Al-Khayri et al. 2023 — Cadmium stress and tolerance in plants, including medicinal herbs
This comprehensive review covers cadmium (Cd) toxicity mechanisms in plants, with direct relevance to food and medicinal herb safety through cited surveillance data. The authors report that 14–16 percent of Menthae piperitae (peppermint) and Anthodium chamomillae (chamomile) samples exceeded the WHO maximum permissible limit of 10 mg/kg (10,000 ppb) Cd in medicinal plant material, establishing real-world exceedance risk in herbal ingredients. The review also covers Cd tolerance mechanisms including phytochelatin synthesis, vacuolar sequestration, antioxidant responses, and the role of root exudates in Cd speciation and uptake.
Key numbers
- WHO maximum permissible limit for Cd in medicinal plants: 10 mg/kg (10,000 ppb)
- Peppermint (Menthae piperitae) Cd exceedance rate: 14–16% of surveyed samples
- Chamomile (Anthodium chamomillae) Cd exceedance rate: 14–16% of surveyed samples
- Cd uptake strongly driven by soil pH, organic matter, and cation exchange capacity
- Phytochelatin production begins at Cd concentrations as low as 0.1–1 µM in sensitive species
Methods (brief)
Narrative review of primary literature on Cd in plants. Exceedance data cited from prior surveillance studies on medicinal herbs. Analytical methods in cited studies vary; total Cd assumed. No original analytical data generated in this paper.
Implications
Certification: Establishes Cd exceedance risk in commonly used herbal ingredients (peppermint, chamomile); relevant to supplement and herbal product certification categories. Courses: Demonstrates that herbal ingredients face Cd contamination comparable to or exceeding staple food crops. App: Supports Cd risk flagging for herbal ingredient categories in supplement products.