Immunosuppressive and antibacterial activities of dihydromorin and norartocarpetin isolated from Artocarpus heterophyllus heartwoods

Objective:To evaluate the immunosuppressive effect on human phagocytes and antibacterial activity of dihydromorin and norartocarpetin isolated from Artocarpus heterophyllus heartwoods.Methods:Dihydromorin and norartocarpetin were isolated from Artocarpus heterophyllus heartwoods.A modified Boyden chamber was used to determine the chemotactic activity of human phagocyte.The respiratory burst was evaluated by chemiluminescence assay.Myeloperoxidase(MPO)activity was quantified using a colorimetric assay.The broth microdilution method was performed to assess their antibacterial activity.Results:Dihydromorin exhibited potent inhibitory effect on the chemotactic activity of polymorphonuclear neutrophils(PMNs)with an IC50 value of 5.03μg/mL.Dihydromorin also inhibited reactive oxygen species production of whole blood cells,PMNs,and monocytes with IC50 values of 7.88,7.59 and 7.24μg/mL,respectively.Interestingly,dihydromorin also strongly inhibited the MPO activity of PMNs with an IC50 value of 5.24μg/mL,which was lower than indomethacin(24.6μg/mL).Molecular docking of dihydromorin and crystal structure of MPO showed that dihydromorin had close interaction with key amino acid residues such as Arg239 and Gln91.Antibacterial activity assay showed that only dihydromorin had a strong effect against Streptococcus pyogenes with MIC and MBC values of 15.62 and 31.25μg/mL,respectively.Conclusions:The results suggest that dihydromorin could be developed as an anti-inflammatory and antibacterial agent.

Synergistic activity of lawsone methyl ether in combination with some antibiotics and artocarpin against methicillin-resistant Staphylococcus aureus, Candida albicans, and Trychophyton rubrum

Objective: One appealing strategy to overcome and prevent resistant problem is the use of combined two or more antibacterial substances. Lawsone methyl ether(LME) is the naphthoquinone found in the leaves of Impatiens balsamina. The objective of this study is to determine the interaction of LME with some antibiotics(ampicillin, tetracycline, norfloxacin, and clotrimazole) and a natural compound, artocarpin against methicillin-resistant Staphylococcus aureus(MRSA), Candida albicans, and Trychophyton rubrum.Methods: A broth microdilution method was used to determine the minimum inhibition concentration(MIC). Synergistic effects were evaluated at their own MIC using the checkerboard method and time-kill assay.Results: LME showed moderate antibacterial activity against MRSA with MIC value of 15.6 μg/mL, and exhibited strong antifungal activities against T. rubrum and C. albicans with MIC values of 7.8 and 3.9 μg/m L,respectively. The interaction of LME with the natural compound artocarpin against MRSA produced a synergy with fractional inhibitory concentration index(FICI) value of 0.31, while the combination of LME and clotrimazole exhibited synergy against C. albicans and T. rubrum with FICI values of 0.38 and 0.24, respectively. The time-kill assays confirmed that the compounds in combination enhanced their antimicrobial activities against the resistant microorganisms with different degrees.Conclusion: LME in combination with clotrimazole exhibited synergy effect against C. albicans and T.rubrum. In combination with artocarpin, it showed synergy effect against MRSA.

High water-soluble curcuminoids-rich extract regulates osteogenic differentiation of MC3T3-E1 cells:Involvement of Wnt/β-catenin and BMP signaling pathway

Objective:The present study aimed to evaluate the effect of a high water-soluble curcuminoids-rich extract(CRE)in a solid dispersion form(CRE-SD)using polyvinylpyrrolidone K30 on osteogenic induction of MC3T3-E1 cells.Methods:CRE was pre-purified using a microwave assisted extraction couple with a Diaion;HP-20 column chromatography.The osteoblastic cell proliferation and differentiation potentials of CRE-SD in MC3T3-E1 cells were tested by cell viability,alkaline phosphatase(ALP)activity,and Alizarin red S activity assays.The m RNA expressions of osteoblast-specific genes and underline mechanisms were assessed by a real time PCR and western blot analysis.Results:CRE-SD 50μg/m L increased alkaline phosphatase(ALP)activity,an early differentiation marker of osteoblasts in both MC3T3-E1 cells and non-osteogenic mouse pluripotent cell line,C3H10T1/2,indicating the action of CRE-SD was not cell-type specific.Alizarin red S activity showed a significant amount of calcium deposition in cells treated with CRE-SD.CRE-SD also upregulated the m RNA expression levels of transcription factors that favor osteoblast differentiation including Bmp-2,Runx2 and Collagen 1 a,in a dose dependent manner.Western blot analysis revealed that noggin attenuated CRE-SD-promoted expressions of Bmp-2 and Runx2 proteins.si RNA mediated blocking of Wnt/β-catenin signaling pathway also annulled the influence of CRE-SD,indicating Wnt/β-catenin dependent activity.Inhibition of the different signaling pathways abolished the influence of CRE-SD on ALP activity,confirming that CRE-SD induced MC3T3-E1 cells into osteoblasts through Wnt/β-catenin and BMP signaling pathway.Conclusion:These results collectively demonstrate that CRE-SD may be a potential therapeutic agent for the treatment of osteoporosis.

Synergistic effect of α-mangostin on antibacterial activity of tetracycline, erythromycin, and clindamycin against acne involved bacteria

Objective:To evaluate the synergistic effect ofα-mangostin with tetracycline,erythromycin,and clindamycin against bacteria involved in acne production.Methods:A broth microdilution method was used to determine the minimum inhibitory concentration(MIC)ofα-mangostin and a range of antibiotics.Synergistic effects on antibacterial activity were determined based on their own MIC,and then using a checkerboard method and a time-kill assay at 37°C for24 h.Results:α-Mangostin exhibited antibacterial activity against Propionibacterium acnes,Staphylococcus aureus,S.epidermidis and S.pyogenes with MIC values of 0.78,3.13,0.78,and 6.25μg/m L,respectively.The results of the checkerboard assay showed thatα-mangostin produced synergistic effects with tetracycline,erythromycin,and clindamycin against all tested bacteria,with a fractional inhibitory concentration index(FICI)between 0.09 and 0.32.Moreover,time-kill curve data indicated thatα-mangostin increased the antibacterial activity of tetracycline,erythromycin,and clindamycin.Conclusion:These findings suggested thatα-mangostin may be used to enhance the antibacterial activity of some antibiotics against bacteria involved in acne production.