Antibacterial Activity Of Leaf Extracts Research Articles

Antibacterial Activity of Leaf Extracts of Aloe Vera, Ocimum Sanctum and Sesbania Grandiflora against the Gram Positive Bacteria

Diseases have been managed traditionally using medicinal plants, as they contain components of therapeutic value. In view of this, in the present investigation, phytochemical analysis of aqueous, ethanol and chloroform extracts of some herbal leaves like Aloe vera, Ocimum sanctum and Sesbania grandiflora and their antibacterial activities against Gram positive bacteria like Staphylococcus aureus, S. epidermis, Streptococcus mutans, S. pyogenes, S. pneumoniae, Micrococcus luteus, Bacillus cerus and B. subtilis were investigated. The phytochemical analysis revealed the presence of triterpenoid, phenol and tannin in all the extracts of the selected plants. All the leaf extracts of the selected plants inhibited the growth of the test organisms and exhibited antibacterial activity. However, the majority of the bacterial species were susceptible to all the extracts of O. sanctum, when compared to A. vera and S. grandiflora. This work supports the traditional use of these plants and the therapeutic value against bacterial pathogens, so that they can be alternate antibacterial agents in future.

Antimicrobial and Radical Scavenging Activity of <i>Memecylon malabaricum</i (C.B. Clarke) Cogn. and <i>Memecylon talboltianum</i> Brandis

The present study was conducted to determine antimicrobial and radical scavenging potential of extract of two species of the genus Memecylon (Melastomataceae) viz., M. malabaricum (C.B. Clarke) Cogn. and M. talboltianum Brandis. The shade dried leaf materials of both Memecylon species were extracted using methanol. Antibacterial activity of leaf extracts was evaluated against five drug resistant uropathogenic bacteria by Agar well diffusion assay. Antifungal activity of leaf extracts was tested on the basis of mycelial growth inhibition of Colletotrichum capsici (isolated from anthracnose of chilli). Radical scavenging activity of extracts was determined by performing DPPH free radical scavenging activity. Total phenolic content of extracts was estimated by Folin-Ciocalteau reagent method. The extracts were subjected to preliminary phytochemical analysis to detect the presence of phytoconstituents. Among extracts, extract of M. malabaricum inhibited all test bacteria and inhibitory potential was marked against Gram positive bacteria than Gram negative bacteria. C. capsici was highly susceptible to extract of M. malabaricum when compared to extract of M. talboltianum. Overall, extract of M. malabaricum displayed marked antimicrobial activity than extract of M. talboltianum. Extract of M. malabaricum scavenged DPPH radicals more efficiently (IC50 6.26μg/ml) when compared to extract of M. talboltianum (IC50 43.80μg/ml). The content of total phenolics was also high in leaf extract of M. malabaricum (112μg GAE/mg) than that of M. talboltianum (28μg GAE/mg). Preliminary phytochemical analysis of leaf extracts revealed the presence of flavonoids, tannins, saponins and glycosides in both extracts. The antimicrobial and radical scavenging activity of leaf extracts could be ascribed to the presence of phytochemicals mainly phenolic compounds. These plants appear to be potential candidates for control of anthracnose disease of chilli and for development of agents active against drug resistant uropathogens and oxidative damage.Keywords: Memecylon; Antimicrobial; Agar well diffusion; Poisoned food technique; Antioxidant; DPPH

Monograph: In vitro efficacy of 30 ethnomedicinal plants used by Indian aborigines against 6 multidrug resistant Gram-positive pathogenic bacteria

ObjectiveTo monitor in vitro antibacterial activities of leaf extracts of 30 common and non-common plants used by aborigines in Kalahandi district, Odisha, against 6 clinically isolated multidrug resistant (MDR) Gram-positive bacteria of 3 genera, Staphylococcus, Streptococcus, and Enterococcus. MethodsThe antibiotic sensitivity patterns of 6 bacterial strains were studied with the disk-diffusion method with 17 antibiotics belonging to 8 classes. Monitored plants have ethno-medicinal use and several are used as traditional medicines. Antibacterial properties were studied with the agar-well diffusion method. Minimum inhibitory concentration and minimum bactericidal concentration values of ethanolic and aqueous extracts of plants were determined by the microbroth-dilution method. ResultsEthanolic plant-extracts had the better antibacterial potencies in comparison to their corresponding aqueous extracts. Plants with most conspicuous antibacterial properties in controlling MDR strains of Gram-positive bacteria were aqueous and ethanolic extracts of plants, Ixora coccinea, Nyctanthes arbor-tristis, Polycythaemia rubra, Pongamia pinnata and Syzygium cumini, Carthamus tinctorius, Cucurbita maxima, Murraya koenigii, Leucas aspera, Plumbago indica and Psidium guajava. Ethanolic extracts of most plants had phytochemicals, alkaloids, glycosides, terpenoids, reducing sugars, saponins, tannins, flavonoids and steroids. ConclusionsThese plants could be used further for the isolation of pure compounds to be used as complementary non-microbial antimicrobial medicines.

Evaluation of Antibacterial Activity of Withania somnifera Leaf Extracts against Antibiotic-Resistant Isolates of Klebsiella pneumoniae

Background: Herbal medicines has been a major remedy in traditional medical systems from thousands of years and made a great contribution in maintaining human health and in preventing many infectious diseases. Objectives: The aim of this study was to evaluate antibacterial activity of leaf extracts of Winter Cheery (Withania somnifera) against antibiotic-resistant isolates of Klebsiella pneumoniae isolated from the urinary tract infection patients. Materials and Methods: All 30 isolates of K. pneumoniae isolated from urine culture of hospitalized patients (Amir al-Mu'minin Hospital, Zabol, southeastern of Iran) suffered from urinary tract infection during the years 2011 and 2012. In this study, the extract of W. somnifera obtained by rotary evaporator. Then the minimum inhibitory concentrations were investigated to characterize the antibacterial activities of this extract. Results: The isolates of K. pneumoniae were resistance to four of the agents including ceftazidime (60% of isolates) cefixime (60% of isolates), erythromycin (66.6% of isolates). The highest MIC values of extract were found to be 250 ppm against K. pneumoniae and MIC values for K. pneumoniae were 63 ppm. Conclusions: This study confirmed the antimicrobial potential of investigated plants and their usefulness in treatment of resistant isolates of K. pneumoniae.

English

The search for the healing properties of plants is an ancient idea that has remained even till date. In this work, the antibacterial activity of leaf extracts of Corchorus olitorius, Pterocarpus santaliniodes, Pentaclethra macrophylla and Azadirachta indica was tested against resistant strains of Staphylococcus aureus, Escherichia coli, Klebsiella species and Streptococcus species using agar well diffusion method. The following concentrations of 100, 50, 25 and 12.5 mg/ml of aqueous, ethanol and methanol leaf extracts were used against the test organisms. Results of this study reveal that all the leaf extracts had antibacterial activity against the test organisms at various concentrations (in particular: at 100 and 50 mg/ml) but the aqueous leaf extracts had higher inhibitory effect for all of them. However, little inhibitory effect was observed with the methanol and ethanol leaf extracts. Our findings justify the therapeutic use of these plants by traditional healers in most part of Nigeria for the treatment of infections caused by these bacteria. Medicinal plants have unlimited possibilities to produce putative compounds for the development of novel drugs to curtail the upward trend in bacterial resistance, thus the need for sustained research towards this objective. Key words: Plant extracts, microorganisms, resistance, herbal medicine, Nigeria. &nbsp

The Antibacterial Activity of Leaf Extracts of Ocimum Gratissimum and Sida Acuta

The antibacterial activities of ethanolic and aqueous extracts of Sida acuta and Ocimum gratissimum on Escherichia coli, Staphylococcus faecalis and Peudomonas aeuginosa were determined using disc diffusion assays. All the extracts exhibited moderate to high level of inhibtion against the four microorganisms.The antibacterial activities were measured by the diammeter by dimeter zone of inhibiton, in which ethanolic extracts of Sida acuta exhibit the highest yield which is 18mm and the lowest yield in aqueous(cold) extract 7mm. The minimum inhibitory concentration (MIC) is 0.125mg/ml on both plant extracts using the ethanollic extracts of Sida acuta and Ocimum gratissimum were positive on both the four microorganism and the minimum inhibitory concentration(MIC) were also positive and gram negative organisms. This research is discussed in relation to the accepatable herbal medicines as a means of disease control.

In vitro evaluation and comparison of antioxidant and antibacterial activities of leaf extracts of Hopea ponga (Dennst.) Mabberly

Background: Hopea ponga has been categorised as an endangered tree species under International Union for Conservation of Nature red list of threatened species. Objective: To study the antibacterial, antioxidant activities, total phenolic and flavonoid contents of Hopea ponga leaf, extracted from different solvents viz., petroleum ether, chloroform and methanol. Materials and Methods: Antibacterial activity of leaf extract of Hopea ponga was determined by disc diffusion method against Escherichia coli, Proteus vulgaris, Bacillus cereus, Streptococcus faecalis and Pseudomonas aeruginosa. The antioxidant activities of the extracts were assayed through in‑vitro models such as 2,2‑diphenyl‑1‑picrylhydrazyl, 2,2’‑azino‑bis (3‑ethylbenzothiazoline‑6‑sulphonic acid), ferric reducing antioxidant power, hydrogen peroxide and hydroxyl scavenging activities. Total flavonoid content was determined using aluminium chloride colorimetric method and total phenolic content determined using Folin ciocaulteu reagent method. Results: Methanol extract showed higher scavenging activity against 2,2‑diphenyl‑1‑picrylhydrazyl and reducing power activity against ferric ion (97.24 ± 0.11 and 88.01 ± 0.03) compared to other extracts. Methanol extract showed significant antibacterial activity against P. vulgaris and B. cereus. Among the tested extracts, methanol extract exhibited higher content of phenols (1318.749 mg of ferulic acid equivalent/100 gram dry weight of extract) and flavonoids (457.832 mg of quercetin equivalent/100 gram dry weight of extract). Conclusions: The present study suggests that the methanol extract may contain active compounds, which have effective antioxidant and antimicrobial activity. Hence, this endangered species have to be explored and conserved to serve the mankind. Key words: Antioxidant, antimicrobial, dipterocarpaceae, Hopea ponga, total phenolic, total flavonoid

Antibacterial activity of leaf extract of Breonadia salicina (Rubeaceae), an endangered medicinal plant of Saudi Arabia

Wild plants can contain bioactive compounds with potential activity against disease-causing microorganisms. In the Kingdom of Saudi Arabia, there are many plant species that may have antibacterial, antifungal, or antiviral activities, among other properties. We extracted bioactive compounds with methanol as well as with water from leaves of Breonadia salicina, which is an endangered plant found in the wild in Saudi Arabia. These extracts were tested against the bacteria Bacillus subtilis, Pseudomonas aeruginosa, Shigella sonnei, Escherichia coli, and Staphylococcus aureus. Both extracts showed antibacterial activity against all of the microorganisms, and thus, B. salicina leaf extract has potential as an antimicrobial agent for the preservation of foods, instead of synthetic chemical compounds. We found that the methanolic leaf extract was more effective than the aqueous crude extract against B. subtilis, P. aeruginosa, and S. aureus.

In vitro evaluation and comparison of antioxidant and antibacterial activities of leaf extracts of Hopea ponga (Dennst.) Mabberly

In vitro evaluation and comparison of antioxidant and antibacterial activities of leaf extracts of Hopea ponga (Dennst.) Mabberly

Antibacterial activity of leaf extracts of some selected traditional medicinal plants of Uttarakhand, North East India

Screenings of methanolic leaf extracts of nine medicinal plants (Cotinus coggygria, Adhatoda vesica, Argemone mexicana, Zanthoxylum armatum, Berberis asiatica, Corissa opaca, Euphorbia hirta, Cassio fistula and Ricinus communis), belonging to selected areas of Uttarakhand, were tested against seven bacterial strains (Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Enterobactor aerogenes, Klebsiella pneumoniae, Proteus vulgaris and Pseudomonas aeruginosa) by disc diffusion method. Leaf extracts of R. communis, B. asiatica and C. opaca showed high (13 – 23) effect on all the bacterial strains while E. hirta, Z. armatum and A. vesica exhibits minimum (6 – 15) effects. Remaining leaf extracts of plants were found moderately (10 - 19) effective.

Agrobacterium-Mediated Genetic Transformation of Pogostemon cablin (Blanco) Benth. Using Leaf Explants: Bactericidal Effect of Leaf Extracts and Counteracting Strategies

An optimized protocol for Agrobacterium tumefaciens-mediated transformation of patchouli using leaf disk explants is reported. In vitro antibacterial activity of leaf extracts of the plants revealed Agrobacterium sensitivity to the extracts. Fluorometric assay of bacterial cell viability indicated dose-dependent cytotoxic activity of callus extract against Agrobacterium cells. Addition of 0.1% Tween 20 and 2 g/l L-glutamine to Agrobacterium infection medium counteracted the bactericidal effect and significantly increased the T-DNA delivery to explants. A short preculture of explants for 2 days followed by infection with Agrobacterium in medium containing 150 μM of acetosyringone were found essential for efficient T-DNA delivery. Cocultivation for 3 days at 22 °C in conjunction with other optimized factors resulted in maximum T-DNA delivery. The Agrobacterium-mediated transformation of leaf disk explants were found significantly related to physiological age of the explants, age and origin of the of the donor plant. Leaf explants from second node of the 3-month-old in vivo plants showed highest transformation efficiency (94.3%) revealed by transient GUS expression assay. Plants selected on medium containing 20 mg/l kanamycin showed stable GUS expression in leaves and stem. The elongated shoots readily developed roots on kanamycin-free rooting medium and on transfer to soil, plants were successfully established. Polymerase chain reaction (PCR) and reverse-transcriptase PCR analysis in putative plants confirmed their transgenic nature. The established transformation method should provide new opportunities for the genetic improvement of patchouli for desirable trait.

Antibacterial activity of mangrove leaf extracts against human pathogens

The antibacterial activity of leaf extract of mangroves, namely, Rhizophora mucronata, Sonneratia alba and Exoecaria agallocha from Chorao island, Goa was investigated against human bacterial pathogens Staphylococcus aureus, Streptococcus sp., Salmonella typhi, Proteus vulgaris and Proteus mirabilis. As compared to aqueous, ethanol extract showed broad-spectrum activity. The multidrug-resistant (MDR) bacteria Salmonella typhi was inhibited by the ethanol extract of S. alba leaf whereas the other two resistant bacteria Staphylococcus aureus and Streptococcus sp. were inhibited by the ethanol extract of leaves of all the species. The aqueous extract of S. alba and E. agallocha showed their activity against P. vulgaris and P. mirabilis, respectively. Phytochemical analysis revealed the presence of saponins, glycosides, tannins, flavonoids, phenol and volatile oils in the leaves of mangroves. Further studies using different solvents for extraction are necessary to confirm that mangroves are a better source for the development of novel antibiotics.

Cytotoxic and antibacterial activities of leaf extracts of Astragalus gombiformis Pomel (Fabaceae) growing wild in Tunisia

Many species of the genus Astragalus have been long used in folk medicine because of their biological properties. The aim of this study was to investigate the antibacterial and cytotoxic activities of extracts from the leaves of wild Astragalus gombiformis Pomel. Antibacterial activity was assayed against several common human pathogenic bacterial strains using the paper disk-agar diffusion method. Cytotoxicity was measured against human lung carcinoma cells using the colorimetric MTT assay. The strongest cytotoxic activity against the human A549 lung epithelial carcinoma cell line was detected for dichloromethane extracts at IC_{50} = 85 ± 21.7 µg/mL. The best incubation time for this extract was 48 h. Most of the tested extracts were active against the tested bacterial strains. The methanol extract was found to be the most active against Pseudomonas aeruginosa and Salmonella typhimurium. This study is the first report on the biological activity of leaf extracts of Astragalus gombiformis with respect to antibacterial activity as well as cytotoxicity.

Phytochemical and antibacterial activities of leaf extracts of Nepeta cataria

The phytochemical screening of the dichloromethane and methanolic extracts showed presence of flavonoids (flavones and flavonols), coumarins and glycosides. These secondary metabolites are considered to be responsible for the antimicrobial activity against Staphyococcus aureus, Kliebsiella pneumoniae and Salmonella typhii. The TLC analysis of the dichloromethane extract revealed presence of 3 components with Rfvalues 0.23, 0.46 and 0.69 using the solvents chloroform: methanol in the ratio of 20: 1. Key words: Nepeta cateria, flavonoids, glycosides, bacteria, dichloromethane.

Phytochemical and antibacterial activities of leaf extracts of Nepeta cataria

The phytochemical screening of the dichloromethane and methanolic extracts showed presence of flavonoids (flavones and flavonols), coumarins and glycosides. These secondary metabolites are considered to be responsible for the antimicrobial activity against Staphyococcus aureus, Kliebsiella pneumoniae and Salmonella typhii. The TLC analysis of the dichloromethane extract revealed presence of 3 components with Rfvalues 0.23, 0.46 and 0.69 using the solvents chloroform: methanol in the ratio of 20: 1. Key words: Nepeta cateria, flavonoids, glycosides, bacteria, dichloromethane.

Antibacterial activity of various leaf extracts of Merremia emarginata

Objective To investigate the antibacterial activity and phytochemical screening of the aqueous, methanol and petroleum ether leaf extracts of Merremia emarginata ( M. emarginata). Methods The antibacterial activity of leaf extracts of M. emarginata were evaluated by agar well diffusion method against four selected bacterial species. Results The presence of tannins, flavonoids, amino acids, starch, glycosides and carbohydrates in the different leaf extracts was established. The methanol extract was more effective against Bacillus cereus and Escherichia coli, whereas aqueous extract was more effective against Staphylococcus aureus and Pseudomonas aeruginosa. Conclusions The results in the present study suggest that M. emarginata leaf can be used in treating diseases caused by the tested organisms.

Antibacterial activity of leaf extracts of Pongamia pinnata from India

This study was designed to examine the efficacy of various organic extracts derived from the leaves of Pongamia pinnata (L.) Pierre (Fabaceae) for antibacterial potential against some representative food spoilage and food-borne pathogenic bacteria. The organic extracts of chloroform, ethyl acetate and methanol, at a concentration of 2500 μg/mL, exhibited a promising antibacterial effect against Bacillus subtilis ATCC6633, Staphylococcus aureus ATCC6538, Listeria monocytogenes ATCC19118, L. monocytogenes ATCC19166, Pseudomonas aeruginosa ATCC6432 and Salmonella typhimurium ATCC2512. The zones of inhibition of various leaf extracts against the tested bacterial pathogens were found in the range of 8.1 to 18 mm, along with their respective MIC values, ranging from 125 to 1000 μg/mL. The chloroform, ethyl acetate and methanol extracts displayed significantly higher antibacterial activity as compared to streptomycin. The results of this study suggest that P. pinnata may have potential use in food industry as an antimicrobial agent, as well as pharmaceutical interest.

Antioxidative, Tyrosinase Inhibiting and Antibacterial Activities of Leaf Extracts from Medicinal Ferns

Leaf extracts of five medicinal ferns, Acrostichum aureum L. (Pteridaceae), Asplenium nidus L. (Aspleniaceae), Blechnum orientale L. (Blechnaceae), Cibotium barometz (L.) J. Sm. (Cyatheaceae) and Dicranopteris linearis (Burm.) underwood var. linearis (Gleicheniaceae), were investigated for their total phenolic content (TPC), and antioxidative, tyrosinase inhibiting and antibacterial activities. The antioxidative activity was measured by assays for radical scavenging against 1,1-diphenyl-2-picrylhydrazyl (DPPH), ferric ion reducing power (FRP), beta-carotene bleaching (BCB) and ferrous ion chelating (FIC). The results revealed B. orientale to possess the highest amount of total polyphenols and strongest potential as a natural antioxidative, tyrosinase inhibiting and antibacterial agent as demonstrated by its strong activities in all related bioassays. The other ferns with antioxidative potential were C. barometz and D. linearis. Except for A. aureum, all ferns showed antibacterial activity which may justify their usage in traditional medicines.