Preventive effects of saponins from the Pueraria lobata root on in vitro immunological liver injury of rat primary hepatocyte cultures

Lactate-Fortified Puerariae Radix Fermented by Bifidobacterium breve Improved Diet-Induced Metabolic Dysregulation via Alteration of Gut Microbial Communities

BACKGROUND

Puerariae Radix (PR), the dried root of Pueraria lobata, is reported to possess therapeutic efficacies against various diseases including obesity, diabetes, and hypertension. Fermentation-driven bioactivation of herbal medicines can result in improved therapeutic potencies and efficacies.

METHODS

C57BL/6J mice were fed a high-fat diet and fructose in water with PR (400 mg/kg) or PR fermented by Bifidobacterium breve (400 mg/kg) for 10 weeks. Histological staining, qPCR, Western blot, and 16s rRNA sequencing were used to determine the protective effects of PR and fermented PR (fPR) against metabolic dysfunction.

RESULTS

Treatment with both PR and fPR for 10 weeks resulted in a reduction in body weight gain with a more significant reduction in the latter group. Lactate, important for energy metabolism and homeostasis, was increased during fermentation. Both PR and fPR caused significant down-regulation of the intestinal expression of the MCP-1, IL-6, and TNF-α genes. However, for the IL-6 and TNF-α gene expressions, the inhibitory effect of fPR was more pronounced (p < 0.01) than that of PR (p < 0.05). Oral glucose tolerance test results showed that both PR and fPR treatments improved glucose homeostasis. In addition, there was a significant reduction in the expression of hepatic gene PPARγ, a key regulator of lipid and glucose metabolism, following fPR but not PR treatment. Activation of hepatic AMPK phosphorylation was significantly enhanced by both PR and fPR treatment. In addition, both PR and fPR reduced adipocyte size in highly significant manners (p < 0.001). Treatment by fPR but not PR significantly reduced the expression of PPARγ and low-density lipoproteins in adipose tissue.

CONCLUSION

Treatment with fPR appears to be more potent than that of PR in improving the pathways related to glucose and lipid metabolism in high-fat diet (HFD)+fructose-fed animals. The results revealed that the process of fermentation of PR enhanced lactate and facilitated the enrichment of certain microbial communities that contribute to anti-obesity and anti-inflammatory activities.

Antineoplastic Constituents from the Chemical Diversified Extract of Radix puerariae

To enhance the structural diversity of isoflavonoids and provide more derivatives for the biological screening, a semisynthetic mixture was generated by diversification of the crude extract of Radix puerariae (Pueraria montana var. lobata) through the chemical reaction with hydrazine hydrate. Eleven 3,4-diarylpyrazoles (1-11) and two 5-phenyl-6-benzyldihydropyridazinones (12 and 13) were isolated from the semisynthetic mixture, and their structures were identified by spectroscopic methods in combination with X-ray crystallographic analysis. Among them, nine compounds (5-13) were new derivatives. All the compounds were evaluated on the inhibitory activities against the prostate cancer cell lines LNCaP and PC3. Compounds 12 and 13 were found to exhibit much more potent inhibitory activities against the androgen dependent LNCaP cells than the androgen independent PC3 cells. Rapid synthesis of new 3,4-diarylpyrazoles and two 5-phenyl-6-benzyldihydropyridazinones with significant biological activity highlights the great potential of one-pot combinatorial modification for the diversification of natural products.

New hepatoprotective isoflavone glucosides from Pueraria lobata (Willd.) Ohwi

Two new isoflavone glucosides, 3'-methoxyneopuerarin A (1) and 3'-methoxyneopuerarin B (2), together with nine known isoflavones including puerarin (3), neopuerarin A (4), neopuerarin B (5), daidzin (6), daidzein (7), 3'-methoxypuerarin (PG-3) (8), puerarin xyloside (9), mirificin (10), 3'-hydroxypuerarin (11) were isolated from the water extraction of the dried roots of Pueraria lobata (Willd.) Ohwi. Their structures were elucidated by the means of spectroscopic and chromatographic analysis methods. All compounds were evaluated for their hepatoprotective activity on HepG2 cells. All of them showed statistically significant hepatoprotective effect.

Comparative molecular docking studies of lupeol and lupenone isolated from Pueraria lobata that inhibits BACE1: Probable remedies for Alzheimer's disease

OBJECTIVE

To discover lead lupane triterpenoid's potential isolated from Pueraria lobata roots against β-site amyloid precursor protein cleaving enzyme 1 (BACE1), which serve as a rate limiting step in amyloid beta (Aβ) production altering the course of Alzheimer's disease. In addition, enzyme kinetics study and molecular docking were conducted to establish the inhibition type and structure activity relationship.

METHODS

A systematic study of 70% ethanolic P. lobata root extract was employed to identify its BACE1 inhibitory potential. Further, BACE1 inhibitory potential of two lupane terpenoids, yielded from ethanolic extract, was assessed. In order to determine their inhibition mode, Lineweaver-Burk plots and Michaelis-Menten model for BACE1 was performed. AutoDock 4.2 program in addition determined the molecular interaction of BACE1 with isolated terpenoids.

RESULTS

Considering the inhibitory potential of 70% ethanolic extract of P. lobata against BACE1 (IC₅₀ = 80.35 μg/mL), lupeol and lupenone were subsequently isolated and exhibited notable or moderate BACE1 inhibitory activity with IC₅₀ values of 5.12 and 62.98 μmol/L, respectively, as compared to the positive control quercetin (IC₅₀ = 21.28 μmol/L). The enzyme kinetics study enabled us to identify both compounds as competitive inhibitors, where lupeol displayed a very potent inhibition against BACE1 with low inhibition constant (K_i) value of 1.43 μmol/L, signifying greater binding affinity. In order to understand the binding mechanism and structure-activity relationship of two triterpene-based BACE1 inhibitors, we employed computer aided docking studies which evidently revealed that hydroxyl group of lupeol formed two hydrogen bonds with the ASP32 (catalytic aspartic residue) and SER35 residues of BACE1 with the binding energy of (-8.2 kcal/mol), while the ketone group of lupenone did not form any hydrogen bonds with BACE1 giving evidence for less binding affinity. These results in turn have predicted the dependence of the inhibitory activity in the presence of hydroxyl group which has provided a new basis for BACE1 blockade.

CONCLUSIONS

Our results have successfully explored the molecular mechanism of lupane triterpenoids via BACE1 inhibition, suggesting that lupeol in particular could be utilized as a useful therapeutic and preventive agent to mitigate Alzheimer's disease.

Antioxidant and preventive effects of extract from nymphaea Candida flower on in vitro immunological liver injury of rat primary hepatocyte cultures

Nymphaea candida is traditional Uighur medicine that is commonly used to treat head pains, cough, hepatitis and hypertension in Xinjiang of China. In this article, the extract of N. candida was measured for antioxidant activity, using 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals scavenging assay and reducing power determination, and compared with those of the positive controls of butylated hydroxytoluene (BHT) and gallic acid (GA). The active extract was further purified by liquid-liquid partition to afford four fractions, of which the ethyl acetate-soluble (EA) fraction (NCE) exhibited the strongest antioxidant capacity with IC₅₀ value of 12.6 μg/mL for DPPH. Thirteen phenolic compounds were isolated from this fraction, and they all showed significant antioxidant activities in DPPH model system. Furthermore, NCE showed potent antioxidant capacity with IC₅₀ value of 59.32 μg/mL, 24.48 μg/mL and 86.85 μg/mL, for O₂⁻, ·OH and H₂O₂ radicals, respectively. Moreover, NCE on BCG plus LPS-induced immunological liver injury was evaluated using primary cultured rat hepatocytes. NCE produced significant hepatoprotective effects as evidenced by decreased supernatant enzyme activities (AST—aspartate transaminase, P <  .01; ALT—alanine transferase, P <  .01) and nitric oxide (NO, P <  .01) production. These results revealed the in vitro antioxidant and hepatoprotective activities of NCE against immunological liver injury. Further investigations are necessary to verify these activities in vivo.

Effects of Puerariae radix extract on the increasing intestinal permeability in rat with alcohol-induced liver injury

AIM OF THE STUDY

Puerariae radix, as an edible plant, has been used for centuries in China to treat alcohol-related problems, including alcoholic liver disease (ALD). However, the mechanisms of Puerariae radix on the liver-protective effect have not been fully explored. Because an increased intestinal permeability is a major factor for ALD, the present study investigates whether Puerariae radix extract (PRE) inhibits ALD through prevention of alterations in intestinal permeability.

MATERIALS AND METHODS

We used an animal model of chronic alcohol-induced liver injury that is associated with increased intestinal permeability. Male Wistar rats were given increasing alcohol doses from 2 g/kg/d to 8 g/kg/d and alcohol plus PRE via intragastric feeding for 10 weeks. Chronic alcohol exposure caused an elevation in serum alanine aminotransferase (ALT) as well as aspartate aminotransferase (AST) levels and a decrease in superoxide dismutase (SOD) activity, and hepatic damages including steatosis, inflammation, and necrosis, determined by serum enzymatic analysis and morphological analysis, respectively. The damage to small intestine induced by chronic alcohol treatment was examined by intestinal histological, immunohistochemical analysis, and permeability assays.

RESULTS

Alcohol-induced hepatic pathological changes, elevations in ALT and AST, and a decrease in SOD activity were significantly inhibited in PRE treated animals. The inhibitory effect of PRE on alcohol-induced liver injury was associated with suppression of alcohol induced the increase of intestinal permeability.

CONCLUSIONS

The results showed that this beneficial effect of PRE on ALD could be partly explained by improving intestinal barrier dysfunction induced by alcohol.

Triterpene glycosides from the roots of Astragalus flavescens

Six new triterpene saponins, 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-epi-kudzusapogenol A (1), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-21-epi-kudzusapogenol A (2), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-beta-D-glucopyranosyl-21-epi-kudzusapogenol A (3), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-beta-D-glucopyranosyl-21-epi-kudzusapogenol A (4), 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-xylopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-alpha-L-arabinopyranosyl-21-epi-kudzusapogenol A (5), and 3-O-alpha-L-rhamnopyranosyl-(1-->2)-beta-D-glucopyranosyl-(1-->2)-beta-D-glucuronopyranosyl-22-O-alpha-L-arabinopyranosyl-21-epi-kudzusapogenol A (6), were isolated from the roots of Astragalus flavescens, together with the known trajanoside B, azukisaponin V, and astragalosides IV, VII, and VIII. Their structures were established mainly by 2D NMR techniques and mass spectrometry.

Establishment ofin vitro test system for the evaluation of the estrogenic activities of natural products

In order to evaluate estrogenic compounds in natural products, an in vitro detection system was established. For this system, the human breast cancer cell line MCF7 was stably transfected using an estrogen responsive chloramphenicol acetyltransferase (CAT) reporter plasmid yielding MCF7/pDsCAT-ERE119-Ad2MLP cells. To test the estrogenic responsiveness of this in vitro assay system, MCF7/pDsCAT-ERE119-Ad2MLP cells were treated with various concentrations of 17beta-estradiol. Treatments of 10(-8) to 10(-12) M 17beta-estradiol revealed significant concentration dependent estrogenic activities compared with ethanol. We used in vitro assay system to detect estrogenic effects in Puerariae radix and Ginseng radix Rubra extracts. Treatment of 500 and 50 microg/ml of Puerariae radix extracts increased the transcriptional activity approximately 4- and 1.5-fold, respectively, compared with the ethanol treatment. Treatment of 500, 50, and 5 microg/ml of Ginseng radix Rubra extracts increased the transcriptional activity approximately 3.2-, 2.7-, and 1.4-fold, respectively, compared with the ethanol treatment. These observations suggest that Puerariae radix and Ginseng radix Rubra extracts have effective estrogenic actions and that they could be developed as estrogenic supplements.