Multifloraflavone and polyphenols from <i>Garcinia multiflora</i> with antioxidant, anti-acetylcholinesterase, and anti- <i>Helicobacter pylori</i> activities

A new tetraflavonoid, named multifloraflavone (<b>1</b>), along with garcinol (<b>2</b>), isogarcinol (<b>3</b>), aromadendrin (<b>4</b>), and morelloflavone (<b>5</b>) were isolated from the fruit pericarp of <i>Garcinia multiflora</i> collected in Vietnam. The three-dimensional arrangements of groups in this complex molecule were analysed using NOESY and CD spectroscopic methods. Compounds <b>1</b>-<b>5</b> were evaluated for their antioxidant, acetylcholinesterase inhibitory, and anti-<i>Helicobacter pylori</i> activities. Multifloraflavone (<b>1</b>) exhibited the strongest antioxidant activity in the DPPH scavenging assay (IC₅₀ = 3.90 µM), surpassing the standard quercetin. Aromadendrin (<b>4</b>) and morelloflavone (<b>5</b>) displayed potent acetylcholinesterase inhibitory effects (IC₅₀ = 0.66 and 1.13 µM, respectively), approaching the efficacy of the reference drug donepezil (IC₅₀ = 0.076 µM). Notably, compounds <b>1</b> and <b>3</b>-<b>5</b> exhibited activity against <i>H. pylori</i> strains. Compound <b>4</b>, with MIC values of 0.1-0.5 mg/mL, showed the strongest inhibition against a <i>H. pylori</i> HP-6.250224 clinical isolate strain, which is -resistant to amoxicillin, metronidazole, and clarithromycin.