloid fraction and synephrine protected Guinea pigs against histamine-induced experimental asthma in a dose-dependent manner. The respective application of high, middle, and low doses of the ‘Chachi’ PCR alkaloid fraction significantly increased specific airway resistance by 284%, 328%, and 355%, and decreased dynamic compliance by 57%, 67%, and 75%. A similar change was observed for synephrine. The expression of eosinophils in bronchoalveolar lavage fluid (BALF) and serum IgE, IL-4, and IL-5 levels in histamine-induced experimental asthmatic Guinea pigs were significantly downregulated by the ‘Chachi’ PCR alkaloid fraction and synephrine compared to the control group, whereas stachydrine did not impart a statistically significant effect on the expression of tested inflammatory cells (leucocytes, eosinophils, neutrophils, and lymphocytes), immunoglobulin (IgE), or cytokines (IL-4 and IL-5). Pathological changes in lung tissues in each treatment group included the infiltration of inflammatory cells around the bronchia.

Dried tangerine peel (Citri reticulatae Pericarpium, CRP; Chenpi in Chinese) possesses medicine and food homology with hypolipidemic, anti-inflammatory and antioxidant activities. This study aimed to explore the protective effect of CRP extract on endothelial function and inflammation in type 2 diabetic rats and the related mechanisms. Type 2 diabetes mellitus was induced by high-fat diet (HFD)/streptozotocin (STZ) in male Sprague Dawley rats, and CRP extract was orally administered at 400 mg/kg/day for 4 weeks. Rat and mouse aortas were treated with high glucose and CRP extract ex vivo. The data showed that the ethanolic extract of CRP normalized blood pressure and the plasma lipid profile as well as the plasma levels of liver enzymes in diabetic rats. Impaired endothelium-dependent relaxations in aortas, carotid arteries and renal arteries were improved. CRP extract suppressed vascular inflammatory markers and induced AMPK activation in aortas of diabetic rats. Exposure to high glucose impaired vasodilation in aortas of rats and mice, and this impairment was prevented by co-incubation with CRP extract. In conclusion, our findings suggest that CRP extract protects endothelial function by inhibiting the vascular inflammatory state on activation of AMPK in diabetic rats.

One new flavanocoumarin, flemicoumarin A (1) was isolated from the EtOAc-soluble partition of the root of Flemingia philippinensis, along with three known compounds, namely 4,2′-epoxy-4′,5-dihydroxy-7,5′-dimethoxy-3-phenylcoumarin (2), kaempferol 6-C-glucoside (3) and dracocephaloside (4). The structure of compound 1 was elucidated on the basis of its 1D, 2D NMR, CD and MS data. The structures of the known compounds were identified by comparison of their spectroscopic data with those reported in the literature. Compounds 1–4 exhibited inactivity against MCF-7, A549 and Hep-G2 human cancer cell lines in vitro by MTT colorimetric assay.