Dendrobium nobile

Dendrobium nobile is a perennial orchid native to Southeast Asia. Its dried stems, commonly called “Shi‑Hu” in traditional Chinese medicine, are used as a dietary supplement. The primary purpose of supplementation is to harness its bioactive phytochemicals—particularly polysaccharides, alkaloids, and phenolic compounds—to support metabolic, immune, and neuro‑protective health pathways.

Dendrobium nobile contains a complex mixture of phytochemicals; the most studied constituents are:

• Polysaccharides: e.g., Dendro‑polysaccharide (C₁₈₀H₃₂₀O₁₈₀; MW ≈ 30–50 kDa).
• Alkaloids: Dendrocin (C₁₈H₂₈N₂O₅; IUPAC: 2‑[(2‑hydroxy‑5‑methoxy‑phenyl)‑1‑(2‑hydroxy‑ethyl)‑pyrrolidine‑3‑yl]‑2‑oxo‑ethyl‑N‑methyl‑amino‑acetate).

• Phenolics: Dendro‑quinone (C₂₁H₂₄O₇; IUPAC: 3‑hydroxy‑5‑methoxy‑2‑phenyl‑1,4‑naphthoquinone).

• Key structural features: Include multiple hydroxyl groups that confer high solubility and antioxidant capacity, as well as a quinone‑type aromatic ring responsible for cholinesterase inhibition.

• Polysaccharide backbone: Primarily β‑(1→3)‑glucan with branching at β‑(1→6) linkages, critical for immune‑modulating activity.

D. nobile is cultivated primarily in China (Yunnan, Sichuan) and Vietnam, where wild populations are protected under CITES.

• Source material: Commercial supplements are derived from the dried stems, harvested after 3–5 years of growth to maximize polysaccharide content.
• Extraction: Typically uses hot water or ethanol‑water (70 % v/v) to yield a polysaccharide‑rich extract, followed by spray‑drying into a powdered form.
• Quality control: Good Manufacturing Practice (GMP)‑certified facilities employ high‑performance liquid chromatography (HPLC) and gel‑permeation chromatography to standardise polysaccharide content (≥30 % w/w) and verify absence of heavy metals (<10 ppm Pb, As, Cd).
• Authenticity: Confirmed by DNA barcoding of the plant material.
• Quality assurance: Assured by third‑party testing for contaminants and consistent phytochemical profiles.