Influence of Ultra-High-Pressure Pretreatment Method on Chemical Constituents, Antioxidant and Cytoprotective Activities of Free, Esterified, and Bound Phenolics from Anneslea Fragrans Wall. Leaves.

Anneslea fragrans Wall., an edible and medicinal plant, is traditionally used to treat liver and gastrointestinal diseases. This paper aimed to investigate the influence of ultra-high pressure (UHP) pretreatment on the phenolics profiling, antioxidant, and cytoprotective activities of free (FP), esterified (EP), and bound (BP) phenolics from A. fragrans leaves. A total of 32 compounds were characterized and quantified. The davidigenin (44.46 and 113.37 mg/g extract) was the highest in A. fragrans leaves. The vitexin (9), afzelin (10), coreopsin (15), and davidigenin (28) were analyzed with MS2 fragment pathways. Results showed that UHP treated A. fragrans leaves had higher total phenolic (TPC) and total flavonoid (TFC) contents of FP, EP, and BP fractions than those in the raw leaves. Moreover, UHP pretreated A. fragrans leaves had higher scavenging activities on DPPH+• and ABTS+•, and inhibitory effects on the intracellular ROS generation in H2O2-induced HepG2 cells. UFP showed the highest inhibition of ROS production among the samples. Therefore, UHP pretreatment method might be used as an effective strategy for elevating the availabilities of A. fragrans leaves to develop functional foods.

Activity Guided Isolation of Phenolic Compositions from Anneslea fragrans Wall. and Their Cytoprotective Effect against Hydrogen Peroxide Induced Oxidative Stress in HepG2 Cells.

Anneslea fragrans Wall., commonly known as "Pangpo Tea", is traditionally used as a folk medicine and healthy tea for the treatment of liver and intestine diseases. The aim of this study was to purify the antioxidative and cytoprotective polyphenols from A. fragrans leaves. After fractionation with polar and nonpolar organic solvents, the fractions of aqueous ethanol extract were evaluated for their total phenolic (TPC) and flavonoid contents (TFC) and antioxidant activities (DPPH, ABTS, and FRAP assays). The n-butanol fraction (BF) showed the highest TPC and TFC with the strongest antioxidant activity. The bio-guided chromatography of BF led to the purification of six flavonoids (1-6) and one benzoquinolethanoid (7). The structures of these compounds were determined by NMR and MS techniques. Compound 6 had the strongest antioxidant capacity, which was followed by 5 and 2. The protective effect of the isolated compounds on hydrogen peroxide (H2O2)-induced oxidative stress in HepG2 cells revealed that the compounds 5 and 6 exhibited better protective effects by inhibiting ROS productions, having no significant difference with vitamin C (p > 0.05), whereas 6 showed the best anti-apoptosis activity. The results suggest that A. fragrans could serve as a valuable antioxidant phytochemical source for developing functional food and health nutraceutical products.

Anneslea fragrans Wall. ameliorates ulcerative colitis via inhibiting NF-κB and MAPK activation and mediating intestinal barrier integrity.

ETHNOPHARMACOLOGICAL RELEVANCE: Anneslea fragrans Wall. is traditionally used as a folk medicine in treating indigestion, fever, dysentery, diarrhea, and liver inflammation in China, Vietnam and Cambodia. However, its anti-inflammatory activity and mechanism under a safety therapeutic dose as well as the main chemical components have not yet been fully investigated. AIM OF THE STUDY: This study aimed to explore the therapeutic effect and possible molecular mechanisms of aqueous-methanol extract (AFE) of A. fragrans leaves on dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) mice and illustrate its potent anti-inflammatory chemical compounds. MATERIALS AND METHODS: The AFE was obtained and then analyzed by high performance liquid chromatography (HPLC). Phytochemical investigation on the AFE was carried out to isolate and characterize its major components. The acute toxicity test was performed to provide the safety information of AFE. Subsequently, the protective effect of AFE on DSS-induced UC was evaluated by physiological changes, histopathological and immunohistochemical analysis, and the expressions of antioxidant enzyme, pro-inflammatory cytokines and anti-inflammatory cytokines. The expressions of target proteins in nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinase (MAPK) were determined by western blot analysis. The tight junction (TJ) proteins in colon tissue were performed by immunohistochemical technique for evaluating the intestinal barrier integrity. RESULTS: HPLC guided isolation of AFE resulted into two dihydrochalcones, which were elucidated as vacciniifolin (1) and confusoside (2). Acute toxicity evaluation revealed that median lethal dose (LD50) of AFE was greater than 5000 mg/kg. Furthermore, AFE significantly attenuated ulcerative colitis symptoms, suppressed myeloperoxidase activity, and increased the expression of superoxide dismutase and glutathione. AFE treatment could also reduce the levels of tumor necrosis factor-α, interleukin-1ß, and interleukin-6 and increase the levels of interleukin-4 and interleukin-10 in colon tissues and serum of DSS-induced UC mice. In addition, AFE significantly increased the expression of zonula occludens-1, occludin and claudin-1, and inhibited the phosphorylation of target protein of the NF-κB and MAPK signaling pathways in colon tissue. CONCLUSION: Dihydrochalcone glycosides are the major chemical constituents in AFE. AFE ameliorated DSS-induced UC in mice by inhibiting the inflammatory response via modulation of NF-κB and MAPK pathways and maintaining the intestinal barrier function, indicating that the plant A. fragrans could be used as a therapeutic candidate for ulcerative colitis.