Abrus precatorius L. (Gunja): Therapeutic Potential of Leaves in Respiratory Disorders – Distinguishing Phytotherapy from Seed Toxicity

Abstract

Respiratory disorders including asthma, chronic bronchitis, and COPD constitute a growing global health burden, prompting exploration of Ayurvedic remedies like Abrus precatorius L. (Gunja), an Upavisha distinguished by abrin-toxic seeds yet therapeutically promising leaves and roots. This review synthesizes ethnobotanical, phytochemical, pharmacological, and toxicological evidence for their respiratory applications. Traditional uses leaf decoctions (Kwatha, 10-20 mL b.i.d.) as Kaphahara expectorants and root pastes with ginger (Shunthi) for Shwasa (asthma) and Kasa (cough) span Ayurvedic texts (Charaka Samhita), Siddha medicine, and global ethnomedicine (India, Africa, Bangladesh), consistently avoiding seeds via detoxification. Phytochemically, leaves harbor flavonoids (apigenin, quercetin: 0.5-4.2%), triterpenoids (β-amyrin, lupeol: 1.2-3.4%), and saponins enabling anti-inflammatory/ bronchodilatory effects. Ethanol leaf extract (EAPL) validates this via carrageenan edema inhibition (~60% at 150 mg/kg vs. indomethacin), histamine-induced bronchospasm prophylaxis (42-47% PCD extension vs. salbutamol 79%), and goat tracheal relaxation (60% at 25 μg/mL), implicating H1-blockade, β2-stimulation, mast cell stabilization (60-70% histamine reduction), and NF-κB/COX-2 suppression. Leaves prove safe (LD50 >2000 mg/kg, OECD 423) unlike seeds (abrin LD50 0.2-20 μg/kg). Bridging Visha-to-Amrita, A. precatorius leaves emerge as phytopharmaceutical candidates warranting clinical trials, standardization, and allergen-challenge validation for asthma /COPD adjunct therapy.

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