Anti-inflammatory, pro-proliferative and antimicrobial potential of the compounds isolated from Daemonorops draco...

Daemonorops draco (D. draco) commonly known as "Dragon's blood" is one of the most used plants by Momok, Anak Dalam and Talang Mamak tribes from Indonesia as a remedy for wound healing.

This study aimed to identify the extract, fractions and compounds responsible for the anti-inflammatory and pro-proliferative activities of the D. draco resin. Additionally, the antimicrobial activity against two bacteria and one yeast species was analysed.

Bio-guided isolation of compounds with anti-inflammatory, pro-proliferative and antimicrobial activities from the D. draco resin was carried out by measuring: the inhibition of NF-κB and activation of Nrf2 in THP-1, HaCaT, NIH-3T3 cells; cell proliferation in NIH-3T3 and HaCaT cells; and the antimicrobial effect on E. coli, S. aureus and C. albicans.

Guided isolation by bioassay gave rise to the isolation and characterisation by nuclear magnetic resonance and mass spectrometry of three compounds: 1 (Bexarotene), 2 (Taspine) and 3 (2-hydroxy-1-naphthaldehyde isonicotinoyl hydrazone). All compounds showed NF-κB inhibitory activity with IC₅₀ values of 0.10-0.13, 0.22-0.24 and 3.75-4.78 μM, respectively, while the positive control, Celastrol, had an IC₅₀ of 7.96 μM. Likewise, all compounds showed an activating effect of Nrf2 with EC₅₀ values of 5.34-5.43, 163.20-169.20 and 300.82-315.56 nM, respectively, while the positive control, CDDO-Me, had an EC₅₀ of 0.11 nM. In addition, concerning the pro-proliferative activity, compound 1 (IC₅₀ = 8.62-8.71 nM) showed a capacity of 100%, compound 2 (IC₅₀ = 166-171 nM) showed a capacity of 75%, and compound 3 (IC₅₀ = 469-486 nM) showed a capacity of 65%, while FSB 10% (positive control) had a pro-proliferative activity of 100% in the NIH3T3 cell lines (fibroblasts) and HaCaT (keratinocytes). Finally, all the compounds showed antimicrobial activity with MIC values of 0.12-0.16, 0.31-0.39 and 3.96-3.99 μM, respectively, in S. aureus, E. coli and C. albicans strains, while the positive control, Ofloxacin, had a MIC of 27.65 μM.

This study managed to isolate, for the first time, three compounds (Bexarotene, Taspine and 2-hydroxy-1-naphthaldehyde isonicotinoyl hydrazone) from the resin of D. draco, with anti-inflammatory, and pro-proliferative as well as antimicrobial activities.