Spatially resolved metabolomics combined with bioactivity analyses to evaluate the pharmacological properties of two Radix Puerariae species

ETHNOPHARMACOLOGICAL RELEVANCE

P. lobata and P. thomsonii are medicinal plants with similar pharmacological functions but different therapeutic effects. A novel method is presented herein to investigate metabolites in terms of their distribution and qualification, quantification is necessary to elucidate the different therapeutic effects of the two Puerariae species.

AIM OF THE STUDY

The aim of the present study was to perform spatially resolved metabolomics combined with bioactivity analyses to systematically compare the metabolite differences in P. lobata and P. thomsonii by distribution, qualification, quantification, and biological activity to evaluate their pharmacological properties.

MATERIALS AND METHODS

Air flow-assisted desorption electrospray ionization-mass spectrometry imaging (AFADESI-MSI) was performed to characterize the differences in the metabolite distributions of P. lobata and P. thomsonii. Further qualitative and quantitative analyses of the differential metabolites were performed using liquid chromatography-mass spectrometry (LC-MS). Biological activities correlated with the differences in the metabolites were validated by MTT assays.

RESULTS

Some metabolites showed complementary distributions of the phloem and xylem in the two species, saccharide, vitamin, and inosine levels were higher in the phloem of P. thomsonii but higher in the xylem of P. lobata. The 3'-hydroxyl puerarin level was higher in the xylem of P. thomsonii but higher in the phloem of P. lobata. Qualitative and quantitative analyses of the metabolites revealed a total of 52 key differential metabolites. MTT assays showed that daidzein, daidzin, puerarin, ononin, genistin, formononetin, 3'-hydroxy puerarin, 3'-methoxy puerarin, mirificin, and 3'-methoxy daidzin exerted protective effects on H9c2 cells against hypoxia/reoxygenation injury. P. lobata extracts exhibited a significantly better protective efficacy than P. thomsonii extracts.

CONCLUSIONS

In this study, AFADESI-MSI combined with LC-MS and biological activities comprehensively elucidated metabolite differences in the distribution, qualification, quantification, and pharmacological properties of P. lobata and P. thomsonii. The results of this study could provide a novel strategy for species identification and quality assessment of similar Chinese herbal medicines.

Quantitative analysis of nine isoflavones in traditional Chinese medicines using mixed micellar liquid chromatography containing sodium dodecylsulfate/β-cyclodextrin supramolecular amphiphiles

Isoflavone is one of the phytoestrogens that have estrogenic effects, so it is usually served as an active ingredient for quality control of traditional Chinese medicines rich in isoflavones. Nine isoflavones commonly found in traditional Chinese medicines were separated in 30 min using mixed micellar liquid chromatography. The mobile phase consisted of 0.08 M sodium dodecylsulfate and 6.05 mM β-cyclodextrin:methanol (87:13, v/v) at pH 3 and eluted isocratically at 1 mL/min through a C18 column. In this study, we systematically optimized the chromatographic conditions including the pH, the composition and concentration of surfactants, the type and ratio of organic solvents, and column temperature. The method was validated according to the International Council for Harmonization of Technical Requirements for Pharmaceuticals for Human Use guidelines. There is no report using micellar liquid chromatography to detect isoflavones, and the optimized method has been successfully applied to quantify isoflavones in red clover and Radix Puerariae. This method is efficient, cheap, and convenient. Finally, we verified the existence of supramolecular amphiphilic vesicles in the mobile phase by transmission electron microscopy to explain the increased chromatographic efficiency.

Radix Puerariae rebalances vasomotor factors and improves left ventricular diastolic dysfunction in patients with essential hypertension

The aim of the present study was to validate the beneficial role of Radix Puerariae in rebalancing the plasma levels of endothelin, angiotensin II (AngII) and calcitonin gene-related peptide (CGRP) in patients with essential hypertension (EHT). A total of 150 patients with EHT were enrolled consecutively and randomized to receive antihypertensive drugs according to guideline-directed medical therapy (GDMT group) and GDMT plus Radix Puerariae (GDMT + RP group). The blood pressure was recorded biweekly. At baseline and at the end of the follow-up (12 weeks), the plasma levels of endothelin, AngII and CGRP were detected, whilst the left ventricular (LV) diastolic function was evaluated by echocardiography. At baseline, the two groups did not differ in terms of demographic characteristics and LV diastolic dysfunction. At the end of the follow-up, lower blood pressure was observed in the GDMT + RP compared with that in the GDMT group. The plasma levels of AngII and endothelin were also significantly lower in the GDMT + RP group. The plasma levels of CGRP increased significantly in the GDMT + RP compared with those in the GDMT group. The addition of Radix Puerariae improved LV diastolic function, with the percentage of dysfunction decreasing to only 9%, while this percentage remained significantly elevated (21%) in the GDMT group. The results of the present study demonstrated that Radix Puerariae is able to regulate blood pressure and the plasma levels of endothelin, AngII and CGRP in patients with EHT. LV diastolic dysfunction was also improved, as detected by echocardiography.

Extraction of high-amylose starch from Radix Puerariae using high-intensity low-frequency ultrasound

High-amylose starch is in great demand in the food industry due to its unique functional properties but has very limited source. In this study, high-amylose starch was successfully extracted from Radix Puerariae using ultrasound extraction. The effects of ultrasound intensity (15.29, 20.38, 22.93, 24.46 and 25.38 kW/m²) and frequency (20 and 45 kHz) on extraction kinetics, and chemical compositions, crystallinity, in vitro digestion behaviour and gelling properties of starches were investigated. It was shown that with the increasing intensity, the extraction rate and content of amylose increased, but for starch the extraction rate increased initially until reached a plateau at an intensity of 24.46 kW/m². With the increasing low-frequency, the extraction rate and content of amylose increased, but the extraction rate of starch decreased. Based on statistical tests, the Logistic model was found to fit well to the extraction kinetics of amylose, and the Peleg model fit well to that of starch. The extraction yield of starch was not significantly affected by ultrasound conditions. The obtained starch has a high-purity with a content of more than 99% dry basis and an unchanged crystallinity. Moreover, the increased amylose content resulted in an increase of the content of slowly digestible starch, resistant starch, and gelling hardness. This study demonstrates that high-amylose starch can be obtained using ultrasound extraction from Radix Puerariae at high-intensity low-frequency.

Puerarin ameliorates allodynia and hyperalgesia in rats with peripheral nerve injury

Puerarin is a major active ingredient of the traditional Chinese plant medicine, Radix Puerariae, and commonly used in the treatment of myocardial and cerebral ischemia. However, the effects of puerarin on neuropathic pain are still unclear. In this study, a neuropathic pain animal model was created by partial sciatic nerve ligation. Puerarin (30 or 60 mg/kg) was intraperitoneally injected once a day for 7 days. Mechanical allodynia and thermal hyperalgesia were examined at 1 day after model establishment. Mechanical threshold and paw withdrawal latency markedly increased in a dose-dependent manner in puerarin-treated rats, especially at 7 days after model establishment. At 7 days after model establishment, quantitative real-time reverse transcriptase-polymerase chain reaction results showed that puerarin administration reversed mRNA expression of transient receptor potential vanilloid 1 (Trpv1) and transient receptor potential ankyrin 1 (Trpa1) in a dose-dependent manner in dorsal root ganglion neurons after peripheral nerve injury. These results suggest that puerarin dose-dependently ameliorates neuropathic pain by suppressing Trpv1 and Trpa1 up-regulation in dorsal root ganglion of neuropathic pain rats.

Radix Puerariae modulates glutamatergic synaptic architecture and potentiates functional synaptic plasticity in primary hippocampal neurons

ETHNOPHARMACOLOGICAL RELEVANCE

Neurologic disorders are frequently characterized by synaptic pathology, including abnormal density and morphology of dendritic spines, synapse loss, and aberrant synaptic signaling and plasticity. Therefore, to promote and/or protect synapses by the use of natural molecules capable of modulating neurodevelopmental events, such as, spinogenesis and synaptic plasticity, could offer a preventive and curative strategy for nervous disorders associated with synaptic pathology. Radix Puerariae, the root of Pueraria monatana var. lobata (Willd.) Sanjappa&Pradeep, is a Chinese ethnomedicine, traditionally used for the treatment of memory-related nervous disorders including Alzheimer's disease. In the previous study, we showed that the ethanolic extracts of Radix Puerariae (RPE) and its prime constituent, puerarin induced neuritogenesis and synapse formation in cultured hippocampal neurons, and thus could improve memory functions.

AIMS OF THE STUDY

In the present study, we specifically investigated the abilities of RPE and puerarin to improve memory-related brain disorders through modulating synaptic maturation and functional potentiation.

MATERIALS AND METHODS

Rat embryonic (E19) brain neurons were cultured in the absence or presence of RPE or puerarin. At predetermined times, cells were live-stained with DiO or fixed and immunostained to visualize neuronal morphologies, or lysed for protein harvesting. Morphometric analyses of dendritic spines and synaptogenesis were performed using Image J software. Functional pre- and postsynaptic plasticity was measured by FM1-43 staining and whole-cell patch clamping, respectively. RPE or puerarin-mediated changes in actin-related protein 2 were assessed by Western blotting. Neuronal survivals were measured using propidium iodide exclusion assay.

RESULTS

RPE and puerarin both: (1) promoted a significant increase in the numbers, and maturation, of dendritic spines; (2) modulated the formation of glutamatergic synapses; (3) potentiated synaptic transmission by increasing the sizes of reserve vesicle pools at presynaptic terminals; (4) enhanced NMDA receptor-mediated postsynaptic currents, and (5) increased cell viability against naturally occurring cell death. Moreover, upregulation of actin-related protein 2 (ARP2) in RPE and puerarin treated brain neurons suggest that RPE and puerarin induced synaptic plasticity might be associated, at least in part, with ARP2-mediated actin-dependent regulation of spinogenesis.

CONCLUSIONS

Our findings indicate that RPE and puerarin might play a substantial role in the morphological and functional maturation of brain neurons and suggest that RPE and puerarin are potentially valuable preventative therapeutics for memory-related nervous disorders.

Radix Puerariae and Fructus Crataegi mixture inhibits renal injury in type 2 diabetes via decreasing of AKT/PI3K

Background

Radix puerariae (RP) is a herbal medicines for diabetes, mainly because of anti-oxidative, insulin resistance and hypoglycemic effect. Fructus crataegi (FC) also possesses strong antioxidant activity in vitro. This study focused on the effects of herbal mixture of RP and FC (RPFC) on renal protection through a diabetic rat model.

Methods

Type 2 Diabetic model was established with high fat diet followed by injecting rats a low dose of STZ (25 mg/kg body weight). Rats were randomly divided into five groups: normal, high fat diet, diabetes mellitus, high fat diet plus RPFC prevention, and RPFC prevention before diabetes mellitus. RPFC was given to rats daily by intragastric gavage. The blood bio-chemical index and renal pathological changes were examined. The later includes hematoxylin and eosin staining, periodic acid schiff staining, and Masson trichrome staining. Protein levels of were determined by Western blot and immunohistochemical staining. mRNA levels were detected by RT-PCR.

Results

Rats prevented with RPFC resulted in decreasing blood glucose with corresponding vehicle treated rats. Glomerulus mesangial matrix expansion, renal capsule constriction, and renal tubular epithelial cell edema were less severe following RPFC prevention. Moreover, RPFC prevention reduced protein levels of PI3K, AKT, α-SMA and collagen IV in the kidney of diabetic rats.

Conclusion

Combined prevention with RPFC may inhibit the PI3K/AKT pathway in the kidney, thereby prevent renal injury in diabetic rats.

Enhancement of antioxidant activity of Radix Puerariae and red yeast rice by mixed fermentation with Monascus purpureus

In this work, a new functional food combined Radix Puerariae and red yeast rice was explored. The pigment intensity, antioxidant activities and the main isoflavones of it were evaluated and compared with traditional red yeast rice and Radix Puerariae. The fermented mixture showed higher contents of isoflavones and pigment intensities than red yeast rice and Radix Puerariae. The DPPH, OH, FRAP and total antioxidant activity results of fermented mixture also showed higher antioxidant potential than those of Radix Puerariae and red yeast rice, owing to the higher pigment intensity and total phenolic contents. It is concluded that the fermented mixture of Radix Puerariae and rice could be widely used as a source of polyphenols with high antioxidative potential, thus introducing numerous health benefits for the consumer.

LC-MS/MS determination and pharmacokinetics study of puerarin and daidzein in rat plasma after oral administration of Gegenqinlian decoction and Radix Puerariae extract

Background:

Gegenqinlian decoction (GQD) is a famous traditional medicine recipe. It is composed of four herbs including Radix Puerariae (GG), Radix Scutellariae (HQ), Rhizoma Coptidis (HL) and Radix Glycyrrhizae (GC), which is widely used for treating gastro-intestinal disorders in the clinical practice of Traditional Chinese medicine (TCM). The aim of this study was to compare the pharmacokinetics of puerarin and daidzein in rats following oral administration of Gegenqinlian Decoction and Radix Puerariae extract. Thus, a sensitive and selective liquid chromatography/tandem mass spectrometry (LC-MS/MS) method was developed and validated for simultaneous determination of puerarin and daidzein in rat plasma following oral administration of Gegenqinlian Decoction and Radix Puerariae extract.

Materials and Methods:

Chromatographic separation was performed on a Shiseido CAPCELL PAK C₁₈ analytical column (100 mm × 2.0 mm i.d., 5 μm) by linear gradient elution, with water (0.1% formic acid)-acetonitrile (0.1% formic acid) as mobile phase. Detection was carried out by multiple reaction monitoring (MRM) mode using electrospray ionization in the positive ion mode.

Results:

The calibration curves were linear over a range of 7.80-1560 ng/mL for puerarin and 6.30-1260 ng/mL for daidzein. The intra- and inter-day precision values were less than 13.6% and their average recoveries was in the range of 77.8% and 88.6% for puerarin and was between 76.3 and 86.8% for daidzein, respectively.

Conclusion:

The validated method was applied to the comparative pharmacokinetic studies of puerarin and daidzein after oral administration of Gegenqinlian Decoction and Radix Puerariae extract. The pharmacokinetic parameters showed that puerarin and daidzein from Gegenqinlian Decoction were absorbed more effectively with slower elimination in rat plasma than that from Radix Puerariae extract. These results revealed that as far as the Radix Puerariae extract was concerned, it is very valuable to be used as a clinical directions of Gegenqinlian Decoction.