Protective effect of hot-water and ethanol-aqueous extracts from Anneslea fragrans against acetaminophen-induced acute liver injury in mice

Anneslea fragrans Wall. (AF) is an important medicinal and edible plant in China. The principal objectives of this study are to explore the hepatoprotective effect of ethanol-aqueous (AFE) and hot-water (AFW) extracts in vitro and in vivo. UPLC-ESI-MS/MS analysis showed that AFW and AFE are rich in dihydrochalcones. Both AFW and AFE significantly up-regulated the expressions of SOD, CAT and GSH, reduced the MDA content in acetaminophen (APAP)-induced HepG2 cells, and suppressed the expressions of NO, TNF-α, IL-1β, and IL-6 in LPS-induced RAW246.7 cells. In APAP-induced mice, AFW and AFE administration significantly decreased the plasma levels of AST and ALT, and improved liver tissue damage, the collagen deposition and fibrosis formation. Moreover, AFW and AFE decreased the MDA and ROS accumulations via activating Nrf2 pathway to increase the hepatic GSH contents and activities of SOD, CAT, HO-1, and NQO-1, reduced the levels of NO, TNF-α, IL-1β, and IL-6 by suppressing the JNK/p38/ERK/NF-κB pathways, and alleviated apoptosis via regulating Bcl-2, Bax, caspase-3/9 protein expressions. This study provides a new sight that AFW and AFE may have a potential natural resource for the treatment of liver injury.

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-1β, 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.

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.