Description

Amaranthus spinosus, commonly known as spiny amaranth, is an erect, annual herbaceous plant that can grow up to 1.5 meters tall. It belongs to the Amaranthaceae family. Its most distinguishing feature is the presence of a pair of sharp, slender spines (up to 1 cm long) at the base of the leaf stalks (petioles). These spines are a key identifier and a defense mechanism against grazing animals. The leaves are simple, alternate, and ovate to rhombic-ovate in shape with a notched tip. They are green, sometimes with a reddish tinge. The plant produces dense clusters of small, greenish flowers arranged in long, terminal spikes or in axillary clusters. The seeds are tiny, glossy, and black or dark brown. It is a highly adaptable weed found in cultivated fields, gardens, waste places, and along roadsides. It thrives in disturbed soils, roadsides, farmlands, and waste places across Nigeria and other tropical regions, often considered both a weed and a valuable medicinal plant.

Other Names

  • English: Spiny amaranth, Thorny amaranth, Pigweed, Spiny pigweed.
  • Yoruba: Tẹ̀tè ọ̀gún, Tẹ̀tè elegun
  • Igbo: Atama, Ugu oyibo, Inine
  • Hausa: Alayyafu, Gazar masallachi
  • Edo: Efẹ́rẹ́

Health Benefits

Amaranthus spinosus is not just a weed but a highly nutritious plant with a long history of use in traditional medicine.

  • Rich in Nutrients: The leaves are an excellent source of vitamins (A, B, C, and K), minerals (iron, calcium, magnesium, potassium), and dietary fiber. This makes it a potent remedy for combating malnutrition and anemia.
  • Antioxidant Properties: The plant is rich in antioxidants like betalains, flavonoids, and phenolic acids, which help protect the body from oxidative stress and chronic diseases.
  • Galactagogue: It is traditionally consumed by nursing mothers to stimulate and increase breast milk production.
  • Anti-inflammatory and Analgesic: Extracts from the plant are used to reduce inflammation and relieve pain associated with conditions like arthritis, headaches, and wounds. Ethanolic extracts reduce carrageenan-induced paw edema and cotton pellet granuloma, comparable to indomethacin.
  • Fever Reduction (Antipyretic): A decoction of the root or whole plant is used to treat fevers, including those from malaria.
  • Gastrointestinal Health: It is used to treat digestive issues like diarrhea, dysentery, and constipation due to its fiber content and antimicrobial properties. The root is specifically used as a laxative.
  • Diuretic: The plant helps promote urine production, aiding in the treatment of urinary tract infections and kidney stones.
  • Diabetes Management: Some studies suggest it may help in lowering blood sugar levels. Leaf extracts lower blood glucose, improve insulin sensitivity, and regenerate pancreatic β-cells in streptozotocin-induced diabetic rats.
  • Antimicrobial: Active against bacteria (e.g., Escherichia coli, Staphylococcus aureus) and fungi (e.g., Candida albicans); root extracts effective against Vibrio cholerae.
  • Hepatoprotective: Aqueous extracts protect against paracetamol-induced liver damage, normalizing ALT/AST levels.
  • Anticancer: Cytotoxic against breast (MCF-7) and colon (HCT-116) cancer cell lines via apoptosis induction.
  • Wound healing: Fresh leaves are applied to cuts and sores to promote recovery.
  • Anthelmintic: Seeds and leaves paralyze and expel worms like Pheretima posthuma.
  • Laxative: Promotes bowel movement.
  • Blood tonic: Rich in iron, helps manage anemia and general weakness.

Other Benefits

  • Food Source: Leaves and seeds are edible, high in protein (up to 25% in seeds), vitamins (A, C), minerals (iron, calcium), and fiber. The young leaves and tender stems are cooked as a nutritious leafy vegetable, similar to spinach. They are used in soups and stews like efo riro (Yoruba) or edikang ikong (Efik).
  • Fodder: Despite the spines, the plant is used as animal feed, especially for pigs (hence the name “pigweed”), rabbits, and cattle when harvested young.
  • Soil Indicator: Its presence can indicate fertile, nitrogen-rich soil.
  • Ecological: Improves soil fertility as a nitrogen-fixing companion plant; supports pollinators and wildlife forage.
  • Agricultural: Potential as green manure or cover crop; fodder for livestock when young (though spines deter grazing).
  • Cultural uses: In some communities, it is used in cleansing rituals and as part of protective charms.
  • Ornamental: Planted for hedges due to spiny branches.

How It is Used

  • As Food: The young, spineless leaves and shoots are harvested, washed, and cooked as a pot herb. The spines are typically removed from older plants before cooking.
  • As Medicine:
    • Decoction/Tea: The roots, leaves, or entire plant are boiled in water. The liquid is strained and drunk to treat fever, diarrhea, or to act as a diuretic.
    • Leaf decoction: Decoctions or aqueous extracts (200–400 mg/kg) orally for diabetes, inflammation, fever, and liver issues.
    • Leaf Poultice: The leaves are crushed into a paste and applied topically to wounds, boils, inflamed joints, or snake bites to reduce pain and inflammation.
    • Root Poultice: The root paste is applied topically for boils, eczema, or eye lotions; extracts for antimicrobial and anthelmintic use.
    • Powder: The Powdered for laxative, antifertility, or anthelmintic treatments; ground into flour for porridge.
    • Juice: The fresh leaves can be pounded and the juice extracted for a concentrated dose of nutrients.

Side Effects / Caution

Amaranthus spinosus is generally safe, with LD50 >5000 mg/kg in acute toxicity studies; no significant adverse effects in subchronic trials up to 1000 mg/kg.

  • Oxalates: Like spinach and other leafy greens, Amaranthus spinosus contains oxalates. Consuming very large quantities raw may contribute to kidney stone formation in susceptible individuals. Cooking significantly reduces the oxalate content.
  • Nitrate Accumulation: The plant can accumulate nitrates from the soil if grown with excessive nitrogen fertilizer. High nitrate levels can be harmful, but this is generally a concern only with contaminated plants.
  • Spines: The sharp spines can cause physical injury during harvesting. Care must be taken to handle the plant properly, especially the older, mature specimens.
  • Pesticide Contamination: As a common weed, it may be sprayed with herbicides. Only harvest plants from areas known to be free of chemical contamination.
  • Pregnancy: While often used as a vegetable, the medicinal use (especially of the root) during pregnancy should be avoided unless under guidance, as high doses may stimulate uterine muscles. 
  • Drug interactions: May interfere with Antidiabetic, antimalarial or diuretic medications.

References (MLA Format)

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Kumar, R. S., et al. “In Vitro α-Amylase Inhibition and Antioxidative Activity of Amaranthus spinosus Leaf Extracts.” International Journal of Pharmacy and Pharmaceutical Sciences, vol. 5, no. 2, 2013, pp. 418-423.

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