Review on the Research Progress of Elderberry Extract on Intestinal Health

1. Introduction 

Intestinal health is a core foundation for maintaining systemic metabolism and immune function. Intestinal flora imbalance, oxidative stress, and chronic inflammation are key triggers of intestinal diseases. Elderberry (Sambucus nigra L., commonly known as black elderberry), an ancient medicinal plant, has attracted significant attention in recent years for its berry extract in the field of intestinal health, owing to its rich bioactive components such as polyphenols and dietary fiber. From the early empirical application of "promoting digestion" to the microbiota regulation, antioxidant, and metabolic synergy effects revealed by modern clinical and mechanistic studies, elderberry extract provides a new perspective for intestinal health intervention. This article systematically reviews its bioactive components, mechanisms of action, and research evidence to provide references for future development. 

2. Bioactive Components of Elderberry Extract and Their In Vivo Metabolism 

2.1 Core Bioactive Components 

The intestinal health effects of elderberry extract mainly depend on two types of substances: 

Polyphenols: Dominated by anthocyanins (e.g., cyanidin-3-glucoside) and flavonoids (quercetin, kaempferol), they account for 60%–70% of the total phenols in the extract and are the core substances for antioxidant activity and microbiota regulation. Dietary fiber: Including pectin and cellulose, it accounts for 3%–5% of the fresh weight. It can directly promote intestinal peristalsis and serve as a prebiotic fermented by intestinal flora. 

2.2 In Vivo Metabolic Characteristics 

Polyphenol metabolism: After preliminary digestion in the oral cavity and stomach, over 90% of anthocyanins are decomposed into phenolic acids by intestinal flora in the colon. These metabolites are more easily absorbed by intestinal cells and exert anti-inflammatory and antioxidant effects. Dietary fiber metabolism: Pectin is fermented by Bifidobacterium and Lactobacillus in the colon to produce short-chain fatty acids (SCFAs), which lower intestinal pH and inhibit the proliferation of harmful bacteria. Bioavailability: Due to their large molecular weight, direct absorption of polyphenols is low (<10%). However, the secondary metabolites produced by intestinal flora metabolism have stronger bioactivity and longer-lasting effects.  

3. Mechanisms of Elderberry Extract in Regulating Intestinal Health 

3.1 Remodeling Intestinal Flora Homeostasis 

Enriching beneficial bacteria: Clinical studies have shown that daily intervention with 600 mg of elderberry extract for 3 weeks significantly increases the α/β diversity of intestinal flora and continuously elevates the abundance of Akkermansia muciniphila (negatively correlated with metabolism and inflammation) and Sutterella (involved in glucose metabolism and immune regulation). Additionally, studies found that elderberry juice promotes the proliferation of beneficial bacteria such as Firmicutes and Actinobacteria in overweight individuals, while reducing the proportion of harmful bacteria (e.g., Bacteroidetes). Inhibiting pathogenic bacteria: In vitro studies indicated that elderberry polyphenols can inhibit the adhesion of Escherichia coli, Helicobacter pylori, and other pathogenic bacteria to the intestinal mucosa by disrupting bacterial membrane structure. 

3.2 Antioxidant Protection of Intestinal Epithelial Cells 

After intestinal digestion, elderberry extract retains its antioxidant activity. In vitro experiments confirmed that the extract after colonic digestion can reduce the production of reactive oxygen species (ROS) in intestinal cells, inhibit oxidative DNA damage, and enhance cellular antioxidant capacity by activating the Nrf2 pathway, thereby alleviating the damage of oxidative stress to the intestinal barrier. 

3.3 Synergistic Metabolism to Improve Intestinal Microenvironment 

Blood glucose regulation: Intervention with elderberry juice reduces fasting blood glucose and insulin levels in overweight individuals, presumably related to SCFAs promoting insulin secretion and improving insulin sensitivity. Lipid metabolism: Experiments showed that after consuming elderberry juice, participants’ postprandial fat-burning capacity is enhanced, which may reduce intestinal fat accumulation through the microbiota-metabolism axis. 

4. Pharmacological Research Evidence of Elderberry Extract 

4.1 Human Clinical Studies 

Joint improvement of flora and metabolism: Studies confirmed that 3-week intervention with 600 mg/day of elderberry extract leads to a continuous increase in the abundance of Akkermansia muciniphila (which does not decrease even after discontinuation), with no negative impact on participants’ quality of life. A trial involving 18 overweight individuals showed that elderberry juice simultaneously improves blood glucose and lipid metabolism through microbiota regulation. Safety verification: No severe gastrointestinal adverse reactions such as diarrhea or abdominal pain were reported in the above trials, indicating that short-term (3–4 weeks) use of elderberry extract at a standardized dose (≤600 mg/day) has good tolerability. 

4.2 Supplementary In Vitro and Animal Studies 

Intestinal barrier protection: In a mouse colitis model, elderberry polyphenols reduce the release of intestinal mucosal inflammatory factors (IL-6, TNF-α) by inhibiting the NF-κB pathway, promote the expression of tight junction protein (ZO-1), and alleviate intestinal leakage. 

Constipation improvement: Rat experiments showed that elderberry dietary fiber increases defecation frequency by 25% and enhances fecal water content, presumably due to water absorption and swelling as well as promotion of intestinal peristalsis. 

5. Safety Analysis 

5.1 Toxic Risks and Mitigation 

Toxicity of raw products: Raw elderberries, branches, and leaves contain cyanogenic glycosides; accidental ingestion can cause nausea and vomiting. However, processed extracts (e.g., boiled or standardized extracted products) have removed toxic components (no cyanide poisoning was reported in clinical studies). 

Dose dependence: In existing clinical studies, no adverse events were observed with 600 mg of extract per day. However, long-term (>12 weeks) safety remains to be verified, and attention should be paid to the potential accumulation effect of polyphenols. 

5.2 Considerations for Special Populations 

Individuals with intestinal sensitivity: The acidity of elderberry extract (pH ≈ 3.5) may irritate the intestinal mucosa; it is recommended to take it with meals. 

Drug interactions: No clear evidence of drug interactions has been found, but since elderberry extract may enhance the effects of hypoglycemic and lipid-lowering drugs, monitoring of relevant indicators is required when used in combination with antidiabetic drugs or anticoagulants.

6. Conclusion and Outlook 

Elderberry extract demonstrates clear potential in improving intestinal flora, protecting the intestinal barrier, and assisting in metabolic regulation through its "microbiota regulation-antioxidation-metabolic synergy" triple mechanism. Human trials have verified its short-term safety and efficacy. However, there are limitations in current research: small clinical sample sizes (mostly <50 participants) and lack of long-term (>6 months) follow-up; insufficient in-depth exploration of mechanisms such as the "microbiota-gut-brain axis"; and inadequate product standardization. Future research should focus on in-depth analysis of precise mechanisms, upgrading clinical evidence with multicenter, large-sample randomized controlled trials (RCTs), and developing synergistic preparations or applying nanotechnology to enhance its efficacy. 

References 

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