Effectiveness of herbs taken concurrently with antihypertensive drugs in managing hypertension and lipid outcomes. A systematic review and meta-analysis

PURPOSE

Hypertension is the primary cause of mortality. Hence globally, there is a growing interest in complementing antihypertensive drugs with herbs to alleviate blood pressure among hypertensive patients. Thus, this review aimed to evaluate the effectiveness of complementing drugs with herbs on blood pressure and lipid profile outcomes, the associated factors and the types of complementary herbs alongside their consumption regimes.

METHODS

This review is registered in PROSPERO on the National Institute of Health Database with an ID: CRD42021270481. Using the PICOS (population, intervention, comparison, outcome, study type) mnemonic formula and search strategy, we searched (January 2010 to February 2024) five electronic databases including Pubmed, Scopus, Web of Science, CINAHL (Cumulative Index for Nursing and Allied Health Literature) and Psychology & Behavioral Sciences Collection (PBSC). The inclusion criteria of the review were that all included papers had to be randomised control trials in English among hypertensive adults who complemented antihypertensive drugs with herbs. A Cochrane risk of bias assessment as well as a meta-analysis and narrative synthesis were conducted to answer the objectives.

RESULTS

Twenty-five randomised controlled trials involving 1996 participants from 14 countries were included. The risk of bias among included articles was assessed and presented using the Cochrane risk of bias tool and the graphs were generated. The effects of complementing antihypertensive drugs with different herb regimes on blood pressure and lipid profile outcomes were compared to those solely on antihypertensive drugs and placebo via a random model effects meta-analysis using the Revman manager. Systolic blood pressure (SBP) and triglycerides gave a significant reduction in favour of the intervention group which complemented herbs. The overall pooled systolic blood pressure showed a reduction of (SMD=0.81, 95 % CI 0.14-1.47, p < 0.02, p for heterogeneity=0.00001, I2 =97 %) while triglycerides were (SMD=0.73, 95 % CI 0.17-1.28, p < 0.01, p for heterogeneity=0.00001, I2 =85 %). However, diastolic blood pressure, total cholesterol, HDL and LDL did not exert significant outcomes.

CONCLUSION

The complemented herbs with antihypertensive drugs did show improvement in overall blood pressure management in the majority of the studies compared to the placebo group. Blood pressure and lipid profiles are the health outcomes that enable access to complementing herbs in controlling high blood pressure. Some limitations of this review are attributed to performance, detection and attrition bias in a few included articles alongside the presence of a high heterogeneity overall.

Design, Synthesis, and Biological Evaluation of SSE1806, a Microtubule Destabilizer That Overcomes Multidrug Resistance

Microtubules are dynamic structures that form spindle fibers during cell division; pharmacological inhibition of microtubule dynamics arrests cells in mitosis, leading to apoptosis, and they have been extensively used to treat various cancers. However, the efficacy of such drugs is often limited by multidrug resistance. This study synthesized and evaluated 30 novel derivatives of podophyllotoxin, a natural antimitotic compound, for their antiproliferative activities. Compound SSE1806 exhibited the most potent antiproliferative activity with GI50 values ranging from 1.29 ± 0.01 to 21.15 ± 2.1 μM in cancer cell lines of different origins; it directly inhibited microtubule polymerization, causing aberrant mitosis and G2/M arrest. Prolonged treatment with SSE1806 increased p53 expression, induced cell death in monolayer cultures, and reduced the growth of mouse- and patient-derived human colon cancer organoids. Importantly, SSE1806 overcame multidrug resistance in a cell line overexpressing MDR-1. Thus, SSE1806 represents a potential anticancer agent that can overcome multidrug resistance.

The Potential Role of Apigenin in Cancer Prevention and Treatment

Cancer is the leading cause of death worldwide. In spite of advances in the treatment of cancer, currently used treatment modules including chemotherapy, hormone therapy, radiation therapy and targeted therapy causes adverse effects and kills the normal cells. Therefore, the goal of more effective and less side effects-based cancer treatment approaches is still at the primary position of present research. Medicinal plants or their bioactive ingredients act as dynamic sources of drugs due to their having less side effects and also shows the role in reduction of resistance against cancer therapy. Apigenin is an edible plant-derived flavonoid that has received significant scientific consideration for its health-promoting potential through modulation of inflammation, oxidative stress and various other biological activities. Moreover, the anti-cancer potential of apigenin is confirmed through its ability to modulate various cell signalling pathways, including tumor suppressor genes, angiogenesis, apoptosis, cell cycle, inflammation, apoptosis, PI3K/AKT, NF-κB, MAPK/ERK and STAT3 pathways. The current review mainly emphases the potential role of apigenin in different types of cancer through the modulation of various cell signaling pathways. Further studies based on clinical trials are needed to explore the role of apigenin in cancer management and explain the possible potential mechanisms of action in this vista.

Potential antidiabetic phytochemicals in plant roots: a review of in vivo studies

Background

Medicinal plants are used to treat various disorders, including diabetes, globally in a range of formulations. While attention has mainly been on the aerial plant parts, there are only a few review studies to date that are focused on the natural constituents present in the plant roots with health benefits. Thus, the present study was performed to review in vivo studies investigating the antidiabetic potential of the natural compounds in plant roots.

Methods

We sorted relevant data in 2001-2019 from scientific databases and search engines, including Web of Knowledge, PubMed, ScienceDirect, Medline, Reaxys, and Google Scholar. The class of phytochemicals, plant families, major compounds, active constituents, effective dosages, type of extracts, time of experiments, and type of diabetic induction were described.

Results

In our literature review, we found 104 plants with determined antidiabetic activity in their root extracts. The biosynthesis pathways and mechanism of actions of the most frequent class of compounds were also proposed. The results of this review indicated that flavonoids, phenolic compounds, alkaloids, and phytosteroids are the most abundant natural compounds in plant roots with antidiabetic activity. Phytochemicals in plant roots possess different mechanisms of action to control diabetes, including inhibition of α-amylase and α-glucosidase enzymes, oxidative stress reduction, secretion of insulin, improvement of diabetic retinopathy/nephropathy, slow the starch digestion, and contribution against hyperglycemia.

Conclusion

This review concludes that plant roots are a promising source of bioactive compounds which can be explored to develop against diabetes and diabetes-related complications.

Graphical abstract

Medicinal Plants in the Treatment of Hypertension: A Review

Traditional medicine is a comprehensive term for ancient, culture-bound health care practices that existed before the use of science in health matters and has been used for centuries. Medicinal plants are used to treat patients with cardiovascular diseases, which may occur due to ailments of the heart and blood vessels and comprise heart attacks, cerebrovascular diseases, hypertension, and heart failure. Hypertension causes difficulty in the functioning of the heart and is involved in atherosclerosis, raising the risk of heart attack and stroke. Many drugs are available for managing these diseases, though common antihypertensive drugs are generally accompanied by many side effects. Medicinal herbs have several active substances with pharmacological and prophylactic properties that can be used in the treatment of hypertension. This review presents an overview of some medicinal plants that have been shown to have hypotensive or antihypertensive properties.

Rhus coriaria L., a new candidate for controlling metabolic syndrome: a systematic review

OBJECTIVES

Rhus coriaria L. (RC) is a deciduous shrub with several pharmacological activities. Evidence of the effects of RC on weight, hyperlipidaemia, hypertension and diabetes mellitus have been presented in this study. Books, thesis and internet-based resources such as PubMed, Web of Science, Scopus, EMBASE, Cochrane, Ovid and Google Scholar were searched for the English, Arabic and Persian literature from 1966 to 2020 (December). The keywords were Rhus coriaria L., Sumac, metabolic syndrome and all its medical conditions (hyperlipidaemia, hypertension, obesity and diabetes mellitus). The inclusion criteria were full-text animal and human studies conducted on RC to evaluate its efficacy on any components of metabolic syndrome (MetS). Jadad scale was used to assess the quality of evidence.

KEY FINDINGS

Reviewing 23 relevant studies demonstrated that RC is able to decrease the level of blood glucose, glycated haemoglobin, serum insulin and insulin resistance. Studies on hyperlipidaemia and obesity have very contradicting results, and there is no definite conclusion on the effect of RC on lipid profile. However, the hypotensive and effect of RC was confirmed in the existing studies.

SUMMARY

According to the literature, RC can be considered as a promising curative candidate for MetS. However, further studies with larger sample size and higher methodological quality are needed.

Sumac fruit supplementation improve glycemic parameters in patients with metabolic syndrome and related disorders: A systematic review and meta-analysis

BACKGROUND

Metabolic syndrome (MetS) is the one of the main causes of mortality worldwide. Several randomized controlled trials (RCTs) have revealed the beneficial effects of sumac (Rhus coriaria) on cardiometabolic risk factors. However, the entirety of the evidence has yet to be summarized in a systematic review.

OBJECTIVE

The aim of this systematic review and meta-analysis was to evaluate the effects of sumac on several cardiometabolic risk factors in patients with MetS and related disorders.

METHODS

We reviewed Medline, Scopus, Web of Science and Cochrane CENTRAL for RCTs published from inception to December 2020 evaluating the impact of sumac in adults with MetS or related disorders. Outcome measures included anthropometric measures, glycemic indices, blood lipids, blood pressure and liver enzymes. Pooled effect sizes were reported as standard mean differences (SMDs) and 95% confidence intervals (CIs). Trials were pooled using a random effects model.

RESULTS

Nine studies enrolling 526 participants met the inclusion criteria for this meta-analysis. Our results indicate that sumac intake significantly decrease fasting blood sugar (FBS) (SMD: -0.28; 95% CI: -0.54, -0.02; I² = 00.0%), insulin (SMD: -0.67; 95% CI: -0.99, -0.36; I² = 03.7%), and insulin resistance (measured through the Homeostatic Model Assessment of Insulin Resistance (HOMA-IR)) (SMD: -0.79; 95% CI: -1.24, -0.34; I² = 50.1%). Sumac intake did not have a significant impact on weight, body mass index (BMI), waist circumference (WC), hip circumference (HC), waist to hip ratio (WHR), HbA1c, total cholesterol (TC), triglycerides (TG), high density lipoproteins (HDL), low density lipoprotein (LDL), systolic blood pressure (SBP), diastolic blood pressure (DBP), aspartate transaminase (AST) and alanine transaminase (ALT).

CONCLUSION

Sumac, as an adjuvant therapy, may decrease serum levels of FBS, insulin and HOMA-IR. However, due to high heterogeneity in the included studies, these findings must be interpreted with great caution. Larger, well-designed placebo-controlled clinical trials are still needed to further evaluate the capacity of sumac as a complementary treatment to control MetS risk factors.

Effect of Spirulina Supplementation on Systolic and Diastolic Blood Pressure: Systematic Review and Meta-Analysis of Randomized Controlled Trials

Spirulina is a microalga that presents various important pro-health properties, for instance lowering blood pressure in the research. The study aims to appraise the efficacy of Spirulina administration on systolic (SBP) and diastolic blood pressure (DBP). Randomized controlled trials (RCTs) were retrieved by a systematic search of PubMed, Web of Science, and the Cochrane Library databases from inception to June 2021 according to a standardized protocol. The effect size of each study was counted from mean and standard deviation before and after the intervention and shown as Un-standardized mean difference and 95% confidence interval. Sensitivity analyses were performed. Meta-analysis on 5 RCTs with 230 subjects was eligible. The amount of Spirulina ranged from 1 to 8 g per day, and intervention durations ranged from 2 to 12 weeks. Data analysis indicated that Spirulina supplementation led to a significant lowering of SBP (Mean Difference (MD): -4.59 mmHg, 95% Confidence Interval (CI): -8.20 to -0.99, I square statistic (I²) = 65%) and significant lowering of DBP (MD: -7.02 mmHg, CI: -8.86 to -5.18, I² = 11%), particularly in a subgroup of hypertensive patients. Spirulina administration might have a supportive effect on the prevention and treatment of hypertension. More exact randomized controlled trials are needed to clarify the effect of Spirulina supplementation on blood pressure.

The Effect of a Persian Herbal Medicine Compound on the Lipid Profiles of Patients with Dyslipidemia: A Randomized Double-Blind Placebo-Controlled Clinical Trial

INTRODUCTION

It has been well established in the world that lipid disorders promote the development of atherosclerosis and its clinical consequences. This study aimed to assess the impacts of a Persian medicinal (PM) compound on lipid profile.

MATERIALS AND METHODS

From June 21 to October 21, 2020, a randomized double-blind controlled clinical trial was conducted with 74 dyslipidemic patients, who were randomly divided into two equally populated groups: one prescribed with a Persian medicinal herbal compound (n = 37) and a placebo group (n = 37). A Persian herbal medicine including fenugreek, sumac, and purslane is introduced. Biochemical parameters including 12-hour fasting serum levels of total cholesterol, low-density lipoprotein (LDL), high-density lipoprotein (HDL), very-low-density lipoprotein (VLDL), and triglyceride (TG) were measured before the initiation and after the completion of study protocol.

RESULTS

Percent changes of biochemical parameters include the following: intervention group = cholesterol: 35.22, Tg: 45.91, LDL: 24.81, HDL: 2.05, VLDL: 8.94 and placebo group = cholesterol: 6.94, Tg: -7.3, LDL: 7.37, HDL: 2.88, VLDL: -0.14. The serum levels of total cholesterol (p=0.01) and LDL (p=0.01) significantly decreased and no increase was recorded in HDL (p=0.03) levels over time in the intervention group. Furthermore, between-group analysis showed a statistically significant difference between the intervention and placebo groups in this regard. VLDL (p=0.2) and TG (p=0.2) levels also decreased, however not significantly.

CONCLUSION

This study showed that a Persian medicinal herbal compound could be safe and beneficial to decrease the levels of serum cholesterol and LDL in dyslipidemic patients. However, larger long-term studies are recommended to clarify this effect.

Effects of artichoke on blood pressure: A systematic review and meta-analysis

PURPOSE

Clinical trials considering the effects of artichoke supplementation on blood pressure have yielded different and contradictory outcomes. Thus, a systematic review and meta-analysis were performed to assess effects of artichoke administration on blood pressure.

METHODS

Related studies were detected by searching the Cochrane Library, PubMed, Embase and Scopus databases up to 15 March 2020. Weighted Mean Differences (WMD) were pooled using a random-effects model. Heterogeneity, sensitivity analyses, and publication bias were evaluated using standard methods.

RESULTS

Pooled analysis of eight randomized controlled trials revealed that artichoke supplementation did not have an effect on systolic blood pressure (SBP), (WMD: -0.77 mmHg, 95 % CI: -2.76 to 1.22) or diastolic blood pressure (DBP) (WMD: -0.11 mmHg, 95 % CI: -1.72 to 1.50) when compared to the placebo group. However, subgroup analyses based on health status suggested that artichoke administration among hypertensive patients may significantly reduce SBP (WMD: -3.19 mmHg, 95 % CI: -3.32 to -3.06) and DBP (WMD: -2.33 mmHg, 95 % CI: -2.23 to -2.43), but no such reduction was found in NAFLD patients. Furthermore, our results indicated that artichoke supplementation for 12 weeks led to a significantly decreased DBP (WMD: -2.33 mmHg, 95 % CI: -2.43 to -2.23), but 8 weeks of intervention did not (WMD: 0.80 mmHg, 95 % CI: -1.06 to 2.66).

CONCLUSION

Artichoke supplementation may potentially lead to SBP and DBP reduction in hypertensive patients. In addition, artichoke supplementation for 12 weeks may significantly improve DBP.

Medicinal Plants in the Treatment of Peptic Ulcer Disease: A Review

Peptic Ulcer Disease (PUD) is the most common disorder of the stomach and duodenum, which is associated with Helicobacter pylori infection. PUD occurs due to an imbalance between offensive and defensive factors and Proton Pump Inhibitors (PPI), Nonsteroidal Anti-Inflammatory Drugs (NSAIDs) and antibiotics are frequently used for the treatment. Recently, medicinal plants have emerged as efficacious, safe and widely available alternative therapies for PUD. The aim of this review was to study the medicinal plants and phytochemicals, which have been used for PUD treatment to evaluate the potential role of natural compounds to develop herbal remedies for PUD. Information was obtained using a literature search of electronic databases, such as Web of Science, Google Scholar, PubMed, Sci Finder, Reaxys and Cochrane. Common and scientific names of the plants and keywords such as 'peptic ulcer', 'gastric ulcer', 'stomach ulcer' and 'duodenal ulcer' were used for search. Eventually, 279 plants from 89 families were identified and information on the plant families, part of the plant used, chemical constituents, extracts, ulcer model used and dosage were abstracted. The results indicated that most of the anti-PUD plants were from Asteraceae (7.1%) and Fabaceae (6.8%) families while flavonoids (49%), tannins (13%), saponins (10%) and alkaloids (9%) were the most common natural compounds in plants with anti-PUD activity.

Medicinal plants in the adjunctive treatment of patients with type-1 diabetes: a systematic review of randomized clinical trials

Propose

This study aims to systematically review the randomized controlled trials that address the effectiveness and safety of herbal medicine in patients with type 1 diabetes.

Methods

The Cochrane Library (latest issue); MEDLINE (until recent); EMBASE (until recent); AMED (Allied and Complementary Medicine Database) (until recent); and CINHAL (until recent) were searched electronically for the identification of trials until October 2019. Articles were initially screened based on title and abstract and then by full text by two independent authors. References of retrieved studies were hand-searched for further studies. Risk of bias was assessed according to the Cochrane handbook of systematic reviews of interventions. The results were summarized into GRADE (grading of recommendations, assessment, development and evaluation) tables. No meta-analysis was applicable as only one study was found for each intervention.

Results

Four RCTs were finally included in the systematic review with an overall moderate quality of conduct and low quality of reporting. The sample sizes were very small. The results of these RCTs show that cinnamon pills and Berberine/Silymarine compound capsules may decrease blood glucose indices from baseline, while fenugreek seeds and fig leaf decoction do not show any statistically significant effect.

Conclusions

The evidence is scarce and no recommendations can be made based on current evidence. Further trials with more rigorous methodology and stronger quality of reporting are needed to make conclusions.

Effect of the consumption of natural products on some biochemical parameters of a type 2 diabetic population

PURPOSE

The use of phytotherapy is common worldwide and especially in Algeria. This practice was transmitted orally and ritually to treat chronic diseases. Safe extracts of edible plants can provide a resource of structurally diverse molecules that can effectively interfere with multifactorial diseases, such as diabetes mellitus. The objective of this work is to study the biochemical parameters of diabetic populations who consume medicinal plants.

METHODS

This study involved 100 T2D subjects, recruited over a five-month period via a questionnaire containing anthropometric information: sex, age, age of diabetes, type of diabetes, plants consumed. Recruited patients were recalled for further examination of the biochemical record (fasting glucose, glycated hemoglobin, total cholesterol, triglycerides, creatinine, ASL and ASP).

RESULTS

We found that diabetic patient associated with prescribed medical treatment uses the medicinal plants. This use is strongly predominant by women in both populations with 76% of them using herbal medicine. 58% of diabetics under herbal medicine had slightly unbalanced diabetes with HbA1c > 7. The difference between the total cholesterol, ASL and ASP parameters of the two populations was not significant. The study of correlation showed that the consumption of plant had an effect on the type of correlation between biochemical parameters of diabetic patients.

CONCLUSIONS

The consumption of medicinal plants did not affect the values of the measured biochemical parameters, while the correlation between these parameters can be modified.

Effect of the herbal medicines in obesity and metabolic syndrome: A systematic review and meta-analysis of clinical trials

Obesity is a medical situation in which excess body fat has gathered because of imbalance between energy intake and energy expenditure. In spite of the fact that the variety of studies are available for obesity treatment and management, its "globesity" still remains a big challenge all over the world. The current systematic review and meta-analysis aimed to evaluate the efficacy, safety, and mechanisms of effective herbal medicines in the management and treatment of obesity and metabolic syndrome in human. We systematically searched all relevant clinical trials via Web of Science, Scopus, PubMed, and the Cochrane database to assess the effects of raw or refined products derived from plants or parts of plants on obesity and metabolic syndrome in overweight and obesity adult subjects. All studies conducted by the end of May 2019 were considered in the systematic review. Data were extracted independently by two experts. The quality assessment was assessed using Consolidated Standards of Reporting Trials checklist. The main outcomes were anthropometric indices and metabolic syndrome components. Pooled effect of herbal medicines on obesity and metabolic syndrome were presented as standardized mean difference (SMD) and 95% confidence interval (CI). A total of 279 relevant clinical trials were included. Herbals containing green tea, Phaseolus vulgaris, Garcinia cambogia, Nigella sativa, puerh tea, Irvingia gabonensis, and Caralluma fimbriata and their active ingredients were found to be effective in the management of obesity and metabolic syndrome. In addition, C. fimbriata, flaxseed, spinach, and fenugreek were able to reduce appetite. Meta-analysis showed that intake of green tea resulted in a significant improvement in weight ([SMD]: -0.75 [-1.18, -0.319]), body mass index ([SMD]: -1.2 [-1.82, -0.57]), waist circumference ([SMD]: -1.71 [-2.66, -0.77]), hip circumference ([SMD]: -0.42 [-1.02, -0.19]), and total cholesterol, ([SMD]: -0.43 [-0.77, -0.09]). In addition, the intake of P. vulgaris and N. sativa resulted in a significant improvement in weight ([SMD]: -0.88, 95 % CI: [-1.13, -0.63]) and triglyceride ([SMD]: -1.67, 95 % CI: [-2.54, -0.79]), respectively. High quality trials are still needed to firmly establish the clinical efficacy of the plants in obesity and metabolic syndrome.

The Effect of Cynara scolymus on Blood Pressure and BMI in Hypertensive Patients: A Randomized, Double-Blind, Placebo-Controlled, Clinical Trial

Background: Recent studies have suggested that artichoke (Cynara scolymus L.) may reduce certain biochemical blood factors but the efficacy of this plant on blood pressure (BP) has not yet been investigated. In this study, we determined the clinical efficacy of C. scolymuson BP and body mass index (BMI) in hypertensive patients as an adjunctive to captopril for the first time. Methods: The total phenolic content and gas chromatography-mass spectrometry metabolite profiling in leaves of C. scolymus have been evaluated. A clinical trial was subsequently carried out on 40 patients to determine the effect of C. scolymus on BP and BMI in hypertensive patients. The treatment group received capsules containing C. scolymus(500 mg twice daily) and the placebo group received starch powder for 8 weeks. Systolic blood pressure (SBP), diastolic blood pressure, and BMI were determined before and after the study. Results: A significant improvement of the BMI was seen in the C. scolymus group compared with the placebo group (p = 0.04). Conclusions: Our findings demonstrated that the consumption of C. scolymus powder as a rich source of phenolic and antioxidant compounds could potentially improve BMI and SBP in hypertensive patients. Therefore, more trials are needed to confirm or reject the antihypertensive impact of artichoke.

The role of artichoke leaf tincture (Cynara scolymus) in the suppression of DNA damage and atherosclerosis in rats fed an atherogenic diet

CONTEXT

Polyphenols and flavonoids in artichoke leaf tincture (ALT) protect cells against oxidative damage.

OBJECTIVES

We examined ALT effects on deoxyribonucleic acid (DNA) damage and lipid profiles in rat plasma and gene expression in rat aorta [haemeoxygenase-1 (HO1), haemeoxygenase-2 (HO2), NADPH oxidase 4 (NOX-4), monocyte chemoattractant protein-1 (MCP-1) and nuclear factor (erythroid-derived 2)-like 2 (Nrf2)].

MATERIALS AND METHODS

Eighteen male Wistar albino rats were divided into three groups (n = 6/group): The control group (CG) was fed with standard pellet chow for 11 weeks; the AD group was fed for a similar period of time with pellet chow supplemented with 2% cholesterol, 3% sunflower oil and 1% sodium cholate. The ADA group was fed with pellet chow (for 1 week), the atherogenic diet (see above) for the following 4 weeks and then with ALT (0.1 mL/kg body weight) and atherogenic diet for 6 weeks. According to HPLC analysis, the isolated main compounds in ALT were chlorogenic acid, caffeic acid, isoquercitrin and rutin.

RESULTS

Normalized HO-1 [0.11 (0.04-0.24)] and MCP-1 [0.29 (0.21-0.47)] mRNA levels and DNA scores [12.50 (4.50-36.50)] were significantly lower in the ADA group than in the AD group [0.84 (0.35-2.51)], p = 0.021 for HO-1 [0.85 (0.61-3.45)], p = 0.047 for MCP-1 and [176.5 (66.50-221.25)], p = 0.020 for DNA scores. HO-1 mRNA was lower in the ADA group than in the CG group [0.30 (0.21-0.71), p = 0.049].

CONCLUSIONS

Supplementation with ALT limited the effects of the atherogenic diet through reduced MCP-1 expression, thereby preventing oxidative damage.

Active phytochemicals of Pueraria tuberosa for DPP-IV inhibition: in silico and experimental approach

Background

We had earlier reported that the extract of Pueraria tuberosa significantly inhibits DPP-IV enzyme, resulting in glucose tolerance response in rats. In this study, we have explored the active phytochemicals responsible for this potential. The results have been validated in both fasting and postprandial states in the plasma of normal rats and also in fasting blood and intestinal homogenates of diabetic models.

Methods

Pueraria tuberosa water extract (PTWE) was administered to normal Charles Foster rats for 35 days and to diabetic model (65 mg/kg bw) for 10 days. After treatments, oral glucose tolerance test (OGTT) and insulin was done for 90 min, and the changes in the levels of GLP-1, GIP, and DPP-IV activities were monitored in fasting and postprandial states. In the case of the diabetic model, DPP-IV activity was measured in intestinal homogenate and basal insulin in plasma. The components of PTWE were analyzed via HPLC-MS based on their chemical formula, molecular mass, and retention time. Using the molecular docking study, we have selected the top five components having strong binding energy with DPP-IV.

Results

The increase in secretion of GLP-1 and GIP was significantly higher in the postprandial state when compared to fasting condition. GLP-1 plasma concentration increased by 5.8 and 2.9 folds and GIP increased by 8.7 and 2.4 folds in PTWE and control rats, respectively. In contrast, the postprandial decrease in DPP-IV specific activities was recorded at 2.3 and 1.4 folds. The response in OGTT and insulin was also consistent with these changes. In comparison to diabetic controls, PTWE-administered rats showed decreased DPP-IV activity in the intestine, leading to enhanced basal insulin concentration. Through molecular docking, we found Puerarone and Robinin to be the most potential phytochemicals of PTWE for DPP-IV inhibition. Binding energy (kcal/mol) and dissociation constant (pM) of Robinin with DPP-IV protein were found to be 7.543 and 2,957,383.75, respectively. For Puerarone, it was 7.376 and 3,920,309, respectively.

Conclusions

Thus, this study provides the novel active components that contribute to the DPP-IV inhibitory property of PTWE.