Zingiber officinale and cinnamomum loureiroi Nees L. Crude extracts: A study on extraction conditions and their potential as cysteine proteases and serine proteases inhibitors

Abstract

Zingiber officinale and Cinnamomum loureiroi are the two medicinal plants that are commonly used for culinary spice as well as traditionally applied for treatment of various health tissues and diseases, such as viral diseases. This study attempted to assess the suitable extraction conditions to obtain these herbal extracts - rich sources of bioactive compounds - and evaluate their biological properties. The extracts were obtained by two different techniques, including conventional extraction (magnetic-stirring, MSAE) and green extraction techniques (ultrasonic-assisted, UAE). The study allowed detailed evaluation in which UAE is alternative to MSAE method in terms of the obtainability of the highest amounts of total polyphenols and flavonoids in the extraction time, 15 minutes for ginger and 45 minutes for cinnamon, by using colorimetric assay. Our findings revealed that the tested ginger and cinnamon extracts exhibited antioxidant (IC50 = 1953.23 ± 23.42 and 113.71 ± 6.16, respectively) along with a moderate antimicrobial activity against Escherichia coli and Staphylococcus aureus with inhibition zone from 6.5mm to 14.5mm. Papain and trypsin were chosen to represent cysteine and serine protease in order to perform enzyme inhibitory activity in cinnamon compared to ginger extracts. These results also highlighted the pharmaceutical potential of these herbs, thereby contributing to treat viral diseases and attenuate infectious conditions.