Rapid evaluation of the quality of Smilax glabra Roxb. using QADS based on FT-NIR combined with multiple intelligent algorithms

Smilax glabra Roxb. (SGR) is known for its high nutritional and therapeutic value. However, the frequent appearance of counterfeit products causes confusion and inconsistent quality among SGR varieties. Herein, this study collected the proportion of SGR adulteration and used high-performance liquid chromatography (HPLC) to measure the astilbin content of SGR. Then Fourier-transform near-infrared (FT-NIR) technology, combined with multivariate intelligent algorithms, was used to establish partial least squares regression quantitative models for detecting SGR adulteration and measuring astilbin content, respectively. The method conducted a quantitative analysis of dual indicators through single-spectrum data acquisition (QADS) to comprehensively evaluate the authenticity and superiority of SGR. The coefficients of determination (R2) for both the calibration and prediction sets exceeded 0.96, which successfully leverages FT-NIR combined with multivariate intelligent algorithms to considerably enhance the accuracy and reliability of quantitative models. Overall, this research holds substantial value in the comprehensive quality evaluation in functional health foods.

Investigation of the molecular mechanism of Smilax glabra Roxb. in treating hypertension based on proteomics and bioinformatics

Background

Smilax glabra Roxb. (named tufuling in Chinese, SGR) has both medicinal and edible value. SGR has obvious pharmacological activity, especially in anti-inflammation and treating immune system diseases. This study investigated differential protein expression and its relationship with immune infiltration in hypertension treated with SGR using proteomics and bioinformatics.

Methods

N-Nitro L-arginine methyl ester (L-NAME) was used to replicate the hypertension model, with SGR administered by gavage for 4 weeks, and the systolic and diastolic blood pressure in each group of rats was measured using the tail-cuff method every 7 days. Furthermore, enzyme-linked immunosorbent assay (ELISA) was used to determine the serum total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and high-density lipoprotein cholesterol (HDL-C) expressions in each group, followed by the detection of protein expression in rat liver samples using the tandem mass tag (TMT) technique. Additionally, hub targets were output using Cytoscape 3.9.1 software, and ALDH2 expression in the liver and serum in each group of rats was detected by ELISA. Moreover, R4.3.0 software was used to evaluate the relationship between acetaldehyde dehydrogenase 2 (ALDH2) and immune cells, and ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was performed to identify the components of SGR. Furthermore, the association between components of SGR and ALDH2 was analyzed with molecular docking and LigPlot1.4.5 software.

Results

Compared with the model group (L-NAME), SGR at high and medium doses reduced systolic and diastolic blood pressure while reducing TC, TG, and LDL-C levels and increasing HDL-C levels in hypertensive rats (p < 0.05). Moreover, 92 differentially expressed proteins (DEPs) were identified using TMT. These DEPs participated in peroxisome functioning, fatty acid degradation, and other signaling pathways, with ALDH2 being the core target and correlated with various immune cells. In addition, 18 components were determined in SGR, with 8 compounds binding to ALDH2. Molecular docking was performed to confirm that SGR played a role in hypertension based on the combined action of multiple components.

Conclusion

In conclusion, SGR has an antihypertensive effect on L-NAME-induced hypertension, with ALDH2 as its hub target. SGR may regulate neutrophil, regulatory T cell, and other cells' infiltration by targeting ALDH2, thereby contributing to the treatment of hypertension.

A network pharmacology-based approach to explore the active ingredients and molecular mechanism of Lei-gong-gen formula granule on a spontaneously hypertensive rat model

Background

Lei-gong-gen formula granule (LFG) is a folk prescription derived from Zhuang nationality, the largest ethnic minority among 56 nationalities in China. It consists of three herbs, namely Eclipta prostrata (L.) L., Smilax glabra Roxb, and Centella asiatica (L.) Urb. It has been widely used as health protection tea for hundreds of years to prevent hypertension in Guangxi Zhuang Autonomous Region. The purpose of this study is to validate the antihypertensive effect of LFG on the spontaneously hypertensive rat (SHR) model, and to further identify the effective components and anti-hypertension mechanism of LFG.

Methods

The effects of LFG on blood pressure, body weight, and heart rate were investigated in vivo using the SHR model. The levels of NO, ANG II, and ET-1 in the serum were measured, and pathological changes in the heart were examined by H&E staining. The main active components of LFG, their corresponding targets, and hypertension associated pathways were discerned through network pharmacology analysis based on the Traditional Chinese Medicine Systems Pharmacology (TCMSP), Traditional Chinese Medicine Integrated Database (TCMID), and the Bioinformatics Analysis Tool for Molecular Mechanism of Traditional Chinese Medicine (BATMAN-TCM). Then the predicted results were further verified by molecular biology experiments such as RT-qPCR and western blot. Additionally, the potential active compounds were predicted by molecular docking technology, and the chemical constituents of LFG were analyzed and identified by UPLC-QTOF/MS technology. Finally, an in vitro assay was performed to investigate the protective effects of potential active compounds against hydrogen peroxide (H₂O₂) induced oxidative damage in human umbilical vein endothelial cells (HUVEC).

Results

LFG could effectively reduce blood pressure and increase serum NO content in SHR model. Histological results showed that LFG could ameliorate pathological changes such as cardiac hypertrophy and interstitial inflammation. From network pharmacology analysis, 53 candidate active compounds of LFG were collected, which linked to 765 potential targets, and 828 hypertension associated targets were retrieved, from which 12 overlapped targets both related to candidate active compounds from LFG and hypertension were screened and used as the potential targets of LFG on antihypertensive effect. The molecular biology experiments of the 12 overlapped targets showed that LFG could upregulate the mRNA and protein expressions of NOS3 and proto-oncogene tyrosine-protein kinase SRC (SRC) in the thoracic aorta. Pathway enrichment analysis showed that the PI3K-AKT signaling pathway was closely related to the expression of NOS3 and SRC. Moreover, western blot results showed that LFG significantly increased the protein expression levels of PI3K and phosphorylated AKT in SHR model, suggesting that LFG may active the PI3K-AKT signaling pathway to decrease hypertension. Molecular docking study further supported that p-hydroxybenzoic acid, cedar acid, shikimic acid, salicylic acid, nicotinic acid, linalool, and histidine can be well binding with NOS3, SRC, PI3K, and AKT. UPLC-QTOF/MS analysis confirmed that p-hydroxybenzoic acid, shikimic acid, salicylic acid, and nicotinic acid existed in LFG. Pre-treatment of HUVEC with nicotinic acid could alleviate the effect on cell viability induced by H₂O₂ and increase the NO level in cell supernatants.

Conclusions

LFG can reduce the blood pressure in SHR model, which might be attributed to increasing the NO level in serum for promoting vasodilation via upregulating SRC expression level and activating the PI3K-AKT-NOS3 signaling pathway. Nicotinic acid might be the potential compound for LFG antihypertensive effect.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13020-021-00507-1.

Lei-gong-gen formula granule attenuates hyperlipidemia in rats via cGMP-PKG signaling pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Lei-gong-gen formula granule (LFG) is a folk prescription derived from Zhuang nationality, the largest ethnic minority among the 56 nationalities in China. It is composed of three herbs, namely Centella asiatica (L.) Urb., Eclipta prostrata (L.) L., Smilax glabra Roxb. It has been widely used as health protection tea for many years to prevent cardiovascular and cerebrovascular diseases such as hyperlipidemia and hypertension.

AIM OF THE STUDY

This study validated the lipid-lowering effect of LFG in a hyperlipidemia rat model. Then we employed network pharmacology and molecular biological approach to identify the active ingredients of LFG, corresponding targets, and its anti-hyperlipidemia mechanisms.

MATERIALS AND METHODS

Hyperlipidemia rat model was established by feeding male Sprague-Dawley rats with high-fat diet for two weeks. LFG (two doses of 10 and 20 g/kg) was administered orally to hyperlipidemia rat model for 4 weeks, twice per day. Serum levels of total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) were monitored in rats pre and post-treatment. Hematoxylin-eosin staining was applied to observe the pathology and lipid accumulation of liver. We then performed network pharmacology analysis to predict the ingredients, their associated targets, and hyperlipidemia associated targets. Pathway analysis with significant genes was carried out using KEGG pathway. These genes and proteins intersectioned between compound targets and hyperlipidemia targets were further verified with samples from hyperlipidemia rats treated with LFG using Real-time RT-PCR and Western Blot.

RESULTS

LFG attenuated hyperlipidemia in rat model, and this was characterized with decreased serum levels of TC, LDL-C, liver wet weight, and liver index. LFG alleviated the hepatic steatosis in hyperlipidemia rats. Network pharmacology analysis identified 53 bioactive ingredients from LFG formula (three herbs), which link to 765 potential targets. 53 hyperlipidemia associated genes were retrieved from public databases. There were 10 common genes between ingredients-targets and hyperlipidemia associated genes, which linked to 20 bioactive ingredients. Among these 10 genes, 3 of them were validated to be involved in LFG's anti-hyperlipidemia effect using Real-time RT-PCR, namely ADRB2 encoding beta-2 adrenergic receptor, NOS3 encoding nitric oxide synthase 3, LDLR encoding low-density lipoprotein receptor. The cGMP-PKG signaling pathway was enriched for hyperlipidemia after pharmacology network analysis with ADRB2, NOS3, and LDLR. Interestingly, expression of cGMP-dependent protein kinase (PKG) was downregulated in hyperlipidemia rat after LFG treatment. Molecular docking study further supported that ferulic acid, histidine, p-hydroxybenzoic acid, and linalool were potential active ingredients for LFG's anti-hyperlipidemia effect. LC-MS/MS analysis confirmed that ferulic acid and p-hydroxybenzoic acid were active ingredients of LFG.

CONCLUSION

LFG exhibited the lipid-lowering effect, which might be attributed to downregulating ADRB2 and NOS3, and upregulating LDLR through the cGMP-PKG signaling pathway in hyperlipidemia rat. Ferulic acid and p-hydroxybenzoic acid might be the underlying active ingredients which affect the potential targets for their anti-hyperlipidemia effect.

Protective Effects of Smilax glabra Roxb. Against Lead-Induced Renal Oxidative Stress, Inflammation and Apoptosis in Weaning Rats and HEK-293 Cells

Lead (Pb) is an important environmental pollutant. Oxidative stress and the inflammatory response have been postulated as mechanisms involved in lead-induced renal damage. Smilax glabra Roxb. has been used for treatment of heavy-metal poisoning in China for 500 years. We investigated S. glabra flavonoids extract (SGF) could attenuate lead acetate-induced nephrotoxicity in weaning rats and human embryonic kidney (HEK)-293 cells, and investigated the possible mechanisms. Compared with Pb exposed group of weaning rats, SGF could significantly promote lead excretion in the blood and kidney, and increase the content of the renal-function indicators blood urea nitrogen, serum uric acid, and serum creatinine. SGF could improve the glomerular filtration rate (GFR) and histologic changes in the kidneys of weaning rats exposed to Pb. SGF could also reduce lead-induced cytotoxicity, improve DNA damage-induced apoptosis and cleaved caspase-3-mediated apoptosis in HEK-293 cells stimulated with Pb. SGF significantly increased the activity of the antioxidant enzymes superoxide dismutase, glutathione peroxidase and catalase, and decreased excessive release of reactive oxygen species (ROS) and malondialdehyde in the kidneys of the weaning rats and in HEK-293 cells. The antioxidant mechanism of SGF related to activation of the Kelch-like ECH-associated protein 1/nuclear-factor-E2-related factor 2/hemeoxygenase-1(Keap1/Nrf2/HO-1) pathway. SGF could inhibit secretion of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α induced by Pb in vivo and in vitro. The anti-inflammatory mechanism of SGF related to inhibition of ROS and pro-inflammatory cytokines triggered the nuclear factor-kappa B (NF-κB) pathway through blockade of inhibitors of I-κB degradation, phosphorylation of NF-κB p65, and nuclear translocation of p65. Our findings indicate that SGF could be a natural antioxidant and anti-inflammatory agent for treating lead-induced nephrotoxicity.

Smilax glabra Roxb. Inhibits Collagen Induced Adhesion and Migration of PC3 and LNCaP Prostate Cancer Cells through the Inhibition of Beta 1 Integrin Expression

Smilax glabra Roxb. (SGR) has been used as a traditional medicine for brucellosis and syphilis. In this study, we investigated whether nontoxicological levels of water extract of SGR (WESGR) are effective for suppressing steps in the progression of prostate cancer, such as collagen-mediated migration and adhesion and identified the target molecule responsible for such effects. We found that nontoxicological levels of WESGR did not attenuate PC3 and LNCaP cell adhesion to serum but did significantly do so with collagen. In addition, using the Boyden chamber assay, we found that nontoxicological levels of WESGR did not inhibit the migration of PC3 and LNCaP cells to a serum-coated area but did significantly attenuate migration to a collagen-coated area. Interestingly, the expression of α2β1 integrin, a known receptor of collagen, was not affected by ectopic administration of WESGR. However, WESGR significantly attenuated the expression of β1 integrin, but not α2 integrin when PC3 and LNCaP cells were placed on a collagen-coated plate, resulting in attenuation of focal adherent kinase phosphorylation. Finally, 5-O-caffeoylquinic acid was determined as a functional single component which is responsible for antiprostate cancer effects of WESGR. Taken together, our results suggest a novel molecular mechanism for WESGR-mediated antiprostate cancer effects at particular steps such as with migration and adhesion to collagen, and it could provide the possibility of therapeutic use of WESGR against prostate cancer progression.

Therapeutic effects of Smilax glabra and Bolbostemma paniculatum on rheumatoid arthritis using a rat paw edema model

Smilax glabra Roxb. (Tufuling) and Bolbostemma paniculatum (Maxim.) Franquet (Tubeimu) are used as couplet medicine in traditional Chinese medicine for the treatment of arthritis. This study is conducted to provide evidence on their therapeutic effects on rheumatoid arthritis (RA) and to explore its possible mechanisms of action. The identification and quantification of representative components (Astilbin and Tubeimoside I) in the n-butyl alcohol fraction of this couplet medicine (BFCM) were carried out by HPLC-UV assays. The contents of Astilbin and Tubeimoside I in BFCM were 13.13% (15.434 min) and 3.4% (18.619 min) respectively. For the assessment of anti-RA and anti-inflammatory activities, a carrageenan-induced paw edema model in rats was used. The swelling rates of paws and levels of IL-1β, IL-6 and TNF-α in the swelling tissue were determined. We observed that the BFCM exhibited significant inhibitory activity on carrageenan-induced paw edema model (p<0.01). The down regulated levels of IL-1β, IL-6 and TNF-α (all p<0.05) were reported. The results indicate that BFCM possesses significant anti-RA and anti-inflammatory effects, and it has a potential to be developed as a new therapeutic agent against RA.

The protective effect of Smilax glabra extract on advanced glycation end products-induced endothelial dysfunction in HUVECs via RAGE-ERK1/2-NF-κB pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Smilax glabra Roxb. (SGR) is a traditional Chinese herb that has been used in folk for the treatment of diabetic vascular complications. Advanced glycation end products (AGEs)-induced endothelial dysfunction has been thought to be a major cause of diabetic vascular complications. The present study was conducted to investigate the protective effect of SGR extract on AGEs-induced endothelial dysfunction and its underlying mechanisms.

MATERIALS AND METHODS

Human umbilical vein endothelial cells (HUVECs) were exposed to 200 μg/ml AGEs to induce endothelial dysfunction. Acridine orange/ethidium bromide (AO/EB) fluorescence assay and Annexin-V/PI double-staining were performed to determine endothelium apoptosis. Dihydroethidium (DHE) fluorescence probe, SOD and MDA kits were used to evaluate oxidative stress. The effect of SGR extract on AGEs-induced TGF-beta1 expression was determined by immunocytochemistry and western blotting. Attenuations of SGR extract on receptor for AGEs (RAGE) expression, extracellular regulated protein kinases (ERK1/2) activation and NF-κB phosphorylation were determined by immunofluorescence assay and western blotting. The blockade assays for RAGE and ERK1/2 were carried out using a specific RAGE-antibody (RAGE-Ab) or a selective ERK1/2 inhibitor PD98059 in immunofluorescence assay.

RESULTS

The pretreatment of SGR extract (0.125, 0.25 and 0.5 mg crude drug/ml) significantly attenuated AGEs-induced endothelium apoptosis, and down-regulated TGF-beta1 protein expression in HUVECs. It was also well shown that SGR extract could down-regulate dose-dependently ROS over-generation, MDA content, TGF-beta1 expression, ERK1/2 and NF-κB activation whereas increase significantly SOD activity. Furthermore, the AGEs-induced ERK1/2 activation could be attenuated by the blockade of RAGE-Ab (5 μg/ml) while the NF-κB activation was ameliorated by ERK1/2 inhibitor PD98059 (10 μM).

CONCLUSION

These results indicated that SGR extract could attenuate AGEs-induced endothelial dysfunction via RAGE-ERK1/2-NF-κB pathways. Our findings suggest that SGR extract may be beneficial for attenuating endothelial dysfunction in diabetic vascular complications.