Taxol — Paclitaxel (Diterpene Taxane · Pharmaceutical Anticancer · Informational Reference)
| Compound | Taxol (Paclitaxel) |
| Chemical class | Terpenoid — Diterpene Taxane (Unique bicyclic taxane ring system with complex esterification) |
| CAS | 33069-62-4 |
| Primary source | Taxus brevifolia (Pacific yew bark); semi-synthetic from Taxus baccata (English yew) |
| Key applications | Pharmaceutical anticancer agent (breast, ovarian, lung, Kaposi’s sarcoma) — informational reference |
| Claim strength | High (as pharmaceutical); not applicable as supplement |
| Typical form | Pharmaceutical injectable (Taxol®; Abraxane®); semi-synthetic precursor 10-DAB from yew needles |
| Buy from Herbuno | Browse HerbIQ Compound Index → |
Name origin: From Taxus (yew genus). The compound was renamed paclitaxel for generic pharmaceutical use; “Taxol®” is the Bristol-Myers Squibb brand name. Taxol is a complex diterpene ester — a taxane ring system with multiple ester linkages and an unusual 8-membered ring fused to the 6-membered ring. Traditional use: Yew trees (Taxus species) have been known as highly toxic plants throughout human history — both bark and needles contain taxine alkaloids (distinct from taxol) that are cardiotoxic. The toxicity of yew was used in ancient warfare (poisoned arrows, suicide). Traditional medicinal use of yew was very limited due to its lethal toxicity profile; the taxol discovery emerged entirely from systematic natural products screening rather than traditional use leads. Research and pharmaceutical status: Taxol (paclitaxel) was discovered in 1971 through an NCI-sponsored plant screening programme (Arthur Barclay’s collection of Pacific yew bark, 1962). It was approved by the FDA in 1992 for ovarian cancer, later for breast, lung, Kaposi’s sarcoma, and other cancers. Its mechanism — binding to and stabilising microtubule polymers (preventing depolymerisation during cell division) — was a novel pharmacological concept that created an entirely new cancer drug class (taxanes). Docetaxel (semi-synthetic taxane derivative, Taxotere®) is a related approved pharmaceutical. Supplement status: Taxol is a controlled pharmaceutical drug, not available as a dietary supplement or herbal ingredient.
Taxol as a Pharmaceutical — Scientific Context
Mechanism of action — microtubule stabilisation: Taxol binds to the beta-tubulin subunit of microtubule polymers, stabilising them against depolymerisation. Normal cells require microtubule dynamic instability for cell division (mitotic spindle assembly/disassembly). By preventing disassembly, taxol arrests cells in the M phase of mitosis, triggering apoptosis. Cancer cells with high proliferation rates are preferentially affected. This mechanism — microtubule stabilisation rather than disruption — was previously unknown and created the taxane drug class. Pharmaceutical approval status: FDA-approved for multiple cancers.
Semi-synthetic production: The original Pacific yew supply (requiring bark from 3 trees per patient course) was environmentally unsustainable. A semi-synthetic process was developed: 10-deacetylbaccatin III (10-DAB), extracted from the more renewable needles of European yew (Taxus baccata), is chemically converted to paclitaxel in 3–4 synthetic steps. This eliminated the dependence on Pacific yew bark harvesting and resolved the supply crisis that threatened taxol availability in the 1990s. Commercial status: Pharmaceutical only.
Nanoparticle albumin-bound formulation (Abraxane®): A second-generation taxol formulation — paclitaxel bound to albumin nanoparticles — was developed to overcome the solubility problem requiring Cremophor EL (polyoxyethylated castor oil) in original Taxol formulations. Cremophor EL caused hypersensitivity reactions requiring premedication. Abraxane eliminates Cremophor, reducing infusion reactions and allowing higher doses. This represents a significant pharmaceutical formulation innovation using nanotechnology for a complex natural product. Pharmaceutical approval status: FDA-approved for breast, lung, and pancreatic cancers.
This compound is documented for research and formulator education purposes. For commercially available botanical ingredients, explore the HerbIQ Compound Index →
Frequently Asked Questions — Taxol
Why is taxol not available as a herbal supplement?
Taxol (paclitaxel) is a regulated pharmaceutical drug (Schedule A in many markets, requiring prescription and oncology supervision). It has a narrow therapeutic window — the difference between the effective anticancer dose and the toxic dose is small, requiring precise dosing, patient monitoring, and management of significant adverse effects (neutropenia, neuropathy, alopecia). No part of yew trees should be consumed as a food or dietary supplement — other yew constituents (taxine alkaloids) are acutely cardiotoxic. Yew is not on the GRAS list in the US and is not approved as a dietary supplement ingredient in any major market.
Is the Pacific yew tree still used to produce taxol?
No — the semi-synthetic route from 10-DAB (extracted from renewable yew needle biomass, primarily Taxus baccata and T. chinensis) replaced bark-derived production entirely. Hazel cell culture (plant cell fermentation technology) was also developed — paclitaxel is now produced by plant cell fermentation of Taxus suspension cultures in large bioreactors, providing a fully renewable and environmentally sustainable supply chain that requires no wild-harvested plant material.
Are there botanicals with similar anticancer mechanisms to taxol?
No naturally occurring botanical supplement replaces pharmaceutical-grade taxol. Several botanical compounds interfere with microtubule dynamics through different mechanisms: vincristine/vinblastine from periwinkle (Catharanthus roseus) destabilise microtubules (opposite to taxol); colchicine from Colchicum binds tubulin at a different site; podophyllotoxin from mayapple prevents polymerisation. All these are pharmaceutical-grade compounds, not supplement ingredients. The taxane class is unique in stabilising (rather than destabilising) microtubules — no approved supplement reproduces this mechanism.
What is taxol’s significance in natural products chemistry?
Taxol is one of the most significant natural product pharmaceutical discoveries of the 20th century — representing both a novel pharmacological mechanism and a supply chain crisis that drove major advances in semi-synthetic and fermentation-based natural product production. The taxol story also demonstrated the value of systematic natural product screening (the NCI’s phytochemical screening programme) that led to the collection and identification, illustrating why comprehensive botanical compound libraries (like the HerbIQ Compound Index) have enduring scientific value for drug discovery.
Related compounds: Artemisinin, Betulinic Acid, Andrographolide, Phytol
Claim-strength scale – High = multiple human RCTs; Moderate = limited trials or strong preclinical convergence; Emerging = early-stage lab or animal data.
← HerbIQ Compound Index · HerbIQ P02: Extraction · HerbIQ P03: Delivery