Triterpenes, TECA and How Centella Is Standardised

The Four Compounds

Centella's actives are pentacyclic triterpenes, and they come in two related pairs:

The glycosides carry sugar units; the acids are the sugar-free cores. Two consequences follow:

• Glycosides are heavier than their aglycones, so a given molar amount contributes more mass — relevant when reading percentages.
• Processing can shift the balance. Hydrolytic conditions convert glycosides to aglycones, so the split partly reflects manufacturing rather than the plant alone.

Why the Total Conceals

All four are quantified individually by HPLC against reference standards — a clean, specific, reproducible method, with none of the class-assay ambiguity affecting gymnemic acids or fenugreek saponins.

The total is then simply their sum. So:

What the concealment permits: material weighted almost entirely toward one member can meet a total, and cosmetic buyers building on madecassoside may receive very little of it.

TECA / TTFCA: Composition as the Specification

The pharmaceutical-heritage approach, and instructive because it solved this problem decades before the cosmetic boom created it.

TECA — titrated extract of Centella asiatica — specifies a defined ratio of asiaticoside to asiatic acid and madecassic acid, in set proportions, rather than a bare total. TTFCA (total triterpenic fraction of Centella asiatica) is used similarly.

Note the last row: a TECA claim cannot be verified from a total figure. If your registration references TECA, requiring the individual numbers is not optional — it is how the specification is checked at all.

Which Triterpene for Which Application

Stated with appropriate caution — these are market conventions and formulation practice rather than settled claims:

A buyer intending a specific claim should verify the evidence base for that claim rather than inheriting the convention — but for specification purposes the practical point stands: name the compound your formulation is built on.

Method Notes Worth Specifying

1. HPLC against reference standards for each of the four. Not a colourimetric total.
2. Dry basis stated.
3. Carrier declared and assay quoted carrier-free.
4. Individual figures on every batch, not qualification only — the pattern that caught buyers out on ginkgo applies here too.

The Heavy-Metal Dimension Is Part of Standardisation Here

Unusual to include in a standardisation article, but on centella the two are linked.

Centella is a wetland plant and an efficient accumulator of heavy metals from water and soil. That means the growing environment is a quality variable in a way it is not for a cultivated dryland crop — and it means a specification that controls triterpenes while ignoring provenance is only half a specification.

Require ICP-MS with numeric per-element limits, collection status declared, and prefer cultivated material where the environment is controlled.

Writing a Centella Specification That Holds

1. Name the species by binomial — Centella asiatica (L.) Urban. Never "brahmi", which is ambiguous between this and Bacopa monnieri.
2. State total triterpenes NLT X% by HPLC, dry basis.
3. Require all four individually reported, every batch.
4. Set a minimum on the specific triterpene your formulation needs — madecassoside for cica work.
5. If TECA applies, specify the ratio explicitly and require the figures to verify it.
6. Require ICP-MS heavy metals with numeric limits and collection status.
7. Require identity vs authentic reference to exclude Hydrocotyle.

When Two Laboratories Disagree

1. Same four compounds summed? Some totals include only two or three — the commonest cause of divergence.
2. Same basis — dry, carrier-free?
3. Do the individual figures agree even where totals differ? If so, the difference is in what was summed, not in the material.
4. Because each compound is HPLC against a reference standard, genuine divergence on an individual figure is a real finding rather than a method artefact.

SV Botanica reports asiaticoside, madecassoside, asiatic acid and madecassic acid individually on every centella batch, supplies TECA-ratio grades to specification, and tests heavy metals by ICP-MS. See the gotu kola extract product specification, or the buyer's guide.