Pharmacological evaluation of medicinal plants with antidiabetic activities in Ethiopia: A review

Antidiabetic effects of Peganum harmala seed extract on streptozotocin-induced diabetes in rats

Objective

Diabetes, a chronic metabolic disease, has many complex complications and an increasing prevalence in various societies. Despite conventional drug treatments and limited surgical and tissue transplant methods, a definitive diabetes treatment remains to be found. Restoring damaged beta cells to insulin production or prompting other pancreatic cells to secrete insulin is an essential goal of diabetes research. The present study investigated the antidiabetic and regenerative effects of Peganum harmala seed extract (PHSE) on streptozotocin (STZ)-induced diabetes in rats.

Materials and Methods

In this experimental in vivo study, male Wistar rats (200±10 g) were placed in 5 groups: control, untreated diabetic and diabetic groups treated with 100, 200, and 400 mg/kg doses of PHSE. Fasting blood sugar (FBS), C-peptide, insulin, and antioxidant parameters (total antioxidant capacity (TAC) and nitric oxide (NO)) of serum were measured. Pancreatic tissue was used for histologic staining and assessment of the expression of genes related to beta cell regeneration.

Results

PHSE significantly improved FBS, weight loss, insulin, c-peptide, TAC, NO, and expression of pancreatic genes (insulin, PDX1 and neurogenin-3) (p<0.05). It also increased the number of pancreatic beta cells.

Conclusion

PHSE has considerable regenerative and antidiabetic effects on changes caused by diabetes in rats' serum and pancreas.

Investigating the potential effects of olive leaves and ginger rhizome extracts on kidney and liver functions in alloxan-induced diabetic rats

Objective

Although there are many drugs on the shelves of pharmacies to manage diabetes mellitus (DM), many people around the world still use herbal preparations to treat it. This study investigated the effect of an aqueous combination of olive leaves and ginger rhizome extracts on type 1 diabetes mellitus (T1DM) using various physiological markers.

Materials and Methods

Fifty-two Wistar rats were distributed into 2 healthy and 6 diabetic groups. Forty rats were given alloxan (150 mg/kg) as an intraperitoneal single-dose to induce T1DM. Treatments including insulin with/without individual and combined extracts, were started 4-day post-induction. The extracts were administered orally (500 mg/kg) and insulin was administered subcutaneously (6 IU/kg) in single-doses once a day. After one week of treatment, the blood samples were collected to measure Fasting blood glucose (FBG), Alanine aminotransferase (ALT), Alkaline phosphatase (ALP), and creatinine.

Results

The diabetic group that received the combination of both extracts with insulin had a lower mortality rate after 14 days of treatment. The diabetic group receiving insulin with the olive leaves extract, demonstrated a decrease in ALT levels to 33.7 U/L (p=0.345) while maintaining the ALP levels within the normal range 126.9 U/L (p=0.463). Creatinine was significantly reduced to 1.1 mg/dl (p=0.028) and 0.7 mg/dl (p=0.028) in diabetic groups that received individual olive leaves and ginger extracts with insulin respectively.

Conclusion

To conclude, this combination with insulin had powerful effects to improve the mortality rate in diabetic rats over other groups, and the two extracts separately were able to decrease the creatinine levels.

Antidiabetic phytochemicals: an overview of medicinal plants and their bioactive compounds in diabetes mellitus treatment

Diabetes mellitus (DM) is a group of metabolic disorders characterized by hyperglycemia due to insufficient insulin secretion or action. Contributing factors include genetic predisposition, obesity, family history, inactivity, and environmental risks. Type 2 diabetes mellitus (T2DM), the most common form, involves impaired insulin secretion by pancreatic β-cells, leading to insulin resistance. By 2045, it is projected that India and China will have approximately 134.3 and 110.8 million diabetic individuals, respectively. Although synthetic drugs are effective in managing DM, they often come with side effects. Consequently, plant-based phytochemicals with antidiabetic properties are gaining attention. Research indicates that around 115 medicinal plants (MPs) have antidiabetic effects, particularly those from the Fabaceae, Liliaceae, and Lamiaceae families. Bioactive compounds like alkaloids, triterpenoids, flavonoids, and phenolics are known to combat DM. Traditional medicinal systems, particularly in developing countries, offer effective DM management. This review highlights the importance of MPs and their bioactive compounds in treating diabetes and underscores the need for further research to commercialize plant-based antidiabetic drugs.

Exploring the Anti-Inflammatory Potential of Ajuga integrifolia Leaves Extract: In Vitro Dual Inhibition of Cyclooxygenase and Lipoxygenase Enzymes

This study investigated the anti-inflammatory properties of Ajuga integrifolia, an herbal preparation. Qualitative and quantitative phytochemical analyses were conducted to identify active compounds in the preparation. The researchers also assessed its ability to inhibit the production of pro-inflammatory enzymes, cyclooxygenases (COX-1, COX-2), and lipoxygenase (5-LOX) in vitro. The extracts demonstrated dose-dependent inhibition of these enzymes, with some extracts showing IC50 values comparable to standard anti-inflammatory drugs. The ethanol extract exhibited significant inhibition of 5-LOX (52.99 μg/mL), compared to the standard drug zileuton (32.41 μg/mL), while the inhibition of COX-1 (66.00 μg/mL) and COX-2 (71.62 μg/mL) was comparable to the standard drug indomethacin (40.57 and 54.39 μg/mL, respectively). These findings suggest that A. integrifolia has the potential to be used as a herbal remedy for treating inflammatory conditions. By inhibiting pro-inflammatory enzymes, the extracts may effectively reduce inflammation and promote tissue healing or repair. The inhibition potential of extract of this plant can be taken as a good candidate of anti-inflammatory agent.

Suppression of the postprandial hyperglycemia in patients with type 2 diabetes by a raw medicinal herb powder is weakened when consumed in ordinary hard gelatin capsules: A randomized crossover clinical trial

INTRODUCTION

Contradictory claims about the efficacy of several medicinal plants to promote glycemic control in patients with type 2 diabetes mellitus (T2DM) have been explained by divergences in the administration form and by extrapolation of data obtained from healthy individuals. It is not known whether the antidiabetic effects of traditional herbal medicines are influenced by gelatin capsules. This randomized crossover trial aimed to evaluate the acute effect of a single dose of raw cinnamon consumed orally either dissolved in water as a beverage or as ordinary hard gelatin capsules on postprandial hyperglycemia (>140 mg/dL; >7.8 mmol/L) in T2DM patients elicited by a nutritionally-balanced meal providing 50 g of complex carbohydrates.

METHODS

Fasting T2DM patients (n = 19) randomly ingested a standardized meal in five experimental sessions, one alone (Control) and the other after prior intake of 3 or 6 g of crude cinnamon in the form of hard gelatin capsules or powder dissolved in water. Blood glucose was measured at fasting and at 0.25, 0.5, 0.75, 1, 1.5 and 2 hours postprandially. After each breakfast, its palatability scores for visual appeal, smell and pleasantness of taste were assessed, as well as the taste intensity sweetness, saltiness, bitterness, sourness and creaminess.

RESULTS

The intake of raw cinnamon dissolved in water, independently of the dose, decreased the meal-induced large glucose spike (peak-rise of +87 mg/dL and Δ1-hour glycemia of +79 mg/dL) and the hyperglycemic blood glucose peak. When cinnamon was taken as capsules, these anti-hyperglycemic effects were lost or significantly diminished. Raw cinnamon intake did not change time-to-peak or the 2-h post-meal glycaemia, but flattened the glycemic curve (lower iAUC) without changing the shape that is typical of T2DM patients.

CONCLUSIONS

This cinnamon's antihyperglycemic action confirms its acarbose-like property to inhibit the activities of the carbohydrate-digesting enzymes α-amylases/α-glucosidases, which is in accordance with its exceptionally high content of raw insoluble fiber. The efficacy of using raw cinnamon as a diabetes treatment strategy seems to require its intake at a specific time before/concomitantly the main hyperglycemic daily meals. Trial registration: Registro Brasileiro de Ensaios Clínicos (ReBEC), number RBR-98tx28b.

Effect of dawri-damaa (Pentas schimperiana) leaf meal supplementation on performances, carcass characteristics, and economic feasibility of sheep fed native grass hay

With a growing export and local market, sheep farming is critical to the economy of smallholder farmers; however, indigenous sheep breeds usually exhibit low carcass output and live weight due to nutritional constraints. The study aimed to investigate the impact of supplementing local sheep with dawri-damaa leaf meal (DDLM) on their performance, carcass characteristics, and profitability when fed native grass hay. The research used a randomized complete block design (RCBD) to administer four feeding treatments (T1, T2, T3, and T4 at 0%, 30%, 50%, and 70% DDLM, respectively) to 20 local uncastrated male lambs having an average 23.72 ± 0.73 kg body weight and average age of 11.72 ± 0.74 months. Greater doses of DDLM in the diet resulted in greater average daily gain (ADG) of 51.4-83.8 g/day and feed conversion efficiency (FCE) of 0.066-0.089 in lambs, compared to 15.0 g/day ADG and 0.025 FCE in lambs under control diet (T1). Additionally, the lambs had increased slaughter body weight (SBW), empty body weight (EBW), and hot carcass weight (HCW) in T4 and T3 compared to other treatments (p < .05). There were no significant differences in dressing percentages (DPs) across any treatment group. The study also discussed the economic viability of supplementing with DDLM, suggesting that feeding 70% daily dry matter of DDLM at 2.5% live weight might be beneficial depending on availability, access, and cost factors. In conclusion, feeding DDLM up to 70% has improved the performance of sheep and is economically feasible. Further research might be required to discover whether such levels of inclusion are harmful and apply different processing methods for feeding animals.

A comprehensive in-vitro/in-vivo screening toolbox for the elucidation of glucose homeostasis modulating properties of plant extracts (from roots) and its bioactives

Plant extracts are increasingly recognized for their potential in modulating (postprandial) blood glucose levels. In this context, root extracts are of particular interest due to their high concentrations and often unique spectrum of plant bioactives. To identify new plant species with potential glucose-lowering activity, simple and robust methodologies are often required. For this narrative review, literature was sourced from scientific databases (primarily PubMed) in the period from June 2022 to January 2024. The regulatory targets of glucose homeostasis that could be modulated by bioactive plant compounds were used as search terms, either alone or in combination with the keyword "root extract". As a result, we present a comprehensive methodological toolbox for studying the glucose homeostasis modulating properties of plant extracts and its constituents. The described assays encompass in-vitro investigations involving enzyme inhibition (α-amylase, α-glucosidase, dipeptidyl peptidase 4), assessment of sodium-dependent glucose transporter 1 activity, and evaluation of glucose transporter 4 translocation. Furthermore, we describe a patch-clamp technique to assess the impact of extracts on KATP channels. While validating in-vitro findings in living organisms is imperative, we introduce two screenable in-vivo models (the hen's egg test and Drosophila melanogaster). Given that evaluation of the bioactivity of plant extracts in rodents and humans represents the current gold standard, we include approaches addressing this aspect. In summary, this review offers a systematic guide for screening plant extracts regarding their influence on key regulatory elements of glucose homeostasis, culminating in the assessment of their potential efficacy in-vivo. Moreover, application of the presented toolbox might contribute to further close the knowledge gap on the precise mechanisms of action of plant-derived compounds.

Medicinal Plants Used by Oromo Community in Kofale District, West-Arsi Zone, Oromia Regional State, Ethiopia

Purpose

The purpose of this study was to record the utilization of medicinal plants by the Oromo people in the Kofale District, Oromia Regional State, Ethiopia, to control human and animal health problems.

Methods

Data regarding the use of medicinal plants were collected using ethnobotanical methods from 84 traditional medicine practitioners and 304 general informants sampled employing purposive and systematic random sampling methods, respectively, in the Kofale District. Data were analyzed using different indices, including a preference ranking exercise, informant consensus factor (ICF), fidelity level (FL) and relative popularity level (RPL).

Results

In the district, 106 medicinal plants were claimed to be used for the treatment of 43 human and 18 livestock illnesses, of which 75 (71%) were used to manage human health problems, 23 (21.5%) were used to treat both human and livestock ailments and eight (7.5%) were utilized to treat manage livestock health problems. Most (76.4%) plants were harvested from the wild. Leaves were the most commonly used plant part (55.6%) in remedy preparations. Skin diseases scored the highest ICF value (0.97), followed by gastrointestinal disorders (ICF = 0.95), cancer (ICF = 0.93), and hemorrhoids (ICF = 0.91). Medicinal plants that record the highest fidelity level (FL) (100%) and rank order priority (ROP) (100%) values included Justicia schimperiana, Embelia schimperi, Ekebergia capensis and Datura stramonium, which have been used to treat liver disorders, tapeworm infections, babesiosis, and rabies, respectively. There were significant differences (p<0.05) in the mean numbers of medicinal plants claimed by different social groups: older, illiterate, and traditional medicine practitioners reported higher mean numbers of medicinal plants than younger, literate, and general informants, respectively.

Conclusion

This study indicated the richness of medicinal plant species in Kofale District. Medicinal plants with the highest FL and ROP values and those used to treat disease categories with the highest ICF values should be prioritized in future phytochemical and pharmacological investigations.

Potential Pharmacological Applications of Nigella Seeds with a Focus on Nigella sativa and Its Constituents against Chronic Inflammatory Diseases: Progress and Future Opportunities

The leading cause of death worldwide has been identified as chronic illnesses, according to the World Health Organization (WHO). Chronic inflammatory conditions such as asthma, cancer, diabetes, heart disease, and obesity account for three out of every five deaths. Although many people benefit from using nonsteroidal anti-inflammatory medicines (NSAIDs) for pain and inflammation relief, there are significant adverse effects to using these medications. Medicinal plants possess anti-inflammatory properties with minimal or no side effects. Nigella sativa (NS), also known as black cumin, is one of the plants used in traditional medicine the most. Many studies on the NS have shown that their therapeutic properties are attributed to the seed, oil, and secondary metabolites. This plant has been studied extensively and has many medical uses, such as anti-inflammatory. NS or its phytochemical compounds, such as thymoquinone, can cause cell apoptosis via oxidative stress, block efflux pumps, enhance membrane permeability, and exert potent biocidal effects. Notwithstanding the extensively documented anti-inflammatory effectiveness observed in the experimental model, the precise mechanisms underlying its anti-inflammatory effects in diverse chronic inflammatory diseases and its multi-targeting characteristics remain largely unexplored. This review examines NS or its secondary metabolites, a valuable source for the therapeutic development of chronic inflammatory diseases. Most clinical studies were done for diabetes and cardiovascular disease; therefore, more studies are required to examine the NS extracts and phytoconstituents to treat cancer, obesity, diabetes, asthma, neurological disorders, and COVID-19. This study will be a significant resource for clinicians and biologists seeking a pharmaceutical solution for inflammatory diseases.

Pharmacologically Active Phytomolecules Isolated from Traditional Antidiabetic Plants and Their Therapeutic Role for the Management of Diabetes Mellitus

Diabetes mellitus is a chronic complication that affects people of all ages. The increased prevalence of diabetes worldwide has led to the development of several synthetic drugs to tackle this health problem. Such drugs, although effective as antihyperglycemic agents, are accompanied by various side effects, costly, and inaccessible to the majority of people living in underdeveloped countries. Medicinal plants have been used traditionally throughout the ages to treat various ailments due to their availability and safe nature. Medicinal plants are a rich source of phytochemicals that possess several health benefits. As diabetes continues to become prevalent, health care practitioners are considering plant-based medicines as a potential source of antidiabetic drugs due to their high potency and fewer side effects. To better understand the mechanism of action of medicinal plants, their active phytoconstituents are being isolated and investigated thoroughly. In this review article, we have focused on pharmacologically active phytomolecules isolated from medicinal plants presenting antidiabetic activity and the role they play in the treatment and management of diabetes. These natural compounds may represent as good candidates for a novel therapeutic approach and/or effective and alternative therapies for diabetes.

Evaluation of Antidiabetic and Antihyperlipidemic Activity of 80% Methanolic Extract of the Root of Solanum incanum Linnaeus (Solanaceae) in Mice

Background

Conventional antidiabetic drugs are linked with a number of contraindications and untoward effects. The root decoction of Solanum incanum L. has traditionally been used to treat diabetes. However, its safety and efficacy have not been scientifically authenticated yet. Hence, the study was conducted in mice to corroborate its antidiabetic potential and safety profile.

Methods

Using normoglycemic, oral glucose-loaded, and streptozotocin-induced diabetic mice models, the hypoglycemic and antihyperglycemic activities of 80% methanolic root extract were investigated. On streptozotocin-induced diabetic mice, the effect of the test extract on diabetic lipid profile and body weight was also investigated. Further, the in vitro α-amylase inhibition activity was assessed.

Results

The test extract was safe at a limit test dose of 2 g/kg. Dose-dependent α-amylase inhibition activity was seen with peak percentage inhibition of 75.95% at 700 μg/mL. In normoglycemic mice, the plant extract showed statistically significant hypoglycemic activity at 200 and 400 mg/kg (P < 0.001) at 6  h and 4 and 6 h of treatment, respectively; in oral glucose-loaded mice, at both the test doses, the glucose level was also significantly dropped at 120 (P < 0.01) and 60 and 120 min (P < 0.001), respectively; whereas, in the third model, the test extract showed significant antihyperglycemic activity at 100 mg/kg (P < 0.05) on the 14^th day and at 200 (P < 0.01) and 400 mg/kg (P < 0.001) on the 7^th and 14^th day of treatment. Similarly, following repeated administration of the test extract at 200 and 400 mg/kg, the body weight was significantly improved on the 14^th day (P < 0.05) and on the 7^th and 14^th day (P < 0.01), respectively, while diabetic dyslipidemia after 14 days (P < 0.05).

Conclusion

The study revealed that the test extract showed promising antihyperglycemic and antihyperlipidemic activity. Thus, the findings back up its use in Ethiopian remedies for diabetes.