Coleus qualification is easier than most in this category, because a clean HPLC assay does a lot of the work for you. That frees your attention for the two things the assay cannot cover: whether the material is genuinely root, and whether the supplier can actually keep supplying it — because coleus is a single-origin, destructively harvested crop and supply security is a real question rather than a formality.
Three Disqualifying Red Flags
- Will not provide a root-only declaration on every batch. Forskolin is confined to the tuberous root and aerial material is free at harvest. A supplier unwilling to make a written representation about the plant part is telling you something.
- Assay by anything other than HPLC against a reference standard. Forskolin is a single defined compound with an available standard — there is no excuse for a non-chromatographic method here, and no method-ambiguity defence.
- Reports "residual solvents: complies" without naming them. Higher-assay grades commonly involve non-polar solvent steps, and hexane carries a far tighter limit than ethanol. A supplier who will not itemise is hiding either ignorance or a number.
The two-question filter: "Will the batch CoA carry a root-only declaration, and will you report residual solvents individually by name?" Neither costs a competent manufacturer anything. Both are routinely absent from certificates in this market, which makes them efficient sorting questions.
The Scoring Framework
Weighted to 100 points. Note that supply security carries more weight here (20 points) than on any other ingredient in this range — a deliberate reflection of coleus being a single-origin, destructively harvested crop.
1. Raw Material and Part Verification — 25 points
| Criterion | Points |
|---|---|
| Root-only declaration on every batch CoA | 9 |
| Species declared by binomial (Plectranthus barbatus) | 6 |
| TLC identity against authentic reference material | 5 |
| Acid-insoluble ash limited at NMT 2% — catches soil from a tuber crop | 3 |
| Cultivation origin and harvest period stated | 2 |
2. Assay and Authenticity — 25 points
| Criterion | Points |
|---|---|
| Forskolin by HPLC against reference standard, dry basis | 10 |
| Related diterpene profile (isoforskolin, deacetylforskolin) available | 8 |
| Batch-specific CoA, not a generic specification sheet | 4 |
| Carriers declared by name and percentage | 3 |
The diterpene profile is the one test the assay does not replace. It is the sole defence against forskolin isolate spiking, as covered in adulteration and authenticity.
3. Processing Transparency — 15 points
| Criterion | Points |
|---|---|
| Residual solvents reported individually by name | 7 |
| Hexane against its own limit where non-polar steps are used | 5 |
| Can describe the concentration process for higher-assay grades | 3 |
4. Supply Security — 20 points
| Criterion | Points |
|---|---|
| Direct relationship with cultivation base, not spot-market buying | 7 |
| Willing to contract ahead of harvest for committed volume | 6 |
| Can state harvest calendar and realistic lead times against it | 4 |
| Transparent about availability constraints rather than over-promising | 3 |
This section deserves its unusual weight. Coleus is harvested destructively — the plant is lifted to obtain the tuber — essentially all supply originates in India, and sustained demand has pressured the cultivation base. A supplier buying on the spot market will be the first to fail you when availability tightens, and you will discover it mid-programme.
The last row is a real signal. A supplier who volunteers that supply is constrained is more useful than one who promises unlimited availability on a crop that plainly cannot deliver it.
5. Compliance and Commercial Terms — 15 points
| Criterion | Points |
|---|---|
| Heavy metals by ICP-MS with numeric per-element limits | 4 |
| Full USP microbiological panel including pathogens | 3 |
| EU pesticide MRL screening and non-ETO declaration | 3 |
| Incoterms and written payment terms properly quoted | 3 |
| Technical questions answered by someone who understands the chemistry | 2 |
Interpreting the Score
| Score | Reading |
|---|---|
| 85–100 | Qualified for bulk supply. Proceed to sample and pre-shipment verification. |
| 70–84 | Workable with conditions. Close the gaps in writing before first bulk order. |
| 55–69 | Trial quantities only, with independent verification on every lot. |
| Below 55 | Not a supplier for a regulated market. |
Apply a floor on section 4: below 10 of 20, treat as a spot-market source regardless of technical score. Excellent material you cannot obtain reliably is a programme risk, not a supply arrangement — and on this crop that distinction is more than theoretical.
The 40% Grade Conversation
If you are considering the 40% grade, add these questions:
- How do they classify it — extract or purified compound?
- What description do they recommend for a finished-product label?
- What solvents are used to reach that concentration, and at what residual levels?
- Do they warn you about dispersibility? A supplier who mentions unprompted that the 40% disperses worse than the 10% understands their product properly.
The Sample Stage
- Check the sample CoA carries the root-only declaration. Absent there, absent on bulk.
- Ask for the chromatogram, not just the number. You want to see the supporting diterpenes alongside forskolin, not a lone peak.
- Test dispersibility yourself if your format needs it — and test the actual grade you intend to buy, not a lower one.
- Check colour against grade. Lower-assay grades are brown; the 40% is markedly paler. A "40%" sample that looks like a 10% deserves a question.
- Did they ask about your volume and timing? On a harvest-constrained crop, a supplier who does not ask about your annual requirement is not planning to supply it.
First-Order Protocol
- Nominate an independent laboratory — Eurofins, SGS or Intertek — for pre-shipment sampling, with forskolin assay and the diterpene profile in scope.
- Take an assay discrepancy seriously. Unlike the class-assay botanicals, there is no method ambiguity to explain it away — a real divergence here is a real finding.
- Verify residual solvents independently on higher-assay grades.
- Retain a sealed, dated sample for the shelf life of the material.
- Discuss next season's volume at first order, not when you run out. On a destructively harvested single-origin crop, forward commitment is the whole supply strategy.
SV Botanica supplies root-only coleus forskohlii extract from India — the world's origin for this crop — with species declared, forskolin by HPLC against a reference standard, the related diterpene profile on request, and residual solvents reported individually. Buyer-nominated third-party pre-shipment testing is welcome. See the product page, the buyer's guide, or adulteration and authenticity.
Source Coleus Forskohlii Extract from India
Forskolin by HPLC at 10%, 20% or 40% · root-only, species declared · direct from the world's origin for this crop · CoA-backed · samples for qualified buyers