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← The ApothecaryBignoniaceaeroot bark, stem bark, young fruits, shoots, seedsFact-checked 24 October 2026

Indian trumpet tree

Oroxylum indicum

Also calledShyonaka (Sanskrit)

A South and Southeast Asian tree whose root bark, shyonaka, is one of the ten roots of the Ayurvedic Dashamoola formula used for joint and nerve disorders; its bitter young pods are eaten as a vegetable in Thailand, Laos and Malaysia. One 12-week placebo-controlled trial of a standardised extract found modest memory gains in older adults; the rest of the evidence is laboratory and animal work.

What it is used for

  • In a randomised double-blind trial of 82 adults with self-reported cognitive complaints, 500 mg twice daily of a standardised extract for 12 weeks improved episodic memory and some computer-based tasks (word recall, working memory) more than placebo, but not the MoCA score or questionnaires. It is the only controlled human trial so far.1,2

  • Used for liver complaints and jaundice; extracts were hepatoprotective in animal studies, but direct evidence for jaundice or hepatitis is lacking.2

  • Shyonaka is used alone for ama vata (roughly, rheumatoid arthritis) and inflammation, and as part of Dashamoola for nerve, muscle, bone and joint disorders. Anti-inflammatory effects are shown only in laboratory and animal studies.3,2

  • Diarrhoea
    Traditional

    Stems and roots are decocted for diarrhoea, and a 2025 systematic review judged gastrointestinal uses to have reasonable laboratory support, without clinical trials.2

  • Stem and root decoctions are used for asthma, bronchitis and other respiratory problems; laboratory work supports anti-allergic activity but there are no human studies.2

  • Cough
    Traditional

    Documented in Thai traditional medicine for cough, fever and fatigue through practitioner interviews. Untested clinically.2

How it is prepared

decoction

Root bark boiled in water, usually with the other nine Dashamoola roots, as a kwatha (decoction) in Ayurvedic practice.

Arthritis and joint pain

dry extract / capsule

Standardised extract capsules, as used in the cognition trial.

Lopresti et al. 2021 (trial dose): 500 mg standardised extract twice daily for 12 weeks.

Memory and cognition

food

Young pods and shoots roasted or cooked as a bitter vegetable in Thailand, Laos and north-east India.

Amounts are as recorded by the named source, not a recommendation.

Safety

Pregnancy
Insufficient data
Breastfeeding
Insufficient data

Side effects

  • Mild digestive complaints and headaches were somewhat more common than with placebo in the 12-week trial

Toxicity

In rats, 28 days of stem-bark extract at 250 mg/kg/day and a single 2,000 mg/kg dose of bark extract caused no toxicity. Long-term, reproductive and developmental safety has not been studied, and safety at dietary levels has not been confirmed.

In the healing traditions

  • Ayurveda

    Shyonaka

    Root bark described as bitter and astringent in taste, light and dry, hot in potency and pungent after digestion. One of the ten roots of Dashamoola, given as Dashamoolarishta, Dashamoola churna, ghrita, kwatha and oil for nerve, muscle, bone and joint disorders; used alone for ama vata and swelling.

  • Southeast Asian (Jamu, Thai, Philippine…)

    Oroxylum indicum (Thai traditional medicine)

    Used for cough, fever and fatigue; young fruits and shoots roasted and eaten as vegetables in Thailand and Laos, and leaves and young fruits eaten raw as ulam in Malaysia.

Active compounds

baicalein, baicalin
major flavones; baicalein linked to liver and neuroprotection in laboratory studies, and both activate the human bitter-taste receptor TAS2R14
oroxylin A, oroxin A, oroxin B
characteristic flavonoids of the plant
chrysin
flavone isolated from the bark; activates p53-driven apoptosis in cancer cells in the laboratory

History

Shyonaka is one of the 'ten roots' that make up Dashamoola, a widely used Ayurvedic formulation. Its pods have also long been eaten as food in Southeast Asia. In 2021 Lopresti and colleagues ran the first human trial of the plant, testing a standardised extract for memory in older adults.

Sources

  1. 1.Lopresti AL et al. Effects of an Oroxylum indicum extract (Sabroxy) on cognitive function in adults with self-reported mild cognitive impairment: a randomized, double-blind, placebo-controlled study. Front Aging Neurosci 2021 (abstract)
  2. 2.Nguyen HL et al. A systematic review of evidence-based health benefits of Oroxylum indicum and its functional food potential. Foods 2025
  3. 3.Menon S et al. Oroxylum indicum root bark extract prevents doxorubicin-induced cardiac damage by restoring redox balance. J Ayurveda Integr Med 2019
  4. 4.GBIF Backbone Taxonomy: Oroxylum indicum (L.) Kurz (with IUCN category)

Reference, not prescription. Nothing here is medical advice. Herbs can interact with medicines and be dangerous in pregnancy; tell your doctor or pharmacist about anything you take.