Antibacterial properties of traditionally used Indian medicinal plants

In search of broad-spectrum antibacterial activity from traditionally used Indian medicinal plants, 66 ethanolic plant extracts were screened against nine different bacteria. Of these, 39 extracts demonstrated activity against six or more test bacteria. Twelve extracts showing broad-spectrum activity were tested against specific multidrug-resistant (MDR) bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and extended spectrum beta-lactamases (ESbetaL)-producing enteric bacteria. In vitro efficacy was expressed in terms of minimum inhibitory concentration (MIC) values of plant extracts. MIC values ranged from 0.32-7.5 mg/ml against MRSA and 0.31-6.25 mg/ml against ESbetaL-producing enteric bacteria. The overall activity against all groups of bacteria was found in order of Plumbago zeylanica > Hemidesmus indicus > Acorus calamus > Camellia sinensis > Terminalia chebula > Terminalia bellerica > Holarrhena antidysenterica > Lawsonia inermis > Mangifera indica > Punica granatum > Cichorium intybus and Delonix regia. In addition, these extracts showed synergistic interaction with tetracycline, chloramphenicol and ciprofloxacin against S. aureus and/or Escherichia coli. The ethanolic extracts of more than 12 plants were found nontoxic to sheep erythrocytes and nonmutagenic, determined by Ames test using Salmonella typhimurium test strains (TA 97a, TA 100, TA 102 and TA 104). Based on above properties, six plants-Plumbago zeylanica, Hemidesmus indicus, Acorus calamus, Punica granatum, Holarrhena antidysenterica and Delonix regia-were further subjected to fractionation-based study. Ethyl acetate, acetone and methanol fractions of more than six plants indicated that the active phytocompounds were distributed mainly into acetone and ethyl acetate fractions, whereas they were least prevalent in methanol fractions as evident from their antibacterial activity against MDR bacteria. Gram-positive and Gram-negative MDR bacteria are almost equally sensitive to these extracts/fractions, indicating their broad-spectrum nature. However, strain- and plant extract-dependent variations in the antibacterial activity were also evident. Time-kill assay with the most promising plant fraction Plumbago zeylanica (ethyl acetate fraction) demonstrated killing of test bacteria at the level lower than its MIC. Further, identification of active constituents in each fraction and their additive and synergistic interactions are needed to exploit them in evaluating efficacy and safety in vivo against MDR bacteria.     

Antimicrobial activity of Hermannia incana

Hermannia incana Cav. (Sterculiaceae) is a prostrate herb used to treat stomachache and diarrhea, and as an emetic by the people of Eastern Cape Province, South Africa. Acetone, methanol, and water extracts from the leaves and roots of the plant were investigated for antibacterial and antimycotic activities. The methanol extracts of the plant showed appreciable activity against Gram-positive and Gram-negative bacteria at concentrations ranging from 0.5 to 7?mg/mL. The acetone and water extracts of both the leaves and the roots showed moderate activity against Gram-positive bacteria and less activity against Gram-negative bacteria. All the extracts inhibited the growth of the fungi Aspergillus flavus, Aspergillus niger, and Mucor hiemalis with growth inhibition based on MIC ranging from 54% to 96% at 0.1-?10?mg/mL. None of the extracts suppressed the growth of Candida albicans at the maximum concentration (10?mg/mL) tested. This study has pointed to the potential application of Hermannia incana as a bacteriocide and fungicide.     

Antimicrobial Activity and Phytochemical Constituents of Leaf Extracts of Cassia auriculata

Plants produce a wide variety of phytochemical constituents, which are secondary metabolites and are used either directly or indirectly in the pharmaceutical industry. ‘For centuries, man has effectively used various components of plants or their extracts for the treatment of many diseases, including bacterial infections. In the present study methanol, chloroform and aqueous extracts of Cassia auriculata leaf were subjected for antimicrobial activity by well-diffusion method against six bacterial strains namely Bacillus cereus, Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Proteus mirabilis. The results revealed that the methanol and chloroform extracts exhibited strong inhibitory activity against all the tested organisms (zone of inhibition of 12-20 mm), except Pseudomonas aeruginosa (zone of inhibition 10 mm or nil). The aqueous extracts showed moderate activity by ‘Zone of inhibition ≤12 or nil). The extracts were screened for their phytochemical constituents by standard protocols’ and were shown to contain carbohydrates, proteins, alkaloids, flavonoids, steroids, saponins and tannins. The antibacterial activity of these extracts is possibly linked to the presence of flavonoids, steroid, saponins and/or tannins. Further studies are needed to determine the precise active principles from Cassia auriculata.     

Antifungal and antibacterial activities of different extracts of Harungana madagascariensis stem bark

The antifungal and antibacterial effects of the stem bark extracts of Harungana madagascariensis Lam. ex Poir. (Clusiaceae) were examined against nine microbial pathogens causing infections in both man and animals. Hexane (H), dichloromethane (D), chloroform (C), ethyl acetate (E), acetone (A), methanol (M), and water (W) extracts were tested in vitro through bioautography and minimum inhibitory concentrations (MIC) determination using the serial micro-dilution assays. Bioautographic results revealed the presence of eight different spots. Extract A exhibited the lowest MIC of 0.04?mg/mL against Microsporum canis, while water extract (W) and methanol (M) showed the highest MIC of 2.5?mg/mL against at least one of the tested fungi when compared to amphotericin B with 0.0625–1?g/mL. Sporotrichum schenckii was the most susceptible fungal pathogen with average MIC of 0.06?mg/mL, while the acetone extract (A) was the most active against three fungal organisms when compared with other extracts. Similarly, extracts D, C, E and A exhibited very high activity with low MIC values of 0.156–0.62?mg/mL, while M and W gave the highest values of 0.31–2.5?mg/mL on bacterial pathogens as compared to gentamicin (0.02–0.62 8?g/mL). The dichloromethane extract is the most active against bacteria with average MIC of 0.19?mg/mL, while Staphylococcus aureus is the most sensitive organism; that shows susceptibility at an average MIC of 0.34?mg/mL. These results provide promising information for the potential use of the crude extracts from the stem-bark of H. madagascariensis in the treatment of bacterial and fungal infections similar to what was obtained in the leaves.     

Phytochemical screening and antibacterial activities of Vernonia ambigua, Vernonia blumeoides and Vernonia oocephala (Asteraceae)

Some Vernonia species (Vernonia ambigua, Vernonia blumeoides and Vernonia oocephala) used in Northern Nigerian traditional medicine, were subjected to phytochemical screening using standard procedures. The antibacterial activity using the disc diffusion method as outlined by the NCCLS was carried out on Klebsiella pneumoniae, Streptococcus pyogenes, Staphylococcus aureus, Corynbacterium ulcerans, methicillin resistant Staphylococcus aureus (MRSA), Salmonella typhi, Pseudomonas aeruginosa, Shigella dysentriae, Proteus mirabilis and Pseudomonas fluorescence. The results of the antibacterial activity as indicated by zone of growth inhibition ranged from 14 to 27 mm for the crude ethanol extracts and chloroform fractions of the Vernonia species being studied. The activity of chloroform fraction of V. blumeoides was higher on C. ulcerans and K. pneumoniae (27 mm), while the chloroform fractions of V. oocephala and V. ambigua were more active on P. mirabilis (27 mm) and S. typhi (22 mm), respectively. It is worth of mention that the chloroform fractions of the three Vernonia species demonstrated activity (20 mm) against MRSA. The minimum inhibitory concentration (MIC) values ranged from 1.25-2.5 mg/mL for all the organisms tested. The MIC of 1.25 mg/mL exhibited by the chloroform fractions on both Gram positive and negative bacteria indicates broad spectrumactivity of the Vernonia species being studied. Phytochemical screening of the extracts/fractions revealed the presence of steroids/terpenes, saponins, flavonoids, alkaloids, tannins and glycosides. The antibacterial activity exhibited in this study may be attributed to flavonoids, saponinss or sesquiterpene lactones. The overall results indicate that the extracts/fractions are potent antibacterial preparations at least in vitro. This lends credence to the use of these plants for the treatment of various infectious diseases.     

Antibacterial activity of aqueous and methanol extracts of selected species used in livestock health management

Context: Salvadora persica L. (Salvadoraceae), Colophospermum mopane (J.Kirk ex Benth.) J. Léonard (Leguminosae) and Dichrostachys cinerea (L.) Wight &; Arn. (Leguminosae) crude extracts are used by local farmers against many livestock infections with little or no side effects usually associated with synthetic antimicrobials. However, their efficacy has rarely been tested.

Objective: These plants were tested for potential antibacterial activity against clinical isolates of Staphylococcus aureus ATCC33862 and Escherichia coli ATCC25922. Minimal inhibitory concentrations (MIC) of the crude plant extracts were determined.

Materials and methods: Aqueous and methanol extraction of 100?g each of the bark of C. mopane, roots of D. cinerea and leaves of S. persica was done by placing the samples in 250?mL of either water or methanol. Nutrient broth was used as growth medium for the bacteria, and McFarland standard for bacterial standardization. 2,3,5-Triphenyltetrazoliumchloride (TTC) was the indicator salt. Each of the aqueous and methanol extracts (100?μL) was tested. Gentamycin and ampicillin were the controls.

Results: MIC of aqueous extracts ranged from 1.03–14.6?mg/mL against S. aureus, and from 12.1–34.3?mg/mL against E. coli. Methanol extracts ranged between 5.31 and 9.64?mg/mL against S. aureus, and between 7.86 and 13.6?mg/mL against E. coli. Aqueous and methanol extracts of S. persica were significantly higher (p?C. mopane and D. cinerea.

Discussion and conclusion: Colophospermum mopane, S. persica and D. cinerea exhibited antibacterial activity, with methanol extracts performing better than aqueous extracts, justifying use as ethnoveterinary medicine. Further study to isolate the active components should be pursued.     

Antimicrobial activity and phytochemical screening of serial extracts from leaves of Aegle marmelos (Linn.)

The in vitro antimicrobial activity of serial petroleum ether, chloroform and methanol extracts from leaves of Aegle mawmelos were investigated against bacterial and fungal species. All the extracts exhibited broad spectrum antimicrobial activity with zones of inhibition ranging from 10 to 22 mm against bacteria: Staphylococcus aureus, beta Streptococcus haemolyticus group A, Proteus mimrabilis, Klebsiella pneumoniae, Pseudomonas aenrginosa, Escherichia coli, Salmonella typhi, fungi: Candida albicans, Candida tropicalis and Aspergillusflavus. The minimal inhibitory concentrations (MIC) and the minimal microbicidal concentrations (MMC) of the extracts ranged from 1.25 to 10 mg/mL and 2.5 to 20 mg/mL respectively. Assessment of antibacterial efficacy of different extract revealed that Staphylococcus aureus, beta Streptococcus haemolyticus group A, Pseudomonas aeruginosa and Escherichia coli showed high susceptibility to petroleum ether extract. Proteus mimrabilis, Klebsiella pneumoniae showed high susceptibility to chloroform extract and Salmonella typhi showed high susceptibility to methanol extract. Petroleum ether extract exhibited the highest antifungal efficacy against all tested fungal species. Phytochemical screening revealed the presence of phenols, sterols in petroleum ether and chloroform extracts, whereas tannins, flavonoids, coumarins, saponins and triterpenoids in methanol extract. The ability of the leaf extracts of Aegle manmelos to inhibit growth of bacteria and fungi is an indication of its broad spectrum antimicrobial activity which could be a potential source for development of novel bioactive antimicrobial agents.     

Antibacterial Activity of Jordanian Medicinal Plants

The antibacterial activity of ethanol extracts of 15 plant species used in the traditional medicine in Jordan and other Middle East countries were tested. Extracts of certain parts of these plants were tested in vitro against 14 pathogenic bacterial species and strains using the agar diffusion method. Results evaluated as the diameter of inhibition zone of bacterial growth showed that 25 mg/well of 12 plant extracts have antibacterial activity on one or more of the tested bacteria. Three plants exhibited broad spectrum antibacterial activity: Punica granatum L., Quercus infectoria Olive., and Rhus coriaria L. The most susceptible bacteria were Pseudomonas aeruginosa, Bacillus cereus and Streptococcus pyogenes (ATCC 12351), and the most resistant species were Escherichia coli (ATCC 25922 and clinical isolates), Klebsiella pneumoniae, Shigella dysentriae (ATCC 49345), and Yersinia enterocolitica (ATCC 9610). The minimum inhibitory concentrations (MIC) of active extracts ranged from 4-32 mg/ml while the minimum bactericidal concentrations (MBC) were exerted at higher doses 8-62 mg/ml.     

Phytochemical Screening and Antimicrobial Activity of Some Medicinal Plants Against Multi-drug Resistant Bacteria from Clinical Isolates

The in vitro antibacterial activity of various solvents and water extracts of aloe vera, neem, bryophyllum, lemongrass, tulsi, oregano, rosemary and thyme was assessed on 10 multi-drug resistant clinical isolates from both Gram-positive and Gram-negative bacteria and two standard strains including Staphylococcus aureus ATCC 25923 and Escherichia coli ATCC 25922. The zone of inhibition as determined by agar well diffusion method varied with the plant extract, the solvent used for extraction, and the organism tested. Klebsiella pneumoniae 2, Escherichia coli 3 and Staphylococcus aureus 3 were resistant to the plant extracts tested. Moreover, water extracts did not restrain the growth of any tested bacteria. Ethanol and methanol extracts were found to be more potent being capable of exerting significant inhibitory activities against majority of the bacteria investigated. Staphylococcus aureus 1 was the most inhibited bacterial isolate with 24 extracts (60%) inhibiting its growth whereas Escherichia coli 2 exhibited strong resistance being inhibited by only 11 extracts (28%). The results obtained in the agar diffusion plates were in fair correlation with that obtained in the minimum inhibitory concentration tests. The minimum inhibitory concentration of tulsi, oregano, rosemary and aloe vera extracts was found in the range of 1.56-6.25 mg/ml for the multi-drug resistant Staphylococcus aureus isolates tested whereas higher values (6.25-25 mg/ml) were obtained against the multi-drug resistant isolates Klebsiella pneumoniae 1 and Escherichia coli 1 and 2. Qualitative phytochemical analysis demonstrated the presence of tannins and saponins in all plants tested. Thin layer chromatography and bioautography agar overlay assay of ethanol extracts of neem, tulsi and aloe vera indicated flavonoids and tannins as major active compounds against methicillin-resistant Staphylococcus aureus.     

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.     

Phytochemical and antimicrobial screening of methanol and aqueous extracts of Agave sisalana

The methanol and the aqueous extracts of the plant, Agave sisalana were prepared and evaluated for its phytochemical properties and antimicrobial activities. The phytochemical analysis of the preparation revealed the presence of some secondary metabolites which include: saponins, glycosides, cardiac glycosides, steroids, tannins and flavonoids. The in vitro antimicrobial activity of the crude methanol and aqueous extract of the Agave sisalana were investigated. The extract showed antimicrobial activities against the test organisms with different zones of inhibition ranging from 28-32 mm and 25-29 mm for methanol and aqueous extract, respectively. The minimum inhibitory concentration (MIC) of both the methanol and aqueous extract was between 10-20 mg/mL, and the minimum bactericidal concentration (MBC) was between 20-40 mg/mL for both extracts. The investigation indicated that the methanol extract inhibited the growth of the microbes more than the aqueous extract. The ability of the crude extracts of A. sisalana to inhibit the growth of the microbes is an indication of its antimicrobial potential, which may be employed in the management of microbial infections.     

Assessment of antimutagenic action of Celtis glabrata Steven ex Planch. (Cannabaceae) extracts against base pair exchange and frame shift mutations on Salmonella typhimurium TA98 and TA100 strains by Ames test

Context: Celtis glabrata is used in Turkey for the treatment of various health disorders. Objective: The acetone, chloroform, ethanol, and methanol extracts of C. glabrata leaf, fruit, and seed were investigated to evaluate their antimutagenic activities. Material and methods: The antimutagenicity of these extracts was determined by Ames test against mutagens (4-nitro-O-phenylenediamine, 2-aminofluorene (2-AF), and sodium azide (SA)). The extracts were used at concentrations between 5 and 0.005?mg/plate. Results: The ethanol extracts of leaves exhibited strong antimutagenicity (70%) against 2-AF with S9 at 5?mg/plate on TA98. But methanol (61%, 53%) and acetone (53%, 52%) also revealed strong inhibition rates at concentrations of ≥0.5?mg/plate. Among the extracts, the highest activity (96%) was obtained from acetone extract against SA without S9, followed by chloroform extract (91%) at a dose of 5?mg/plate on TA100 with S9. Ethanol (without S9) and chloroform (with S9) extracts showed strong antimutagenicity at all doses. Exception of chloroform and acetone (without S9), all fruit extracts (with/without S9) manifested strong antimutagenicity at doses of?≥0.5?mg/plate on TA98 strain. Ethanol extracts revealed 68% inhibition against 2-AF on TA98. Acetone and ethanol extracts manifested 84% and 82% inhibition against SA on TA100, respectively. All the extracts of seeds revealed strong inhibition against 2-AF at?≥0.5?mg/plate doses on TA98, but acetone extract showed excellent antimutagenicity (94%). Moreover, the chloroform (74, 73, 63, 54%), acetone (74, 72, 70, 65%) and methanol (74, 67, 63, 61%) extracts of seeds revealed strong antimutagenic activity on TA100 against SA with S9. Discussion and conclusion: This plant may be natural source of antimutagenic agents.     

安妥沙星纸片扩散法外抗菌活性测定折点初步研究

目的：确定安妥沙星对葡萄球菌属、肠杆菌科、非发酵菌及嗜血杆菌属的纸片扩散法体外抗菌活性测定折点。方法：采用标准琼脂二倍稀释法与纸片扩散法（5μg和10μg）测定安妥沙星对临床常见致病菌的敏感性,并与临床常用的氟喹诺酮类药物相比较分析,结合人体药代动力学参数,利用MIC与抑菌圈直径散点图,初步确定安妥沙星纸片扩散法对常见细菌的折点。结果：安妥沙星的体外抗菌作用与左氧氟沙星接近且相关性最好,根据安妥沙星琼脂稀释法体外抗菌活性测定的临界浓度（嗜血杆菌敏感临界浓度为≤1mg／L,其他细菌敏感、中介与耐药临界浓度分别为≤2、4、≥8mg／L）,利用MIC与抑菌圈直径散点图初步确定安妥沙星（10扯g）纸片对嗜血杆菌抑菌圈直径≥21mm为敏感,其它菌种耐药、中介与敏感的抑菌圈直径分别为≤14mm、15～17mm和≥18mm。标准菌株质控范围分别为大肠埃希菌ATCC2592224～31mm,铜绿假单胞菌ATCC2785322～26mm,金黄色葡萄球菌ATCC2592322～28mm。结论：通过体外抗菌活性比较,利用MIC与抑菌圈直径散点图,初步确定了安妥沙星纸片扩散法体外抗菌活性测定对常见细菌的折点,供临床应用参考与验证。     

Antibacterial and antifungal activities of extracts of combretum molle

OBJECTIVE: In traditional medical practices of Ethiopia the aqueous extracts obtained from the stem bark of Combretum molle (R. Br. Ex. G. Don.) Engl & Diels (Combretaceae) have a longstanding reputation for the treatment of liver diseases malaria and tuberculosis. Owing to the widespread traditional uses of this plant, the studyinvestigated the antimicrobial activity the bark extract of this plant against Gram positive and and Gram negative bacteria. METHODS: Petroleum ether, dichloromethane and acetone fractions of the bark of the plant were prepared by soxhlet extraction and screened for their antimicrobial activity. The acetone fraction exhibited a powerful activity and was therefore further tested against twenty-one bacterial and six fungal strains. The minimum inhibitory concentration (MIC) of this extract was determined by checker board technique using nutrient agar medium. The zones of inhibition produced by the extract against bacteria and fungi were determined and compared by disc diffusion technique with those of pure ciprofloxacin and griseofulvin, respectively. RESULTS: The highest antibacterial action of the acetone extract was against the Gram negative organisms EscherIchia coli and Shigella spp with an MIC value of 50 mg/ml. The activity of the extract against these bacteria was comparable to that of ciprofloxacin when assessed by the disc diffusion technique. Among the fungal strains tested Candida albicans showed high susceptibility to the extract and growth was completely inhibited at a concentration of 400 microg/ml. At the same concentration, the acetone extract and the standard antifungal drug griseofulvin produced comparable zones of inhibition on C. albicans. Studies on the mode of action of the extract indicated that it was bactericidal and fungicidal. The antimicrobial activity of the extract was attributed to the high amount of hydrolysable tannins present in the bark of the plant. CONCLUSION: The acetone extract of the stem bark of C. molle has the potential for use as a natural antimicrobial agent. Further in vivo antimicrobial, phytochemical and toxicological studies are requireed to evaluate the chemotherapeutic effect of the plant.     

Medicinal Potential of the Root of Arctotis arctotoides.

Abstract

The antioxidant and antimicrobial activity of the acetone, methanol, and water extracts from the root of Arctotis arctotoides. (L.f.) O. Hoffm (Asteraceae) were assessed in an effort to validate the medicinal potential of the subterranean part of the herb. The antioxidant activities of acetone and methanol extracts as determined by the ABTS, DPPH, and FRAP methods were higher than that of water extracts. The extracts showed significant activity against both Gram-positive and Gram-negative bacteria. The strongest activity was found in the acetone extract on Bacillus cereus., Staphylococcus aureus., Micrococcus kristinae., and Streptococcus pyrogens. with an MIC of 0.1 mg/mL. Although not completely fungicidal, these extracts showed significant growth inhibition against all the fungi tested. Antioxidant and antimicrobial activities of the extracts were strongly correlated with total phenols and to a lesser extent with their flavonoids and proanthocyanidins contents. This study has validated the medicinal potential of the underground part of A. arctotoides..     

Anti-insect Screening of Medicinal Plants from Kukrail Forest,Lucknow, India

Ten medicinal plants were evaluated at a dose of 10mg/ml for insecticidal, ovicidal, feeding-deterrence, growth inhibition and morphogenetic effects against various life stages of a noxious lepidopteran insect-pest, Spilarctia obliqua Walker. The acetone extract of Ageratum conyzoides, methanol extract of Justicia adhatoda, and chloroform extract of Plumbago zeylanica showed strong feeding-deterrence, growth inhibition and ovicidal effects against eggs and larvae of S. obliqua. In addition, the chloroform extract of P. zeylanica also created strong morphogenetic disorders in treated pupae of S. obliqua. The methanol extracts of Chenopodium ambrosioides and Ailanthus excelsa showed only feeding-deterrence and growth inhibitory effects but no ovicidal effect, whereas all the five extracts (hexane, chloroform, acetone, methanol and water) of Catharanthus roseus exhibited strong growth inhibition towards larvae of S. obliqua. The acetone extract of Vitex negundo was found to exhibit all the activities tested against S. obliqua. Other plants tested, Ajuga remota, Andrographis paniculata and Clerodendrum inermre, were found to have low to moderate effects towards S. obliqua.     

Polyphenolic Contents and Biological Activities of Rumex ecklonianus.

Abstract

Rumex ecklonianus. Meissner (Polygonaceae) is a wild South African herb whose leaves are edible when young. It is mildly purgative and is used in the treatment of chlorosis and anemia. The polyphenolic content and antioxidant and antibacterial activity of the acetone, methanol, and water extracts were determined in this study. The concentrations of the different classes of phenolic compounds were higher in the acetone and methanol extracts when compared with the water extracts; this also correlates highly with the total phenolic content. Antioxidant activities of acetone and methanol extracts as assessed by three established in vitro. methods, namely, 2,2-azinobis.-(3-ethyl benzothiazoline-6-sulfonic acid) (ABTS), 1,1-diphenyl-2-picrylhydrazyl (DPPH), and ferric reducing antioxidant power (FRAP) methods were comparable with that of butylated hydroxyl toluene. The extracts showed significant activity against both Gram-positive and Gram-negative bacteria. The strongest antibacterial activity was found in the acetone extract, whose activity was pronounced on 7 of the 10 bacterial strains used, with a MIC value of 2.0 mg/mL. None of the extracts, however, inhibited Staphylococcus epidermidis. or Salmonella pooni.. The data obtained in this study suggest that R. ecklonianus. may be a good candidate for functional foods as well as pharmaceutical plant-based products. This is the first report on the biological activity of R. ecklonianus..     

Bioactivity of Extractives from Stachytarpheta urticaefolia

The n-hexane and methanol extracts of Stachytarpheta urticaefolia leaves exhibited significant antinociceptive effects (p < 0.01) in acetic acid-induced writhing model at a dose of 250 mg/kg b.w. Two compounds isolated from the plant, ipolamiide (1) and α-spinasterol (2), were also found to be potent inhibitors of acetic acid-induced writhing on mice at 50 mg/kg b.w. (p < 0.01). Abortifacient activity was demonstrated within 20 h of administration of a methanolic leaf extract at 200 mg/kg b.w. The methanolic leaf extract and compounds 1 and 2 were also tested for in vitro antibacterial activities against 18 bacterial strains. The extract showed mean zones of inhibition ranging from 17 to 30 mm at 500 µg/disk, but the compounds demonstrated only mild or no in vitro antibacterial activity even at 400 µg/disk. Finally, in a cytotoxicity study, the n-hexane and methanol extracts of leaves and root bark of the plant and the purified compounds (1, 2) exhibited LC₅₀ values of 5.42, 4.42, 17.15, 5.38, 3.93, and 13.65 µg/ml, respectively, against the brine shrimp nauplii, whereas the positive control, vincristine sulfate, showed an LC₅₀ of 0.583 µg/ml.     

Screening of Ethanol, Petroleum Ether and Chloroform Extracts of Medicinal Plants, Lawsonia inermis L. and Mimosa pudica L. for Antibacterial Activity

Organic extracts (ethanol, petroleum ether and chloroform) of two medicinal plants Lawsonia inermis L. and Mimosa pudica L. were proven for antibacterial properties against 15 Gram-positive and Gram-negative human pathogenic bacteria. Among the three types of extracts tested, ethanol extract was found to possess maximum antibacterial activity. The diameter of the zone of inhibition of bacterial growth showed that Gram-negative bacteria are more sensitive than Gram-positive bacteria to plant extracts. Between the two plants species studied, Lawsonia inermis extract showed more antibacterial activity compared to Mimosa pudica extract.     

Phytochemistry and Antibacterial Activity of Senna alata Flower

Phytochemistry and antibacterial potency of some crude and partially purified fractions of Senna alata flower was examined against 22 bacterial strains. The crude plant extracts, containing steroids, anthraquinone glycosides, volatile oils and tannins, exhibited a high minimum inhibitory concentration of 500 µg/mL against Staphylococcus aureus, Streptococcus faecalis, Micrococcus luteus, Bacillus subtilis and Pseudomonas putida, but was generally inactive against Escherichia coli, Proteus vulgaris, Pseudomonas aeruginosa, Serratia marcescens, and Pseudomonas fluorescens (above 1000 µg/mL). However, the partially purified plant extract was bacteriostatic at a low concentration of 100 µg/mL, with a minimum bactericidal concentration of 500 µg/mL, primarily against the Gram positive organisms. At a concentration slightly above the minimum inhibitory concentration, the purified extract was nearly as potent as standard antibiotics, exhibiting zones of bacterial growth inhibition ranging from 10 to 25 mm, even against multiple antibiotic resistant local isolates that were not susceptible to methicillin, penicillin and streptomycin.