Carnosic Acid (Rosemary Diterpene Antioxidant · Nrf2 Activator · E392 Food Preservative)
| Compound | Carnosic Acid |
| Chemical class | Terpenoid — Diterpene Acid (Abietane-type phenolic diterpene; ortho-diphenolic) |
| CAS | 3650-09-7 |
| Primary source | Rosmarinus officinalis / Salvia rosmarinus (rosemary leaves), Salvia officinalis (sage) |
| Key applications | Antioxidant; neuroprotective; Nrf2 activation; lipid oxidation prevention (food preservation); antimicrobial |
| Claim strength | Moderate |
| Typical form | Rosemary extract standardised to carnosic acid (12–70%); food-grade rosemary antioxidant (E392) |
| Buy from Herbuno |
Rosemary Leaf Extract Powder → Organic Rosemary (Rosmarinus officinalis) Leaf Powder → |
Name origin: From carnosus (Latin: flesh/meat) — historically, rosemary extract was used as a natural preservative for meat. Carnosic acid is an abietane diterpene phenolic acid (an ortho-diphenol with two adjacent hydroxyl groups on the diterpene scaffold) — the primary lipophilic antioxidant in rosemary alongside carnosol (its oxidation product). The two phenolic hydroxyl groups confer exceptional radical-scavenging capacity. Traditional use: Rosemary has been used as a food spice and preservative since antiquity across Mediterranean cultures — the food preservation function now understood to be primarily due to carnosic acid’s antioxidant properties. In traditional medicine, rosemary was used for memory improvement, circulatory conditions, and as an antimicrobial. The memory association is reflected in the scientific finding that carnosic acid is neuroprotective and may activate NGF (nerve growth factor) expression. Food additive status: Rosemary antioxidant (primarily carnosic acid + carnosol) is approved as a food antioxidant E392 in the EU and GRAS in the US — the most widely used natural antioxidant in food processing for oil/fat oxidation prevention in meat, bakery, and snack applications. This dual role (food additive and supplement active) is pharmacologically important. Commercial source: Rosemary Leaf Extract Powder and water-soluble extract, both rich in carnosic acid/carnosol is available from Herbuno.
Evidence for Carnosic Acid Applications
Antioxidant — food preservation (High evidence): Carnosic acid is one of the most potent natural antioxidants characterised — DPPH IC50 approximately 1.4 μM (comparable to BHT, superior to vitamin E on a molar basis). In food systems, rosemary extract standardised to carnosic acid prevents lipid peroxidation in oils, fats, meat, and baked goods at concentrations of 50–200 ppm. This is an established industrial application with extensive evidence. Claim strength: High (food antioxidant application).
Neuroprotection via Nrf2 activation: Carnosic acid activates the Nrf2/ARE (antioxidant response element) pathway — specifically, carnosic acid undergoes auto-oxidation to its quinone form in cells with elevated ROS, and this quinone Michael acceptor activates Nrf2 by alkylating KEAP1 (the Nrf2 suppressor). This “electrophilic stress-sensing” mechanism is considered neuroprotective in oxidative stress states. Animal models of Alzheimer’s (5XFAD transgenic) show carnosic acid reduces amyloid burden and oxidative damage. Claim strength: Moderate (animal; mechanistic).
Anti-inflammatory and metabolic: Carnosic acid inhibits NF-κB via KEAP1/Nrf2 crosstalk and direct IKK inhibition. In adipogenesis models, it inhibits PPAR-γ-driven fat accumulation. Relevant for metabolic syndrome and inflammatory supplement formulations. Claim strength: Moderate.
Rosemary Leaf Extract Powder →
Organic Rosemary (Rosmarinus officinalis) Leaf Powder →
Browse Standardised Extract Powders →
Dosage & Formulator Specification
Food antioxidant applications: 50–200 ppm carnosic acid in lipid-based food matrices. Supplement applications: 200–500 mg/day rosemary extract standardised to 12–25% carnosic acid (delivering 24–125 mg carnosic acid/day). High-concentration extracts (40–70% carnosic acid) are available for applications requiring potent antioxidant content in small volumes. Carnosic acid is highly unstable in solution (rapidly oxidises to carnosol, which has its own antioxidant activity but different potency) — specify dry encapsulated formats with nitrogen flushing and antioxidant packaging. Shelf life of carnosic acid-standardised extracts: 12–24 months in sealed, cool, dark storage. The GRAS food antioxidant status facilitates inclusion in food-supplement hybrid products (functional foods).
Frequently Asked Questions — Carnosic Acid
What is the relationship between carnosic acid and carnosol?
Carnosol is the primary oxidation product of carnosic acid — carnosic acid loses two electrons (forming a quinone intermediate) which then cyclises to carnosol. In rosemary plant tissues, both carnosic acid and carnosol are present; during extraction and storage, carnosic acid progressively converts to carnosol. Carnosol retains significant antioxidant, anti-inflammatory, and anticancer activity, but with somewhat different potency and receptor interaction profiles from carnosic acid. Commercial “rosemary antioxidant” preparations contain a mixture of both — specify carnosic acid + carnosol combined content for full antioxidant specification.
Is rosemary extract safe for all food applications?
Rosemary extract (E392) is approved for use in fats and oils, meat products, soups, sauces, confectionery, bakery, breakfast cereals, and numerous other categories under EU Regulation (EC) No 1333/2008, with specific use levels per food category (typically 100–400 mg/kg as carnosic acid + carnosol). In the US, rosemary extract is GRAS for use in fats and oils, seasonings and flavourings, and other food uses. Both regulatory frameworks limit use in some categories. Formulation chemists should verify category-specific limits for their target application.
Can carnosic acid improve memory?
The traditional association of rosemary with memory (“rosemary for remembrance” — Shakespeare, Hamlet) has been partially validated by research. Aromatherapy studies with rosemary essential oil (predominantly 1,8-cineole, not carnosic acid) show improved cognitive performance in some controlled studies. Carnosic acid’s neuroprotective mechanisms (Nrf2 activation, NGF induction, amyloid-beta reduction in animal models) provide mechanistic support for cognitive effects. However, direct human RCT evidence for oral carnosic acid supplementation and cognitive outcomes is limited. The aromatherapy evidence uses volatile terpene components, not carnosic acid.
Is carnosic acid present in rosemary essential oil?
No — carnosic acid is a non-volatile diterpene acid and is absent from rosemary essential oil (which contains 1,8-cineole, camphor, borneol, and other volatile monoterpenes). Rosemary essential oil and rosemary extract (standardised to carnosic acid) are pharmacologically different products with different bioactive components. For antioxidant food preservation or supplement applications, rosemary extract (carnosic acid source) is required; for aromatherapy and volatile applications, rosemary essential oil (1,8-cineole, camphor) is the appropriate product.
Related compounds: Tanshinone IIA, Rosmarinic Acid, Ursolic Acid, Oleuropein
Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.
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