Screening of secondary metabolites quinine alkaloid by endophytic bacteria from cinchona plants (Cinchona ledgeriana moens.) root

Abstract

Malaria in Indonesia exceeds more than 300.000 cases in two consecutive years since 2016. Recently, a synthetic drug called chloroquine was used for the treatment. Unfortunately, the massive consumption of chloroquine gives rise to Plasmodium resistance. This research aims to determine the potency of endophytic bacteria obtained from cinchona plants root producing quinine compound and characterize its morphological properties. Quinine extraction starts with bacterial cultured in 7 mL Nutrient Broth inside vial supplemented with 140 μL (1:20) tryptophan. All bacteria cultures were incubated at 27 °C and agitated in a shaker with 120 rpm for 48 hours. The extraction process was carried out with additional 8.4 ml (1:1.2) chloroform to each sample. The qualitative measurement uses Thalleioquin test method with hydrochloric acid (HCl), Bromine-solution (KBr + KBrO3 + H2O), and ammonium chloride (NH4Cl) as the main reagent. This screening test indicator is the color in the upper phase of the sample compared with the Green-Yellow color (5GY 8/6) from Munsell Color Chart. We found all isolates could produce quinine, and isolate a11 and a13 has the highest color strength. Both isolate a11 and a13 are classified as negative Gram, non-capsulated, and bacilli shape properties.