Magenta Plant Leaves - Medicinal Herb and Safe Natural Food Coloring

Magenta Plant Leaves - Medicinal Herb and Safe Natural Food Coloring

Magenta plant.

Many synthetic dyes once widely used in food are now banned or restricted due to evidence linking them to cancer risks and adverse health effects. In this context, finding and using natural colorants such as magenta plant leaves (lá cẩm) is encouraged. Magenta leaves not only provide an appealing color to dishes but also ensure consumer safety.

Specialist Doctor II Huynh Tan Vu from the University Medical Center HCMC stated that in Vietnam, magenta leaves are one of the traditional ingredients commonly used to give a natural purple color to dishes such as sticky rice, bánh tét, taro cakes, steamed buns, and more. Beyond its appealing and stable color during storage, numerous studies have shown that magenta leaves are highly safe and contain bioactive compounds with noteworthy medicinal value.

Magenta plant (La cam), scientific name: Peristrophe bivalvis (L.) Merr. – Justicia bivalvis L.; Peristrophe roxburghiana (Schult.) Bremek. Plant family: Acanthaceae.

1. Botanical characteristics and distribution

The magenta plant is a perennial herbaceous plant widely used as a medicinal herb, food colorant, and hedge plant. It is primarily distributed in Southeast Asia, Southern China, and Taiwan. In Vietnam, it can be found in various localities such as Muong Khuong (Lao Cai), Moc Chau (Son La), Thai Nguyen, and more.

The plant thrives in moist soil, reaching a height of about 30–50 cm. Leaves are oppositely arranged, lanceolate to ovate, 4–9 cm long, 2–4 cm wide, with a slightly sweet taste. The flowers are purplish-pink with a distinctive two-lipped corolla. The plant produces ovoid capsules containing black seeds.

The magenta plant grows well in humus-rich, well-drained soil, high humidity, low temperatures, and low light conditions. Propagation is commonly done by stem cuttings in early spring.

In Vietnam, four types of magenta plant are recorded:

Magenta plant (red): Oval-shaped, dark green leaves, hairy, without white spots.
Magenta plant (purple): Large, thin, light green leaves with a prominent white patch along the leaf vein.
Magenta plant (bright red): Thick, dark green leaves with a few white spots.
Magenta plant (yellow): Leaves are usually wrinkled; grows wild, also known as wild magenta plant.

Currently, red magenta and purple magenta plants are the two varieties commonly grown for food and medicinal herbs.

2. Chemical composition and pharmacological effects of magenta plant leaves

Numerous studies show that extracts from magenta leaves (Peristrophe bivalvis) possess significant biological value:

- Antibacterial activity: Ethanolic extracts from the leaves and stems of magenta plant can inhibit food spoilage bacteria such as Bacillus subtilis, Staphylococcus aureus, Pseudomonas aeruginosa and Escherichia coli even at low concentrations.

- Antifungal activity: The methanolic extract demonstrated activity against Candida albicans.

- Anti-inflammatory: Many phytochemical compounds such as β-sitosterol, lupeol, oleanolic acid, and cyanidin have the ability to inhibit pro-inflammatory cytokines such as TNF-α, IL-1β, and IL-6.

- Antioxidant: Carotenoids and their derivatives help protect the retina and reduce the risk of age-related macular degeneration.

- Liver protection: Polysaccharides extracted from magenta leaves have been shown to inhibit enzymes that cause liver damage.

- Therapeutic potential: The compound Zizilan/Zilanine has been noted for its role in improving metabolic disorders, enhancing immunity, and applications in cosmetics and natural coloring. Ethanolic extract has been demonstrated to be more effective than aqueous extract in studies on anticancer activity.

3. Benefits of magenta leaves in traditional medicine

According to traditional medicine, magenta plant leaves (lá cẩm) have a bitter taste and neutral nature, with effects of clearing heat, stopping bleeding, reducing swelling, and detoxifying. This medicinal herb is used in treating acute bronchitis, coughing or vomiting blood, pulmonary tuberculosis, and dysentery, as well as sprains and bruises caused by trauma.

In folk practices, magenta leaves are also brewed as a decoction, powdered, or boiled into bathwater to support digestion and treat skin ailments. Magenta leaf water is often used to bathe young children suffering from heat rash and boils, or applied topically to relieve swelling, pain, and inflammation.

Specialist Doctor II Huynh Tan Vu noted that, according to traditional medicine in several regions of China, magenta plant leaves have long been used to support the treatment of hypertension. In addition, this herbal remedy is used for lung-heat cough, hemoptysis, swollen and red sore throat, mouth and tongue ulcers, painful urination, as well as soft-tissue injuries such as abscesses, boils, pain and swelling from trauma, falls, or external bleeding.

Traditional medicine records indicate that magenta plant leaves are also applied externally to treat venomous snake bites and may improve hematological conditions, helping to prevent blood clot formation in vessels.

4. Some traditional folk remedies from magenta plant leaves

- Bronchitis treatment: Use 40 g of magenta plant stems and leaves, along with 20 g each of platycodon root, dwarf lilyturf root, and mulberry root bark; decoct and drink to relieve phlegm and treat bronchitis.

- Acne treatment: 1 bundle of magenta plant leaves, 1.5 liters of clean water. Wash the leaves thoroughly with clean water, bring 1.5 liters of water to a boil, then reduce heat to simmer for about 10 minutes before turning off the stove. Once lukewarm, strain a sufficient amount to wash your face as normal without rinsing with plain water. Store the remaining liquid in the refrigerator for use over 3 to 4 days.

5. How to make natural food coloring from magenta leaves

Wash fresh magenta plant leaves thoroughly, remove the stems, gently crush or cut them into small pieces, and place them in a pot with an adequate amount of water. Boil for about 10–15 minutes until the water turns a deep purple, then strain out the leaves to obtain the extract. This magenta leaf extract is used to soak glutinous rice or knead dough for cakes, giving food a natural purple hue. When cooking, keep the heat moderate and avoid boiling for too long to maintain a vibrant, beautiful color without darkening.

Magenta plant leaves are not only a safe natural colorant for traditional Tet dishes but also a promising medicinal herb with various researched biological activities. However, using magenta plant leaves for therapeutic purposes requires professional medical advice to avoid unintended risks.