Research On Chemical Composition And Antimicrobial Mechanism Of Mangosteen Peel

Mangosteen (Garcinia mangostana L.) is a valuable plant in medicine. Recent years, lots ofnew compounds have been separated from the mangosteen’s pericarp, heartwood, leavesconstantly. Theirs medicine value were also been studied. The major bioactive secondarymetabolites of mangosteen were reported to be xanthone derivatives， Previous studies havedemonstrated that xanthone compounds possess a wide range of bioactivities, includinganti-inflammatory, antibacterial, antioxidant, antifungal, antiviral, cytotoxic and otherpharmacological properties.this study is focus on the antibacterical activities and mechanisms ofthree xanthones, which is α-mangostin, γ-mangostin and garcinone E. They were separate from thepericarp of mangosteen. This study were divide into several sections：（1）We have separated the three xanthones from the pericarp of mangosteen, and testedtheirs antibacterial activities against P. acnes and S. aureus. The results show that those threexanthones own the same antibactericial activities against P. acnes, the MIC value was0.78μg/mL,which is lower than the value of BPO over60-fold and10-fold higher than erythromycin.（2）Pharmacological features of garcinone E against P. acnes. In this section we study themechanism of garcinone E against. According to the time-kill assay, TEM and SEM, TritonX-100-induced autolysis, biofilm assay and mutipassage resistance selection studies we found thatthe garcinone E rapidly killed the P. acnes within30to60mins. The TEM and SEM photographsshowed that the membrane of P. acnes were seriously disrupted after treating the P. acnes withgarcinone E, this result along with the autolysis results that the gacinone E induced46%decreasedagainst the initial absorbance mentioned us that due to the garcinone E destroyed the membranceof P. acnes coursed the rapid death of the bacterial that was the mechanism of garcinone E againstP. acnes.The biofilm assay and mutipassage resistance selection studies show us the potential ofgarcinone E to be an antibacterical agent.（3）We also investigate the mechanism of garcinone E and α-mangostin induced autolysis ofS. aureus. The genes cidAB, lrgAB, lgtAB, were consider to regular the murein hydrolase andautolysis. In this section, we treated S. aureus with garcinone E and garcinone E, after that, theRNA of S. aureus were collected and reversed transcription into cDNA. the cDNA were used as athe real-time PCR to test the expression of those genes.