# Coffeeberry (Rhamnus californica)

**Canonical URL:** https://ingredients.hermeticasuperfoods.com/ingredients/coffeeberry
**Data Source:** Hermetica Superfoods Ingredient Encyclopedia
**Updated:** 2026-03-24
**Evidence Score:** 2 / 10
**Category:** Fruit
**Also Known As:** Frangula californica, California buckthorn, California coffeeberry, Pigeon berry, Yerba del oso, California cascara, Western buckthorn

## Overview

Coffeeberry (Rhamnus californica) contains anthraquinone glycosides like emodin that promote digestive motility by stimulating smooth muscle contractions in the large intestine. Methanolic extracts demonstrate antibacterial activity against methicillin-resistant Staphylococcus aureus comparable to streptomycin.

## Health Benefits

• Antibacterial activity: In vitro methanolic extracts showed activity against MRSA comparable to streptomycin (PMID: 26025138) - evidence quality: preliminary
• Digestive support: Contains anthraquinone glycosides like emodin that increase smooth muscle action in the large intestine - evidence quality: traditional/preliminary
• Wound healing: Traditional use by Native American tribes for infected wounds and bleeding - evidence quality: traditional only
• Skin conditions: Leaves traditionally used for poison oak dermatitis treatment - evidence quality: traditional only
• Natural laxative: Bark preparations traditionally used as purgative for constipation, similar to related cascara sagrada - evidence quality: traditional only

## Mechanism of Action

Coffeeberry's anthraquinone glycosides, particularly emodin, stimulate smooth muscle contractions in the large intestine through direct irritation of intestinal mucosa and increased peristalsis. The antibacterial effects appear to involve disruption of bacterial cell wall synthesis and protein function, though specific molecular targets require further investigation.

## Clinical Summary

Current research on coffeeberry is limited to preliminary in vitro studies. One laboratory study demonstrated that methanolic extracts showed antibacterial activity against MRSA with potency comparable to the antibiotic streptomycin. The digestive effects are based on known mechanisms of anthraquinone compounds rather than specific clinical trials. Human studies with controlled dosing and clinical endpoints are needed to validate therapeutic applications.

## Nutritional Profile

Limited compositional data exists for Coffeeberry (Rhamnus californica) fruit specifically, but known constituents include: Anthraquinone glycosides (primary bioactives) — emodin, aloe-emodin, and chrysophanol, collectively estimated at 0.5–1.5% dry weight in bark/fruit; these compounds have low oral bioavailability due to partial [metabolism](/ingredients/condition/weight-management) by gut microbiota into active aglycone forms. Flavonoids — quercetin and kaempferol derivatives identified in methanolic extracts (quantification limited in fruit specifically). Tannins (condensed and hydrolyzable) contributing astringency, estimated 2–5% dry weight by analogy with related Rhamnaceae species. Dietary fiber: likely moderate-to-high (10–20% dry weight estimated), consistent with related Rhamnus species; soluble and insoluble fractions support laxative action synergistically with anthraquinones. Sugars: fructose and glucose as primary simple carbohydrates in ripe fruit pulp; no precise concentration data published for californica fruit. Organic acids: malic and citric acids likely present based on genus-level data. Minerals: calcium, potassium, and magnesium reported in Rhamnus genus fruits at trace-to-moderate levels (exact mg/100g data absent for this species). Vitamin C: presumed present in fresh fruit based on botanical family norms but unquantified. Fatty acids: negligible in fruit pulp. Protein: low, estimated <2% dry weight. Bioavailability note: anthraquinone glycosides require colonic bacterial hydrolysis to exert laxative/bioactive effects; absorption of aglycones occurs primarily in the large intestine.

## Dosage & Preparation

No clinically studied dosage ranges are available as no human trials exist. Traditional preparations involve aged bark (requiring one year aging or heat treatment to avoid toxicity), but specific standardization or doses for F. californica extracts are not established. Consult a healthcare provider before starting any new supplement.

## Safety & Drug Interactions

Coffeeberry safety profile in humans is not well-established due to limited clinical research. Anthraquinone-containing plants may cause gastrointestinal irritation, cramping, and diarrhea, particularly with higher doses. Potential interactions with anticoagulant medications and cardiac glycosides are possible but not specifically documented. Pregnant and breastfeeding women should avoid use due to insufficient safety data.

## Scientific Research

Research on coffeeberry is limited to in vitro studies, with no human clinical trials, RCTs, or meta-analyses identified. The primary study (PMID: 26025138) tested methanolic extracts against bacteria in laboratory conditions, showing antibacterial activity in zone inhibition assays but providing no human data or clinical outcomes.

## Historical & Cultural Context

Native American tribes including Ohlone, Kumeyaay, and Kawaiisu traditionally used coffeeberry bark as a purgative, leaves for treating poison oak rashes and wounds, and berries as food or medicine. Use dates to pre-colonial practices in western North America, with related species like cascara sagrada later adopted for commercial laxative preparations.

## Synergistic Combinations

Cascara sagrada, Senna, Aloe vera, Psyllium husk, Triphala

## Frequently Asked Questions

### What is the active compound in coffeeberry extract?

The primary bioactive compounds are anthraquinone glycosides, particularly emodin, which are responsible for the digestive and potential antibacterial effects. These compounds are concentrated in the bark and berries of Rhamnus californica.

### How does coffeeberry compare to cascara sagrada?

Both coffeeberry (Rhamnus californica) and cascara sagrada (Rhamnus purshiana) belong to the same genus and contain similar anthraquinone compounds. However, cascara sagrada has more established research and traditional use as a laxative, while coffeeberry research is more preliminary.

### What dosage of coffeeberry extract is recommended?

No standardized dosage exists for coffeeberry due to limited clinical research. Traditional preparations varied widely, and modern supplements lack sufficient safety and efficacy data to establish recommended dosing guidelines.

### Can coffeeberry extract treat bacterial infections?

While laboratory studies show antibacterial activity against MRSA, coffeeberry cannot be considered a treatment for bacterial infections. The research is preliminary and limited to test tube studies, not human clinical trials.

### Is coffeeberry extract safe for daily use?

Daily use safety is not established due to insufficient human studies. Anthraquinone-containing supplements can cause digestive side effects and may lead to electrolyte imbalances with prolonged use, so medical supervision is recommended.

### Does coffeeberry extract interact with common medications like antibiotics or blood thinners?

Coffeeberry contains anthraquinone compounds that may interact with certain medications, particularly those metabolized through the same liver pathways or medications affecting electrolyte balance. Because coffeeberry has documented effects on intestinal smooth muscle activity, it may theoretically reduce absorption of some orally administered medications. Consult with a healthcare provider before combining coffeeberry with antibiotics, anticoagulants, or other chronic medications, especially given the limited human safety data.

### Is coffeeberry extract safe to use during pregnancy or while breastfeeding?

There is insufficient clinical evidence on coffeeberry's safety during pregnancy and lactation, and traditional use does not establish safety in these populations. The anthraquinone glycosides in coffeeberry stimulate intestinal contractions, which raises theoretical concerns during pregnancy. Pregnant and breastfeeding women should avoid coffeeberry extract unless explicitly approved by their healthcare provider.

### What does the scientific evidence actually show about coffeeberry's effectiveness for digestive and antimicrobial benefits?

In vitro studies demonstrate that coffeeberry extracts show antibacterial activity against MRSA comparable to streptomycin, but this evidence is preliminary and has not been validated in human clinical trials. Its digestive effects are supported primarily by traditional use and the known pharmacology of anthraquinone compounds, rather than robust human studies. More rigorous clinical research is needed to establish efficacy, dosing, and safety for both antimicrobial and digestive applications in humans.

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