Bioassay-Guided Separation Approach for Characterization of New Antibacterial Fractions from the Stem Roots Extracts of Archidendron jiringa

Abstract

Infectious diseases caused by bacteria has become a global health issue, especially antibacterial drug resistance. The most serious concern with antibacterial resistance is that some bacteria became resistant to almost all antibacterial drugs, which makes them less effective. Archidendron jiringa is one of the most potent medicinal plants to be developed as a new source of antibacterial components. In current study, based on the antibacterial assay-guided approach, the separation of bioactive fractions of A. jiringa stem roots was carried out through several stages including isolation, fractionation, and characterization. The stages of isolation of secondary metabolites were conducted by gradually extraction followed by fractionation using chromatographic methods. The antibacterial potential of extracts was evaluated by the disc diffusion and microdilution methods employing the resazurin assay against one Gram-negative resistant bacteria, Escherichia coli, and one Gram-positive bacteria, Bacillus subtilis. Among three extracts obtained, ethyl acetate and methanol extracts demonstrated to be the most significant antibacterial effects, while no antibacterial activity was shown on the n-hexane extract. The fractionation of ethyl acetate extract led to the isolation of the most bioactive fractions (E2815 and E2816) with the MIC's values ranging of 12.5-25 µg/mL for both resistant bacteria. Due to the low amount, only the fraction E2816 was subjected to analysis by 1 H-NMR spectroscopy. The results exhibited that the bioactive fraction was obtained as a mixture of at least three major constituents. However, the purification of the bioactive fraction is required, to further clarify the antibacterial compound that can be utilized as a new promising antibacterial agent. The bioassay-guided separation approach and the dye resazurin as an indicator of the growth of bacteria are applied for the first time for the phytopharmacological investigation from this plant. The present study represented the most effective method for subsequent finding and isolation of potential novel antibacterial constituents from A. jiringa stem roots, in particular against the multi-drug resistant strains.

The Attractant Bioactivity Test of Semi-Polar Fraction of the Datuan Stem Bark (Ficus vasculosa Wall. Ex Miq) against Warehouse Pest (Sitophilus oryzae L.)

“…The sample (1 mg) was dissolved in 5 mL n-hexane, and the spectrum was recorded within the range of 190-380 cm -1 and 0-1.5 absorbance. [18][19][20][21]…”

“…3a. The same TLC tracks were merged to produce D1, D2, D3, D4, D5, D6, D7, D8 (8)(9)(10)(11), D9 (12-13), D10 (14-18), D11 (19)(20)(21)(22)(23)(24),D(25-29), and D13 (30-33) fractions. Among all the fractions, D8 was selected for re-column using eluent variations of n-hexane and ethyl acetate.…”

“…This isolated compound of the Datuan plant has no absorption at the aromatic areas at about 3000 cm -1 , and also overtone areas at 1604, 1801, 1870, and 1941 cm -1 , which showed the isolated compound of D8.3.5.7 fraction has no aromatic chain compounds. [18][19][20][21] This leads to the absorption spectrum of UV-Vis spectrophotometry measurement which is the absorption under visible light. For details, the bonding properties of FTIR are presented in Table 6.…”