A family is not one molecule
Polyphenols describe a broad group of plant constituents. Catechins are a more specific group encountered in tea and other materials. The analytical question must be clear: a total-polyphenol result and an individual catechin result do not describe the same composition. Keep the identity of the tested preparation attached to the result rather than using the plant name alone.
Compare methods before numbers
Colour-based group assays and chromatographic methods can have different selectivity and reference conventions. Ask the laboratory which compounds the result represents and how the calibration was established. Do not silently translate a group assay into a sum of individually measured molecules, or interpret antioxidant activity in a test system as a demonstrated human outcome.
Apply the information to formulation
For a tea-extract project, pair the marker profile with the intended caffeine specification, sensory needs and physical-stability plan. Check behaviour in the actual beverage or other matrix and retain a representative sample for comparison. The linked green-tea supply page and existing beverage buyer guide are procurement starting points, not confirmation of a current batch or clinical claim.
Analytical brief
Name the individual compounds or group result required in the test request and retain the method reference.