Influence of Extracts from Bark of Deciduous Trees on the Activity of the Amylolytic Enzyme - Alpha Amylase

Abstract

The effect of water extracts obtained from bark of growing in Latvia and widely spread in Europe grey alder (Alnusincana), black alder (Alnusglutinosa) and aspen tree (Populustremula), on the amylase activity in human saliva was evaluated. The extracts were obtained using advanced ACE equipment and distilled hot water as a solvent. The total yields of extractives from bark were rather similar and varied from 16 % to 21 % based on dry bark. However, the content of proantocianidine and salicine derivatives used as diagnostic characteristic for evaluation of effect of extracts on activity of amylase – a glucose-polymers cleavage enzyme - differed significantly. The results of in-vitro tests realized using the model of human gastrointestinal pass have shown that the abovementioned extracts in micro dosages are able to increase significantly activity of amylase. However, this effect is dose dependent and when the dose is exceeded the opposite effect – inhibition of amylase activity - is observed. This effect is explained by increasing of proantocianidins component in the volume of the tested extract dose, because pure proantocianidins, isolated from grey alder bark significantly inhibited activity of amylase. The further investigation is necessary in order to estimate effective and safe dosages for application of extracts providing a guaranteed unambiguous effect of activation or inhibition of amylase activity.