Renal protective effect and action mechanism of Huangkui capsule and its main five flavonoids.

ETHNOPHARMACOLOGICAL RELEVANCE: The flower of Abelmoschus manihot (Linn.) Medicus (A. manihot), as a traditional Chinese Herbal medicine, was used widely in China with efficacy of inducing diuresis for treating strangurtia, and subdhing swelling and detoxicating. It has been reported that Huangkui capsule, prepared by the extract of the flower of A. manihot, can reduce the content of urinary protein, serum creatinine and serum urea nitrogen in nephropathy rats and processes renoprotective activity, while the action mechanism need to illuminate deeply. AIMS OF THE STUDY: In this study, we investigated the protection effect of Huangkui capsule on tubulointerstitial fibrosis in chronic renal failure (CRF) rats and its mechanism against high glucose-induced epithelial to mesenchymal transition (EMT) in renal tubular epithelial cells (HK-2) of its bioactive components. MATERIALS AND METHODS: The animals were divided into normal group, CRF model group and Huangkui capsule-treated group. Hematoxylin eosin (HE) staining and Masson staining were applied to observe pathological changes in renal tissue of different groups. Biochemical indicators including serum urea nitrogen (BUN), urine protein (UP) and serum creatinine (Scr) were measured according to the manufacturer's instructions of kits. HK-2 cell damaged model was established to access the protection effect and action mechanism of five main flavonoids from Huangkui capsule. The experimental cells were divided into eight groups: control group, model group, positive drug group and five main flavonoids treated groups. The dichlorodihydrofluorescein diacetate (DCFH-DA) assay was used to determine the reactive oxygen species (ROS) in different groups. Western blot was applied to analyze the expression of pathogenesis-related proteins in different groups. RESULTS: The results stated that Huangkui capsule significantly inhibited the elevation of Scr, BUN, UP, the expression of α-smooth muscle actin (α-SMA), phosphorylation-extracellular signal-regulated kinase (p-ERK1/2), NADPH Oxidase 1, NADPH Oxidase 2 and NADPH Oxidase 4 in adenine-induced CRF rats. The main bioactive components of quercetin (QT), hyperoside (HY), isoquercitrin (IQT), gossypetin-8-O-ß-D-glucuronide (GG) and quercetin-3'-O-glucoside (QG) at the dosage of 100µM, like NADPH oxidase inhibitor diphenyleneiodonium, exhibited a significant effect on inhibiting the expression of α-SMA, p-ERK1/2, NADPH Oxidase 1, NADPH Oxidase 2 and NADPH Oxidase 4 in high glucose-induced HK-2 cells, especially GG. CONCLUSIONS: These results demonstrated that Huangkui capsule and the flavonoids components prevent tubulointerstitial fibrosis in CRF rat involvement in the action mechanism of inhibiting NADPH oxidase/ROS/ERK pathway.

[Antidepressant activity of flavonoid ethanol extract of Abelmoschus manihot corolla with BDNF up-regulation in the hippocampus].

Abelmoschus manihot (L.) Medic., a folk herbal medicine in China, is a flowering plant belonging to Abelmoschus L. genus and Malvaceae family, which has been reported with an antidepressant activity. The study was designed to isolate flavonoids from Abelmoschus manihot corolla and explore the action mechanism of antidepressant activities. The flavonoids were isolated and purified by D101 macroporous resin column, polyamide column and Sephadex LH-20 sequentially and identified as myricetin-3-O-ß-D-glucoside (1), gossypetin-8-O-ß-D-glucuronide (2, G-8-G), gossypetin-3'-O-ß-D-glucoside (3), quercetin-3'-glucoside (4, Q-3-G), isoquercitrin (5, IQT), hyperoside (6, HY), myricetin (7), quercetin (8, QT). Compounds 2, 4, 5, 6 and 8 (15, 30 and 60 mg·kg−1) were orally administered to mice and the reaction was observed in tail suspension test (TST) and forced swimming test (FST). Western blot analysis was used in determination of the protein expressions of brain-derived neurotrophic factor (BDNF), tyrosine receptor kinase B (TrkB) and phosphorylation eukaryotic elongation factor 2 (p-eEF2). The results revealed that only Q-3-G and G-8-G (15, 30, 60 mg ·kg−1) significantly reduced the immobility time in FST and TST. Furthermore, Q-3-G and G-8-G remarkably increased the expression of BDNF and TrkB, and decreased the expression of p-eEF2. These results suggest that Q-3-G and G-8-G had an obvious antidepressant activity via up-regulation of BDNF expression. The new observation will provide a new direction in the development of antidepressant in the treatment of major depressive disorder (MDD).