Allelopathic effect of aqueous leaf extracts of selected trees on germination and seedling growth of rice

Aim: The present investigation aimed to study the allelopathic effects of aqueous leaf extracts of Emblica officinalis, Inga dulcis, Alstonia scholaris, Syzygiumcuminis, Madhuca indica and Azadirachta indica trees on germination and seedling growth of rice.Methodology: The studies on germination and seedling growth was conducted in a BOD incubator. The number of seeds germinated daily was counted to study speed of germination, germination energy and number of days to 50% germination. DMSO was used to extract the chlorophyll and carotenoid pigments of leaves. The chlorophyll and carotenoid contents were estimated by measuring the optical density through UV-VIS spectrophotometer. Relative watercontent of leaves was determined by soaking of leaves in water followed by oven drying. Results: The effect of leaf extracts (5 and 10%) of Emblica officinalis, Inga dulcis, Alstonia scholaris, Syzygium cuminis, Madhuca indica and Azadirachta indica was studied on two rice cultivars viz. NK-5251 (Hybrid) and Gontra Bidhan-2 (high yielding variety). The experimental findings revealed that leaf extracts of different trees had significant effect on the germination and seedling growth of rice. The leaf extract of most of the trees, except Madhuca indica, reduced germination, chlorophyll content and RWC at higher concentration. The aqueous extracts of Madhuca indica significantly increased germination, seedling vigour, seedling dry weight,germination energy, speed of germination, chlorophyll content and RWC as compared to control. However, 5% extract of Madhuca indica recorded the highest germination percentage, seedling vigour, speed of germination, germination energy, seedling dry weight, chlorophyll content and RWC among all the treatments. Interpretation: The leaf extract of Emblica officinalis, Inga dulcis, Alstonia scholaris, Syzygium cuminis and Azadirachta indica plants at higher concentration reduced germination and early seedling growth of rice. The leaf extract of Madhuca indica plant, however, enhanced the performance. The positive allelopathic effect of Madhuca indica leaf extract may be attributed to the presence of phytohormones and biostimulants

Orthosiphon stamineus water extracts inhibit human herpes virus 1 KOS-1 and acyclovir-resistant strains by virucidal activity and suppressing virus early infection

Aim@#To determine the efficacy and mode of action of hot and cold water extracts of Orthosiphon stamineus leaves against two strains of human herpes virus 1 (HHV-1) i.e. KOS-1 and acyclovir (ACV)-resistant UKM-1 (UKM-1) strains. @*Methodology and results@#Hot and cold water extracts of O. stamineus were not cytotoxic to vero cells as determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) (MTT) assay with 50% cytotoxicity concentration (CC50) values of 3.4 and 3.3 mg/mL respectively. Antiviral activity was determined by plaque reduction assay in post-treatment, pre-treatment and virucidal assays followed by time-addition and time removal assay to relate with the stages during the viral infection cycle. Both extracts displayed antiviral activity against HHV-1 KOS-1 and HHV-1 UKM-1 strains with 50% effective concentration (EC50) values between 0.12-0.15 mg/mL in reducing plaque formation. The calculated selectivity indices (SI) were 23 and 28 for hot and cold water extract respectively, indicating that they have good potential as antiviral agent. The extracts were virucidal towards both HHV-1 KOS-1 and HHV-1 UKM-1 strains which may directly affects the virus structure. This is supported with the fact that exposure of the extracts inhibit viral attachment and penetration to the vero cells. In time-of addition assay, both extracts were effective during the early stage of virus infection cycle for HHV-1 KOS-1 strain which is in parallel with the results from the attachment and penetration studies. For HHV-1 UKM-1 strain, contact to the extracts at any time during post-infection inhibits virus replication and also progeny release. @*Conclusion, significance and impact of study@#Cold and hot water extracts of O. stamineus have good potential as antiviral agent against HHV-1 strain KOS-1 and more importantly against UKM-1 strain which is ACV-resistant. The extracts displayed virucidal effect and inhibition of early virus replication cycle involving viral attachment and penetration to cells.

New seminal variety of Stevia rebaudiana: Obtaining fractions with high antioxidant potential of leaves

ABSTRACT The aim of this study was to determine the composition and antioxidant potential of leaves of a new variety of Stevia rebaudiana (Stevia UEM-13). Stevia leaves of UEM-13 contain rebaudioside A as the main glycoside, while most wild Stevia plants contain stevioside. Furthermore can be multiplied by seed, which reduces the cost of plant culture techniques as other clonal varieties are multiplied by buds, requiring sophisticated and expensive seedling production systems. Ethanol and methanol were used in the extraction to determine the bioactive compounds. The methanolic extract was fractionated sequentially with hexane, chloroform, ethyl acetate and isobutanol, and the highest concentration of phenolic compounds and flavonoids was obtained in the ethyl acetate fraction (524.20 mg galic acid equivalent/g; 380.62 µg quercetin equivalent/g). The glycoside content varied greatly among the fractions (0.5% - 65.3%). Higher antioxidant potential was found in the methanol extract and the ethyl acetate fraction with 93.5% and 97.32%, respectively. In addition to being an excellent source for obtaining of extracts rich in glycoside, this new variety can also be used as raw material for the production of extracts or fractions with a significant amount of antioxidant activity and potential to be used as additives in food.

Synergistic effects of Persicaria odorata (Daun Kesom) leaf extracts with standard antibiotics on pathogenic bacteria

Antibacterial activity of different types of P. odorata leaf extracts was evaluated in combination with standard antibiotics. Persicaria. odorata leaves were extracted with n-hexane (n-hex), dichloromethane (DCM) and methanol (MeOH). Each extract was applied on vancomycin (30μg), erythromycin (15μg) and gentamicin (10μg) discs, respectively. Disk diffusion method was used to evaluate the synergistic activity of each combination on Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pyogenes, Streptococcus pneumoniae, Pseudomonas aeruginosa, Salmonella typhi, and Escherichia coli. Minimum inhibitory concentration (MIC) and gas chromatography mass spectrometry (GCMS) analysis was performed on the active extract. Synergistic effects seen were mainly from the n-hex+antibiotics combinations, mainly on the Gram-positive bacteria (7 additive, 5 antagonistic), with MIC range from 50 μg/ml to 100 μg/ml, as well as Gram-negative bacteria (2 additive, 2 indifferent, 5 antagonistic). In particular, synergism showed by the combination of n-hex+van were all additive against the susceptible bacteria. DCM extract combination showed synergistic effects on three Gram-positive species (S. aureus, S. epidermidis, S. pyogenes). Meanwhile, MeOH+antibiotics combination showed significant additive synergistic effects (p<0.05) on S. aureus and S. epidermidis. The major compounds of leaves extract were decanal and β-citral. n-Hex extract superiorly inhibited Gram-positive bacteria growth as compared to DCM and MeOH extracts. The additive synergistic property of the n-hex P. odorata extract could be further studied for possible use as an antibacterial agent.

In vitro and in vivo evaluation of efficacy and safety of photoprotective formulations containing antioxidant extracts

ABSTRACT Chronic exposure to solar radiation could contribute to premature skin aging and skin cancer. Skin presents its own antioxidant defense, however when defenses are out of balance, reactive oxygen species could damage biological structures. In the present work, an oil-in-water photoprotective emulsion was developed and Bauhinia microstachya var. massambabensis Vaz, Fabaceae, extracts at 1% (obtained by extraction with different solvents) were added to this emulsion. In vitro and in vivo efficacy and safety of the formulations were evaluated. Spectrophotometric methods and in vivo Colipa test were performed to evaluated efficacy of the formulations, through sun protection factor (SPF) determination and UVA protection factor assessment. To the in vitro safety assessment HET-CAM, CAM-TBS and Red Blood Cell tests were performed. Results showed that both extracts contributed to a higher in vivo photoprotection (SPF 18) when compared to the formulation without extract (SPF 13), this result could be attributed to the antioxidant activity of the plant extracts that act by capturing reactive oxygen species. Concerning safety, all formulations were considered non-irritant according to in vitro tests. Formulations containing extracts could be considered efficient and safe for cosmetic use since they presented higher sun protection factor and passed the toxicity tests.

Phytochemical and Antioxidant Effect of Spathodea campanulata leaf Extracts.

Aim: Spathodea campanulata is a medicinal plant useful in traditional medicine for the treatment and prevention of some diseases of bacterial and non microbial origins. As a result of this, it becomes very important to investigate the phytochemical and antioxidant (in vitro and in vivo) activities of the plant leaf extracts by chemical methods to ascertain its potential role in folklore medicine. Study Design: In vitro and in vivo by chemical methods. Methodology: 1.5 kg each of S. campanulata air dried leaves ground to powder was extracted separately with ethanol, methanol and petroleum ether at room temperature (25±2°C). Results: The leaf extracts showed qualitatively the presence of saponin, steroid, flavonoids, glycoside, alkaloids, phenol, tannin, terpenoids, phlobatanin and antraquinone. Amount of quantitative phytochemicals screened from the extracts was more in ethanol followed by aqueous, methanol and was least in petroleum ether. Valuable in vitro antioxidant activities were exhibited by the aqueous, ethanol, methanol and petroleum ether extracts in free radical (DPPH), hydroxyl scavenging activities and ferric reducing antioxidant properties. Decrease in values was observed in the in vivo antioxidant assay of glutathione and catalase levels in group of mice infected with Salmonella typhi for three days while there was increase in lipid peroxidation on comparison with negative control value. However improvement in enzymatic antioxidant levels of mice was observed when treated with the plant ethanol leaf extract. The recorded data in the study proposed the use of leaf extract of S. campanulata in traditional medicine hence its inhibition potentials and barrier to generation of free radicals.

Phytochemical and Antimicrobial Evaluation of Leaf-extracts of Pterocarpus santalinoides.

Aim: This study was undertaken to examine the phytochemical constituents and antimicrobial activity of leaf-extracts of Pterocarpus santalinoides, a plant with wide application in Igede people’s traditional medicine against microbial infections. Methodology: Successive extraction of leaves of this plant at room temperature using petroleum ether, ethyl acetate, butanol, ethanol and water was carried out. These extracts were phytochemically screened qualitatively for the presence of alkaloids, flavonoids, saponins, tannins and terpenoids using established literature procedures. Agar well diffusion technique was used to screen the extract for antimicrobial activity. MICs, MBCs and MFCs for the various extracts were determined by the tube dilution technique. Graded concentrations of the extract solutions in Mueller Hinton broth were used for the tests. MBCs and MFCs were done to establish the nature of antimicrobial activity of these extracts. Results: Qualitative phytochemical screening of leaf-extracts of P. santalinoides revealed presence of alkaloids, flavonoids, terpenoids, saponins-glycosides and tannins (except ethanol extract that contained no tannins). These extracts inhibited growth of test organisms, and implies antimicrobial activity on E. coli, P. mirabilis, S. typhi, S. aureus and C. albicans. Zones of inhibition ranged from 17-24 mm. The MICs ranged from 5.0 mg/ml to 10 mg/ml while MBCs and MFCs ranged from 10 mg/ml to 20 mg/ml. Ethanol extracts showed the widest zone of inhibition followed by aqueous extracts (24 mm and 21 mm, respectively). Conclusion: These results lend support to the ethnomedicinal applications of this plant by the Igede people of North Central Nigeria, in treating infections caused by these test organisms which are human pathogens. The ethanol extract in particular, may be exploited as a possible antimicrobial agent for the management of infectious pathogenic diseases caused by these microorganisms.

Mosquitocidal properties of Solanum trilobatum L. (Solanaceae) leaf extracts against three important human vector mosquitoes (Diptera: Culicidae)

OBJECTIVE@#To determine the larvicidal and pupicidal activites of Solanum trilobatum (S. trilobatum) leaf extracts against Aedes aegypti (Ae. aegypti), Culex quinquefasciatus (Cx. quinquefasciatus) and Anopheles stephensi (An. stephensi).@*METHODS@#The larvicidal and pupucidal was determined at five different concentrations of 50, 100, 150, 200 and 250 ppm. Percentage of larval mortality was assessed after 48 h.@*RESULTS@#Methanol extracts of S. trilobatum was found to be more susceptible against the larvae of Ae. aegypti, Cx. quinquefasciatus and An. stephensi at 250 ppm with a LC50 value of 125.43, 127.77 and 116.64 ppm respectively. Leaf methanol extracts of S. trilobatum also exhibited pupicidal and adult emergence properties.@*CONCLUSIONS@#These results suggested that the leaf extracts of S. trilobatum showed potential to be used as an ideal ecofriendly approach for the control of the Ae. Aegypti, Cx. quinquefasciatus and An. stephensi.

A standardized bamboo leaf extract inhibits monocyte adhesion to endothelial cells by modulating vascular cell adhesion protein-1

Bamboo leaves (Phyllostachys pubescens Mazel ex J. Houz (Poacea)) have a long history of food and medical applications in Asia, including Japan and Korea. They have been used as a traditional medicine for centuries. We investigated the mechanism of anti-inflammatory activity of a bamboo leaf extract (BLE) on tumor necrosis factor-alpha (TNF-alpha)-induced monocyte adhesion in human umbilical vein endothelial cells (HUVECs). Exposure of HUVECs to BLE did not inhibit cell viability or cause morphological changes at concentrations ranging from 1 microg/ml to 1 mg/ml. Treatment with 0.1 mg/ml BLE caused 63% inhibition of monocyte adhesion in TNF-alpha-activated HUVECs, which was associated with 38.4% suppression of vascular cell adhesion molecule-1 expression. Furthermore, TNF-alpha-induced reactive oxygen species generation was decreased to 47.9% in BLE treated TNF-alpha-activated HUVECs. BLE (0.05 mg/ml) also caused about 50% inhibition of interleukin-6 secretion from lipopolysaccharide-stimulated monocyte. The results indicate that BLE may be clinically useful as an anti-inflammatory or anti-oxidant for human cardiovascular disease including atherosclerosis.

Pharmacological studies on Buchanania lanzan Spreng.-A focus on wound healing with particular reference to anti-biofilm properties

Objective:To evaluate the wound healing activity of the methanolic root extract of Buchanania lanzan Spreng. (B. lanzan), with a focus on antimicrobial and anti-biofilm properties. Methods: The extract was evaluated for its wound healing properties (excision and incision models) as evident from the analysis of tensile strength and wound contraction. The extract was also screened for antibacterial properties against different Gram positive and Gram negative bacterial strains. B. lanzan was also studied for its effect on biofilm formation and disruption of preformed biofilms. The synergistic effect of B. lanzan was determined in combination with gentamicin. Results:Topical application of B. lanzan (10%w/w ointment) significantly increased (40.84%) the tensile strength in the incision wound model. B. lanzan also showed significant wound healing activity in excision model and such significant activity was observed from the 9th day. Whereas Soframycin displayed significant wound healing activity from the 6th day. It was found that root extracts of B. lanzan revealed significant inhibition against all tested pathogens. B. lanzan displayed antimicrobial activity against Gram positive (MIC 0.625 mg/mL) and Gram negative (MIC 0.625-1.25 mg/mL). B. lanzan was able to reduce biofilm formation and also caused disruption of preformed biofilms in a manner similar to ciprofloxacin. However, gentamicin was found to be ineffective against biofilms formed by Gram negative organism. According to the fractional inhibitory concentration index, B. lanzan displayed synergistic activity when it was combined with gentamicin. Conclusions:From this study it may be concluded that the root extract of B. lanzan revealed significant wound healing potential, which was supported and well correlated with pronounced antibacterial activity of the tested plant parts.

Larvicidal and Antifungal Properties of Picralima nitida (Apocynaceae) Leaf Extracts.

larvicidal and antifungal activities of ethanolic and aqueous leaf extracts of Picralima nitida were evaluated in static bioassays on 4th instar larvae of Anopheles gambiae and three fungal species: Aspergillus flavus, Candida albicans and Microsporum canis. All extractions were done using distilled water and 50% ethanol. Larvicidal assays were carried out at extract concentrations of 0.15, 0.30, 0.45, 0.60 and 0.75% w/v, for 72h. For the antifungal studies extract concentrations used were 200, 100, 50 and 25mg/ml. At the end of larvicidal assay the highest concentration recorded mortality of 57.60% and 38.40% for ethanolic and aqueous leaf extracts respectively. 72h LC50 values obtained from Probit analysis, using SPSS version 17 were 0.660% and 1.057% w/v for ethanolic and aqueous leaf extracts respectively. Larvae in the control experiments registered no death throughout the period of experiment, rather they were actively wriggling and some even metamorphosed into pupae. For the antifungal studies the agar well diffusion technique was employed. Antifungal effects were determined using measurements of inhibition zone diameter (IZD). Results obtained revealed that both the aqueous and ethanolic leaf extracts exerted antifungal effect on A. flavus and C. albicans, but no antifungal effect was exhibited against M. canis, at the extract concentrations used in this study, rather a steady growth in the test plates seeded with M. canis was observed. The same was applicable with the negative controls. The drug, ketoconazole exerted antifungal effect on all test organisms. Phytochemical screening of the leaf revealed the presence of alkaloids, cardiac glycosides, saponins and terpenes. The leaf of P. nitida possesses larvicidal and antifungal potential and therefore warrants a more thorough exploitation.

Preliminary phytochemical studies of the leaf extracts of Rhododendron arboreum Sm. ssp. nilagiricum (Zenker) Tagg

Objective: To examine the secondary metabolites present in the leaf extracts of Rhododendron arboreum Sm. ssp. nilagiricum (Zenker) Tagg. Methods: Phytochemical screening of the leaf extract was done to determine the phytochemical constituents in the various solvents studied.Results:nilagiricum (Zenker) Tagg. confirm the existence of secondary metabolites such as phenols, saponins and tannins. Conclusions: The study suggests that the leaf extracts of R. arboreum Sm. ssp. nilagiricum (Zenker) Tagg. can be best utilized in developing bioactive compounds against pathogenic infection. The phytochemical study carried out on the leaf extracts of R. arboreum Sm. ssp.

Interactions among insect-resistant soybean genotypes extracts with populations of Anticarsia gemmatalis Hübner (Lepidoptera: Noctuidae) susceptible and resistant to its nucleopolyhedrovirus

Anticarsia gemmatalis nucleopolyhedrovirus (AgMNPV) is being used in Brazil as a biological insecticide. Host plant resistance of soybean to insects is been searched for and some authors have mentioned the interference of plant chemistry in virus efficiency. Interactions among soybean extracts of genotypes used as a source of resistance (PI 274454 and PI 227687) with different AgMNPV concentrations in populations of A. geatalis susceptible (S) and resistant (R) to the virus were studied at laboratory condition. Higher mortality was observed when larvae fed on diets with extracts of the soybean genotypes compared with those fed on a plain diet (control). The mean lethal concentration (LC50) was reduced about 10 ties in the S-population fed on diets containing PI 274454 extracts and different concentrations of AgMNPV, compared to control diet. Additive effect was predominantly observed when larvae fed on diets with extracts of soybean genotypes (PI 274454 and PI 227687) and AgMNPV for both larval populations. The pupal weight was negatively influenced by the extracts incorporated to the diets compared to control, for both larval populations, notably for R-population. The results suggest that, in general, leaf extracts of soybean resistant genotype did not cause any harmful effect on virus efficiency.

O nucleopoliedrovirus de Anticarsia gemmatalis (AgMNPV) tem sido utilizado como um inseticida biológico no Brasil. A resistência de plantas de soja a insetos tem sido pesquisada e alguns autores têm mencionado a interferência de substâncias químicas de plantas sobre a eficiência de vírus. As interações entre extratos de genótipos de soja utilizados como fontes de resistência (PI 274454 e PI 227687) com diferentes concentrações do AgMNPV em populações de A. gemmatalis suscetível (S) e resistente (R) ao vírus foram estudadas em condições de laboratório. Mortalidades elevadas foram observadas quando as larvas foram alimentadas com dietas contendo extratos dos genótipos de soja, em relação às larvas alimentadas com dieta artificial sem a presença de extratos (testemunha). A concentração letal média (CL50) foi reduzida em aproximadamente 10 vezes, na população s alimentada com dieta contendo extratos da PI 274454 e diferentes concentrações do AgMNPV, comparada à dieta testemunha. Um efeito aditivo foi predominantemente observado quando as larvas se alimentaram em dietas com extratos dos genótipos de soja (PI 274454 e PI 227687) e o AgMNPV, para ambas as populações (S e R). O peso de pupa foi negativamente influenciado pela dieta contendo os extratos em relação à dieta testemunha, para ambas as populações, com destaque para a população R. Os resultados indicam que, no geral, os extratos de folhas de genótipos de soja resistentes não causam efeitos negativos na eficiência do vírus.

Anti-Inflammatory and Antipyretic Activities of Hygrophila spinosa T. Anders Leaves (Acanthaceae)

Purpose: Hygrophila spinosa T. Anders (Acanthaceae) is commonly used in the traditional system of medicine for the treatment of inflammation; pain; jaundice; rheumatism; arthritis; anaemia; etc. In the present study; we investigated the anti-inflammatory and antipyretic activities of the petroleum ether; chloroform; alcoholic and aqueous extracts of the leaf of this plant. Methods: The anti-inflammatory activity of the various extracts was studied based on their effects on carrageenan-induced paw oedema in rats while antipyretic activity was evaluated on the basis of their effect on Brewer's yeast-induced pyrexia in rats. The extracts were screened for alkaloids; steroids; proteins; flavonoids; saponins; mucilage; carbohydrates; organic acids; fats and oils. Results: Preliminary phytochemical screening revealed the presence of alkaloids; steroids; proteins; flavonoids; fats and oils; tannins; mucilage and organic acids in the leaves of H. spinosa. Chloroform and alcoholic extracts of leaves of H. spinosa produced significant (p 0.05 and p 0.01) anti-inflammatory and antipyretic activities in a dose-dependent manner. On the other hand; petroleum ether and aqueous extracts did not show significant anti- inflammatory and antipyretic activities. The maximum anti-inflammatory activities produced by chloroform and alcoholic extracts (400 mg/kg) were 33.7and 47.5; respectively. These two extracts also reduced elevated body temperature in rats at 200 and 400 mg/kg body weight doses throughout the observation period of 6h .Conclusion: Chloroform and alcoholic extracts of H. spinosa leaves have anti-inflammatory and antipyretic activities

Effects of ginkgo leat extracts and dioyridamole injection on the Alzheimer's diseases rats / 中国基层医药

Objective To observe the depositing regions of the cerebral neurons containing A?_ 42 neurons and to study the effects of ginkgo leaf extracts and dioyridamole injection on the memory,the deposition of A?_ 42 in the brain of Alzheimer's disease(AD) model rats induced by aluminium chloride(AlCl_3).Methods The experimental AD model of rats was established by 30% AlCl_3.The rats of treatment group received ginkgo leaf extracts and dioyridamole injection for consecutive six months.Latent period and the intensity of electric shock was evaluated by a passive-avoidence test before and after administration respectively.The morphology and the number of A?_ 42 neurons of the model rats brain by light microscope observation as well as immnohistochemistry.Results (1)After treatment,latent period of the rats prolonged and the intensity of electric shock reduced as compared with AlCl_3 group.(2)The depositing regions of A?_ 42 were found mainly in pyramidal cell layer of CA_1 hippocampus formation and polymorphical cell layer of dentate gyrus,external main stratum of entorhinal region and Ⅲ,Ⅵ,Ⅴ cell layer of cortex(parietal,temporal).The color of A?_ 42 positive substance was brown or brown yellow in the cytoplasm and its dendrites or branches.Significant reducing of A?_ 42 neurons occurred in treatment group(hippocampus P0.05).Conclusion Ginkgo leaf extracts and dioyridamole injection can improve the AD model rats ability of learn and memorizing,which mechanisms are achived by preventing A? from depositing and clearing deposited A?.