Antibiofilm activity of α-mangostin extracted from Garcinia mangostana L. against Staphylococcus aureus

Objective To isolate α-mangostin (AMG) from the peels of mangosteen (Garcinia mangostana L.), grown in Vietnam, and to investigate antibiofilm activity of this compound against three Staphylococcus aureus (S. aureus) strains, one of which was methicillin-resistant S. aureus (MRSA) and the other two strains were methicillin-sensitive S. aureus (MSSA). Methods AMG in n-hexane fraction was isolated on a silica gel column and chemically analyzed by HPLC and NMR. The antibiofilm activity of this compound was investigated by using a 96-well plate model for the formation of biofilms. Biofilm biomass was quantified using crystal violet. The viability of cells was observed under confocal microscopy using LIVE/DEAD BacLight stains. Biofilm composition was determined using specific chemical and enzyme tests for polysaccharide, protein and DNA. Membrane-damaging activity was assayed by measuring the hemolysis of human red blood cells in presence of AMG. Results The results indicated that the isolated AMG, with a purity that exceeded 98%, had minimal inhibitory concentrations in the range of 4.6–9.2 μmol/L for the three strains tested. Interestingly, the MSSA strains were more sensitive to AMG than the MRSA strain. Minimal bactericidal concentrations were 2-fold higher than the minimal inhibitory concentration values for the three strains, indicating that AMG was a bactericidal compound. AMG also prevented biofilm formation effectively, albeit that again the MRSA strain was the most resistant. Interestingly, biofilms of the MRSA strain contained protein as a main component of the extracellular matrix, whereas this was polysaccharide in the MSSA strains. This might relate to the resistance of the MRSA 252 strain to AMG. Assays using human red blood cells indicated that AMG caused significant membrane damage with 50% of cell lysis occurred at concentration of about 36 μmol/L. Conclusions Our results provide evidence that the isolated AMG has inhibitory activity against biofilm formation by S. aureus, including MRSA. Thus, isolated AMG proposes a high potential to develop a novel phytopharmaceutical for the treatment of MRSA.

Antibiofilm activity of α-mangostin extracted from Garcinia mangostana L. against Staphylococcus aureus

OBJECTIVE@#To isolate α-mangostin (AMG) from the peels of mangosteen (Garcinia mangostana L.), grown in Vietnam, and to investigate antibiofilm activity of this compound against three Staphylococcus aureus (S. aureus) strains, one of which was methicillin-resistant S. aureus (MRSA) and the other two strains were methicillin-sensitive S. aureus (MSSA).@*METHODS@#AMG in n-hexane fraction was isolated on a silica gel column and chemically analyzed by HPLC and NMR. The antibiofilm activity of this compound was investigated by using a 96-well plate model for the formation of biofilms. Biofilm biomass was quantified using crystal violet. The viability of cells was observed under confocal microscopy using LIVE/DEAD BacLight stains. Biofilm composition was determined using specific chemical and enzyme tests for polysaccharide, protein and DNA. Membrane-damaging activity was assayed by measuring the hemolysis of human red blood cells in presence of AMG.@*RESULTS@#The results indicated that the isolated AMG, with a purity that exceeded 98%, had minimal inhibitory concentrations in the range of 4.6-9.2 μmol/L for the three strains tested. Interestingly, the MSSA strains were more sensitive to AMG than the MRSA strain. Minimal bactericidal concentrations were 2-fold higher than the minimal inhibitory concentration values for the three strains, indicating that AMG was a bactericidal compound. AMG also prevented biofilm formation effectively, albeit that again the MRSA strain was the most resistant. Interestingly, biofilms of the MRSA strain contained protein as a main component of the extracellular matrix, whereas this was polysaccharide in the MSSA strains. This might relate to the resistance of the MRSA 252 strain to AMG. Assays using human red blood cells indicated that AMG caused significant membrane damage with 50% of cell lysis occurred at concentration of about 36 μmol/L.@*CONCLUSIONS@#Our results provide evidence that the isolated AMG has inhibitory activity against biofilm formation by S. aureus, including MRSA. Thus, isolated AMG proposes a high potential to develop a novel phytopharmaceutical for the treatment of MRSA.

Growth Inhibitory Activity of Garcinia Hanburyi extracts on Cholangiocarcinoma Cell Lines.

Background: Cholangiocarcinoma (CCA) is the highest incident of primary liver cancer in the northeastern  Thailand. All of the treatment approaches remain poor. One attractive strategy is the discovery of new drugs from medicinal plants which have a potential growth inhibitory activity on cholangiocarcinoma cells.Objective: To examine the growth inhibitory activity of crude extracts and fractions from barks and fruits of Garcinia hanburyi on human cholangiocarcinoma cell lines.Method: Growth inhibitory activity was assessed by sulforhodamine B assay. The mean IC50 values of three independent experiments were reported.Results: The growth inhibitory activity of four extracts from barks and fruits of G. hanburyi on five human CCA cell lines was performed. It was found that the ethyl acetate extracts from barks (VR12874) and fruits (VR11626) of G. hanburyi exhibited strong growth inhibitory activity against five CCA cell lines with IC50 values range from 1.84±0.10 to 2.49±0.03 mg/ml and 1.69±0.04 to 4.41±0.10 mg/ml, respectively whereas the methanol extracts from barks (VR12875) and fruits (VR11627) showed no growth inhibitory activity on CCA cell lines tested. Subsequent to these results eight fractions from VR12874 were examined for their growth inhibitory activities against 5 human CCA cell lines. It was found that five fractions including  VR12877, VR12878, VR12881, VR12882 and VR12883 showed strong growth inhibitory activity whereas VR12876 and VR12879 exhibited low growth inhibitory activity and VR12880 showed no effect.Discussion and conclusion: It could be concluded that the ethyl acetate extracts from barks and fruits of G. hanburyi showed strong growth inhibitory effect against 5 human CCA cell lines whereas the methanol extracts had no effect. These results indicated that the ethyl acetate extracts might contain active constituents. Variation in the growth inhibitory activities among fractions might  depend on the type or concentration of active constituents containing in each fractions.Key words: Garcinia hanburyi, growth inhibitory activity, cholangiocarcinoma cell lines 

Anti-inflammatory and analgesic effects of the methanol extract from " garcinia wallichii " choisy in animal models

Pharmacological studies were conducted with the methanol extract from Garcinia wallichii Choisy (GW extract) on experimental animals to evaluate anti-infl ammatory and analgesic activities. The GW extract was found to exert an inhibitory activity on the acute phase of infl ammation, as seen in EPP-induced ear edema as well as carrageenin- and arachidonic acid- induced hind paw edema in rats. The GW extract showed weak inhibitory activity on cotton pellet-induced granuloma formation; a chronic inflammatory model. The extract also showed very strong analgesic activity on both acetic acid-induced writhing response in mice and the tail-fl ick test in rats. The single high GW extract dose 3,000 mg/kg taken orally did not cause mortality or show any signs of toxicity or changes in the internal organs of rats, indicating the non-toxic nature of the extract. Chiang Mai Medical Journal 2009;48(3):105-115.