Changes in Secondary Metabolite Contents Following Crude Drug Preparation

Crude drug is commonly prepared by directly drying of freshly harvested plant organ or after slicing. These processes may decrease or maintain the content of the desired metabolites presence in the crude drug. Plant rhizome can be directly sliced followed by drying or after storage at certain period. Certain rhizome can maintain the secondary metabolites after being stored for three months (12 weeks), while others decreased just after being stored for two weeks. Drying process can be performed under the sun or in an air circulated oven with temperature not higher than 60 °C. Phenolic content of crude drugs on the other hand is the lowest if it is dried at 60 °C. Drying at 40 °C, 80 °C and 100 °C produce crude drug with higher phenolic content compared to those dried at 60 °C. This may associated with the activity of peroxidase that has optimal activity at 60° C. At above 60 °C, the activity of peroxidase may decrease due to the degradation of the enzyme. Moist treatment of fresh material may increase the content of the secondary metabolites. Boiling of Cosmos caudatus leaves increased the content of the flavonoid glycoside. However, part of the flavonoid was presence in the aliquot that hamper further step of crude drug preparation. Steaming of potato peels increased the chlorogenic acid content. From these observations, steaming can be considered as one of pre-treatment steps in the preparation of crude drugs prior drying process. The increase of flavonoid glycoside in Cosmos caudatus leaves upon boiling has been confirmed not due to the increase the extractability of the flavonoid. The increase of key enzyme activity that involved in the biosynthetic pathway upon moist-heat treatment need to be further studied