Introduction/Overview
Stevioside is a plant endemic to South America, Stevioside(Stevia rebaudiana)Natural sweeteners obtained through separation have received widespread attention in the fields of food, medicine, and health products in recent years due to their high sweetness and low calorie characteristics. As an orally active compound, steviol glycosides not only have significant sweet taste effects, but also exhibit various potential pharmacological activities, including lowering blood pressure, blood sugar, antioxidant, anti-inflammatory, and anti-tumor effects, demonstrating their therapeutic potential in chronic metabolic diseases and related pathological states. This article will provide a systematic review of the chemical structure and physicochemical properties of steviol glycosides, their plant sources and extraction methods, pharmacological activities and mechanisms of action, drug evaluation and pharmacokinetic characteristics, and explore their clinical application prospects in depth.
Chemical structure and physicochemical properties
The chemical name of steviol glycoside is (structural formula omitted), with a molecular formula of C ∝₈ H ₆₀ O ₁₈ and a molecular weight of 804.8800. Its structure belongs to diterpenoid saponins, with the core being the steviol skeleton, which connects multiple glucose residues to form a complex glycoside structure. This polysaccharide structure endows steviol glycosides with high hydrophilicity, exhibiting a low LogP value (-0.2684), water solubility of 1.5121, and a polar surface area (TPSA) of 294.98 Å ², indicating strong polarity and good water solubility.
The molecular structure of steviol glycosides contains multiple hydroxyl and ether bonds, forming a stable molecular conformation. Its low blood-brain barrier permeability and lack of hERG channel inhibition suggest its high safety. The Ames test result is 0.0, indicating that steviol glycosides have no significant genetic toxicity risk, which lays a good safety foundation for their use as food additives and drug development.
Plant sources and extraction methods
Stevioside mainly exists in the leaves of stevia, and its content varies depending on the variety, planting environment, and harvesting time. Stevia is a plant in the Asteraceae family, native to South American countries such as Paraguay and Brazil, and is now widely cultivated in multiple regions around the world. The extraction of steviol glycosides is usually carried out by soaking dried leaves with water or alcohol solvents, combined with modern techniques such as ultrasound assisted extraction, hot reflux, or microwave-assisted extraction to improve extraction efficiency.
The extract was filtered, concentrated, and purified by column chromatography to obtain high-purity steviol glycosides. In recent years, the application of supercritical CO ₂ extraction and membrane separation technology has further improved the extraction purity and process economy of steviol glycosides. In addition, research on chemical modifications and biosynthetic pathways based on the structure of steviol glycosides has provided new ideas and methods for their production.
Pharmacological activity research
The pharmacological activity research of steviol glycosides covers multiple aspects, mainly focusing on its metabolic regulation and antioxidant and anti-inflammatory effects.
Hypoglycemic effect
Stevioside showed significant hypoglycemic effect in diabetes model. It promotes glucose uptake and metabolism, and improves insulin sensitivity by activating the AMPK (5 'AMP activated protein kinase) signaling pathway. Meanwhile, steviol glycosides can inhibit the activity of SGLT2 (sodium glucose cotransporter 2), reduce renal glucose reabsorption, and lower blood glucose levels. In addition, steviol glycosides also regulate the expression of glucokinase (GCK), promote liver glucose metabolism, and have a comprehensive effect on improving glucose metabolism disorders.
Hypotensive effect
Stevioside has the effect of dilating blood vessels and lowering blood pressure, which involves enhancing the synthesis of nitric oxide (NO) and inhibiting the activity of angiotensin-converting enzyme (ACE), thereby improving vascular function. In addition, steviol glycosides also exert antihypertensive effects by regulating the sympathetic nervous system and sodium ion channels.
Antioxidant and anti-inflammatory effects
Stevioside can significantly eliminate free radicals, enhance antioxidant enzyme activity in the body, and alleviate oxidative stress damage. Its anti-inflammatory effect is manifested by inhibiting pro-inflammatory cytokines (such as TNF - α, IL-6) and nuclear factor kappa B (NF - κ B) signaling pathways, reducing tissue inflammatory responses, and protecting cells from inflammation mediated damage.
antitumor activity
Preliminary studies have shown that steviol glycosides exert certain anti-tumor activity by inducing tumor cell apoptosis, inhibiting cell proliferation and migration. Its mechanism of action involves regulating cell cycle proteins, promoting mitochondrial pathway apoptosis, and inhibiting tumor related signaling pathways (such as PI3K/Akt).
Mechanism of action and molecular targets
The multi-target mechanism of action of steviol glycosides is the basis for its various pharmacological effects. Through molecular biology and pharmacology research, multiple key targets have been identified:
- AMPK(PRKAA1)As a central regulatory factor in energy metabolism, stevia glycosides activate AMPK, promote glucose metabolism and lipid oxidation, and improve metabolic syndrome.
- SGLT2 Stevioside inhibits renal SGLT2, reduces glucose reabsorption, and lowers blood sugar.
- GCK (Glucokinase)Regulate liver glucose metabolism and promote glucose utilization.
- PTPN1 (protein tyrosine phosphatase 1B)This enzyme is a negative regulator of insulin signaling, and stevia glycosides may enhance insulin sensitivity by inhibiting PTPN1.
- MAOA (monoamine oxidase A)and ESR2 (estrogen receptor beta)Participating in neuroprotective and anti-inflammatory effects, it suggests that steviol glycosides have potential value in neurological diseases.
- APP (amyloid precursor protein)Related to neurodegenerative diseases, the regulatory mechanism of stevia glycosides is still under exploration.
The synergistic regulation of these targets constitutes a multidimensional pharmacological network of steviol glycosides, promoting their therapeutic potential in metabolic diseases and inflammation related disorders.
Evaluation of drug properties and pharmacokinetics
The molecular weight of steviol glycoside is relatively large (804.88 Da) and its polarity is high (TPSA 294.98 Å ²), which limits its oral bioavailability and cell membrane permeability. Its LogP value is -0.2684, indicating strong hydrophilicity, but low blood-brain barrier permeability, which limits the efficacy of the central nervous system.
In terms of safety, steviol glycosides have no hERG channel inhibition and negative Ames test results, indicating low genetic toxicity risk and a good safety foundation. Moderate water solubility is beneficial for formulation design and in vivo distribution.
Pharmacokinetic studies have shown that after oral administration, steviol glycosides are partially hydrolyzed into steviol alcohol in the gastrointestinal tract, which can be absorbed and exert biological activity. Stevioside itself has poor absorption, but its metabolites have certain biological activity. The liver is the main metabolic organ, mainly transformed through the action of glucosidase. The main excretion pathways are bile and urine.
Overall, the pharmacological properties of steviol glycosides are limited by their molecular structure and pharmacokinetic properties. However, through strategies such as structural modification, nanocarrier encapsulation, and combination therapy, it is expected to improve their in vivo pharmacokinetic performance and enhance their clinical application potential.
Clinical application prospects and prospects
Stevioside, as a natural sweetener, has been widely used in the food industry to replace traditional sugars and has the advantages of low calorie and low glycemic load. Its pharmacological activity shows a good prospect in the adjuvant treatment of diabetes, hypertension and metabolic syndrome.
Future clinical research should focus on the following directions:
- Long term efficacy and safety assessment of diabetes and metabolic diseases Systematic clinical trials have verified the comprehensive regulatory effects of steviol glycosides on blood glucose, blood lipids, and blood pressure.
- Combination therapy strategy Exploring the possibility of synergistic enhancement and reduction of drug side effects in combination with existing hypoglycemic and antihypertensive drugs.
- Optimization of formulations and innovation of administration routes Develop oral sustained-release, nanocarrier, and transdermal drug delivery systems to enhance bioavailability and targeting.
- Clinical validation of anti-inflammatory and anti-tumor potential Based on basic research, conduct preclinical and clinical trials for related diseases to expand the indications of steviol glycosides.
- Safety monitoring and toxicology research Safety assessment of long-term medication, especially its impact on special populations such as pregnant women, children, and patients with liver and kidney dysfunction.
With the development of molecular biology and medicinal chemistry, the structural modification and target optimization of steviol glycosides will further promote their potential as a new type of natural medicine.
Conclusion
Stevioside, as a natural diterpenoid glycoside derived from stevia, has shown broad application prospects due to its unique sweet taste characteristics and diverse pharmacological activities. Its multi-target mechanism of action in diabetes, hypertension and inflammation related diseases provides rich examples for natural product pharmacology research. Despite the challenges of high molecular weight and low absorption rate, the development of modern drug design and formulation technology provides strong support for the clinical translation of steviol glycosides. In the future, through in-depth mechanism research and clinical validation, steviol glycosides are expected to become a safe and effective natural medicine, contributing new strategies and choices for the prevention and treatment of metabolic diseases and related chronic diseases.