Secondary Metabolite Diversity
VC-MET-212 — the Shannon diversity of detected secondary metabolites — a fingerprint of cultivar chemical complexity.
Definition
Secondary Metabolite Diversity is the Shannon index (H′) computed over the relative abundances of resolved secondary-metabolite peaks in a lot's chromatographic profile, summarizing how chemically varied the extract is.
Why it matters
Diversity is a stability and authenticity signal: a collapsing H′ often precedes a potency or quality problem and can indicate cultivar drift, contamination, or a stressed cultivation cycle before single-compound assays move.
Formula
H' = − Σ p_i · ln(p_i)
p_i = relative abundance of metabolite peak i
(peak area / total resolved area)
Computed over the top-N resolved peaks (N ≥ 20) above a
0.5 % area threshold; reported per batch.
Inputs
| Input | Detail | Source |
|---|---|---|
| Peak table | Resolved metabolite areas | Lab HPLC |
| Abundance p_i | Area fraction per peak | CHLORA |
| Reference H′ | Cultivar baseline | CHLORA |
Units & Scale
Dimensionless Shannon units (H′), two decimals. Compared against the cultivar's registered baseline; not pooled across cultivars.
Sampling & Source
- Computed per batch from the resolved peak table.
- Peaks below 0.5 % total area excluded.
- Trended against cultivar baseline for drift detection.
Thresholds
OK
WARN
CRIT
Recent Trend
Zone roll-up, last 14 sampling periods (current 2.21):
Interpretation Guidance
| Band | Reading | Likely Driver | Action |
|---|---|---|---|
| 2.3–2.6 | Rich profile | Healthy cultivar | Reference profile. |
| 1.8–2.29 | Nominal | Normal variation | None. |
| 1.4–1.79 | Narrowing | Stress or early drift | Compare to baseline; check VC-MET-200. |
| < 1.4 | WARN / CRIT | Drift or contamination | Hold; authenticity review. |
Related Metrics
Alkaloid Concentration
Single-compound potency.
VC-MET-217Extraction Purity
Profile cleanliness.
VC-MET-216Phytotoxicity Index
Bioactivity correlate.
VC-MET-001Canopy Vitality Index
Cultivation health.
Related SOPs
- Authenticity & contamination review — SOP Library.