Pharmacognostic specifications and quantification of (+)-catechin and (-)-epicatechin in Pentace burmanica stem bark

BACKGROUND: According to Thai traditional medicine, Pentace burmanica Kurz. stem bark has been used as crude drug for treating diarrhea. However, the crude drug is also found susceptible to adulteration. OBJECTIVES: To develop specific standardization parameters of P. burmanica stem bark in Thailand and to determine the (+)-catechin and (-)-epicatechin contents of P. burmanica stem bark by HPLC analysis. MATERIALS AND METHODS: P. burmanica stem barks from various sources throughout Thailand were investigated according to WHO guideline of the pharmacognostic specification. High performance liquid chromatography (HPLC) was performed for (+)-catechin and (-)-epicatechin quantification. RESULTS: Macroscopic evaluation was demonstrated as whole plant drawing. Microscopic evaluation of stem bark powdered drug showed fragment of fibers, resin masses, tannin masses, starch grain, calcium oxalate, and fragment of parenchyma. Physico-chemical parameters revealed that total ash, acid insoluble ash, loss on drying, and water content should be not more than 3.58, 0.50, 8.40, and 9.70% of dry weight respectively; while ethanol and water soluble extractive values should not be less than 21.90 and 19.06% of dry weight respectively. Both (+)-catechin and (-)-epicatechin were existed in P. burmanica ethanolic extract. Owing to the small amount of (+)-catechin, quantitation of its content was omitted. However, (-)-epicatechin contents was found as 59.74 ± 1.69μg/mg of crude extract. CONCLUSION: The pharmacognostic investigations can be used to set the standard parameters of P. burmanica stem bark in Thailand. HPLC method can be applied to determine (+)-catechin and (-)-epicatechin content in plant materials.