Activity Of Crude Leaf Extracts Research Articles

Antimicrobial Effect of Cassia alataLeaf Extracts on Fungal Isolates from Tinea Infections

Dermatophytoses are caused by fungi in the genera Microsprum, Trichophyton and Epidermophyton. Africans use extracts of medicinal plants to treat dermatophytosis. This study aimed to determine the in vitro antifungal activity of crude leaf extract of Cassia alata on fungal isolates from dermatophytosis lesions. Subjects with suspected lesions of dermatophytosis were recruited for the study. Skin scrapings were obtained from lesions for microscopy and culture. Isolates were identified macroscopically and microscopically. Fresh Cassia alata leaves were plucked and authenticated by a Botanist. Aqueous and alcohol extraction was done using the Soxhlet extractor. Isolates were subjected to in vitro leave extracts antifungal testing using disc diffusion methods. A total of 50 subjects were recruited for the study comprising 28(56.0%) males and 22(44.0%) females with a male to female ratio of 2.5: 1. The prevalence of dermatophytes infection in the study was 14(28.0%). Trichophyton rubrum was the most encountered isolates (42.8%). Males 10(71.4%) were more infected than females 4(28.5%). The susceptibility rates of dermatophytes to anfungals range between 0 100% with 30(78.6%) susceptibility to Griseofulvin. The aqueous extract was more effective with susceptibility rates 33.3% - 83.3% than ethanolic extract 16.7% - 50.0%. The dermatophytes were more susceptible to the 50µg/mL aqueous extract with rates between 50% - 83.3% while the range for the 50µg/mL ethanolic extract was 25.0% - 50.0%. Trichophyton veruccosum and E. floccosum were resistant to extracts. Cassia alata leaf extracts had antifungal activities against dermatophytes.

In-vitro antibacterial activity of crude leaf extracts of Withania somnifera and Moringa oleifera against some selected bacterial pathogens

In-vitro antibacterial activity of crude leaf extracts of Withania somnifera and Moringa oleifera against some selected bacterial pathogens

Preliminary study of plant extract on seed germination

The present study was aimed to evaluate the phytotoxic activity of crude leaf extract from Dilleniaceae family on seed germination of goosegrass (E. indica) under different concentrations, ranging from 0-10 mg/mL. The total phenolic content (TPC) was studied and found to be about 209 mg GAE/g extract. Crude extract was significantly inhibitory towards germination of E.indica seeds. Concentration of 10 mg/mL extract demonstrated high germination inhibition rate at 90 % of goosegrass seeds as compared to the control. The bioassay results illustrated that the extract markedly inhibited the germination of goosegrass seeds which may require further investigation for the potential use in crop protection. Introduction

EFEITO INSULINOTRÓPICO E CITOPROTETOR DO EXTRATO BRUTO DE FOLHAS DE EUGENIA UNIFLORA L.

Eugenia uniflora L. leaves (“pitangueira”) are popularly used as an alternative to the treatment of diabetes mellitus. The objective of this work was to evaluate the cytotoxicity, antioxidant, cytoprotection and insulinotropic activity of crude leaf extracts of Eugenia uniflora L. on RINm5f cells. The antioxidant activity was analyzed by the Folin-Ciocalteau method; cytotoxicity and cytoprotection using the methods of MTT reduction and HE staining and the insulinotropic effect by radioimmunoassay. The aqueous extract (AQ) presented higher phenolic content than the alcoholic extract (ALC). Both showed low cytotoxicity and ALC presented a significant insulinotropic effect. AQ and ALC showed a cytoprotective effect, increasing cell viability and preventing changes in cell morphology induced by H2O2. The results obtained in this work are indicative of the potential of these extracts as coadjuvants in the prevention and treatment of diabetes mellitus. Key words: antioxidants, cytotoxicity, cytoprotection, flavonoids, hydrogen peroxide.

In vivo antiplasmodial activity evaluation of the leaves of Balanites rotundifolia (Van Tiegh.) Blatter (Balanitaceae) against Plasmodium berghei.

Balanites rotundifolia (BR) (Van Tiegh.) Blatter (Balanitaceae) has been used in Ethiopian folk medicine to treat malaria, despite the lack of scientific validation. Therefore, the present study was carried out to evaluate the antiplasmodial activity of 80% methanol leaf extract of BR in mice. Both the 4-day suppressive test and Rane’s test were employed. Three extract doses (BR100 mg/kg, BR200 mg/kg, and BR400 mg/kg/d) were given orally, and chloroquine was the standard drug administered through the same route. Outcome measures for evaluating antiplasmodial efficacy were parasitemia level, packed cell volume, survival time, and body temperature as well as body weight change. Moreover, preliminary phytochemical and acute toxicity studies were carried out. With the 4-day suppressive test, BR demonstrated dose-dependent significant reduction in parasitemia level at all test doses compared to the negative control: BR400 (67%, P<0.001), BR200 (42%, P<0.01), and BR100 (37%, P<0.05). With Rane’s test as well, BR significantly (P<0.001 for all test doses) reduced the parasitemia level by 38% (BR100), 45% (BR200), and 69% (BR400) in comparison to vehicle treatment. The crude extract was estimated to have oral median lethal dose higher than 2,000 mg/kg, and the presence of alkaloids and cardiac glycosides was confirmed. Therefore, this study for the first time validated the antiplasmodial activity of crude leaf extract of BR. Further investigations for isolating specific phytochemicals and elucidating mechanisms are needed to address the quest for novel antimalarial drugs.

Antimicrobial activity of crude leaf extracts from medicinal plants against Enterococcus faecalis

Enterococcus faecalis is a Gram negative, commensal enteric bacterial pathogen usually located in the intestinal tracts of either animals or human beings. The pathogenic members of enteric bacteria’s are usually associated to infections that are characterized by enteric fevers, abdominal pain, and diarrhoea and vomiting. This study aimed at determining the effects of the selected medicinal plants extracts against Clinical isolate of Enterococcus faecalis obtained from Kenyatta University health Centre. Kirby Bauer method was used to determine the antimicrobial activity of the plants extracts against Enterococcus faecalis. All the plant extracts showed antimicrobial activity against Enterococcus faecalis with Tagetes minuta producing the largest average zones of inhibition of 18.67±1.03mm when compared to the other plant extracts. Vernonia lasiopus was more active at low concentrations (MIC 3.9µg/ml; MBC 5.0µg/ml) while Aloe secundiflora was less active (MIC 7.0µg/ml; 9.7µg/ml). Ciprofloxacin (5µg/ml) was used as a positive control producing an average zone of inhibition of 21.67±2.66mm while Methanol (33.50±2.56mm) and 4% Dimethyl sulphoxide (0.00±0.00mm) were used as negative control. Qualitative phytochemical screening showed the presence of four phytochemicals namely; saponins, tannins, alkaloids and flavonoids. The study provides insight about the antimicrobial activity of the plant extracts and if they can be used in treatment of as an antimicrobial agent against infections caused by Enterococcus faecalis.

Effect of Crude Leaf Extract of Bauhinia strychnifolia in BALB/c Mice Infected with Plasmodium berghei

Continuous emergence of antimalarial drug resistant malaria parasites and their rapid spread across the globe warrant urgent search for new antimalarials. Traditional medicinal plants have been the main sources for screening active phytochemicals against malaria. Accordingly, this study was aimed at evaluating the antimalarial activity of crude leaf extract of Bauhinia strychnifolia against Plasmodium berghei infected mice. Aqueous crude leaf extract of B. strychnifolia have been prepared and tested for acute toxicity and antimalarial efficacy in P. berghei ANKA infected BALB/c mice. At three oral doses of 100, 500 and 1,000 mg/kg of extract were safe, chemosuppressive and thus prevented body weight loss, packed cell volume reduction and increased mice mean survival time in a dosedependent manner compared to the untreated control group. The maximum efficacious extract was found at the dose of 1,000 mg/kg which prolonged mean mouse survival past day 26 of infection with all the mice in this group having the highest parasitemia suppression rate (85%). This study suggests that the crude leaf extract of this plant have promising antimalarial activity against P. berghei in a dose dependent manner, which supports the folkloric use of the plant for treating malaria.

Insecticidal and growth regulating activity of crude leaf extracts of Cassia occidentalis L. (Caesalpinaceae) against the urban malaria vector, Anopheles stephensi Liston (Diptera: Culicidae)

ObjectiveTo investigate insecticidal and growth regulating activity of crude leaf extracts of Cassia occidentalis L. (Caesalpinaceae) against the urban malaria vector, Anopheles stephensi Liston. (Diptera: Culicidae). MethodsLarvicidal activity was studied against third instar larvae for 24 h at concentrations of 62.5, 125.0, 250.0, 500.0, 1 000.0, 2 000.0, 4 000.0 and 8 000.0 mg/L. The effect on development and growth of immature mosquitoes was studied at concentrations of 125.0, 250.0 and 500.0 mg/L and was assessed by growth index. Adulticidal activity on topical application was studied on test dosages of 0.01, 0.05, 0.10, 0.25 and 0.50 μg per newly emerged unfed adult female mosquito. ResultsLarvicidal activity was poor, not proportional to concentration and LC50 values were above the acceptable dose of 10 mg/L. Potential growth regulating activity was observed and the growth index was 277.5, 111.0 and 27.5 times less than control, respectively. Average larval pupal transformation was 5.8, 4.3 and 96.0 times greater than pupal adult transformation in hexane, 5.0, 4.3 and 48.4 in ethyl acetate, and 4.8, 4.2 and 10.2 in methanol extract, respectively. Adulticidal activity was the highest in ethyl acetate, followed by hexane and methanol extract with LD50 values of 0.23, 0.32 and 0.64 μg/female mosquito, respectively. ConclusionsThe crude leaf extracts of Cassia occidentalis studied showed poor larvicidal, potential growth regulating and a moderate level of adulticidal activity.

In vitro antibacterial activity of crude leaf extracts of Mangifera indica Linn

The active components of leaves of Mangifera indica L. were extracted using cold water and organic solvents (acetone and methanol) and were tested againstStaphylococcus aureus, Streptococcus pyogenase, Streptococcus pneumoniae, Bacillus cereus, Escherichia coli, Pseudomonas aerugenosa, Proteus mirabilis, Salmonella typhi and Shigella flexnerri using the agar well (cup plate) diffusion method. Both the acetone and methanol extracts inhibited the growth of gram positive bacteria, with acetone extract exerting more activities on all the gram positive bacteria with zone of inhibition between 15 - 16 mm, and a gram negative bacterium S. typhi (14 mm) at 250 mg/ml. Whereas, water extract was not active on any of the bacterial pathogens tested at any of the concentration of the extract used. The activities of the plant extracts on the inhibited pathogens using the zone of inhibition were not as effective as the standard commercial antibacterial disks of gentamicin and erythromycin (t = 2.23, p < 0.05). Increased temperature (60 and 100°C for 1 h) had a multiplier effect on the activity of the extracts, but alkaline pH decreased the activity. Preliminary phytochemical analysis revealed the presence of tannins, glycosides, saponins and phenols. The MIC and MBC of the extracts was in the range of 12.5 - 75 and 25 - 175 mg/ml respectively. There is a basis for the traditional use of the plant as a local health remedy. Key words: Antibacterial activity, MIC, MBC, gram-positive bacteria, gram-negative bacteria, Mangifera indica, extract.

The state of activation of ribulose-1,5-bisphosphate carboxylase in wheat leaves

In light and in darkness, exposure of leaf segments to CO2-free atmospheres caused a marked reduction in extractable RuBP carboxylase activity. By contrast, darkness caused a relatively small decrease in carboxylase activity in extracts from leaf segments kept in air containing CO2. Recovery of carboxylase activity in leaves during illumination in air after exposure to CO2-free conditions paralleled recovery of capacity for photosynthesis; in darkness recovery of carboxylase activity in leaves was slower than in the light. Extracts from leaves exposed to CO2-free conditions recovered activity when provided with CO2 and Mg(2+); there were clearly, however, substances in the extracts that modified the activity achieved and caused anomalous decreases and increases with time after extraction. Studies of the effect of orthophosphate on the activity of purified wheat carboxylase in vitro were consistent with the view that many of the effects observed on the activity of crude leaf extracts were due to orthophosphate content.

Reversal of Low Temperature Effects on a Tropical Plant by Gibberellic Acid1

SummaryPangolagrass plants (Digitaria decumbens Stent.) exposed to 10C night temperature had increased starch contents and decreased amylolytic activities, dry weights, leaf areas, and shoot lengths as compared with control plants exposed to 30C night temperatures. Application of 10‐5 M gibberellic acid (GA3) reversed these effects of 10C night temperature. The direct addition of GA3 to the reaction mixture did not alter the in vitro amylolytic activity of crude leaf extracts of pangolagrass during their incubation either at 10C or 30C, which indicates that perhaps the effect of low temperature was on synthesis of amylolytic enzymes.