Exploring the Efficacy of Herbal Antidiabetic Preparations: A Review of Current Research and Future Directions

Diabetes mellitus, particularly type 2 diabetes, continues to pose a significant global health burden, with increasing prevalence, healthcare costs, and long-term complications. Conventional treatments, including insulin therapy and oral hypoglycemic agents, although effective, often come with limitations such as side effects, high costs, and reduced patient compliance. In this context, herbal antidiabetic preparations have gained growing attention as alternative and complementary therapeutic options, driven by traditional medicinal knowledge and an increasing body of scientific evidence. This review explores the efficacy, mechanisms of action, and therapeutic potential of various herbal formulations in the management of diabetes, while also identifying gaps in current research and proposing future directions. A wide range of medicinal plants, including Momordica charantia (bitter melon), Gymnema sylvestre, Trigonella foenum-graecum (fenugreek), Cinnamomum verum (cinnamon), and Berberis aristata, have demonstrated hypoglycemic activity in both experimental and clinical studies. These herbs contain bioactive constituents such as charantin, gymnemic acids, berberine, trigonelline, and cinnamaldehyde, which act through multiple mechanisms. These include enhancing insulin secretion, regenerating pancreatic beta cells, improving insulin sensitivity, inhibiting intestinal glucose absorption, and exerting antioxidant and anti-inflammatory effects. Unlike synthetic drugs that typically target a single pathway, herbal preparations often provide a multifaceted approach, making them particularly suitable for the complex pathophysiology of diabetes.

Despite these promising results, the clinical adoption of herbal antidiabetic therapies remains limited due to several challenges. These include variability in phytochemical content based on geographical and processing factors, lack of standardized formulations, and insufficient large-scale randomized controlled trials with inconsistent methodologies and small sample sizes. Moreover, concerns regarding safety, potential herb-drug interactions, and regulatory inconsistencies further hinder their widespread integration into mainstream healthcare. While preclinical evidence is robust, the translation of findings into clinically approved treatments necessitates rigorous evaluation, including toxicity studies, pharmacokinetic profiling, and long-term efficacy trials. Recent advances in biotechnology, phytochemistry, and computational biology have opened new avenues for enhancing the reliability and efficacy of herbal medicine. Standardization of active ingredients, use of nanotechnology for improved bioavailability, and integration of systems biology approaches such as metabolomics and network pharmacology are transforming the field. Furthermore, the development of herbal-drug combination therapies, precision herbal medicine tailored to individual genetic profiles, and the incorporation of herbal remedies into public health strategies represent important future directions. In conclusion, herbal antidiabetic preparations offer a promising, accessible, and culturally acceptable alternative for managing diabetes, especially in regions with limited access to modern medical care. However, realizing their full potential requires a multidisciplinary effort to bridge traditional knowledge with modern scientific validation. By addressing current limitations and investing in high-quality research and regulatory frameworks, herbal medicines can become an integral part of evidence-based diabetes management and prevention strategies globally, including multi-center randomized trials and pharmacovigilance mechanisms.

Introduction

Diabetes mellitus, a chronic metabolic disorder characterized by high blood glucose levels, has emerged as a global health crisis, affecting over 500 million people worldwide. The disease is primarily categorized into type 1 diabetes, which results from autoimmune destruction of pancreatic beta cells, and type 2 diabetes, which is associated with insulin resistance and relative insulin deficiency. The long-term complications of uncontrolled diabetes include neuropathy, nephropathy, retinopathy, and cardiovascular diseases. Despite the availability of several synthetic antidiabetic drugs and insulin therapy, the management of diabetes remains challenging due to side effects, cost of treatment, and limited accessibility in under-resourced areas. In this context, herbal antidiabetic preparations have garnered significant attention as alternative or complementary therapeutic options [1]. Derived from plant sources, these preparations are formulated from medicinal herbs traditionally recognized for their glucose-lowering and insulin-sensitizing properties. Unlike synthetic medications, herbal remedies often provide a multifaceted approach, targeting various pathways of glucose metabolism and offering additional antioxidant, anti-inflammatory, and lipid-lowering benefits.

Historical background

The use of medicinal plants for treating diabetes is not a novel concept. Historical records indicate that herbal therapies for managing symptoms akin to diabetes have been practiced for thousands of years in diverse medical systems across the globe. In India, the traditional system of Ayurveda, which dates back to 5000 BCE, extensively documents herbs such as Gymnema sylvestre, Momordica charantia (bitter melon), and Trigonella foenum-graecum (fenugreek) for balancing "Madhumeha" — a condition analogous to modern diabetes. Similarly, in Traditional Chinese Medicine (TCM), the Huang Di Nei Jing, one of the oldest known medical texts, refers to "Xiaoke" disease, which exhibits symptoms of excessive thirst and urination, treated with herbs like Panax ginseng, Astragalus membranaceus, and Coptis chinensis. In the Middle East and North Africa, the Unani system of medicine and folk practices have long utilized herbs such as Nigella sativa and Allium sativum (garlic) for glycemic control [2].

With the evolution of pharmacognosy in the 19th and 20th centuries, researchers began to investigate the bioactive constituents of antidiabetic plants, isolating compounds such as alkaloids, flavonoids, glycosides, and saponins with hypoglycemic activity. For instance, charantin from bitter melon, trigonelline from fenugreek, and gymnemic acids from Gymnema sylvestre have all demonstrated insulin-mimetic or beta-cell regenerative effects. Despite this growing scientific interest, herbal medicine remained largely on the fringes of mainstream healthcare until the last few decades, when the rising prevalence of type 2 diabetes, coupled with growing concerns over adverse drug reactions, rekindled interest in natural and holistic therapies [3].

Scientific evidence and current applications

The past few decades have witnessed a surge in preclinical and clinical research on herbal antidiabetic preparations. Numerous in vitro and animal studies have confirmed the efficacy of plant extracts in reducing blood glucose levels, improving insulin sensitivity, and protecting pancreatic beta cells from oxidative stress. Clinical trials, though fewer and often limited by sample size and methodological heterogeneity, have provided encouraging results. For example, a randomized controlled trial on Momordica charantia extract demonstrated significant reductions in fasting and postprandial glucose levels among patients with type 2 diabetes. Another study involving Gymnema sylvestre showed a decrease in insulin requirements among insulin-dependent patients, attributed to its beta-cell regenerative capacity. Standardized herbal formulations are now increasingly being developed and commercialized, either as standalone treatments or adjuncts to conventional therapy. These products are available in various forms (However, differences in formulation and lack of standardization affect reproducibility) such as capsules, powders, teas, and tinctures, often marketed as dietary supplements or nutraceuticals [4]. Multicomponent formulations, combining several antidiabetic herbs, are particularly popular due to their synergistic effects. For instance, combinations of Tinospora cordifolia, Syzygium cumini (jamun), Ocimum sanctum (holy basil), and Cinnamomum verum have shown promising results in improving glucose control and reducing HbA1c levels (Table 1).

Despite these advances, challenges persist. One major issue is the variability in potency and composition of herbal products due to differences in cultivation, harvesting, processing, and storage conditions. Standardization of active constituents remains a critical hurdle. Furthermore, the lack of rigorous regulatory frameworks for herbal products in many countries raises concerns about safety, quality control, and potential herb-drug interactions. Adulteration and contamination with heavy metals or pharmaceuticals further complicate the picture. Consequently, integrating herbal medicine into modern diabetes care requires not only scientific validation but also robust regulatory oversight and professional education [5].

Assessment of clinical study quality

While numerous studies have highlighted the potential antidiabetic properties of various herbal formulations, the overall quality and reproducibility of the evidence remain variable. A critical evaluation reveals several common limitations across the literature:

• Small sample sizes: Many clinical trials cited in support of herbal treatments have involved fewer than 100 participants, limiting statistical power and generalizability of results.
• Short study duration: Several studies conducted intervention periods of less than 12 weeks, which may be insufficient to assess long-term glycemic control or side effects.
• Lack of blinding and randomization: A number of trials lack rigorous design components such as double-blinding, random allocation, or placebo control, which increases the risk of bias.
• Inconsistent endpoints: Some studies focus solely on fasting blood glucose or HbA1c, while others include biochemical markers, making cross-study comparison difficult.
• Reproducibility concerns: Repeated studies with standardized protocols are rare. Many investigations rely on region-specific or lab-specific formulations without clear standardization of extract composition or dosage.
• Regulatory oversight: Few of the clinical studies are registered with clinical trial registries or adhere to CONSORT guidelines, further affecting their credibility.

Consequently, while existing evidence is promising, the methodological heterogeneity and design flaws underscore the urgent need for large-scale, multi-center Randomized Controlled Trials (RCTs) with standardized protocols, validated outcome measures, and long-term safety assessments.

Herbal antidiabetic formulations

Several herbal formulations have shown significant potential in the management of diabetes mellitus due to their bioactive constituents and diverse mechanisms of action. One of the most widely studied plants is Momordica charantia, commonly known as bitter melon. It contains charantin, polypeptide-p, and vicine, compounds that help lower blood glucose levels and improve insulin sensitivity. Gymnema sylvestre, often referred to as "sugar destroyer" in Ayurvedic medicine, contains gymnemic acids and gurmarin, which stimulate insulin secretion and aid in the regeneration of pancreatic beta cells [6]. Trigonella foenum-graecum, or fenugreek, is rich in trigonelline, 4-hydroxyisoleucine, and galactomannan. These constituents improve glucose tolerance and slow down the absorption of carbohydrates in the intestine. Another commonly used spice, Cinnamomum verum (cinnamon), possesses cinnamaldehyde and procyanidins that enhance insulin receptor function and reduce fasting blood glucose levels. Similarly, Ocimum sanctum, known as holy basil, has eugenol and ursolic acid, which contribute to reduced oxidative stress and better glucose metabolism [7].

The fruits and seeds of Syzygium cumini, or jamun, contain jamboline and ellagic acid. These substances help lower blood sugar and exhibit antioxidant properties. Aloe vera, a plant widely used for its therapeutic benefits, contains glucomannan and phytosterols, which stimulate insulin production and reduce fasting blood glucose levels. Berberis aristata, known for its golden-yellow stem and root, is a source of berberine, a potent alkaloid that activates AMP-activated protein kinase (AMPK) and reduces insulin resistance. Pterocarpus marsupium is another important herb used in diabetes management. Its key constituents—pterostilbene and marsupsin—support the regeneration of beta cells and reduce blood sugar levels. Tinospora cordifolia, a traditional Indian herb, contains tinosporine and cordifolioside, which enhance insulin action and exert antioxidant effects [8]. Andrographis paniculata is rich in andrographolide, known for reducing oxidative stress and improving the function of pancreatic cells. Curcuma longa, or turmeric, contains curcumin, a powerful anti-inflammatory agent that also improves insulin sensitivity. Allium sativum, or garlic, includes allicin and S-allyl cysteine, which are effective in lowering blood glucose and cholesterol levels while providing antioxidant protection. Ficus racemosa offers leucocyanidin and bergapten, contributing to both hypoglycemic and antihyperlipidemic effects [9].

Cassia auriculata contains flavonoids and tannins that delay the absorption of glucose in the intestines and provide antioxidant benefits. Zingiber officinale, commonly known as ginger, includes gingerols and shogaols that help reduce insulin resistance and improve overall glycemic control. Mangifera indica, particularly its leaves, is a source of mangiferin, a polyphenol that promotes glucose uptake and acts as a strong antioxidant. Salacia reticulata, an herb used in Ayurvedic and traditional Sri Lankan medicine, contains salacinol and kotalanol, which inhibit the enzyme alpha-glucosidase and thus reduce postprandial blood glucose spikes. Eugenia jambolana (also known as jamun or java plum) contains anthocyanins and jambosine, which slow down the conversion of starch to sugar and enhance pancreatic function. Finally, Bauhinia forficata, often referred to as Brazilian orchid tree, contains kaempferol and quercetin—flavonoids known for reducing blood sugar and exerting antioxidant effects. These herbs, with their bioactive compounds, offer promising alternatives or adjuncts to conventional antidiabetic drugs by addressing multiple pathways involved in glucose homeostasis, insulin regulation, and oxidative stress reduction [10] (Table 2).

Mechanisms of action

Herbal antidiabetic preparations work through multiple mechanisms, reflecting the complexity of diabetes pathophysiology [11]. These include enhancement of insulin secretion, improvement of insulin sensitivity, inhibition of intestinal glucose absorption, modulation of hepatic glucose production, and reduction of oxidative stress and inflammation. For example, Berberine, an alkaloid found in Coptis chinensis and Berberis aristata, activates AMP-activated protein kinase (AMPK), which plays a key role in energy homeostasis and glucose metabolism. Cinnamaldehyde from cinnamon improves insulin receptor phosphorylation, thereby enhancing insulin signalling [12]. Flavonoids from various herbs exert potent antioxidant effects, protecting pancreatic beta cells from damage induced by chronic hyperglycemia [13].

Some plants also contain compounds that inhibit carbohydrate-hydrolyzing enzymes such as alpha-glucosidase and alpha-amylase, thereby reducing postprandial glucose spikes. Saponins and polysaccharides, particularly from ginseng and Astragalus membranaceus, modulate immune responses and reduce systemic inflammation, which is increasingly recognized as a contributor to insulin resistance. By acting on multiple targets simultaneously, herbal preparations offer a holistic approach that complements the often singular action of conventional antidiabetic drugs [14].

Conclusion

Herbal antidiabetic preparations, rooted in ancient healing traditions and increasingly validated by modern science, represent a valuable resource in the global fight against diabetes mellitus. Their multifaceted mechanisms of action, relative safety, and affordability make them attractive alternatives or complements to conventional therapies [15]. While challenges related to standardization, regulation, and evidence-based integration remain, ongoing research and innovation are paving the way for more effective and reliable herbal interventions. The future lies in harnessing the synergistic potential of traditional knowledge and modern biomedical science to develop safe, effective, and sustainable therapies that address the growing burden of diabetes across the globe.

Future prospects and innovations

The future of herbal antidiabetic preparations appears promising, driven by advances in ethnopharmacology, biotechnology, and personalized medicine [16]. One of the most significant trends is the integration of traditional knowledge with modern scientific tools such as metabolomics, genomics, and molecular docking studies. These approaches facilitate the identification of bioactive compounds, elucidation of mechanisms, and optimization of formulations [17]. Nanotechnology is also being explored to improve the bioavailability and targeted delivery of herbal compounds. For instance, nanoencapsulation of berberine or curcumin has shown improved absorption and therapeutic efficacy in experimental models. Artificial intelligence and machine learning are now being applied to screen plant databases, predict bioactivity, and design novel combinations based on pharmacological synergy [18]. This computational ethnobotany could accelerate the discovery of effective herbal therapies. Moreover, the concept of "herbal precision medicine" is gaining ground, where individual genetic, metabolic, and lifestyle factors are used to tailor herbal interventions for better outcomes [19]. On the regulatory front, efforts are being made to develop standardized protocols for quality control, safety assessment, and clinical evaluation of herbal products. The World Health Organization has issued guidelines for the assessment of herbal medicines, and countries like India, China, and Germany have established pharmacopeias that include monographs on medicinal plants. As awareness grows among healthcare professionals and patients, integration of herbal medicine into mainstream diabetes management is likely to expand. Collaborative efforts between traditional healers, scientists, and clinicians are essential to ensure that herbal therapies are evidence-based, safe, and accessible [20]. The globalization of herbal medicine, however, also raises ethical and ecological concerns. Unsustainable harvesting of medicinal plants can lead to biodiversity loss and ecological imbalance. Therefore, sustainable cultivation practices, fair trade policies, and conservation efforts must accompany the expansion of herbal antidiabetic therapies. Furthermore, the intellectual property rights of indigenous communities who have preserved traditional knowledge must be respected and protected through equitable benefit-sharing frameworks.

Global guidelines and oversight

International regulatory bodies have made efforts to address the growing use of herbal medicines. The World Health Organization (WHO) has developed several key documents, including the WHO Guidelines on Safety Monitoring of Herbal Medicines in Pharmacovigilance Systems and Monographs on Selected Medicinal Plants, which provide standardized information on dosage, preparation, and safety profiles.

In Europe, the European Medicines Agency (EMA), through its Committee on Herbal Medicinal Products (HMPC), has developed herbal monographs and a simplified registration pathway for traditional herbal medicinal products. These regulatory frameworks aim to improve quality assurance, monitor adverse events, and guide evidence-based use.

Despite these developments, many countries still lack comprehensive pharmacovigilance systems for herbal medicines, leading to underreporting of adverse effects and herb–drug interactions. Establishing mandatory reporting mechanisms, integrating traditional medicine data into national health systems, and harmonizing global standards remain critical next steps for safer integration of herbal therapies in diabetes care.

Another emerging area is the development of combination therapies that integrate herbal products with conventional drugs to achieve synergistic effects and reduce drug dosages. For example, combining metformin with berberine or fenugreek extract may enhance glycemic control while minimizing gastrointestinal side effects [21]. However, such combinations require thorough pharmacokinetic and pharmacodynamic studies to avoid adverse interactions. Clinical guidelines will need to be updated to incorporate evidence-based recommendations on the use of herbal medicines in diabetes care. In the public health context, herbal antidiabetic preparations offer a viable and culturally acceptable solution for diabetes prevention and management, especially in low- and middle-income countries where access to healthcare is limited. Community-based interventions, health education, and inclusion of herbal medicine in national diabetes programs could enhance early detection and holistic care. The development of mobile health platforms and apps to guide the use of herbal remedies and monitor treatment outcomes also holds potential for improving patient adherence and engagement [22].

1. Sahu MK, Tiwari SP. Role of nanomaterials in pharmaceutical preparation: a review. Int J Nanomater Nanotechnol Nanomed. 2024;10(2):56–67. Available from: https://www.chemisgroup.us/articles/IJNNN-10-163.pdf
2. Sahu MK, Tiwari SP. Phytochemical and ethnopharmacological review of Aegle marmelos. Bull Pioneer Res Med Clin Sci. 2024;3(2):29–47. Available from: https://doi.org/10.51847/K3rPdVPzLe
3. Sahu MK, Tiwari SP. Epidemiology, pathogenesis and treatment of diabetes: a comprehensive review. Wor J Dia Res Pract. 2024;1(1):1–9. Available from: https://mkscienceset.com/articles_file/573-_article1708434044.pdf
4. Sahu MK. A review on glaucoma: causes, symptoms, pathogenesis & treatment. J Clin Res Ophthalmol. 2024;11(1):1–4. Available from: https://www.clinsurggroup.us/articles/JCRO-11-202.pdf
5. Sahu MK, Nayak AK, Hailemeskel B, Eyupoglu OE. Exploring recent updates on molecular docking: types, method, application, limitation & future prospects. Int J Pharm Res Allied Sci. 2024;13(2):24–40. Available from: https://ijpras.com/article/exploring-recent-updates-on-molecular-docking-types-method-application-limitation-amp-future-p-xqlkubawc6eu8xl
6. Sahu B, Sahu M, Sahu M, Yadav M, Sahu R, Sahu C. An updated review on Nelumbo nucifera Gaertn: chemical composition, nutritional value and pharmacological activities. Chem Biodivers. 2024;e202301493. Available from: https://doi.org/10.1002/cbdv.202301493
7. Sahu MK, Yadav R, Tiwari SP. Recent advances in nanotechnology. Int J Nanomater Nanotechnol Nanomed. 2023;9(1):15–23. Available from: https://doi.org/10.17352/2455-3492.000053
8. Sahu MK, Tiwari SP. A systemic review on recent outbreaks of dengue and newer US FDA approved drug. J Infect Dis Virus Res. 2023;2(2):1–6. Available from: https://mkscienceset.com/articles_file/575-_article1687167234.pdf
9. Sahu MK, Dubey N, Pandey R, Shukla SS, Gidwani B. Formulation, evaluation, and validation of microspheres of cyclophosphamide for topical delivery. Pharmacophore. 2023;14(1):1–8. Available from: https://doi.org/10.51847/e4GvuoN96z
10. Mahendra KS, Mandavi G, Dushika S, Surendra S. Recent challenges and opportunities on Middle East Respiratory Syndrome Corona Virus (MERS CoV). Vaccines Vaccin. 2023;8(1):154. Available from: https://doi.org/10.23880/vvoa-16000154
11. Drammeh I, Yadav R, Sahu MK. Exploring uterine fibroids and its treatment in current scenario. IP Int J Compr Adv Pharmacol. 2023;8(3):143–8. Available from: https://doi.org/10.18231/j.ijcaap.2023.025
12. Mahendra Kumar S. Development and preclinical evaluation of anti-analgesic, anti-pyretic, anti-inflammatory and antioxidant potential of polyherbal formulation on experimental animal model. Int J Cell Sci Mol Biol. 2023;7(3):555716. Available from: https://juniperpublishers.com/ijcsmb/pdf/IJCSMB.MS.ID.555716.pdf
13. Sahu MK, Saraf S. Convection-enhanced delivery of alkaloid-loaded maghemite nanoparticles against 9L gliomass cell line. Adv Pharm Clin Tria. 2022;7(4):000210. Available from: https://doi.org/10.23880/apct-16000210
14. Kumar A, Kumar D, Kumar R, Prasad J, Kumar M, Joshi P, Fulzele P. Peptic ulcers and their complications. J Drug Deliv Ther. 2020;10(3-s):256–61. Available from: https://jddtonline.info/index.php/jddt/article/view/4082
15. Sahu MK, Satapathy T, Netam AK, Prasad J. Structural architecture and signal transduction of ion channels: a review. Res J Pharmacol Pharmacodyn. 2018;10(1):38–44. Available from: https://doi.org/10.5958/2321-5836.2018.00007.1
16. Satapathy T, Kaushik S, Netam AK, Prasad J, Rao SP, Sahu MK, Baghel P. Nano delivery: a smart carrier for treatment of ovarian cancer. [Journal name and year not provided – please specify for complete citation]
17. Singh VK, Sahu MK. Antidiabetic medicinal plants having insulin mimetic property: a review. Kenkyu J Pharm Pract Health Care. 2018;60:56–60. Available from: http://www.kenkyugroup.org/article/14/162/Antidiabetic-Medicinal-Plants-Having-Insulin-Mimetic-Property--A-Review
18. Prasad J, Netam AK, Singh R, Sahu M, Satapathy T, Rao SP, Baghel P, Sahu MK. Therapeutic approaches for the management of Parkinson's disease. Res J Pharmacol Pharmacodyn. 2019;11(1):46–52. Available from: https://doi.org/10.5958/2321-5836.2019.00009.0
19. Sahu MK, Singh VK, Rao SP. Development and evaluation of antidiabetic potential of polyherbal formulation in streptozotocin induced animal model. Int J Cell Sci Mol Biol. 2018;5(2):29–37. Available from: https://juniperpublishers.com/ijcsmb/pdf/IJCSMB.MS.ID.555656.pdf
20. Jain S, Saraf S, Sahu MK. Recent trends and strategies for targeting M-cells via oral vaccine against Hepatitis B: a review. Int J Cell Sci Mol Biol. 2019;5(5):86–92. Available from: https://ideas.repec.org/a/adp/ijcsmb/v5y2019i5p86-92.html
21. Sahu AK, Satapathy T, Kumar R, Joshi P, Kumar M, Singh R, Prasad J, Latkar J. Recovery from addiction: a strong will but rare success. Eur J Pharm Med Res. 2019;6(7):553–8. Available from: https://www.researchgate.net/profile/Akhilesh-Kumar-44/publication/348575097_European_Journal_of_Pharmaceutical_and_Medical_Research_wwwejpmrcom_553_RECOVERY_FROM_ADDICTION_A_STRONG_WILL_BUT_RARE_SUCCESS/links/6005950da6fdccdcb861f2c3/European-Journal-of-Pharmaceutical-and-Medical-Research-wwwejpmrcom-553-RECOVERY-FROM-ADDICTION-A-STRONG-WILL-BUT-RARE-SUCCESS.pdf
22. Prasad J, Netam AK, Sahu MK, Satapathy T. Current concepts in clinical based management of diabetic foot infections: a review. Res J Pharmacol Pharmacodyn. 2017;9(3):157–66. Available from: https://doi.org/10.5958/2321-5836.2017.00027.1