Research Progress on the Weight Loss Effects of Hawthorn Extract

1. Introduction 

Obesity and its associated metabolic syndrome have become a global public health challenge, making the search for safe and effective weight-loss strategies a research hotspot. Crataegus pinnatifida Bge. (hawthorn), a plant with dual food and medicinal values in traditional Chinese medicine (TCM), has been historically used to “digest meat accumulation and resolve turbid lipids”. The Compendium of Materia Medica records that it “transforms food and eliminates meat stagnation”. Modern studies have revealed that hawthorn extract exerts synergistic effects via multiple components to regulate lipid metabolism, demonstrating potential in weight management. This review systematically summarizes the weight-loss effects of hawthorn extract from the perspectives of active ingredients, fat-reducing mechanisms, pharmacological research, safety, and application prospects.

2. Active Components and Their Metabolism

2.1 Active Components 

The main active components of hawthorn extract include flavonoids (hyperoside, quercetin, proanthocyanidins), triterpenoids (oleanolic acid, ursolic acid), organic acids (crataegolic acid, malic acid), and polysaccharides (hawthorn polysaccharide, HP). 

(1) Flavonoids: Inhibit the activity of cholesterol synthase (HMG-CoA reductase), reducing cholesterol synthesis in the liver. Their antioxidant effects reduce the oxidative modification of low-density lipoprotein (LDL-C), delaying atherosclerosis. 

(2) Triterpenoids: Oleanolic acid promotes fatty acid oxidation by activating the AMPK pathway, while ursolic acid inhibits the expression of genes related to adipocyte differentiation (PPARγ and C/EBPα). 

(3) Organic Acids: Crataegolic acid directly stimulates gastric acid secretion, enhances lipase activity, and promotes the decomposition and absorption of fats from food. Malic acid participates in the tricarboxylic acid (TCA) cycle, accelerating energy metabolism. 

(4) Polysaccharides: Hawthorn polysaccharides modulate the gut microbiota, improve intestinal barrier function, and reduce chronic inflammation induced by lipopolysaccharides. 

2.2 Metabolism 

The flavonoid components in hawthorn extract are primarily metabolized in the liver via the CYP450 enzyme system (e.g., CYP3A4) through oxidative decomposition. Triterpenoids are converted into more easily absorbed aglycone forms by gut microbiota, increasing bioavailability by approximately threefold.

3. Mechanisms of Hawthorn in Fat Reduction 

Hawthorn extract exerts its weight loss effects through multiple targets and pathways: 

3.1 Promoting Fat Digestion and Metabolism

Crataegolic acid and lipase directly decompose triglycerides in food, shortening the residence time of high-fat foods in the digestive tract. Animal experiments show that hawthorn extract can increase gastric emptying rate by 37%, reducing fat absorption. 

3.2 Regulating Lipid Synthesis and Decomposition

Inhibiting Synthesis: Flavonoids inhibit HMG-CoA reductase activity, reducing cholesterol synthesis in the liver. Oleanolic acid downregulates SREBP-1c and FAS genes, reducing fat generation. 

Promoting Decomposition: Hawthorn flavonoids activate hormone-sensitive lipase (HSL) and adipose triglyceride lipase (ATGL), promoting the hydrolysis of triglycerides in adipocytes into fatty acids and accelerating oxidative energy supply. 

3.3 Improving Insulin Resistance and Glucose Metabolism 

Hawthorn extract increases the expression of GLUT4 transporters, promoting glucose uptake. Its antioxidant effects improve oxidative stress-induced damage to insulin signaling pathways, reducing blood glucose fluctuations. 

3.4 Regulating Gut Microbiota and Metabolic Axis

Hawthorn polysaccharides function through the "gut microbiota-liver metabolism axis": increasing the production of short-chain fatty acids (acetate, propionate), activating the intestinal PPARγ pathway, and inhibiting liver fat synthesis. Simultaneously, they reduce the negative impact of gut microbiota metabolites (e.g., endotoxins) on metabolism. 

4. Pharmacological Studies 

4.1 Animal Experiments 

Lipid-Lowering Effects: In SD rat high-fat models, hawthorn flavonoid extract (50-200 mg/kg) reduced total cholesterol (21.3%-30.4%) and low-density lipoprotein (59.6%-70.5%), while regulating triglyceride and high-density lipoprotein levels. 

Weight Loss Effects: In high-fat diet-fed hamsters, intervention with hawthorn extract reduced weight gain by 30%-40%, significantly decreased liver lipid content, and reduced atherosclerotic plaque area. 

4.2 Human Clinical Trials 

Short-Term Intervention: Daily intake of 500 mg hawthorn extract for 12 weeks resulted in an average 12% reduction in total cholesterol and a 3-5 cm reduction in waist circumference. Compound Preparations: Hawthorn extract combined with red yeast rice and salvia (e.g., Hawthorn Essence Lipid-Lowering Soft Capsules) synergistically reduced LDL-C (15% reduction after 8 weeks) and improved liver function in patients with non-alcoholic fatty liver disease (NAFLD). 

5. Safety Validation 

5.1 Dosage and Side Effects

Recommended Dosage: The daily intake of hawthorn extract is 300-800 mg (calculated as total flavonoids). Exceeding 1000 mg may cause gastrointestinal discomfort (nausea, diarrhea). Long-Term Safety: Animal experiments show that high doses of hawthorn seed extract (2000 mg/kg) may cause liver and kidney damage, but no significant toxicity has been observed at clinical common doses (≤800 mg/day). 

5.2 Drug Interactions 

Hawthorn extract may enhance the effects of anticoagulant drugs (e.g., warfarin), increasing the risk of bleeding. When combined with statins, liver function should be monitored to avoid synergistic hepatotoxicity. 

6. Summary and Outlook 

6.1 Summary  

Hawthorn extract demonstrates significant potential in weight loss and lipid metabolism regulation through multi-pathway synergism, including promoting fat digestion, inhibiting lipid synthesis, and regulating metabolic axes. 

6.2 Outlook

(1) Mechanistic Depth: Further analysis is needed on the interaction network between hawthorn polysaccharides and gut microbiota, as well as the regulation of mitochondrial function by triterpenoids. 

(2) Clinical Evidence: There is a lack of long-term, large-sample human clinical trials to verify its efficacy and safety in different populations. 

(3) Formulation Optimization: Nano-carrier technologies (e.g., liposomes) could improve the bioavailability of hawthorn extract and reduce gastrointestinal irritation. 

References 

[1] Kim M J, Choi Y, Shin N R, et al. Anti-obesity effect of Crataegus pinnatifida through gut microbiota modulation in high-fat-diet induced obese mice[J]. 2019. 

[2] Lee Y H, Kim Y S, Song M, et al. A herbal formula HT048, Citrus unshiu and Crataegus pinnatifida, prevents obesity by inhibiting adipogenesis and lipogenesis in 3T3-L1 preadipocytes and HFD-induced obese rats[J]. Molecules, 2015, 20(6): 9656-9670. 

[3] Song J, Kim D Y, Lee H S, et al. Efficacy of crataegus extract mixture on body fat and lipid profiles in overweight adults: a 12-week, randomized, double-blind, placebo-controlled trial[J]. Nutrients, 2024, 16(4): 494. 

[4] Li T, Zhu R, Dong Y, et al. Effects of pectin pentaoligosaccharide from Hawthorn (Crataegus pinnatifida Bunge. var. Major) on the activity and mRNA levels of enzymes involved in fatty acid oxidation in the liver of mice fed a high-fat diet[J]. Journal of agricultural and food chemistry, 2013, 61(31): 7599-7605.