Shikimic acid

Shikimic acid is a naturally occurring cyclohexanecarboxylic acid found in star anise, plants, and microorganisms, serving as a critical intermediate in the shikimate pathway for synthesizing aromatic amino acids like phenylalanine, tyrosine, and tryptophan. It gained pharmaceutical prominence as the primary precursor in the industrial synthesis of oseltamivir (Tamiflu), though direct human supplementation lacks clinical trial support.

Origin & History

Shikimic acid is a cyclohexene carboxylic acid naturally occurring in all living species from bacteria to plants and humans, first isolated in 1885 from Japanese star anise (Illicium anisatum). It is produced via the shikimate pathway in plants and microorganisms and is found in foods like barley, macadamia nuts, nutmeg, winter squash, and borage.

Historical & Cultural Context

Despite being isolated from Japanese star anise (shikimi) in 1885, no traditional medicinal uses are documented in the available sources. The compound's naming reflects its botanical origin rather than any historical therapeutic application.

Health Benefits

• No human clinical trials or health benefits are documented in the available research • Serves as a key intermediate in the shikimate pathway for aromatic amino acid synthesis (biochemical role only) • Functions as a precursor for plant compounds like alkaloids, flavonoids, and tannins (plant metabolism) • Detected as a food biomarker in various plant foods (analytical use only) • No therapeutic benefits established through clinical evidence

How It Works

Shikimic acid enters the shikimate pathway where it is phosphorylated by shikimate kinase to form shikimate-3-phosphate, which subsequently condenses with phosphoenolpyruvate via 5-enolpyruvylshikimate-3-phosphate (EPSP) synthase to form chorismate. Chorismate serves as the branch-point precursor to aromatic amino acids, secondary metabolites including alkaloids, lignins, flavonoids, and tannins. In pharmaceutical manufacturing, shikimic acid undergoes a multi-step chemical conversion to produce the neuraminidase inhibitor oseltamivir, which blocks influenza viral replication by preventing release of virions from host cells.

Scientific Research

No human clinical trials, randomized controlled trials, or meta-analyses were identified in the research for shikimic acid as a therapeutic agent. The available literature focuses exclusively on its chemical properties and role in plant biosynthetic pathways rather than human health applications.

Clinical Summary

No published human clinical trials have evaluated shikimic acid as a direct oral supplement for any health outcome as of the available literature. Most research is confined to in vitro and preclinical animal studies examining its antioxidant, anti-inflammatory, and antiplatelet aggregation properties at concentrations that have not been validated in human pharmacokinetic models. One preclinical study noted inhibition of platelet aggregation and thrombosis in rodent models, but sample sizes and doses used cannot be extrapolated to human supplementation guidelines. The overall evidence base is insufficient to support any clinical health claims for isolated shikimic acid supplementation in humans.

Nutritional Profile

Shikimic acid is a cyclitol carboxylic acid (C7H10O5, molecular weight 174.15 g/mol), not a macronutrient or micronutrient itself, but a naturally occurring plant-derived organic acid and biochemical intermediate. It is not classified as a vitamin, mineral, or essential nutrient. Macronutrient contribution: negligible in typical dietary exposure — present in trace to low milligram quantities per serving in most plant foods. Notable natural concentrations: Chinese star anise (Illicium verum) contains the highest documented levels at approximately 3–7% dry weight (up to ~70 mg/g dried spice), making it the primary commercial extraction source. Other sources include pine needles (~2–3 mg/g), wheatgrass (~1–2 mg/g), fennel, and various berries (typically <1 mg/g fresh weight). Detected as a urinary and plasma biomarker after consumption of fruits, vegetables, and whole grains, with plasma concentrations in the low micromolar range (1–10 µmol/L) reported in biomarker studies. It is a water-soluble polar compound with estimated good intestinal absorption based on its small molecular size and hydrophilicity, though formal human bioavailability studies are limited. It contains no fiber, protein, fat, or recognized vitamin/mineral content. Bioactive role is primarily as a metabolic intermediate in the shikimate pathway and as a pharmaceutical precursor (notably for oseltamivir/Tamiflu synthesis); no established Dietary Reference Intake (DRI) or Recommended Daily Allowance (RDA) exists.

Preparation & Dosage

No clinically studied dosage ranges, standardized forms, or therapeutic preparations have been established for shikimic acid supplementation. Consult a healthcare provider before starting any new supplement.

Synergy & Pairings

No synergistic ingredients identified due to lack of clinical research

Safety & Interactions

Shikimic acid has no established safe supplementation dosage for humans, and its tolerability profile in clinical populations has not been formally studied in controlled trials. Theoretical concern exists around its antiplatelet activity observed in preclinical models, suggesting potential additive bleeding risk when combined with anticoagulants such as warfarin, aspirin, or clopidogrel, though this interaction has not been confirmed in humans. Pregnancy and lactation safety data are entirely absent, making its use inadvisable in these populations without medical supervision. Individuals with clotting disorders or those scheduled for surgery should avoid shikimic acid supplementation pending further human safety data.