Diabetes mellitus, a metabolic disorder with several causes, is defined by sustained hyperglycaemia and metabolic disturbances in lipids, carbs, and proteins resulting from inadequate insulin synthesis and activity.1 Diabetes is a disorder that impacts the metabolism of proteins, lipids, and carbohydrates, resulting from either diminished insulin production or heightened resistance to its effects.2 Diabetes mellitus (DM), a metabolic disorder with potential environmental or genetic causes, increases a patient's risk of getting many other diseases.3 Diabetes mellitus is the most common endocrine disorder worldwide, marked by insulin resistance, impaired insulin signalling, beta-cell dysfunction, and aberrant metabolism of glucose, proteins, and lipids.4 One of the most common outcomes of untreated diabetes is hyperglycaemia. The condition is referred to as hyperglycaemia or increased blood glucose levels.5 Insulin is a hormone that regulates blood sugar levels. Diabetes increases the likelihood of stroke and cardiovascular disease. Cardiovascular disease is responsible for 50% of fatalities among individuals with diabetes. Diabetes is a primary cause of renal failure.6
The four principal types of diabetes are:
1. Type 1 diabetes (T1DM)
2. Type 2 diabetes (T2DM)
3. gestational diabetes (GDM)
4. Monogenic diabetes, particularly maturity-onset diabetes of the young (MOD), is widely acknowledged.
These four principal types of diabetes are widely acknowledged and are broadly recognised. Because they affect a considerably larger number of patients than other types.7 T1DM and T2DM are the most recognised forms of diabetes. Type 1 Diabetes Mellitus (T1DM), formerly referred to as insulin-dependent diabetes, predominantly impacts adolescents and young adults.8 The demise of β-cells in the pancreas complicates insulin production. Type 2 diabetes constitutes almost 90% of all instances. Type 2 diabetes predominantly impacts individuals over 40; nevertheless, the escalating rates of juvenile obesity are leading to a growing incidence among younger populations. This condition is characterised by insufficient organ resistance and the dysfunction of pancreatic beta cells, leading to insulin depletion.9 Chronic insulin resistance and pancreatic beta cell dysfunction, which may occur during pregnancy, are associated with gestational diabetes mellitus (GDM). MODY is a rare genetic variant of diabetes mellitus that usually presents during adolescence or early adulthood.10
Common Symptoms of Type 2 Diabetes: Dehydration, emesis, polyphagia, myalgia, anorexia, peripheral neuropathy, foot infections, polydipsia, delayed wound healing, renal failure, cardiovascular disorders, polyuria, coma, and, in severe cases, mortality.11 Individuals with type 2 diabetes frequently utilise various categories of oral hypoglycaemic agents. The list includes α-glucosidase inhibitors, meglitinides, sulfonylureas, thiazolidinediones, amylin analogues, SGLT-2 inhibitors, metformin, GLP-1 mimetics, DPP-4 inhibitors, and incretin receptor dual agonists. Insulin is solely utilised for the treatment of type 1 diabetes. Should alternative drugs be ineffectual, we subsequently give insulin.12 Hypoglycaemia is a significant side effect of antidiabetic medicines, as reported. Frequently reported adverse effects encompass gastrointestinal disturbances, gas production, bloating, nausea, and infections of the respiratory and urinary tracts.13
The role of natural treatments in diabetes management: Botanical sources produce diverse pharmaceuticals. Plant-based medications are regarded as the principal method for maintaining human health by averting diseases and their related effects or responses.14 Incorporating edible plants with established antihyperglycemic qualities, such as clove, bitter melon, neem, moringa, black seeds, turmeric, or cinnamon, into daily meals may be less detrimental than conventional drugs.15 Pharmaceuticals derived from flora have historically served as a valuable alternative. Ethnobotanical findings indicate that over 800 plants may possess preventative capabilities against diabetes.16 The World Health Organisation WHO has recommended the investigation of traditional plant remedies for diabetes, as they can be efficiently treated, exhibit minimal toxicity and adverse effects, and are considered promising candidates for oral medication.17 The scientific validation of several plant species has proven the efficacy of botanicals in reducing blood glucose levels. Plant-based compounds are believed to have a key role in the treatment of diabetes, according to reports of their potential efficacy against the illness. This requires further investigation to develop suitable pharmaceuticals and nutraceuticals from natural sources. Herbal medicines have been utilised to treat diabetic retinopathy, diabetic peripheral neuropathy, insulin-dependent diabetes, non-insulin-dependent diabetes, and other related disorders.18 Researchers have recently identified many phytochemicals having antidiabetic effects in plants. Polysaccharides, alkaloids, amino acids, flavonoids, saponins, glycosides, dietary fibres, glycolipids, peptidoglycans, and other phytoconstituents obtained from diverse plants are potent hypoglycaemic agents.19 Plants synthesise alkaloids, flavonoids, tannins, terpenoids, ferulic acid, and many secondary metabolites, all of which have hypoglycaemic effects. Alkaloids reduce blood sugar levels by inhibiting alpha-glucosidase activity and decreasing the absorption of glucose across the intestinal epithelium. They likely achieve this by stimulating insulin secretion from the pancreatic islets. Flavonoids reduce blood sugar levels and enhance glucose metabolism in the liver. Steroid glycosides, triterpenoids, and saponins enhance insulin secretion and inhibit the formation of blood glucose in circulation. Polysaccharides reduce blood glucose levels, improve glucose tolerance, and increase serum insulin levels. Compounds such as ferulic acid enhance insulin secretion. 20 Additionally, unlike conventional medicine, which addresses a singular, isolated active compound, herbal therapy encompasses the entire plant or particular portions of the plant. The utilisation of the entire plant is believed to yield a superior synergistic effect due to the collaborative action of all its compounds, resulting in a more potent and integrated influence. 21
Phytochemicals for the treatment of diabetes mellitus:
Alkaloids:
Alkaloids are secondary metabolites in plants characterised by the presence of basic nitrogen atoms.22 Various therapeutic plants contain distinct types of alkaloids. Bacteria, fungi, and various other organisms also possess alkaloids.23
Alkaloid classification:
1. True alkaloids: Atropine, nicotine, morphine.
2. Protoalkaloids: Ephedrine, Adrenaline, Mescaline.
3. Pseudoalkaloids—Theophylline, Theobromine, Caffeine
4. Polyamine alkaloids—putrescine, spermidine, and spermine
5. Peptide and Cyclopeptide Alkaloids
Alkaloids employ several mechanisms to elicit a wide range of antidiabetic benefits. Species such as Tinospora cordifolia and Berberis spp. possess berberine in their root and stem bark. The foliage and stems of Catharanthus roseus contain catharanthine, vindoline, and vindolinine, which aid in the treatment of diabetes mellitus.24
Table 1. A list of significant alkaloids that are used to treat diabetes.
|
Plant name |
Phytoconstituents |
Plant parts |
References |
|
Berberis spp. Tinospora cordifolia |
Berberine |
Roots, stem-bark |
25 |
|
Catharanthus roseus |
Catharanthine, vindoline and vindolinine |
Leaves, stems |
26 |
|
Syzygium malaccense |
Casuarine 6-o—glucoside |
Bark |
27 |
|
Nicandra physalodes |
Calystegine B2 |
Fruits |
28 |
|
Tribulus terrestris |
Harmane, norharmane, |
- |
29 |
|
Cryptolepis sanguinolenta |
Cryptolepine |
- |
30 |
|
Syzygium cumini |
Jambosine |
Seeds, fruits, bark |
31 |
|
Trigonella- foenum-graecum |
Trigonelline |
Seeds |
32 |
|
Swertia chirayita |
Swerchirin |
- |
33 |
|
Morus alba |
1-deoxynojirimycin |
Morus alba |
34 |
Glycosides:
A glycoside is a chemical that consists of a sugar moiety linked to a non-sugar moiety. Plants possess glycosides, which are vital for living organisms. The glycoside Jamboline, present in the seeds of Eugenia jambolana, may assist in reducing blood sugar levels. Before the availability of insulin, individuals commonly utilised Vaccinium myrtillus L. (Ericaceae) leaves as a remedy for diabetes. 35
Table 2. A list of significant Glycosides that are used to treat diabetes.
|
Plant name |
Phytoconstituents |
Plant parts |
References |
|
Kalopanax pictus |
Kalopanax |
Stem bark |
36 |
|
Syzygium cumini |
Jamboline or antimellin |
Seeds |
37 |
|
Myrcia multiflora |
Myrciacitrins I and II and myrciaphenones A and B |
Leaves |
38 |
|
Vaccinium myrtillus |
Neomyrtillin |
Leaves |
39 |
|
Ficus bengalensis |
Perlargonidin 3-o—l rhamnoside |
Bark |
40 |
|
Anemarrhena asphodeloides |
Pseudoprototinosaponin AIII & prototinosaponin AIII |
Rizomes |
41 |
|
Microcos paniculata |
Vitexin, isovitexin and isorhamnetin 3-O—D-rutinoside Microcos paniculata Leaves |
Leaves |
42 |
Flavonoids:
Plants possess polyphenolic compounds known as flavonoids, which have numerous medical applications and are abundantly present in seeds, nuts, flowers, stems, fruits, vegetables, and green tea.43 Flavonoids are a beneficial category of naturally occurring compounds having hypoglycaemic properties.44
There are six distinct classes of flavonoids:
1. Anthocyanins
2. Catechins
3. Flavanols
4. Flavones
5. Flavanones
6. Isoflavones
The antioxidant properties of flavonoids and their capacity to alter particular cellular signals enhance their antidiabetic effects.
The Function of Flavonoids in Diabetes Management:
1.Aldose Reductase Inhibition:
Flavonoids inhibit aldose reductase, reducing glucose conversion to sorbitol. This prevents sorbitol accumulation, hence reducing oxidative stress and diabetes-related complications such as retinopathy and neuropathy.
2. Pancreatic β-Cell Regeneration:
Flavonoids reduce oxidative stress and apoptosis, facilitating the regeneration of pancreatic β-cells. They enhance antioxidant defences and activate Nrf2 (nuclear factor erythroid 2-related factor 2).
3. Insulin Release Enhancement:
Flavonoids enhance insulin secretion by modulating the GLP-1 and PKA pathways. Moreover, they enhance β-cell functionality by mitigating inflammation.
4. Augmentation of Calcium Ion Uptake:
An increase in the absorption of calcium ions. Flavonoids enhance the exocytosis of insulin granules by augmenting Ca²? influx in pancreatic β-cells. Increased calcium levels also enhance glucose regulation by promoting insulin secretion. 45
Table 3. A list of significant flavonoids that are used to treat diabetes.
|
Plant name |
Phytoconstituents |
Plant parts |
References |
|
Ficus benghalensis |
Bengalenoside |
Stem bark |
46 |
|
Camellia sinensis |
Epigallocatechin gallate |
Leaves |
47 |
|
Bergenia ciliata |
--3-O-galloylepicatechin, --3- O-galloylcatechin |
- |
48 |
|
Glycine spp. |
Genistein |
Soya beans |
49 |
|
Citrus spp. |
Hesperidin, naringin |
|
50 |
|
Amygdalus davidiana var. Davidiana |
Prunin |
Stems |
51 |
|
Bauhinia forficate |
Kaempferitrin |
Leaves |
52 |
|
Jindai soybean |
|
Rutuja Pangavhane *
Mukund Pache
10.5281/zenodo.15122232