Industrial Production, Estimation, and Utilization of Artemisinin

 

Industrial Production, Estimation, and Utilization of Artemisinin

Industrial Production of Artemisinin
Artemisinin is a sesquiterpene lactone with a unique peroxide bridge, extracted primarily from the leaves and flowering tops of Artemisia annua (commonly known as sweet wormwood or Qinghao), belonging to the Asteraceae family. It is one of the most important phytochemicals in modern medicine, especially for the treatment of malaria. Industrial production of artemisinin begins with the large-scale cultivation of A. annua, which grows well in temperate and subtropical climates. China, Vietnam, and India are major producers due to favorable growing conditions and established extraction industries.

After harvesting, the aerial parts (mainly leaves and flowers) are shade-dried to preserve the active constituents. The dried material is powdered and subjected to solvent extraction. Traditionally, non-polar solvents such as hexane, petroleum ether, or dichloromethane are used to extract artemisinin, as it is poorly soluble in water. The extract is filtered and concentrated under reduced pressure to remove the solvent, resulting in a crude oleoresin containing artemisinin along with other sesquiterpenes and waxes.

Purification involves recrystallization using solvents such as ethanol or acetone to obtain pure crystalline artemisinin. Advanced industrial facilities often use supercritical CO₂ extraction, which provides higher yield, purity, and environmental safety by avoiding toxic solvents. In recent years, semi-synthetic production of artemisinin has been developed to overcome the limitations of plant yield variability. This process involves biosynthesis of artemisinic acid through genetically engineered yeast (Saccharomyces cerevisiae) using fermentation technology, followed by chemical conversion of artemisinic acid into artemisinin. This biotechnological approach ensures consistent supply and reduces dependency on agricultural factors, making large-scale production more efficient and sustainable.

Estimation of Artemisinin
Quantitative estimation of artemisinin is a critical step in ensuring quality control of raw material and finished pharmaceutical products. Among the available methods, High-Performance Liquid Chromatography (HPLC) is the most accurate and widely employed technique. In HPLC analysis, a reverse-phase C18 column is used with a mobile phase consisting of methanol and water or acetonitrile, and detection is typically carried out at around 210–254 nm using a UV detector. The concentration of artemisinin is calculated by comparing the sample peak area with that of a standard artemisinin reference solution.

Other analytical methods include Thin Layer Chromatography (TLC) for qualitative identification and spectrophotometric methods for approximate estimation. TLC uses silica gel plates and solvents such as toluene and ethyl acetate, with detection achieved by spraying with vanillin–sulfuric acid reagent to visualize the spots. Gas Chromatography (GC) and LC-MS (Liquid Chromatography–Mass Spectrometry) are advanced methods used for research and high-precision analysis, offering high sensitivity and the ability to detect artemisinin and its derivatives even in complex matrices. Nuclear Magnetic Resonance (NMR) spectroscopy is used for structural elucidation and purity confirmation during industrial production and formulation development.

Utilization of Artemisinin
Artemisinin and its derivatives (such as artesunate, artemether, and dihydroartemisinin) are highly valued for their potent antimalarial properties. They act rapidly against Plasmodium falciparum, the parasite responsible for the most severe forms of malaria, including those resistant to other antimalarial drugs. The mechanism of action involves cleavage of the endoperoxide bridge in artemisinin by ferrous iron in the parasite’s digestive vacuole, generating free radicals that damage parasite proteins and membranes, ultimately leading to cell death.

Due to its short half-life, artemisinin is rarely used alone; instead, it is formulated in Artemisinin-based Combination Therapies (ACTs) such as artemether-lumefantrine, artesunate-mefloquine, and dihydroartemisinin-piperaquine. These combinations enhance efficacy, reduce the risk of resistance, and provide sustained therapeutic action. ACTs are recommended by the World Health Organization (WHO) as the first-line treatment for uncomplicated malaria worldwide.

Beyond malaria, artemisinin and its derivatives have shown promise in several other therapeutic areas. Research has revealed potential anticancer, antiviral, and anti-inflammatory properties due to their ability to induce oxidative stress and modulate cell signaling pathways. Artemisinin has been investigated for use in treating schistosomiasis, leishmaniasis, and certain viral infections. Moreover, it is being explored in the field of pharmacognosy and biotechnology as a lead compound for developing new drugs with improved pharmacokinetic profiles.

In industrial applications, artemisinin serves as a precursor molecule for the synthesis of more stable and water-soluble derivatives such as artesunate and artemether, which are formulated into tablets, injections, and suppositories. Standardization and quality assurance of artemisinin content are mandatory for all formulations under global pharmacopeial standards (IP, BP, USP).

 

Point Recap:-

Artemisinin – Industrial Production, Estimation, and Utilization

Introduction

Artemisinin is a sesquiterpene lactone containing a peroxide bridge, isolated from the leaves of Artemisia annua (commonly known as Sweet Wormwood). It is the active principle responsible for the potent antimalarial activity of the plant.
It is particularly effective against Plasmodium falciparum, including strains resistant to other antimalarial drugs such as chloroquine.

Artemisinin and its derivatives (artemether, artesunate, dihydroartemisinin) are the cornerstone of modern antimalarial therapy, forming the basis of Artemisinin-based Combination Therapies (ACTs) recommended by the World Health Organization (WHO).

1. Industrial Production of Artemisinin

The industrial production of artemisinin involves plant cultivation, extraction, and semi-synthetic production methods. Due to the low natural content in the plant, modern techniques have been developed to increase yield and sustainability.

a) Cultivation of Artemisia annua

• Botanical Source: Artemisia annua L. (Family: Asteraceae)
• Common Name: Sweet Wormwood, Qinghao (Chinese)
• Native Regions: China, Vietnam, India, and East Africa.
• Climate: Temperate to subtropical; prefers well-drained loamy soil with good sunlight.
• Propagation:
• Usually done by seed sowing or tissue culture.
• Seedlings are transplanted after 6–8 weeks.
• Harvesting:
• Leaves are harvested at flowering stage (after 5–6 months), when artemisinin content is highest.
• Dried in shade at 40–45°C to avoid decomposition of active constituents.

b) Extraction of Artemisinin

Artemisinin is present in very small quantities (0.01–1% w/w) in the dried leaves of the plant, so efficient extraction and purification are crucial.

1. Solvent Extraction Process

• Dried leaf powder is extracted using non-polar organic solvents such as hexane, petroleum ether, or toluene.
• Extract is filtered and concentrated under reduced pressure.
• The crude extract is purified by recrystallization or column chromatography using silica gel.

2. Supercritical CO₂ Extraction

• A modern, eco-friendly method that uses CO₂ under high pressure and temperature to extract artemisinin.
• Advantages: No toxic solvent residues, higher selectivity, and improved purity.

3. Chemical Purification

• Crude artemisinin is purified using solvents like ethanol, acetone, or ethyl acetate.
• Recrystallization yields pure crystalline artemisinin (white needle-like crystals).

4. Industrial Yield Optimization

• Biotechnological methods are used to increase yield:
• Genetic engineering of A. annua to increase biosynthesis of artemisinin.
• Hairy root cultures using Agrobacterium rhizogenes.
• Synthetic biology: Production using genetically modified yeast (Saccharomyces cerevisiae) — known as semi-synthetic artemisinin production developed by Sanofi and PATH (funded by the Gates Foundation).

c) Semi-Synthetic Production

To overcome limited natural availability, semi-synthetic artemisinin (SSA) is produced industrially.

Process:

1. Biosynthesis of artemisinic acid in genetically engineered yeast.
2. Oxidation and photo-chemical conversion of artemisinic acid to artemisinin.
3. Purification by crystallization and filtration.

Advantages:

• Stable and scalable supply.
• Consistent quality independent of agricultural variation.
• Lower production cost over time.

d) Standardization and Quality Control

• Crude extracts or formulations are standardized for artemisinin content (≥98%) using HPLC or UV methods.
• Quality control ensures purity, potency, and absence of residual solvents.

2. Estimation of Artemisinin

Quantitative analysis of artemisinin is essential for standardization, dosage accuracy, and quality assurance in pharmaceuticals.

a) High-Performance Liquid Chromatography (HPLC)

• Most accurate and commonly used method.
• Column: Reverse-phase C18.
• Mobile phase: Acetonitrile : water (typically 60:40 or 70:30).
• Detection wavelength: 210–260 nm.
• Retention time: 4–7 minutes depending on conditions.
• Application: Used for both crude extracts and finished dosage forms.

b) Thin Layer Chromatography (TLC)

• Used for qualitative identification.
• Mobile phase: Hexane : ethyl acetate (1:1 or 3:2).
• Spots visualized under UV light or by spraying with vanillin-sulfuric acid reagent (orange-yellow color indicates artemisinin).

c) UV–Visible Spectrophotometry

• Based on reaction of artemisinin with sodium hydroxide, forming chromophore measurable at λmax ≈ 254 nm.
• Used for routine analysis where HPLC is not available.

d) LC–MS / GC–MS

• Highly sensitive methods for detecting artemisinin and its metabolites in biological samples.
• Used in pharmacokinetic and bioavailability studies.

3. Utilization of Artemisinin

Artemisinin and its derivatives have wide applications in medicine, pharmaceuticals, and research.

a) Pharmaceutical Uses

1. Antimalarial Action

• The peroxide bridge in artemisinin is essential for its activity.
• Inside malaria-infected erythrocytes, artemisinin reacts with iron (from heme), generating free radicals that damage the parasite.
• Effective against multi-drug resistant Plasmodium falciparum.

2. Artemisinin-Based Combination Therapies (ACTs)

To prevent resistance, artemisinin is used in combination with other antimalarial drugs, e.g.:

• Artemether + Lumefantrine
• Artesunate + Amodiaquine
• Dihydroartemisinin + Piperaquine
• Artesunate + Mefloquine

3. Other Potential Medical Uses

• Antiviral: Shows inhibitory effects against certain viruses (e.g., hepatitis B, SARS-CoV-2 in early research).
• Anticancer: Induces apoptosis in cancer cells by generating reactive oxygen species.
• Anti-inflammatory: Suppresses inflammatory cytokines.

b) Veterinary Uses

• Used for treatment of parasitic infections in animals, especially in poultry and livestock.

c) Research Applications

• Used as a biochemical tool to study free-radical generation and parasite metabolism.
• Helps in developing new antimalarial analogs and drug delivery systems.

d) Industrial and Economic Importance

• Global demand driven by WHO’s malaria control programs.
• Major producers: China, Vietnam, India, and East Africa (especially Kenya, Tanzania).
• Leading pharmaceutical manufacturers: Sanofi, Novartis, Guilin Pharma.
• Semi-synthetic production has reduced dependence on agriculture.

4. Safety and Toxicity

• Therapeutic dose: Usually 2–4 mg/kg/day (depending on formulation).
• Adverse effects: Nausea, dizziness, mild headache; very safe compared to older antimalarials.
• Overdose toxicity: Rare but may cause cardiac or neurotoxic effects in animals.
• Contraindications: Pregnancy (early trimester), hypersensitivity.
• Drug interactions: Avoid with drugs affecting CYP450 enzymes.

 

Recap Table

Parameter	Details
Source	Artemisia annua (Sweet Wormwood)
Family	Asteraceae
Active Compound	Artemisinin (Sesquiterpene lactone with peroxide bridge)
Extraction Solvent	Hexane, petroleum ether, supercritical CO₂
Estimation Methods	HPLC, TLC, UV, LC–MS
Main Uses	Antimalarial, antiviral, anticancer, anti-inflammatory
Formulations	ACTs (Artemether-Lumefantrine, Artesunate-Amodiaquine, etc.)
Producing Countries	China, India, Vietnam, Kenya
Standardization	≥98% purity
Toxicity	Low; mild GI or CNS effects