Antibacterial Activity Of Extracts Research Articles

Antibacterial activities of extracts from Nigerian chewing sticks

Antibacterial activities of extracts from Nigerian chewing sticks

Antibacterial activities of extracts from Nigerian chewing sticks.

Ten aqueous extracts from wooden chewing sticks widely used in Nigeria for teeth cleaning were studied for antibacterial activities against 25 different bacteria using an agar diffusion assay. The extracts from five sticks, namely Garcinia kola, Anogeissus leiocarpus, Terminalia glaucescens, Sorindeia warneckei and Vitex doniana, exhibited strong activities against a wide spectrum of bacteria including medically and dentally relevant bacteria. Notably, these five chewing stick extracts showed potent activities against methicillin-resistant Staphylococcus aureus, vancomycin-resistant Enterococcus, and multidrug-resistant Burkholderia cepacia and Pseudomonas aeruginosa. Extracts from Vernonia amygdalina, Fagara zanthoxyloides and Massularia acuminata also showed activities against bacteria significant to periodontal disease. Methanol extracts prepared from G. kola, A. leiocarpus and V. doniana were further fractionated by solvent extraction. Results showed that the antibacterial activities were distributed into different fractions suggesting that the sticks contain different active antibacterial principles. In conclusion, the results showed that most of the Nigerian chewing sticks do contain antibacterial activities which may contribute to the reported anticaries effect of chewing sticks. These sticks may be sources for new lead antibacterial agents for therapeutic or preventive applications.

Differential Antibacterial Activity of Extracts from Selected Southern African Macroalgal Thalli

Eight southern African seaweeds (5 Phaeophyta, 2 Rhodophyta and 1 Chlorophyta), previously shown to exhibit antibacterial activity, were analysed to assess the distribution of antibacterial activity in extracts from selected portions of their thalli. Seaweeds were separated into meristem and thallus (stipe, meristem and blade in the case of members of the Laminariales), milled, extracted and tested for antibacterial activity against ten Gram positive and Gram negative food-associated bacteria by agar diffusion. Extracts of the intercalary meristem of Ecklonia radiata showed significantly greater (P < 0.1) antibacterial activity than corresponding blade and stipe extracts, whereas Laminaria pallida showed a uniform distribution of antimicrobial activity throughout its thallus against all test bacteria. For seaweeds showing apical growth, the antibacterial activity of meristem extracts was either significantly greater (P < 0.1) or equal to that of thallus extracts. Thallus extracts never exhibited greater antibacterial activity than meristem extracts.

Antibacterial activity of extracts and constituents of Pelargonium sidoides and Pelargonium reniforme.

The antibacterial activity of extracts and isolated constituents (scopoletin, umckalin, 5,6,7-trimethoxycoumarin, 6,8-dihydroxy-5,7-dimethoxycoumarin, (+)-catechin, gallic acid and its methyl ester) of Pelargonium sidoides and Pelargonium reniforme (Geraniaceae), plant species used in folk medicine by the Southern African native population, was evaluated against 8 microorganisms, including 3 Gram-positive (Staphylococcus aureus, Streptococcus pneumoniae, and beta-hemolytic Streptococcus 1451) and 5 Gram-negative bacteria (Escherichia coli, Klebsiella pneumoniae, Proteus mirabilis, Pseudomonas aeruginosa, Haemophilus influenzae). Minimum inhibitory concentrations (MICs) varied with the preparation of the extracts and microorganisms tested, from about 0.6 mg/ml for aqueous phases to over 10 mg/ml for crude Pelargonium extracts. With the exception of the ineffective (+)-catechin, all the potentially active compounds exhibited antibacterial activities with MICs of 200-1000 micrograms/ml. The results provide for a rational basis of the traditional use of the titled Pelargonium species.

Antibacterial activity in Actinidia chinensis, Feijoa sellowiana and Aberia caffra

The antibacterial activity of extracts from various parts of plants (leaves, fruits and stems) was studied in Actinidia chinensis, Feijoa sellowiana and Aberia caffra. These are tropical plants used for food. The fruits (subdivided into skin, pulp and seeds), leaves and stems were separately extracted and tested, in triplicate, against eight Gram positive and Gram negative bacterial strains. All the extracts, except from the leaves of A. caffra, showed activity against all the strains employed. Inhibition of bacterial growth was tested against Na-cefotaxime, benzyl penicillin and tetracycline. The antibiotic activity of fruit resides essentially in the seeds. The antibacterial activity of extracts from vegetative plant parts was generally less active that from fruit extracts. The minimum inhibiting concentration (MIC) and minimum bactericidal concentration (MBC) were determined for all the extracts and showed exclusively bacteriostatic activity.

Antibacterial activity of Helichrysum aureonitens (Asteraceae)

The antibacterial activity of extracts from Helichrysum aureonitens was investigated. The dichloromethane extract was active against all five gram positive bacteria tested and the methanol extract was active only against Bacillus cereus, B. pumilus and Micrococcus kristinae, while the water extract had no activity against any of the organisms. None of the extracts inhibited the growth of the five gram negative bacteria tested.

A Novel Clerodane Ascorbate Adduct From Brachyglottis bidwillii

Investigation of the antibacterial activity of extracts from Brachyglottis bidwillii var. bidwillii revealed the major activity to be associated with four compounds (1)-(4). Two of these compounds are novel diterpene-ascorbate adducts, 5-O-acetyl-2-C-(cleroda-3,13-dien-15-yl)-β-L-xylo-3-hexulofuranosonic acid γ- lactone (1) and the 5-hydroxy equivalent (2). The structures of (1) and (2) were determined from X-ray and spectroscopic data. The two other compounds are known diterpenes labda-7,13-dien-15-ol (3) and kolavenol (4).

Anti-bacterial activity of extracts from the brown seaweed Stoechospermum marginatum

The methanol extract of the brown seaweed Stoechospermum marginatum was found to inhibit the growth of Staphylococcus aureus. The active constituents were found to be a mixture of diterpenoid monoacetates having the spatane skeleton.

Antibacterial activity of extracts from some African chewing sticks

The antibacterial activity of aqueous, isobutanol, and benzene extracts of five popular African chewing sticks was studied by the agar ditch plate method. The isobutanol extract produced the greatest antimicrobial activity, and the benzene extract the least. Streptococci were the most sensitive to the extracts, while Escherichia coli was the most resistant. It would appear that the active principles of the various chewing-stick extracts are not the same and that the extract from a given chewing stick is chemically heterogeneous. It is suggested that the regular use of the African chewing stick, acting as an antiseptic, may control the formation and activity of dental plaque and therefore reduce the incidence of gingivitis and possibly dental caries.

Determination of the inhibitory effect of the extracts of the Euphorbia helioscopia and the pH effect of these extracts in the growth of Gram positive and negative bacteria

This research aim to study antibacterial activity of aqueous, alcoholic and methanolic extracts of aerial parts of Euphorbia helioscopia which belong to Euphorbiaceae family against some pathogenic bacteria. The results showed that aqueous extract was more active than alcoholic and methanolic extracts on growth of Staphylococcus aureus , Bacillus subtilis, Klebsiella pneumoniae, Escherichia coli , Pseudomonas aeruginosa and Salmonella typhi, comparing with Amoxycillin as a typical antibiotic. Methanolic extract showed no antibacterial activity against all bacteria studied except in Bacillus subtilis and Salmonella typhi. Minimum Inhibitory Concentration (MIC) and Minimum bactericidal concentration (MBC) value ranged from (25 ــ 200) mg/cm³, The antibacterial activity of the extracts are enhanced under acidic condition at pH = 2 and basic condition at pH = 10.