Molecular approach to identify antidiabetic potential of Azadirachta indica

Ethnobotanical assessment of antidiabetic medicinal plants in District Karak, Pakistan

BACKGROUND

Diabetes is a leading health disorder and is responsible for high mortality rates across the globe. Multiple treatment protocols are being applied to overcome this morbidity and mortality including plant-based traditional medicines. This study was designed to investigate the ethnomedicinal status of plant species used to treat diabetes in District Karak, Pakistan.

MATERIALS AND METHODS

A semi-structured survey was created to collect data about traditionally used medicinal plants for diabetes and other ailments. The convenience sampling method was applied for the selection of informants. The collected data was evaluated through quantitative tools like frequency of citation (FC), relative frequency of citation (RFC), informant consensus factor (FIC), fidelity level (FL), and use value (UV).

RESULTS

A total of 346 local informants were selected for this research. Out of them, 135 participants were men and 211 participants were women. Overall 38 plant species belonging to 29 plant families were used to treat diabetes. The most dominant plant family was Oleaceae having 11 species. Powder form (19%) was the most recommended mode of preparation for plant-based ethnomedicines. Leaves (68%) were the most frequently used parts followed by fruit (47%). The highest RFC was recorded for Apteranthes tuberculata (0.147). The maximum FL was reported for Apteranthes tuberculata (94.4) and Zygophyllum indicum (94.11) for diabetes, skin, and wounds. Similarly, the highest UV of (1) each was found for Brassica rapa, Melia azedarach, and Calotropis procera. Based on documented data, the reported ailments were grouped into 7 categories. The ICF values range between 0.89 (diabetes) to 0.33 (Cardiovascular disorders).

CONCLUSION

The study includes a variety of antidiabetic medicinal plants, which are used by the locals in various herbal preparations. The species Apteranthes tuberculata has been reported to be the most frequently used medicinal plant against diabetes. Therefore, it is recommended that such plants be further investigated in-vitro and in-vivo to determine their anti-diabetic effects.

Underutilized green leafy vegetables: frontier in fortified food development and nutrition

From the ancient period, Green leafy vegetables (GLV) are part of the daily diet and were believed to have several health beneficial properties. Later it has been proved that GLV has outstanding nutritional value and can be used for medicinal benefits. GLV is particularly rich in minerals like iron, calcium, and zinc. These are also rich in vitamins like beta carotene, vitamin E, K, B and vitamin C. In addition, some anti-nutritional elements in GLV can be reduced if it is grown properly and processed properly before consumption. Tropical countries have a wide variety of these green plants such as Red Spinach, Amaranth, Malabar Spinach, Taro Leaf, Fenugreek leaf, Bengal Gram Leaves, Radish Leaves, Mustard Leaves, and many more. This review focuses on listing this wide range of GLVs (in total 54 underutilized GLVs) and their compositions in a comparative manner. GLV also possesses medicinal activities due to its rich bioactive and nutritional potential. Different processing techniques may alter the nutritional and bioactive potential of the GLVs significantly. The GLVs have been considered a food fortification agent, though not explored widely. All of these findings suggest that increasing GLV consumption could provide nutritional requirements necessary for proper growth as well as adequate protection against diseases caused by malnutrition.

Nimbin analogs stimulate glucose uptake and glycogen storage in the insulin signalling cascade by enhancing the IRTK, PI3K and Glut-4 mechanism in myotubes

BACKGROUND

Diabetes Mellitus is a metabolic disorder characterized by insulin dysfunction or failure of the pancreatic β-cells to produce insulin resulting in hyperglycemia. Adverse effects of hyperglycemic conditions continue to be common, reducing treatment adherence. Intensified therapies are required for the constant loss of endogenous islet reserve.

AIM

This study aimed to evaluate the effect of Nimbin semi-natural analogs (N2, N5, N7, and N8) from A. indica on high glucose-induced ROS and apoptosis with insulin resistance in L6 myotubes evaluated along with Wortmannin and Genistein inhibitors and the expression of key genes in the insulin signalling pathway.

MATERIALS AND METHODS

The analogs were screened for anti-oxidant and anti-diabetic activity using cell-free assays; The ability of analogs to suppress ROS and prevent apoptosis induced by High glucose and uptake glucose and glycogen storage in L6 myotubes was evaluated using DCFH-DA, AO-PI and 2NBDG staining. Further, the glucose uptake was performed in the presence of Insulin Receptor Tyrosine Kinase (IRTK) inhibitors, and the expression of key genes PI3K, Glut-4, GS and IRTK in the insulin signalling pathway were evaluated.

KEY FINDINGS

The Nimbin analogs were not toxic to the L6 cells, and the analogs could scavenge ROS and suppress cellular damage induced due to high glucose. Enhanced glucose uptake was observed in N2, N5 and N7 compared to N8. The maximum activity of optimum concentration was found to be 100 μM. The N2, N5 and N7 showed an increase in IRTK, which is equivalent to insulin at a concentration of 100 µM. The IRTK inhibitor with Genistein (50 µM) confirmed the presence of IRTK-dependent glucose transport activation; it also supports the expression of key genes PI3K, Glut-4, GS and IRTK. As a result of PI3K activation, N2, N5, and N7 exhibited the insulin-mimetic effect by enhancing glucose uptake and glycogen conversion regulating glucose metabolism.

SIGNIFICANCE

N2, N5 and N7 could therapeutically benefit against insulin resistance by glucose metabolism modulation, insulin secretion, β-cell stimulation, inhibition of gluconeogenic enzymes and ROS protection.

EXPLORING the prophylactic potential of Azadirachta indica leaf extract against dyslipidemia

ETHNOPHARMACOLOGICAL RELEVANCE

Several studies revealed that different parts of Azadirachta indica A. Juss, has therapeutic potential against inflammatory issues and dyslipidemia which is a major contributing cause to cardiovascular diseases, oxidative stress and serum glucose levels, etc. AIM OF STUDY: Present study was conducted to evaluate anti-dyslipidemic capacity of Azadirachta indica leaf extract in dyslipidemic rabbits.

MATERIALS AND METHODS

Ethanolic extract of Azadirachta indica leaves was obtained by using Soxhlet apparatus. This extract was used for efficacy study on rabbits. In this context, 25 healthy rabbits were selected for study, Efficacy trial involved five groups of rabbits, 5 rabbits in each group; NC (Negative Control); healthy rabbits received normal diet. In remaining 20 rabbits, dyslipidemia was induced by using high fat diet for 28 days followed by administration of Azadirachta indica leaf ethanolic extract for 60 days in a dose-dependent manner. PC (Positive Control) include dyslipidemic rabbits received normal diet while G₁, G₂, G₃ groups included dyslipidemic rabbits receiving different concentrations of Azadirachta indica leaf extract (i.e. 300, 500 and 700 mg/kg of body weight, respectively). Blood samples were analyzed for serum lipid profile after every 15 days to determine the effect of treatments.

RESULTS

Significant reduction in total cholesterol (60 ± 3.4 mg/dL), triglycerides (40.31 ± 2.5 mg/dL) and low-density lipoprotein (28.87 ± 2.1 mg/dL) was observed in G₂ (P ≤ 0.05)while a significant increase was observed in high-density lipoprotein (60.47 ± 1.7 mg/dL) of G₂ (P ≤ 0.05) as compared to other groups.

CONCLUSION

Results revealed that ethanolic extract of Azadirachta indica leaves in G₂ group (@ 500 mg/kg of body weight) normalized lipid profile in dyslipidemic rabbits after 60 days of extract administration which significantly lowered TC, TG, LDL levels (P ≤ 0.05) and improved HDL level.

Aqueous Azadirachta indica (Neem) Extract Attenuates Insulin Resistance to Improve Glycemic Control and Endothelial Function in Subjects with Metabolic Syndrome

Neem (Azadirachta indica) exhibits multiple therapeutic benefits in preclinical studies, but clinical studies are lacking. This clinical study investigated the efficacy and safety of an aqueous A. indica leaf and twig extract (NEEM) on metabolic parameters in subjects with metabolic syndrome (MetS). Subjects were randomized to receive (1) placebo or (2) 125 mg, (3) 250 mg, or (4) 500 mg of NEEM twice daily (n = 20/group) for 12 weeks. Fasting blood sugar (FBS) and insulin, postprandial blood sugar (PPBS), insulin resistance (IR), hemoglobin A1c (HbA1c), endothelial function, circulating markers of inflammation and oxidative stress, lipid profiles, and platelet aggregation were measured at weeks 0, 4, 8, and 12. NEEM supplementation dose dependently improved the trajectories for FBS, PPBS, IR, and HbA1c over time, as well as endothelial function and most markers of inflammation and oxidative stress. Therefore, NEEM may be considered a promising therapeutic to attenuate the hyperglycemia and associated cardiometabolic derangements in people with MetS. Clinical trial registration no.: CTRI/2019/03/018034 [registered on: March 12, 2019].

Trends in diabetes care with special emphasis to medicinal plants: Advancement and treatment

Diabetic mellitus (DM) is a common metabolic disorder prevailing throughout the world. It may affect a child to an older person depending upon the physiology and the factors influencing the internal metabolic system of the body. Several treatments are available in the market ranges from synthetic drugs, insulin therapy, herbal drugs, and transdermal patches. Interestingly, the development of technologies and digital health have proving very helpful in improving the lifestyle of diabetic patients. All treatment approaches have their own advantages and disadvantages in the form of effectiveness and side effects. Medicinal plants have a long history of traditional application in the treatment of diabetes and even the use of plants are growing day-by-day due to the significant results against diseases and fewer side effects as compared to other treatment therapies. The intention behind writing this review is to gather all information and discussed them exhaustively in an article. The novel Coronavirus 2019 (COVID-19) pandemic has affected my lives including diabetic patients. The antidiabetic treatment strategies during this period has also discussed. In this article, we highlighted the molecular mechanism and herbal phytoconstituents that are responsible for lowering blood glucose level. The factors responsible for the progression of metabolic disorders can be controlled with the use of phytoconstituents present in herbal plants to maintain β-cells performance and restore blood glucose level. It can be concluded that medicinal plants are effective and affordable with lesser side effects for treating DM.

Improvement in serum amylase and glucose levels in diabetic rats on oral administration of bisdemethoxycurcumin from Curcuma longa and limonoids from Azadirachta indica

Curcuma longa and Azadirachta indica are traditionally used in Indian cuisine and Ayurvedic medicine as nutraceuticals against diabetes. The crude C. longa isopropanol extract, bisdemethoxycurcumin (BDMC), the purified bioactive component from C. longa, and limonoids azadiradione, gedunin from A. indica, are able to inhibit in vitro the antidiabetic target human pancreatic α-amylase independently. However, no reports on their in vivo efficacy in animal models exist. Thus, the antidiabetic effect of these orally administered human pancreatic α-amylase inhibitors was performed on streptozotocin-induced Sprague-Dawley rats. Initially, the normal rats were treated with test compounds (10-100 mg/kg of body weight) in corn oil (5 ml/kg), and as no lethality was observed in these doses, further studies were carried out with lowest concentration of 10 mg/kg of body weight. A reduction in area under curve (AUC) suggested glucose-lowering effect of these compounds in starch fed diabetic rats. The efficacy study showed a significant improvement in body weight, blood glucose levels, serum amylase, and fructosamine levels as well in other serum parameters associated with diabetes with respect to liver and renal functions. Hence, under in vivo conditions, inhibition of α-amylase activity by BDMC and limonoids affirms it as one of the mechanisms of action resulting in reduction of blood glucose levels. PRACTICAL APPLICATIONS: Bisdemethoxycurcumin from C. longa and limonoids, namely, azadiradione and gedunin, from A. indica are potent inhibitors of the antidiabetic target human pancreatic α-amylase. Oral Starch Tolerance Test (OSTT) and 28-day efficacy study to check the effect of these orally administered inhibitors in diabetic rat models showed significant improvements in serum blood glucose and amylase levels as well as in other diabetes related serum parameters, namely, bilirubin, lipids, lactate dehydrogenase, alkaline phosphatase, and urea. The study contributes to understanding the action and efficacy of these pancreatic α-amylase inhibitors and suggests a potential role for them as nutraceuticals/therapeutics in management of post-prandial hyperglycemia.

Middle East Medicinal Plants in the Treatment of Diabetes: A Review

Diabetes is a global health problem, and the number of diabetic patients is in continuous rise. Conventional antidiabetic therapies are associated with high costs and limited efficiency. The use of traditional medicine and plant extracts to treat diabetes is gaining high popularity in many countries. Countries in the Middle East region have a long history of using herbal medicine to treat different diseases, including diabetes. In this review, we compiled and summarized all the in vivo and in vitro studies conducted for plants with potential antidiabetic activity in the Middle East region. Plants of the Asteraceae and Lamiaceae families are the most investigated. It is hoped that this review will contribute scientifically to evidence the ethnobotanical use of medicinal plants as antidiabetic agents. Work has to be done to define tagetes, mechanism of action and the compound responsible for activity. In addition, safety and pharmacokinetic parameters should be investigated.

Medicinal plants utilized in Thai Traditional Medicine for diabetes treatment: Ethnobotanical surveys, scientific evidence and phytochemicals

ETHNOPHARMACOLOGICAL RELEVANCE

Diabetes mellitus remains the most lethal metabolic disease of contemporaneous times and despite the therapeutic arsenal currently available, research on new antidiabetic agents remains a priority. In recent years, the revitalization of Thai Traditional Medicine (TTM) became a clear priority for the Thai government, and many efforts have been undertaken to accelerate research on herbal medicines and their use in medical services in various hospitals. Additionally, and particularly in rural areas, treatment of diabetes and associated symptomatology frequently relies on herbal preparations recommended by practitioners of TTM. In the current work, medicinal plants used in Thailand for treating diabetes, as well as their hypoglycaemic pharmacological evidences and potential therapeutic use for diabetes-related complications were reviewed.

MATERIALS AND METHODS

Ethnopharmacological information on the plant materials used in TTM for diabetes treatment was collected through literature search in a range of scientific databases using the search terms: diabetes, folk medicine, Thailand medicinal plants, traditional medicine. Information regarding scientific evidence on the antidiabetic effects of surveyed species was obtained considering not only the most common taxonomic designation, but also taxonomic synonyms, and including the keywords 'diabetes' and 'hypoglycaemic effect'.

RESULTS

A total of 183 species known to be used for diabetes management in TTM were reviewed, with 30% of them still lacking experimental evidences to support claims regarding the mechanisms and phytochemicals underlying their antidiabetic properties. Moreover, a total of 46 bioactives displaying effective antidiabetic effects have been isolated from 24 species, their underlying mechanism(s) of action being fully or partially disclosed.

CONCLUSIONS

We deliver the most extensive survey dealing with the ethnomedicinal knowledge of Thai medicinal plants utilized on diabetes management. We are certain that the current review will spark further research on Thai plants for the development of new standardized phytomedicines through drug discovery programmes.

Indian Traditional medicinal plants as a source of potent Anti-diabetic agents: A Review

Objective

The present review aims to provide an overview of traditional medicinal plants known to be of anti-diabetic potential.

Methods

A literature search was conducted using the scientific databases including PubMed, EMBASE and google scholar and a total of fifty herbs have been described and their possible mechanism of anti-diabetic action has been mentioned. Among them, in-depth discussion on five most potent anti-diabetic herbs has been provided with respect to their mechanism of action, in-vivo studies and clinical efficacies.

Results

The present review has highlighted the usefulness of the herbal source for the treatment and management of diabetes mellitus. With the help of previous literature published on In-vivo animal studies and human clinical studies; the effectiveness of Gymnema sylvestre, Momordica charantia, Trigonella foenum graecum, Tinospora cordifolia and Curcuma longa in the treatment and management of Diabetes has been proved.

Conclusion

Based on this review it can be concluded that herbs can serve as more efficient, safer, and cost-effective adjuvant therapy in the management and treatment of diabetes. Further investigations mainly focusing on the isolation of phytocompounds from these herbs can lead to the discovery of newer antidiabetic agents.

Myricetin bioactive effects: moving from preclinical evidence to potential clinical applications

Several flavonoids have been recognized as nutraceuticals, and myricetin is a good example. Myricetin is commonly found in plants and their antimicrobial and antioxidant activities is well demonstrated. One of its beneficial biological effects is the neuroprotective activity, showing preclinical activities on Alzheimer, Parkinson, and Huntington diseases, and even in amyotrophic lateral sclerosis. Also, myricetin has revealed other biological activities, among them as antidiabetic, anticancer, immunomodulatory, cardiovascular, analgesic and antihypertensive. However, few clinical trials have been performed using myricetin as nutraceutical. Thus, this review provides new insights on myricetin preclinical pharmacological activities, and role in selected clinical trials.

Patterns of concomitant use of Ayurveda and conventional anti-diabetic formulations - Experiences at a tertiary care Ayurveda hospital, India

Background:

Majority of the population relies on traditional medicines for many of their health related problems. Particularly individuals with chronic illness like diabetes mellitus (DM) are more likely to simultaneously use herbal medicines. Many of such users believe that traditional medicines are natural and therefore safe, but this is a dangerous over simplification. Some herbal medicines may be associated with adverse effects, which include interactions with prescribed drugs. Information on such concomitant use of anti-diabetic drugs along with Ayurveda medicines is limited in Indian scenario.

Aims and objectives:

To survey the patterns of concomitant use of Ayurveda and conventional anti-diabetic drugs by diabetic patients attending an out-patient department of a tertiary care teaching hospital in New Delhi, India through a validated questionnaire.

Materials and methods:

This is a questionnaire-based survey, carried out after the approval of the Institutional Ethics Committee, subsequently registered at CTRI. A questionnaire to assess the pattern of concomitant use was developed; content was validated and pre-tested by a pilot study in 40 patients, further refined and used in the survey. The data was analyzed to evaluate the patterns of concomitant use of Ayurvedic and conventional anti-diabetic drugs.

Results:

About 95.9% of diabetic patients were taking herbo-mineral formulations concomitantly with conventional anti-diabetic drugs. Although 45.3% of diabetics were using Ayurveda interventions under the supervision of qualified AYUSH physicians, remaining involved in procuring the drugs over the counter (OTC) or from the local vendors. In majority of these instances, the use of Ayurveda formulations was not communicated with their physicians.

Conclusion:

The observations reveal that a majority of the diabetics (95.9%) were taking one or the other form of herbal preparations along with their conventional anti-diabetic drugs and about 44% among them were using these concomitantly. Thus, generating awareness on good practices of drug use seems to be essential.

Evaluation of the Effect of an Aqueous Extract of Azadirachta indica (Neem) Leaves and Twigs on Glycemic Control, Endothelial Dysfunction and Systemic Inflammation in Subjects with Type 2 Diabetes Mellitus - A Randomized, Double-Blind, Placebo-Controlled Clinical Study

PURPOSE

Neem tree (Azadirachta indica) offers different bioactives ranging from pesticides to therapeutic molecules, depending on which part of the plant is used and the extraction methodology and the solvent used. This study was aimed at evaluating the safety and efficacy of a standardized aqueous extract of Azadirachta indica leaves and twigs (NEEM) on glycemic control, endothelial dysfunction, and systemic inflammation in patients with type 2 diabetes mellitus (T2DM).

METHODS

In this randomized, double-blind, placebo-controlled clinical study (RCT), 80 T2DM subjects, who have already been on standard metformin therapy, received either 125 mg, 250 mg, 500 mg of NEEM or placebo twice daily for 12 weeks. Postprandial blood sugar level (PPBS), fasting blood sugar level (FBS), glycosylated hemoglobin (HbA1c), insulin resistance (IR), endothelial function, oxidative stress, systemic inflammation, IL-6 and TNF-α, platelet aggregation and lipid profile were assessed. Adverse drug reactions, if any, were noted. GraphPad Prism 8 was used to perform statistical analysis.

RESULTS

NEEM at the doses of 125, 250, and 500 mg BID significantly reduced PPBS (from 194.4±14 to 173.1±12.8mg/dL, 192.3±17.1 to 161.8±9.7mg/dL, and 205.9±7.2 to 159.3±7.1mg/dL, respectively), FBS (from 119.2±5.0 to 109.2±5.7mg/dL, 115.5±4.4 to 103.7±4.2mg/dL, and 120.7±4.2 to 97.3±3.7mg/dL, respectively), HbA1c (from 6.87 ± 0.4% to 6.64 ± 0.4%, 7.52 ± 0.4% to 6.86 ± 0.3%, and 7.78 ± 0.2% to 6.26 ± 0.4%, respectively), and IR (from 4.5 ± 1.2 to 3.4 ± 0.9, 3.8 ± 1.1 to 2.5 ± 0.6, and 4.6 ± 1.3 to 2.0 ± 0.6, respectively) compared to placebo. Also, NEEM significantly improved endothelial function, decreased oxidative stress and systemic inflammation compared to placebo. The efficacy was significant with all the doses, but no effect on platelet aggregation or lipid profile was observed.

CONCLUSION

NEEM may significantly ameliorate hyperglycemia, endothelial dysfunction, and systemic inflammation, on top of what metformin could do, in subjects with T2DM.

Nimbandiolactone-21 and nimbandioloxyfuran, two new 28-norlimonoids from the leaves of Azadirachta indica (Meliaceae)

From an EtOAc-soluble fraction of the leaves of Azadirachta indica, two new 28-norlimonoids named nimbandiolactone-21 (1) and nimbandioloxyfuran (2), together with nimbandiolactone-23 (3), were isolated. Their relative structures were elucidated based on NMR spectroscopic interpretation and biosynthetic consideration. Nimbandioloxyfuran (2) and nimbandiolactone-23 (3) showed potent α-glucosidase inhibitory activity, with the IC₅₀ values of 46.2 and 38.7 μM, respectively.

Medicinal plants brought by Indian indentured immigrants: A comparative review of ethnopharmacological uses between Mauritius and India

ETHNOPHARMACOLOGICAL RELEVANCE

Mauritius is famous for its floricultural diversity and traditions practiced across the island by various ethnic groups. During the British rule in the 1835s, Indian indentured labourers migrated to Mauritius and played a very important role in shaping the Mauritian culture. They brought along their high heritage of traditional knowledge of certain medicinal herbs and spices. Nonetheless, there has been no comparative study to investigate whether these past traditional knowledge are still preserved in Mauritius and India.

AIM OF THE STUDY

To document and compare the traditional uses of medicinal herbs and spices brought by Indian indentured labourers with their current uses in Mauritius and India, and to review pharmacological studies of such plants.

MATERIALS AND METHODS

Locally published textbooks, research dissertations, and relevant records from the 'Mauritiana' section of the University of Mauritius library were scrutinised for possible early records of such herbs and spices brought by Indian indentured immigrants. Field trips and site visits to Mauritius Herbarium and The National Folk Museum were conducted to gather data on their traditional uses as practiced by the Indian indentured immigrants. A literature search was performed to gather the current ethnomedicinal uses of these plants in Mauritius and India using key databases such as ScienceDirect and PubMed, as well as thesis from local university website. Pharmacological studies on these plants were also reviewed in an attempt to compare the ethnomedicinal uses against reported ailments.

RESULTS

Indian labourers brought 18 medicinal plants for medicinal purposes as documented at the folk museum of Indian Immigration. Piper betle L., Azadirachta indica A. Juss., and Curcuma longa L. were common plants used by Indian indentured immigrants against a wide range of ailments. Data obtained from recent ethnomedicinal surveys revealed that A. indica and C. longa were the most traditionally used plants in India, while in Mauritius, C. longa was the most popular plant followed by Allium sativum L. and Ocimum tenuiflorum L. It was also found that all these plants are currently being used against a wide range of diseases in both countries. In addition, several studies have highlighted the pharmacological properties such as analgesic, anti-inflammatory, anti-microbial, anti-pyretic, and anti-diabetic for some plants.

CONCLUSION

This investigation can be considered as a first attempt to document and compare traditional knowledge of medicinal plants brought by Indian immigrants. We observed that some of these knowledge are preserved and still practiced in Mauritius. It is anticipated that this study will revive the interest in safeguarding and promoting the ancestral knowledge on the uses of such plants.

A new lactam 28-norlimonoid from the leaves of Azadirachta indica A. Juss. (Meliaceae)

From an EtOAc-soluble fraction of the leaves of Azadirachta indica, one new lactam 28-norlimonoid named nimbandiolactam-21 (1), together with 2 known limonoids (2 and 3) were isolated. Their relative structures were elucidated based on NMR spectroscopic analysis. Nimbandiolactone-23 (2) showed the most potent α-glucosidase inhibitory activity, with an IC₅₀ value of 38.7 μM. Compound 1 represents the first naturally occurring example of a 28-norlimonoid having the lactam moiety. The plausible biosynthetic pathway for the formation of lactam moiety in 1 was proposed.

Phytotherapy in the Management of Diabetes: A Review

Phytotherapy has long been a source of medicinal products and over the years there have been many attempts to use herbal medicines for the treatment of diabetes. Several medicinal plants and their preparations have been demonstrated to act at key points of glucidic metabolism. The most common mechanisms of action found include the inhibition of α-glucosidase and of AGE formation, the increase of GLUT-4 and PPARs expression and antioxidant activity. Despite the large amount of literature available, the actual clinical effectiveness of medicinal plants in controlling diabetes-related symptoms remains controversial and there is a crucial need for stronger evidence-based data. In this review, an overview of the medicinal plants, which use in the management of diabetes is supported by authoritative monographs, is provided. References to some species which are currently under increasing clinical investigation are also reported.

Nimbolide attenuate the lipid accumulation, oxidative stress and antioxidant in primary hepatocytes

Nimbolide is a bioactive compound found in Azadirachta indica. This work was devised to investigate the potential effects of nimbolide on intracellular lipid deposition and its associated redox modulation in primary hepatocytes (Heps). Lipid accumulation was induced in Heps by supplementing 1 mM oleic acid for 24 h which was marked by significant accumulation of lipids. The results demonstrated that nimbolide can decrease intracellular cholesterol, free fatty acids and triglycerides. Nimbolide may also improve hepatocytes function through its antioxidant effects by inhibiting oxidative DNA damage and lipid peroxidation by curtailing the reactive oxygen species levels. Further it also restore the mitochondrial potential, improving the endogenous antioxidant levels such as GSH and antioxidant enzyme activities. Nimbolide increased (P < 0.05) liver X receptor-α (LXRα), peroxisome proliferator-activated receptor-γ (PPARγ) and sterol regulatory element-binding protein-1c (SREBP1c) gene expression in Heps. The biological significance of nimbolide may involve hypolipidemic effect, lipid peroxidation inhibition, DNA damage inhibition, ROS inhibition, restoring mitochondrial function, increases in GSH and SOD & CAT activities, and direct regulation of LXRα, PPARγ and SREBP1c gene expression. Nimbolide may be used as effective lipid lowering compound and lipid deposition-induced Heps changes.

Neem (Azadirachta indica): An indian traditional panacea with modern molecular basis

BACKGROUND

For centuries, agents derived from natural sources (mother nature), especially plants have been the primary source of medicine. Neem, also referred to as Azadirachta indica is one such plant that has been so named because it provides freedom from all diseases, and used for thousands of years in Indian and African continents. Different parts of the plant including flowers, leaves, seeds and bark have been used to treat both acute and chronic human diseases; and used as insecticide; antimicrobial, larvicidal, antimalarial, antibacterial, antiviral, and spermicidal.

PURPOSE

What is there in neem and how it manifests its wide variety of effects is the focus of this review. How neem and its constituents modulate various cellular pathways is discussed. The animal and human studies carried out with neem and its constituents is also discussed.

CONCLUSION

Over 1000 research articles published on neem has uncovered over 300 structurally diverse constituents, one third of which are limonoids including nimbolide, azadarachtin, and gedunin. These agents manifest their effects by modulating multiple cell signaling pathways.

In vitro screening for protein tyrosine phosphatase 1B and dipeptidyl peptidase IV inhibitors from selected Nigerian medicinal plants

Background/Aim:

Protein tyrosine phosphatase 1B (PTP 1B) and dipeptidyl peptidase IV (DPP IV) have been identified as one of the drug targets for the treatment of Type-2 diabetes. This study was designed to screen for PTP 1B and DPP-IV inhibitors from some Nigerian medicinal plants.

Materials and Methods:

PTP 1B and DPP-IV drug discovery kits from Enzo Life Sciences were used to investigate in vitro inhibitory effect of crude methanolic extract of 10 plants; Mangifera indica, Moringa oleifera, Acacia nilotica, Arachis hypogaea, Senna nigricans, Azadirachta indica, Calotropis procera, Leptadenia hastata, Ziziphus mauritiana, and Solanum incanum.

Results:

The results indicated PTP IB inhibition by S. nigricans (68.2 ± 2.29%), A. indica (67.4 ± 2.80%), A. hypogaea (57.2 ± 2.50%), A. nilotica (55.1 ± 2.19%), and M. oleifera (41.2 ± 1.87%) were significantly (P < 0.05) higher as compared with standard inhibitor, sumarin while that of L. hastata (18.1 ± 2.00%) was significantly lower as compared with sumarin. The PTB 1B inhibition by M. indica (31.5 ± 1.90%) was not significantly (P > 0.05) different from that of sumarin. The DPP-IV inhibition by S. incanum (68.1 ± 2.71%) was significantly higher as compared with a known inhibitor, P32/98. S. nigrican (57.0±1.91%), Z. mauritiana (56.6±2.01%), A. hypogaea (51.0±1.30%), M. indica (44.6 ± 2.40%), C. procera (36.2 ± 2.00%), A. nilotica (35.4 ± 2.10%), and A. indica (33.6 ± 1.50%) show significantly (P < 0.05) lower inhibitions toward DPP-IV.

Conclusion:

The work demonstrated that these plant materials could serve as sources of lead compounds in the development of anti-diabetic agent(s) targeting PTP 1B and/or DPP-IV.

Preconditioning with Azadirachta indica ameliorates cardiorenal dysfunction through reduction in oxidative stress and extracellular signal regulated protein kinase signalling

BACKGROUND

Azadirachta indica is widely distributed in Africa, Asia and other tropical parts of the world. A. indica (AI) is traditionally used for the treatment of several conditions including cancer, hypertension, heart diseases and skin disorders. Intestinal ischaemia-reperfusion is a common pathway for many diseases and may lead to multiple organ dysfunction syndrome and death.

OBJECTIVE

In this study, we investigated the ameliorative effects of AI on intestinal ischaemia-reperfusion injury-induced cardiorenal dysfunction.

MATERIALS AND METHODS

Sixty rats were divided into 6 groups; each containing 10. Corn oil was orally administered to group A (control) rats for 7 days without intestinal ischaemia-reperfusion injury. Group B underwent intestinal ischaemia-reperfusion injury (IIRI) without any pre-treatment. Groups C, D, E and F were pre-treated orally for 7 days with 100 mg/kg AI (100 and (200 mg/kg) vitamin C (100 and 200 mg/kg) respectively and thereafter underwent IIRI on the 8th day.

RESULTS

The cardiac and renal hydrogen peroxide increased significantly whereas serum xanthine oxidase and myeloperoxidase levels were significantly elevated (p < 0.05) in IIRI only when compared to the control. The cardiac and renal reduced glutathione, glutathione peroxidase, protein thiol, non-protein thiol and serum nitric oxide (NO) decreased (p < 0.05) significantly following IIRI. Immunohistochemical evaluation of cardiac and renal tissues showed reduced expressions of the extracellular signal regulated kinase (ERK1/2) in rats with IIRI only. However, pre-treatment with A. indica and vitamin C significantly reduced markers of oxidative stress and inflammation together with improvement in antioxidant status. Also, reduced serum NO level was normalised in rats pre-treated with A. indica and vitamin C with concomitant higher expressions of cardiac and renal ERK1/2.

CONCLUSIONS

Together, A. indica and vitamin C prevented IRI-induced cardiorenal dysfunction via reduction in oxidative stress, improvement in antioxidant defence system and increase in the ERK1/2 expressions. Therefore, A. indica can be a useful chemopreventive agent in the prevention and treatment of conditions associated with intestinal ischaemia-reperfusion injury.