A total is not an individual compound
Total alkaloids describes a combined measurement under a particular analytical method. Mesembrine is an individual alkaloid. A result for mesembrine as a percentage of the alkaloid fraction is different from its percentage by mass in the supplied powder. Other identified alkaloids should also be considered where reported; the named profile provides more context than total alkaloids alone.
Ask for the measurement basis
Request the method, units, sample preparation and reporting basis. Confirm whether the result concerns the extract, the carrier-containing powder or a liquid. Water content and dry-basis reporting can also affect comparisons.
Use the whole specification
Compare actual mesembrine and other identified alkaloid results where available, carrier composition, physical form, residual solvents and intended application. A high headline percentage is not by itself a complete purchasing specification or proof of suitability for a finished product.