Yew

Yew (Taxus spp.): A Comprehensive Reference

1. Identity: Botanical Names, Natural Source, and Common Forms

Taxonomy and Botanical Classification

The genus Taxus, comprising plants commonly known as yews, belongs to the family Taxaceae — a group of coniferous trees or shrubs distributed in temperate zones of the northern hemisphere, northernmost in Norway and southernmost in the South Celebes. The oldest known fossil species date from the Early Cretaceous. Yews are relatively slow-growing and can be very long-lived, reaching heights of 2.5–20 m, with trunk girth averaging 5 m.

Several species are of primary medicinal and pharmacological relevance:

• Taxus baccata (European or English yew) — native throughout Europe, North Africa, and western Asia, widely planted as an ornamental tree in Europe and the USA
• Taxus brevifolia (Pacific yew) — native to the Pacific Northwest of North America; along with the Canada yew (Taxus canadensis), the initial source of paclitaxel (Taxol), a chemotherapeutic drug used in breast and lung cancer treatment
• Taxus wallichiana (Himalayan yew) — found in Europe, North America, North India, Pakistan, China, and Japan; in India, this evergreen tree is found at altitudes between 1800 and 3300 m above mean sea level
• Taxus chinensis (Chinese yew) — cultivated in China as a primary source of taxane precursors for semi-synthesis
• Taxus canadensis (Canada yew) — of Eastern and Central North America, also a recognized source of taxane intermediates

Morphological Description

Yews have reddish bark, lanceolate, flat, dark-green leaves 10–40 mm long and 2–3 mm broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flat rows either side of the stem. Seed cones are highly modified — a single ovule produces a solitary seed enclosed within an aril, open at the end. Seeds are hard; the aril is at first green and fleshy, ripening to red (sometimes orange or yellow).

Parts Used and Preparations

The foliage, bark, and seeds — but not the aril — of most Taxus species are toxic due to the presence of taxine. Most species contain the anti-cancer agent taxol. Parts used medicinally or pharmacologically across different traditions and research settings include:

• Bark (primary source of paclitaxel in early extraction)
• Needles/leaves (source of 10-deacetylbaccatin III for semi-synthesis; also used in traditional decoctions)
• Aril (the red, fleshy seed covering — the only non-toxic part; emerging research interest)
• Seeds (toxic; contain a range of alkaloids and flavonoids)
• Twigs and heartwood (also contain taxanes)

In traditional medicine, the plant is consumed as decoctions, herbal tea, and juice. In pharmaceutical contexts, the relevant preparations are isolated chemical compounds (paclitaxel, docetaxel) derived by extraction and semi-synthesis, formulated as intravenous infusion solutions.

2. Traditional and Historical Use

Cultural and Spiritual Significance in Europe

The genus Taxus, commonly known as yew, includes a group of long-lived gymnosperms with a rich botanical and medicinal heritage. Recognized as one of Europe's most ancient tree lineages, Taxus species are esteemed for their longevity and mythological significance in various cultural contexts, including Celtic, Greek, and Roman traditions. Their durable wood and physiological resilience contributed not only to their practical applications in traditional societies but also to their spiritual symbolism of death, rebirth, and immortality. These attributes made yew trees prominent features of sacred spaces across Europe.

Notable examples of ancient living yews include the Fortingall Yew in Scotland, estimated to be between 2,000 and 5,000 years old, and the Defynnog Yew in Wales, believed to be over 3,000 years old, both found in churchyards likely built over pre-Christian sanctuaries. The enduring association of yew trees with sacredness across pagan and Christian traditions demonstrates their role as living witnesses of spiritual continuity and transformation throughout European history.

Historical Utilitarian Use

Yew wood was historically important, finding use in the Middle Ages in items such as musical instruments, furniture, and longbows. The species was felled nearly to extinction in much of Europe. The English yew holds deep historical significance, particularly in medieval England, where its strong yet flexible wood was the preferred material for crafting longbows, making it an important resource for warfare and hunting throughout the centuries.

Traditional Medicinal Use: European Traditions

An alkaloid, taxine, was isolated in 1856 and found responsible for the European yew's poisonous nature. Despite its recognized toxicity, the plant was used medicinally in limited contexts. In Europe, small doses of yew extracts were historically applied as sedatives or for treating rheumatism, though such use carried high risk and is no longer practiced. The arils of Taxus, particularly in the Mediterranean region, have been used to produce medicinal wine, believed to possess restorative properties.

Traditional Medicinal Use: Native American Traditions

Many Native American and First Nation peoples used Pacific yew bark in traditional medicines. Native Americans used yew plant to impart strength, induce perspiration, and treat internal injuries and lung diseases.

Traditional Medicinal Use: Ayurveda, Unani, and Himalayan Systems

The Himalayan yew (Taxus wallichiana) has been used by native populations for treating common cold, cough, fever, and pain. Its uses are described in Ayurveda and Unani medicine. Himalayan yew has been used traditionally for the treatment of high fever and painful inflammatory conditions. It is consumed as decoctions, herbal tea, and juice for treating cold, cough, respiratory infections, indigestion, and epilepsy. As a poultice, it is used locally on infected wounds and burns. Its bark and leaves are used in steam baths to treat rheumatism.

Traditionally, T. wallichiana is used to treat disorders of the digestive, respiratory, nervous, and skeletal systems.

Traditional Medicinal Use: Traditional Chinese Medicine

In Traditional Chinese Medicine (TCM), Taxus chinensis (known as Hong Dou Shan) has been used historically to treat a range of conditions. Historical TCM applications have included use for tapeworms, swollen tonsils, seizures, rheumatism, and liver conditions, though these uses are documented in ethnobotanical records rather than controlled clinical evidence.

Ritual and Ceremonial Use

As an incense, yew has long been used in ceremonies to protect and contact ancestors and the dead and to assist in ritual contexts across multiple traditional cultures.

3. Key Constituents and Active Compounds

Taxane Diterpenoids

Botanically, Taxus species are of exceptional interest due to their phytochemical profiles, especially their production of taxanes — diterpenoid alkaloids that serve as precursors for anticancer drugs like paclitaxel (Taxol®), docetaxel (Taxotere®), and cabazitaxel (Jevtana®). Over a hundred taxanes have been characterized from various Taxus species, and taxol is a member of a small group of compounds possessing a four-membered oxetane ring and a complex ester side-chain in their structures, both of which are essential for antitumor activity.

Paclitaxel (Taxol)

The name taxol was given to a diterpene ester with anticancer properties when it was first isolated in 1971 from Taxus brevifolia. When this compound was subsequently exploited commercially as a drug, Taxol was registered as a trademark. Accordingly, the generic name paclitaxel has been assigned to the compound. The groundbreaking discovery of paclitaxel from Taxus brevifolia bark in 1965 by Wall and Wani marked a new era in cancer chemotherapy.

Paclitaxel is found at very low concentrations — less than 400 parts per million — in the bark or needles of yew trees. It can be isolated from the bark of the Pacific yew tree (Taxus brevifolia) and ground hemlock (Taxus canadensis), but the yield is very low (0.01%–0.02%). It requires the bark from about three mature 100-year-old trees to provide one gram of taxol, and a course of treatment may need 2 grams of taxol.

Taxine Alkaloids (A and B)

The yew contains cardiotoxic alkaloids including taxine A and B, which are present in all parts of the plant except the red arils. The main compound responsible for the toxicity of the European yew (T. baccata) is taxine B. These alkaloids are distinct from the therapeutic taxane diterpenoids and are the primary agents responsible for the plant's acute toxicity.

10-Deacetylbaccatin III (10-DAB) and Baccatin III

The problem of overharvesting was resolved by the development of practical semi-synthesis of paclitaxel from 10-deacetylbaccatin III (10-DAB III), which is much more abundant in the needles of European yew (Taxus baccata), up to approximately 1 g/kg of fresh biomass, and these yew needles are renewable. Docetaxel is semisynthetically produced from 10-deacetyl baccatin III, a noncytotoxic precursor extracted from the needles of Taxus baccata, esterified with a chemically synthesized side chain.

Flavonoids

So far, 59 flavonoids in total with different skeletons have been identified from Taxus plants. These compounds have been reported to display significant antibacterial, antiaging, anti-Alzheimer's, antidiabetes, anticancer, antidepressant, antileishmaniasis, anti-inflammatory, antinociceptive and antiallergic, antivirus, antilipase, neuronal protective, and hepatic-protective activities, as well as promotion of melanogenesis. Specific flavonoids identified in seeds include naringenin, aromadendrin, galanin, epigallocatechin, and gallocatechin.

Additional Phytochemicals

The leaves also contain taxine, taxinine, hydrocyanic acid, formic acid, reducing sugars, resins, tannins, ephedrine, glucoside, and taxiphyllin. In the context of Taxus species seeds, a diverse array of phytochemicals has been documented, encompassing alkaloids, flavonoids, lignans, polysaccharides, and steroid derivatives, thereby underscoring the extensive chemical diversity inherent in these seeds. Besides being the source of taxol, T. wallichiana has been investigated for its essential oil, diterpenoids, lignans, steroids, sterols, and biflavonoids.

Essential Oils

In addition to the taxane diterpenoids and the cancer drug taxol, Taxus species contain many essential oils with actual or potential biological activity. Research covering the chemical constituents and biological activities of these oils spans fourteen countries over 46 years (1975–2021). Essential oils extracted from studied Taxus plant parts were found to be composed mainly of alcohols.

4. Mechanisms of Action

Paclitaxel: Microtubule Stabilization

Paclitaxel is an anti-microtubule agent that promotes assembly of microtubules from tubulin dimers and stabilizes microtubules by preventing depolymerization. This stability results in the inhibition of the normal dynamic reorganization of the microtubule network that is essential for vital interphase and mitotic cellular functions. In addition, paclitaxel induces abnormal arrays or "bundles" of microtubules throughout the cell cycle and multiple asters of microtubules during mitosis.

Upon administration, paclitaxel binds to the beta-tubulin subunit of microtubules. This binding promotes the polymerization of tubulin into stable microtubules and simultaneously inhibits their depolymerization. As a result, microtubules become excessively stabilized and resistant to the normal disassembly processes required for mitosis. Consequently, the formation of stable, non-functional microtubule bundles interferes with the mitotic spindle formation, leading to cell cycle arrest at the G2/M phase. Cells are unable to proceed through mitosis, resulting in apoptosis or programmed cell death.

Additional and Non-Mitotic Mechanisms of Paclitaxel

Questions on how paclitaxel suppresses cancer persist, as other specific mitotic inhibitors are impressive in pre-clinical studies but fail to achieve significant clinical activity. Thus, additional mechanisms, such as promoting mitotic catastrophe and impacting non-mitotic targets, have been proposed and studied. A recent study provides a potential non-mitotic mechanism of paclitaxel action: paclitaxel-induced rigid microtubules act to break malleable cancer nuclei into multiple micronuclei. Previous studies have established that cancer cells have a less sturdy, more pliable nuclear envelope due to the loss or reduction of lamin A/C proteins. Such changes in nuclear structure provide a selectivity for paclitaxel to break the nuclear membrane and kill cancer cells over non-neoplastic cells that have a sturdier nuclear envelope.

Taxine Alkaloids: Cardiotoxic Mechanism

Taxines are poisonous constituents in yew plants that block sodium and calcium channels in the heart, leading to life-threatening cardiotoxicity — including atrioventricular block, ventricular tachycardia, and refractory ventricular fibrillation. Taxine-derived alkaloids (e.g., taxine A and B, isotaxine B, paclitaxel), taxane-derived substances (e.g., taxol A and B), and glycosides (e.g., taxicatine) all contribute to the toxicity of Taxus baccata. The general mechanism of action involves the disruption of microtubule function.

Flavonoid and Polyphenol Mechanisms

Compounds isolated from T. wallichiana, especially tasumatrol B, have shown significant anti-inflammatory activity in the carrageenan-induced paw edema model. Taxusabietane A, isolated from the bark extract of T. wallichiana, has also shown significant anti-inflammatory activity in the lipoxygenase inhibitory assay and the carrageenan-induced paw edema model. Taxol and related bioactive taxoids from T. wallichiana may be responsible for its antimicrobial activities, which may also be attributed to the presence of phenols, polyphenols, tannins, saponins, anthraquinones, alkaloids, steroids, and especially diterpenes — families of natural products known to display antimicrobial activities.

5. Scientific Evidence by Area of Use

5.1 Oncology: Paclitaxel-Based Therapies

This section covers the strongest and most extensively documented area of clinical evidence from Taxus-derived compounds — namely, the FDA-approved chemotherapy agent paclitaxel and its semisynthetic derivative docetaxel.

Ovarian Cancer

The U.S. Food and Drug Administration (FDA) granted accelerated approval for paclitaxel in 1992 to treat refractory ovarian cancer. Subsequently, paclitaxel also received complete approval as the first-line treatment option for ovarian cancer. Paclitaxel was initially tested in patients with recurrent ovarian cancer every 3 weeks, and response rates of 21–37% were seen, including response rates of 21–33% in patients with platinum-resistant disease who had not previously received paclitaxel. Phase I trials evaluating weekly administration of paclitaxel in patients with platinum/paclitaxel-resistant recurrent ovarian cancer also demonstrated responses. Additional clinical trials utilizing weekly paclitaxel have reported response rates ranging from 21–54%. Paclitaxel has demonstrated efficacy when given every 3 weeks as well as on a weekly schedule for patients with both platinum-sensitive and platinum-resistant disease.

Breast Cancer

Over the years, the FDA extended paclitaxel's indications to include breast cancer. Phase II trials in breast cancer using paclitaxel as first chemotherapy for metastatic disease have reported response rates of 56–62%, giving paclitaxel as a 24-hour infusion with or without G-CSF support. In 2005, the FDA approved nanoparticle albumin-bound paclitaxel (nab-paclitaxel) for breast cancer treatment. Nab-paclitaxel is cremophor-free and has a short infusion time without cremophor EL-related side effects and allergic reactions.

Non-Small Cell Lung Cancer (NSCLC)

The FDA also extended paclitaxel's indications to include non-small cell lung cancer (NSCLC). Significant activity has been documented in small-cell and non-small cell lung cancer, head and neck cancers, and in metastatic melanoma. Paclitaxel, in combination with other agents, has been evaluated in large phase III trials for metastatic NSCLC. In the IMpower130 trial (NCT02367781) — a multicenter, randomized (2:1), open-label study — 724 patients with stage IV non-squamous NSCLC were randomized to receive atezolizumab plus paclitaxel protein-bound and carboplatin versus paclitaxel protein-bound and carboplatin with maintenance pemetrexed.

Docetaxel: Prostate and Other Cancers

Docetaxel is a semi-synthetic congener of paclitaxel. Docetaxel, in combination with cisplatin, is approved by the FDA as a first-line treatment for prostate cancer and is the standard of care for castration-resistant prostate cancer. The medication is also effective in non-small cell lung cancer (NSCLC). Both paclitaxel and docetaxel have been clinically used to treat various tumors, including metastatic breast cancer, advanced ovarian cancer, head and neck cancers, non-small cell lung cancer, and Kaposi's sarcoma.

Evidence Strength: Oncology

The clinical evidence for paclitaxel and docetaxel in their approved oncological indications is robust — supported by large-scale phase III randomized controlled trials, regulatory approval in multiple jurisdictions, and decades of clinical practice. In the late 1980s and early 1990s, phase 2 trials demonstrated promising antitumor activity of paclitaxel in various solid tumors, including ovarian, breast, and lung cancers. Large-scale randomized phase 3 trials compared paclitaxel-based treatment regimens with standard chemotherapy or best supportive care across various cancer types, and the results revealed significant improvements in response rates, progression-free survival, and overall survival among patients receiving paclitaxel-based therapies.

5.2 Anti-inflammatory Activity

Evidence for anti-inflammatory effects of Taxus extracts (distinct from isolated paclitaxel) is largely preclinical. In Ayurveda and Unani medicine, practitioners utilize Taxus for its efficacy in addressing common cold symptoms and inflammation reduction, highlighting its role as an anti-inflammatory agent. In laboratory settings, compounds isolated from T. wallichiana, including tasumatrol B, showed significant anti-inflammatory activity in the carrageenan-induced paw edema model. Taxusabietane A, isolated from the bark extract of T. wallichiana, showed significant anti-inflammatory activity in both the lipoxygenase inhibitory assay and the carrageenan-induced paw edema model. These are animal model studies only; no controlled human clinical trials evaluating raw yew extracts specifically for anti-inflammatory indications have been identified in the current literature.

5.3 Antimicrobial Activity

Some research indicates various medicinal properties of T. wallichiana, including analgesic, antipyretic, anti-inflammatory, immunomodulatory, antibacterial, antifungal, antiplatelet, antispasmodic, antiallergic, anticonvulsant, antiosteoporotic, and vasorelaxing effects. These properties have been investigated primarily in laboratory models using plant extracts. Although pharmacologically underexplored, T. wallichiana has been used for antiepileptic, anti-inflammatory, anticancer, antipyretic, analgesic, immunomodulatory, and antimicrobial activities. Evidence for antimicrobial effects in humans is absent; available data are limited to in vitro studies and animal models.

5.4 Flavonoid-Associated Biological Activities

Biological activities of the flavonoids in Taxus plants have been demonstrated in laboratory research, including antibacterial, antiaging, anti-Alzheimer's, antidiabetes, anticancer, antidepressant, antileishmaniasis, anti-inflammatory, antinociceptive and antiallergic, antivirus, antilipase, neuronal protective, and hepatic-protective activities, as well as the promotion of melanogenesis. Several flavonoids can also ameliorate oral absorption of paclitaxel. These findings are based on in vitro studies and, in some cases, animal models; human clinical evidence for these specific effects is not currently available.

5.5 Aril: Emerging Research

Emerging research on the aril — the non-toxic and antioxidant-rich plant part — suggests novel biomedical applications. The aril is of interest because it does not share the alkaloid toxicity profile of the other plant parts. However, clinical evidence for aril-based applications remains at a very early, exploratory stage.

6. Supply, Semi-Synthesis, and Production

Over-harvesting of the Pacific yew for paclitaxel led to fears that it would become an endangered species, since the drug was initially extracted from the bark of the yew, the harvesting of which kills the tree. This problem was resolved by the development of practical semi-synthesis of paclitaxel from 10-deacetylbaccatin III (10-DAB III), which is much more abundant in the needles of European yew (Taxus baccata), up to approximately 1 g/kg of fresh biomass, and these yew needles are renewable. Abundantly culturable European yew thus secured the production of paclitaxel and docetaxel, with INDENA SpA, Italy, supplying 10-DAB III to most of the global market.

The "South No.1 Yew," an elite clone from Taxus wallichiana var. mairei — the fastest growing species of Taxus spp. — is now widely cultivated in Fujian and Yunnan provinces of China to produce 10-DAB III (0.9–1% of dry biomass) at lower cost. Another method for large-scale production of paclitaxel is cell fermentation using Taxus cell suspension cultures.

Due to persistent over-exploitation of the Himalayan yew for its leaves and bark, it is now on the verge of extinction and classified as endangered by the International Union for Conservation of Nature (IUCN).

7. Dosage Forms and Dosages Reported in Studies

Paclitaxel — Pharmaceutical (Intravenous)

Paclitaxel is typically formulated as a concentrated solution containing paclitaxel at 6 mg per milliliter of Cremophor EL (polyoxyethylated castor oil) and dehydrated alcohol (50% v/v), which must be further diluted before administration. Paclitaxel is commercially available in 30 mg (5 mL), 100 mg (16.7 mL), and 300 mg (50 mL) multidose vials.

Key dosing regimens reported in clinical research:

• In a GOG trial, weekly paclitaxel was administered at 80 mg/m² in 48 evaluable patients.
• In a Memorial Sloan-Kettering/MD Anderson trial in esophageal carcinoma, paclitaxel was administered at 250 mg/m² by 24-hour infusion, recycled every 21 days, administered together with G-CSF. Paclitaxel showed significant antitumor activity, with 16 major responses (32%), including one complete response (2%), seen in 51 patients.
• Phase II trials in breast cancer for metastatic disease using paclitaxel as first chemotherapy reported response rates of 56–62% with a 24-hour infusion schedule, with or without G-CSF support. A trial using a 3-hour infusion of paclitaxel at 250 mg/m² as first-line chemotherapy for metastatic breast cancer reported a response rate of 32%.
• Severe neutropenia (<500/mm³) occurs in 28–74% of patients depending on dose and schedule, with higher rates at 175 mg/m² compared to 135 mg/m².

Peripheral neuropathy symptoms typically occur between 24 and 72 hours following paclitaxel treatment with higher doses of the drug (>250 mg per square meter).

Nab-Paclitaxel (Albumin-Bound Paclitaxel)

Albumin-bound or nab-paclitaxel was developed to overcome limitations of cremophor-containing standard paclitaxel, to ensure more convenient drug administration and improved toxicity profiles.

Traditional Preparations

Traditional preparations of Taxus leaves and bark — including decoctions, herbal teas, and juices — have been used in Himalayan folk medicine, but no standardized or safe dosing ranges for raw plant preparations in humans have been established in the peer-reviewed literature. The extreme toxicity of most plant parts renders self-administration of non-pharmaceutical preparations hazardous.

8. Safety Considerations

Raw Plant Toxicity — Taxine Alkaloids

Lethal oral doses of yew leaves in humans are 0.6–1.3 g/kg, corresponding to 3.0–6.5 mg taxines/kg. Taxines block sodium and calcium channels in the heart, leading to life-threatening cardiotoxicity including atrioventricular block, ventricular tachycardia, and refractory ventricular fibrillation. Patients who ingest a lethal dose frequently die despite resuscitation efforts. Serious poisoning occurs in the setting of suicidal ingestion.

In the case of overdose with yew plants, symptoms include nausea, dizziness, abdominal pain, shallow breathing, and tachycardia. Taxines remain in the plant throughout the year, with maximal plant taxine concentrations appearing during the winter. Dried yew plant material retains its toxicity for several months and remains a hazard to domestic animals.

In instances where ingestion has recently occurred, treatment involves symptomatic and supportive care, primarily because there is no specific antidote for taxine poisoning. Prompt initiation of venoarterial extracorporeal membrane oxygenation has been reported as essential to bridge critically ill patients to recovery, as there is no antidote available.

The Aril: The Non-Toxic Exception

The plant has a very characteristic bright red, berry-like structure called an aril. All parts of the plant are highly toxic except this aril. This enables the cones inside the aril to be eaten by birds. However, the seed enclosed within the aril is itself highly toxic. The fleshy aril alone is the one non-toxic part of the yew plant.

Paclitaxel (Pharmaceutical) Adverse Effects

The most prevalent adverse effects of paclitaxel use are alopecia, nausea and vomiting, mucositis, neutropenia, leukopenia, anemia, hypersensitivity reactions, arthralgia, myalgia, and weakness. Peripheral neuropathy is another common adverse effect, and patients with preexisting neuropathies may have an increased risk.

Paclitaxel causes dose-limiting peripheral neuropathy in up to 60% of patients and severe myelosuppression requiring close monitoring, along with hypersensitivity reactions that mandate premedication with corticosteroids, diphenhydramine, and H2 antagonists before every infusion. Severe neutropenia (<500/mm³) occurs in 28–74% of patients depending on dose and schedule. Grade 3–4 neutropenia occurs in 37–48% of patients according to NCCN guidelines.

The early development of paclitaxel was hampered by the high incidence of major hypersensitivity reactions which, in some studies, approached 30%. Oral premedication with dexamethasone given at 12 and 6 hours before infusion of paclitaxel has been shown to significantly reduce the incidence of paclitaxel-induced hypersensitivity reactions.

Paclitaxel is able to induce peripheral neuropathy characterized by sensory symptoms such as paresthesia and numbness in a glove-and-stocking distribution. Symmetrical loss of sensations including proprioception, vibration, pinprick, and temperature is also frequently noted.

A 20% reduction in dose should be considered for patients who develop severe neuropathy.

Myelosuppression is dose- and schedule-dependent but not cumulative, with neutropenia being less common when paclitaxel is given as a 3-hour infusion compared to a 24-hour infusion schedule.

Drug Interactions: Paclitaxel

Paclitaxel is metabolized via CYP2C8 and CYP3A4 pathways; co-administration with strong inhibitors or inducers may alter drug exposure. Concomitant use with other myelosuppressive agents increases the risk of hematologic toxicity. Hepatic dysfunction increases risk for toxicity, and caution is required in patients with compromised liver function. Pregnancy and breastfeeding are contraindicated due to teratogenic potential.

Pollen Allergy

Male yews are extremely allergenic, blooming and releasing abundant amounts of pollen in the spring. While yew pollen does not contain sufficient taxine alkaloids to cause poisoning, its allergenic potential has been implicated in adverse reactions to paclitaxel treatment.

Conservation and Sustainability

The Botanic Gardens Conservation International has identified yew trees among approximately 400 medicinal plants at risk of extinction from over-collection and deforestation, threatening the discovery of future cures for disease. Due to overexploitation, many species are now endangered and on the verge of extinction; several species are disappearing at an alarming rate, mainly at higher altitudes, due to over-harvesting, habitat destruction, and climate change.

9. Body Systems and Health Areas Associated with Taxus

• Oncology (Established, High-Level Evidence): Breast cancer, ovarian cancer, non-small cell lung cancer, prostate cancer (via docetaxel), Kaposi sarcoma, head and neck cancers, esophageal carcinoma, bladder cancer, and melanoma — via pharmaceutical-grade paclitaxel and docetaxel.
• Cardiovascular System (Toxicological Context): Taxine alkaloids produce life-threatening cardiac arrhythmias, atrioventricular block, and cardiogenic shock.
• Neurological System: Traditional use for epilepsy and convulsions (T. wallichiana); paclitaxel causes peripheral neuropathy as a major adverse effect.
• Respiratory System: Traditional use for coughs, colds, and respiratory infections across Ayurvedic, Unani, and Native American traditions.
• Musculoskeletal System: Traditional use in steam baths and poultices for rheumatism.
• Immune System / Antimicrobial: Preclinical evidence for antibacterial and antifungal properties of Taxus extracts, attributed to taxoids, polyphenols, and diterpenes.
• Digestive System: Traditional use for indigestion across Himalayan folk medicine traditions.

References

• A Deep Dive into the Botanical and Medicinal Heritage of Taxus — PMC/NIH
• Ethnomedical Properties of Taxus Wallichiana Zucc. (Himalayan Yew) — PMC/NIH
• Discovery of Camptothecin and Taxol — American Chemical Society National Historic Chemical Landmark
• Taxus brevifolia — ScienceDirect Overview
• Taxus baccata — ScienceDirect Overview
• Pacific Yew — Royal Botanic Gardens Kew
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• Chemical Compositions and Biological Activities of the Oils from the Genus Taxus — PMC/NIH
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• Docetaxel — StatPearls, NCBI Bookshelf/NIH
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• Flavonoid Components, Distribution, and Biological Activities in Taxus: A Review — PMC/NIH
• Evaluation of Antimicrobial, Antioxidant and Cytotoxic Properties of Bioactive Compounds from Endophytic Fungi of Himalayan Yew — PMC/NIH
• An Integrated Strategy Based on 10-DAB Extraction and In Situ Whole-Cell Biotransformation of Renewable Taxus Needles to Produce Baccatin III — PMC/NIH
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• Anti-Cancer, Anti-Inflammatory, and Analgesic Effects of Taxus wallichiana Extracts — PMC/NIH
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• Taxus baccata — Wikipedia
• Taxus (Yew) Description — Gymnosperm Database, Conifers.org
• FDA Approval: Atezolizumab with Nab-Paclitaxel and Carboplatin for Metastatic NSCLC — U.S. FDA
• Evaluation of the Anticancer Activity of Enzymatically Synthesized Baccatin III — PMC/NIH