Search

Methanol extracts from M. caulifloria leaves and fruit were tested for antimicrobial activity and toxicity in vitro. M. caulifloria leaf extractinhibited the growth of 9 of the 14 bacteria tested (64%) whilst the fruit extract inhibited the growth of 11 of the 14 bacteria tested (79%). Both Gram-positive and Gram-negative bacterial growth were inhibited by M. caulifloria leaf and flower extracts. 7 of the 10 Gram-negative bacteria (70%) and 2 of the 4 Gram-positive bacteria (50%) tested had their growth inhibited by M. caulifloria leaf extract whereas the fruit extract inhibited 7 of the 10 Gram-negative bacteria (70%) and 100% of the Gram-positive bacteria tested. M. caulifloria leaf extract proved to be toxic in the Artemia fransiscana bioassay with 24, 48 and 72h [LC.sub.50]'s of 232.9 [+ or -] 36.3 [micro]g/ml, 169.1 [+ or -] 11.5 [micro]g/ml and 128.1 [+ or -] 5.6 [micro]g/ml respectively, making it more toxic than Mevinphos (24, 48 and 72h [LC.sub.50]'s 1346.0 [+ or -] 78.2 [micro]g/ml, 505.3 [+ or -] 37.7 [micro]g/ml, 103.9 [+ or -] 12.8) at all time points except 72h but less toxic than potassium dichromate (24, 48 and 72h [LC.sub.50]'s 86.3 [+ or -] 5.1 [micro]g/ml, 80.4 [+ or -] 4.3 [micro]g/ml, 77.9 [+ or -] 4.9). M. caulifloria fruit extract was non-toxic in the Artemia fransiscana bioassay indicating its potential as an antibacterial agent for medicinal use. Keywords: Myrciaria cauliflora | jaboticaba | antibacterial | methanolic extracts | medicinal plants | phytotoxicity, S. Mohanty Biomolecular and Physical Sciences Griffith University I.E. Cock Biomolecular and Physical Sciences Griffith University Methanol extracts from M. caulifloria leaves and fruit were tested for antimicrobial activity and [...]

The antimicrobial activity of a methanolic extract of Buckinghamia celsissima leaves was investigated by disc diffusion assay against a panel of bacteria and fungi. B. celsissima leaf extractinhibited the growth of 5 of the 14 bacteria tested (36%). Gram-positive and Gram-negative bacteria were both affected by B. celsissima extract although Gram-positive bacteria were more susceptible. 3 of 11 Gram-negative (27%) and 2 of the 3 Gram-positive bacteria tested (67%) had their growth inhibited by B. celsissima extract. B. celsissima leaf extractdisplayed antifungal activity towards Candida albicans when tested by disc diffusion assay and inhibited the growth of the yeast Saccharomyces cerevisiae. The antibacterial activity of B. celsissima leaf extractwas further investigated by growth time course assays which showed significant growth inhibition in cultures of Bacilluscereus, Bacillus subtilis, Pseudomonas fluorescens and Aeromonas hydrophilia within 1 h. Keywords: Buckinghamia celsissima | Australian plants | antibacterial activity | medicinal plants | methanol extracts, Introduction Plants contain many biologically active compounds which have potential for development as medicinal agents. Herbal medicines already form the basis of therapeutic use in developing countries but recent years [...]

The antimicrobial activity of methanolic extracts of Eucalyptus baileyana leaves and Eucalyptus major leaves and flowers were investigated by disc diffusion assay against a panel of bacteria and fungi. E. baileyana leaf extract inhibited the growth of 6 of the 14 bacteria tested (43%). Gram-positive and Gram-negative bacteria were both inhibited by E. baileyana leaf extract although Gram-positive bacteria were more susceptible. 4 of 11 Gram-negative (36%) and 2 of 3 Gram-positive bacteria (67%) had their growth inhibited by E. baileyana extract. E. major leaf extract displayed broad antibacterial activity, inhibiting the growth of 10 of the 14 bacteria (71%). E. major flower extract inhibited the growth of 7 of the 14 bacteria (50%). E. major leaf and flower extracts both preferentially inhibited Gram-positive bacteria (100%) compared to Gram-negative bacteria (64% inhibition by leaf extract; 36% inhibition by flower extracts). None of the Eucalyptus extracts showed any antifungal activity. The antibacterial activity of E. major leaf extract was further investigated by growth time course assays which showed significant growth inhibition in cultures of Bacilluscereus and Pseudomonas fluorescens within 1 h and in Bacillus subtilis and Aeromonas hydrophilia within 2 h. Keywords: Australian plants | antibacterial activity | medicinal plants | methanol extracts, Introduction Plants produce a wide variety of compounds which in addition to giving them characteristic pigment, odour and flavour characteristics, may also have antimicrobial properties (Cowan, 1999). For thousands of [...]

Artemia franciscana nauplii lethality bioassay and compared to the reference toxins potassium dichromate and Mevinphos. 7 extracts (18 %) showed marked lethality towards Artemia franciscana nauplii at 24 h, 11 extracts (28 %) at 48 h and 19 extracts (49 %) at 72 h. Of the positive controls, only Mevinphos displayed significant lethality at 24 h. Potassium dichromate treatment resulted in only approximately 10 % mortality at 24 h but induced 100% mortality by 48 h. Of the non-toxic extracts, A. aulacocarpa leaf, L. bracteata leaf, L. juniperium leaf and flower, S. australe leaf and B. celsissima leaf extracts have previously been shown to be good antibacterial agents, confirming their potential for antibiotic usage. Keywords: Australian plants, antibacterial, medicinal plants, toxicity, Artemia franciscana, Table of Contents Abstract Introduction Materials and Methods Results Discussion References Financial support of this work was provided by the School of Biomolecular and Physical Sciences, Griffith University, Australia. Introduction [...]

The antimicrobial activity of a methanolic extract of Allocasuarina littoralis leaves was investigated by disc diffusion assay against a panel of bacteria and fungi. A. littoralis leaf extract inhibited the growth of 8 of the 14 bacteria tested (57%). Gram-positive and Gramnegative bacteria were both inhibited by A. littoralis extract although Gram-positive bacteria were more susceptible. 5 of the 11 Gramnegative bacteria (45%) and 100% of the Grampositive bacteria tested had their growth inhibited by A. littoralis extract. A. littoralis leaf extract displayed no antifungal activity towards any of the fungi when tested by disc diffusion assay. The antibacterial activity of A. littoralis leaf extract was further investigated by growth time course assays which showed significant growth inhibition in cultures of Bacillus cereus, Bacillus subtilis and Pseudomonas fluorescens within 1 h but not of Aeromonas hydrophilia. Keywords: Allocasuarina littoralis, She-oak, Australian plants, antibacterial activity, medicinal plants, Table of Contents Abstract Introduction Materials and Methods Results and Discussion References Introduction Allocasuarina littoralis (black she-oak; previously known as Casuarina littoralis and Casuarina suberosa), a member of the genus [...]

This study reports on the acute toxic effects of Aloe barbadensis Miller (Aloe vera) juice as well as high doses of the antioxidants vitamin C, vitamin E and Trolox[TM] (a water soluble vitamin E analogue) to the salt water crustacean Artemia franciscana. Aloe vera juice exposure resulted in acute toxicity, being capable of inducing mortality at dilutions as low as 4 % juice and having an [LC.sub.50] at 24 h of 4.6 % [+ or -] 0.3. 6% Aloe vera juice dilutions were capable of causing 100% mortality within 4 h of exposure to A. franciscana. All of the antioxidants tested were also toxic to A. franciscana when tested in high doses. Toxicity of the antioxidants at 24 h was in the following order of toxicity: vitamin C ([LC.sub.50] 203.1 [micro]g/ml [+ or -] 11.3) > Trolox[Tm] ([LC.sub.50] = 283.3 [micro]g/ml [+ or -] 25.8) > vitamin E (only low toxicity was observed at 24 h with the tested concentrations). However, in lower doses vitamin E and Trolox[TM] were non-toxic and could block the toxicity induced by Aloe vera juice. Vitamin E was more effective than Trolox[TM] at blocking Aloe vera juice induced toxicity. Treatment of A. franciscana with antioxidants prior to exposure to juice was significantly more effective than the simultaneous treatment of antioxidant and the toxin. These data suggest that the lethality induced by Aloe vera juice is due to oxidative stress which can be blocked by antioxidant addition. Keywords: Aloe barbadensis Miller, Aloe vera, antioxidant, Artemia, oxidative stress, vitamin E, Trolox[TM], Table of Contents Abstract Introduction Materials and Methods Results Discussion References Financial support of this work was provided by the School of Biomolecular and Physical Sciences, Griffith University. Introduction (Aloe [...]

Table of Contents Abstract Introduction Materials and Methods Results and Discussion References Abstract Thirty nine methanolic extracts from twenty five Australian native plants were investigated for their antibacterial activity against [...]