Objective:To examine the acanthamoebicidal effects of ethyl acetate,aqueous and butanol fractions of dried flower buds of Lonicera japonica(L.japonica) Thunb.(Flos Lonicerae) in vitro.Methods:Acanthamoeba triangularis...Objective:To examine the acanthamoebicidal effects of ethyl acetate,aqueous and butanol fractions of dried flower buds of Lonicera japonica(L.japonica) Thunb.(Flos Lonicerae) in vitro.Methods:Acanthamoeba triangularis isolates were obtained from environmental water samples and identified by PCR.They were exposed to ethyl acetate,water and butanol fractions of L.japonica Thunb.at concentrations ranging from 0.5 mg/m L to 1.5 mg/m L.The extracts were evaluated for growth inhibition at 24,48 and 72 h,respectively.Chlorogenic acid at a concentration of 1 mg/mL was examined for inhibition of encystment.Results:Ethyl acetate fraction at a concentration of 1.5 mg/mL evoked a significant reduction of trophozoite viability by 48.9% after 24 h,49.2% after 48 h and 33.7% after 72 h Chlorogenic acid,the major active constituent of L.japonica Thunb.at the concentration of 1 mg/mL reduced the cysts/trophozoite ratio by 100% after 24 h,84.0% after 48 h and 72.3% after 72 h.This phenolic compound at concentration of 1 mg/mL concurrent with 0.6% hydrogen peroxide inhibited hydrogen peroxide-induced encystment by 92.8% at 72 h.Conclusions:Results obtained from this study show that ethyl acetate fraction at 1.5 mg/m L is the most potent fraction of L.japonica Thunb.and its major constituent chlorogenic acid showed the remarkable inhibition of encystment at a concentration of 1 mg/mL.展开更多
Objective: To determine antiacanthamoebic activity of natural and marketed honey samples.Methods: Natural honey samples were collected directly from the bee hive and marketed honey samples were purchased from the loca...Objective: To determine antiacanthamoebic activity of natural and marketed honey samples.Methods: Natural honey samples were collected directly from the bee hive and marketed honey samples were purchased from the local market in Karachi, Pakistan. Both honey samples were tested for their flavonoid content(quercetin equivalent per gram of the extract) and phenolic content(gallic acid equivalent per gram). Furthermore, their antioxidant activity was determined by measuring 2,2-diphenyl-1-picrylhydrazyl. Using amoebistatic and amoebicidal assays, the effects of honey samples were tested against growth and viability of Acanthamoeba parasites.Results: Natural honey exhibited potent amoebistatic and amoebicidal effects, in a concentration-dependent manner. Honey-treated Acanthamoeba castellanii showed loss of acanthopodia, following which amoebae detached, rounded up, reduced in size,decreased in cytoplasmic mass and they were observed floating in the culture medium.Importantly, honey-treated amoebae did not revive when inoculated in fresh growth medium, however, glycerol-treated amoebae exhibited viable trophozoite and active growth. In contrast, marketed honey samples varied in their efficacy against Acanthamoeba castellanii. The proportion of flavonoid, as determined by quercetin measurements and the proportion of phenolic, as determined by gallic acid measurements was higher in natural honey compared with marketed honey. Similarly, the antioxidant activity, as determined by 2,2-diphenyl-1-picrylhydrazyl scavenging activity was higher in natural honey vs. marketed honey.Conclusions: This study shows that natural honey has antiacanthamoebic properties and possesses higher flavonoid, phenolic and antioxidant properties compared with the marketed honey. These findings are of concern to the public, health officials, and to the manufacturers regarding production of honey for medical applications.展开更多
Pathogenic strains of Acanthamoeba cause keratitis (AK), granulomatous amoebic encephalitis (GAE), amoebic pneumonitis (AP), and skin infection in human and animals. The treatment of an Acanthamoeba infection is invar...Pathogenic strains of Acanthamoeba cause keratitis (AK), granulomatous amoebic encephalitis (GAE), amoebic pneumonitis (AP), and skin infection in human and animals. The treatment of an Acanthamoeba infection is invariably very difficult and not always effective, and compounds that are amebicidic or amebistatic are frequently toxic and/or irritating for humans. Squaramides and polyamine derivatives have been demonstrated to have antitumor and antiprotozoal activity. The aim of this study was to investigate the activity of 5 squaramides and 5 acyclic polyamines against trophozoites and cysts of A. castellanii Neff. Amoebicidal activity against the trophozoites and cytotoxicity against Vero cells were evaluated with a colorimetric assay, using Alamar Blue?, and chlorhexidine digluconate was assayed as the reference drug. The squaramides 3 and 5 and the acyclic polyamine 6 appeared to be the most active against the trophozoites and their cytotoxicity was low, showing selectivity indexes of 28.3, 26, and 25.7, respectively, similar to the control drug, chlorhexidine digluconate (27.6). But only the squaramide 3 showed complete cysticidal activity at the concentrations of 100 and 200 μM, as the chlorhexidine digluconate. Further studies of the mechanism of action and in vivo assays are needed, but squaramide 3 could be used for developing novel therapeutic approaches against Acanthamoeba infections.展开更多
基金supported by Fundamental Research Grant Scheme(FRGS/1/2014/SG01/UNIM/02/1)Ministry of Higher Education Malaysia and University of Malaya Research Grant(UMRG 544/14HTM and UMRG 362-15AFR)
文摘Objective:To examine the acanthamoebicidal effects of ethyl acetate,aqueous and butanol fractions of dried flower buds of Lonicera japonica(L.japonica) Thunb.(Flos Lonicerae) in vitro.Methods:Acanthamoeba triangularis isolates were obtained from environmental water samples and identified by PCR.They were exposed to ethyl acetate,water and butanol fractions of L.japonica Thunb.at concentrations ranging from 0.5 mg/m L to 1.5 mg/m L.The extracts were evaluated for growth inhibition at 24,48 and 72 h,respectively.Chlorogenic acid at a concentration of 1 mg/mL was examined for inhibition of encystment.Results:Ethyl acetate fraction at a concentration of 1.5 mg/mL evoked a significant reduction of trophozoite viability by 48.9% after 24 h,49.2% after 48 h and 33.7% after 72 h Chlorogenic acid,the major active constituent of L.japonica Thunb.at the concentration of 1 mg/mL reduced the cysts/trophozoite ratio by 100% after 24 h,84.0% after 48 h and 72.3% after 72 h.This phenolic compound at concentration of 1 mg/mL concurrent with 0.6% hydrogen peroxide inhibited hydrogen peroxide-induced encystment by 92.8% at 72 h.Conclusions:Results obtained from this study show that ethyl acetate fraction at 1.5 mg/m L is the most potent fraction of L.japonica Thunb.and its major constituent chlorogenic acid showed the remarkable inhibition of encystment at a concentration of 1 mg/mL.
基金Support provided by Aga Khan University,Pakistan,and Sunway University through INT-FST-DBS-2015 with grant No.005,Bandar Sunway,Malaysia
文摘Objective: To determine antiacanthamoebic activity of natural and marketed honey samples.Methods: Natural honey samples were collected directly from the bee hive and marketed honey samples were purchased from the local market in Karachi, Pakistan. Both honey samples were tested for their flavonoid content(quercetin equivalent per gram of the extract) and phenolic content(gallic acid equivalent per gram). Furthermore, their antioxidant activity was determined by measuring 2,2-diphenyl-1-picrylhydrazyl. Using amoebistatic and amoebicidal assays, the effects of honey samples were tested against growth and viability of Acanthamoeba parasites.Results: Natural honey exhibited potent amoebistatic and amoebicidal effects, in a concentration-dependent manner. Honey-treated Acanthamoeba castellanii showed loss of acanthopodia, following which amoebae detached, rounded up, reduced in size,decreased in cytoplasmic mass and they were observed floating in the culture medium.Importantly, honey-treated amoebae did not revive when inoculated in fresh growth medium, however, glycerol-treated amoebae exhibited viable trophozoite and active growth. In contrast, marketed honey samples varied in their efficacy against Acanthamoeba castellanii. The proportion of flavonoid, as determined by quercetin measurements and the proportion of phenolic, as determined by gallic acid measurements was higher in natural honey compared with marketed honey. Similarly, the antioxidant activity, as determined by 2,2-diphenyl-1-picrylhydrazyl scavenging activity was higher in natural honey vs. marketed honey.Conclusions: This study shows that natural honey has antiacanthamoebic properties and possesses higher flavonoid, phenolic and antioxidant properties compared with the marketed honey. These findings are of concern to the public, health officials, and to the manufacturers regarding production of honey for medical applications.
文摘Pathogenic strains of Acanthamoeba cause keratitis (AK), granulomatous amoebic encephalitis (GAE), amoebic pneumonitis (AP), and skin infection in human and animals. The treatment of an Acanthamoeba infection is invariably very difficult and not always effective, and compounds that are amebicidic or amebistatic are frequently toxic and/or irritating for humans. Squaramides and polyamine derivatives have been demonstrated to have antitumor and antiprotozoal activity. The aim of this study was to investigate the activity of 5 squaramides and 5 acyclic polyamines against trophozoites and cysts of A. castellanii Neff. Amoebicidal activity against the trophozoites and cytotoxicity against Vero cells were evaluated with a colorimetric assay, using Alamar Blue?, and chlorhexidine digluconate was assayed as the reference drug. The squaramides 3 and 5 and the acyclic polyamine 6 appeared to be the most active against the trophozoites and their cytotoxicity was low, showing selectivity indexes of 28.3, 26, and 25.7, respectively, similar to the control drug, chlorhexidine digluconate (27.6). But only the squaramide 3 showed complete cysticidal activity at the concentrations of 100 and 200 μM, as the chlorhexidine digluconate. Further studies of the mechanism of action and in vivo assays are needed, but squaramide 3 could be used for developing novel therapeutic approaches against Acanthamoeba infections.
