Study on The Whitening Effect of a Composite Plant Extract

By compounding the cranberry extract,lavender flower extract,Kakadu plum extract,edelweiss flower/leaf extract and aloe vera extract into a composite plant extract(BIRC-Rosée WT100),the whitening effects of this composite plant extract in antioxidation,anti-inflammation,skin barrier maintenance,and inhibition of melanin production and transport were evaluated.By comparing the inhibitory effects on tyrosinase activity between the composite plant extract andα-arbutin,and then analyzing the decline of apparent chromaticity,apparent brightness and melanin content through 3D melanin skin model platform,the comprehensive whitening effect was evaluated and compared with that of kojic acid.The results showed that,the composite plant extract(BIRC-Rosée WT100)had a tyrosinase inhibition rate of 98.99%at the original concentration,which was much higher than that ofα-arbutin.In 3D melanin skin model,the apparent chromaticity and brightness could be effectively improved,and moreover,the total amount of melanin in the skin could be reduced,showing remarkable whitening effect.

Sperm immobilization activity of Allium sativum L. and other plant extracts

<abstract>Aim: To identify possible spermicidal agents through screening a number of edible medicinal plants with antimicrobial activity. Methods: Initial screening was made on the basis of ram cauda epididymal sperm immobilization immediately after addition of extracts. The most potent extract was selected and was evaluated on both ram and human spermatozoa. To unravel its mode of action several sperm functional tests were carried out, namely viability of cells, hypo-osmotic swelling test for membrane integrity and assays of membrane-bound enzyme 5'-nucleotidase and acrosomal marker enzyme acrosin. Results: The crude aqueous extract of the bulb of Allium sativum L. showed the most promising results by instant immobilization of the ram epididymal sperm at 0.25 g/mL and human ejaculated sperm at 0.5 g/mL. Sperm immobilizing effects were irreversible and the factor of the extract responsible for immobilization was thermostable up to 90 癈. On boiling at 100 癈 for 10 minutes, this activity was markedly reduced. Moreover, this extract was able to cause aggregation of ram sperms into small clusters after 30 minutes of incubation at 37 癈. However this property was not found in human spermatozoa. More than 50 % reduction in sperm viability and hypo-osmotic swelling occurred in treated sperm as compared with the controls, indicating the possibility of plasma membrane disintegration which was further supported by the significant reduction in the activity of membrane bound 5'-nucleotidase and acrosomal acrosin. Conclusion: The crude aqueous extract of A. sativum bulb possesses spermicidal activity in vitro.

Anti-quorum sensing and anti-biofilm formation activities of plant extracts from South Korea

Objective: To investigate anti-quorum sensing(anti-QS) and anti-biofilm formation(antiBF) activities of the ethanol extracts of 388 plants. Methods: The anti-QS activity of the plant extracts was evaluated by disc-diffusion assays using the bio-reporter strain, Chromobacterium violaceum CV017. Pseudomonas aeruginosa PAO1, Yersinia enterocolitica ATCC 9610, and Agrobacterium tumefaciens C58, which possess QS systems, were used to evaluate the antiBF activity of the plant extracts. Results: Among 388 plant extracts, the Cornus controversa(C. controversa) and Cynanchum wilfordii extracts exhibited the strongest anti-QS activity. The C. controversa extract exhibited anti-BF activity against Pseudomonas aeruginosa, Yersinia enterocolitica and Agrobacterium tumefaciens, whereas the Cynanchum wilfordii extract exhibited no anti-BF activity against Pseudomonas aeruginosa. In addition, the C. controversa extract suppressed soft rot of cabbage. Conclusions: The C. controversa extract inhibits bacterial QS and BF, and is capable of controlling soft rot. Therefore, this extract has potential for the prevention and treatment of bacterial infections and for the development of alternatives to antibiotics.

Dietary plant extracts modulate gene expression profiles in alveolar macrophages of pigs experimentally infected with porcine reproductive and respiratory syndrome virus

Background: Our previous study showed that 3 plant extracts enhanced the immune responses and growth efficiency of weaned pigs infected with porcine reproductive and respiratory syndrome virus(PRRSV), which is one of the most economically important disease in swine industry. However, each plant extract differently effected on growth efficiency and immune responses. Therefore, the objective of this study was conducted to characterize the effects and investigate the potential underlying mechanisms of 3 plant extracts on gene expression of alveolar macrophages in weaned pigs experimentally infected with PRRSV.Results: PRRSV infection altered(P < 0.05) the expression of 1,352 genes in pigs fed the control(CON;755 up, 597 down). Compared with the infected CON, feeding capsicum(CAP), garlic botanical(GAR), or turmeric oleoresin(TUR) altered the expression of 46 genes(24 up, 22 down), 134 genes(59 up, 75 down), or 98 genes(55 up, 43 down) in alveolar macrophages of PRRSV-infected pigs, respectively. PRRSV infection up-regulated(P < 0.05) the expression of genes related to cell apoptosis, immune system process, and response to stimulus, but downregulated(P < 0.05) the expression of genes involved in signaling transduction and innate immune response.Compared with the infected CON, feeding TUR or GAR reduced(P < 0.05) the expression of genes associated with antigen processing and presentation, feeding CAP up-regulated(P < 0.05) the expression of genes involved in antigen processing and presentation. Supplementation of CAP, GAR, or TUR also enhanced(P < 0.05) the expression of several genes related to amino acid metabolism, steroid hormone synthesis, or RNA degradation, respectively.Conclusions: The results suggest that 3 plant extracts differently regulated the expression of genes in alveolar macrophages of PRRSV-infected pigs, especially altering genes involved in immunity.

Larvicidal efficacy of plant extracts and isolated compounds from Annonaceae and Piperaceae against Aedes aegypti and Aedes albopictus

The Aedes(Ae.)aegypti and Ae.albopictus mosquitoes are vectors of epidemiologically relevant arboviruses in the public health context,such as the dengue,Zika and chikungunya viruses.Among the alternatives to synthetic insecticides for the control of these vectors,the use of natural plant products deserves attention.This review summarizes findings on the larvicidal potential of plant extracts on Ae.aegypti and Ae.albopictus,as well as the potential of isolated compounds from plants of the Annonaceae and Piperaceae families against these vectors.Descriptors related to larvicidal activity of plant extracts and isolated compounds in Aedes spp.in the Web of Science database were used,for plant extracts considering publications between 2000 and 2019.A total of 859 articles were analyzed for plant extracts and estimates of lethal concentration values(LC50 and LC90).In the end,95 articles that presented the larvicidal potential of 150 plant species from 52 families were analyzed.The two families most studied for this activity were Fabaceae and Asterace Aedes.The plant families with the best LC50 values against mosquitoes were Piperaceae and Annonaceae.Larvicidal activity of 50 acetogenins has already been identified on Ae.aegypti,and 29 of them presented LC50 below 10μg/mL,as well as the larvicidal activity of 8 compounds isolated from Piperaceae.Therefore,plants of these two families are promising for the development of commercial botanical larvicides in the form of extracts and isolated substances,as well as the production via organic synthesis of the most active compounds.

Contact Activities of 20 Plant Extracts against Lipaphis erysimi Kaltenbach

[Objective] The aim was to screen out plants which had strong contact activity against Lipaphis erysimi Kaltenbach. [Method] Twenty plant species which were collected from Gupo Mountain in Hezhou of China were extracted with methanol by cold soaking method. Contact activities of 20 methanol plant extracts against L. erysimi were determined by capillary micro spot method. [Result] The methanol extracts from Mussaenda esquirolli Levi. and Folium trematis Orientalis had the highest contact activities against L. erysimi at the dose of 10 p^g/head, and their 24 h corrected mortality rates were 92.22% and 92.15%, respectively; followed by Folium trematis and Viola hossei, with 24 h corrected mortality rate of 87.59% and 82.95%, respectively. The methanol extract of Hedyotis lancea had medium activity, with 24 h corrected mortality rate of 65.52%. Methanol extracts of the other plants had low contact activities against L. erysimi, with the corrected mortality rate lower than 50%. The methanol extracts of M. esquiroUi, F. variolosa and F. trematis had high contact toxicity, with LDS0 of 0. 768 6, 0.784 1 and 1. 504 4 μg/head, respectively. [ Conclusion] M. esquirolli, F. variolosa and F. trematis show exploitation potential, and they are worth further studying.

Plant Extracts and Essential Oils at Concentrations Acceptable to a Sensory Panel Inactivate Salmonella Typhimurium DT104 in Ground Pork

A potential method to inhibit pathogenic bacterial growth in meat is through the introduction of plant-derived antimicrobials. Because these antimicrobials may also adversely affect the sensory characteristics of the meat, the objectives of this study were 1) to define the appropriate concentrations of olive extract, apple extract, oregano oil, and cinnamon oil added to ground pork that are acceptable to a sensory panel, and 2) to determine their antimicrobial activities against Salmonella Typhimurium DT104 in inoculated ground pork. Plant extracts were evaluated against two initial inoculum levels (6 and 4 log CFU/g of pork) of Salmonella. Sensory tests showed that acceptable concentrations of oregano and cinnamon oils were 0.5% and of olive and apple extracts were 3%, respectively. Ground pork samples were inoculated with Salmonella, treated with antimicrobials at various concentrations (0.1% - 0.5% cinnamon and oregano essential oils and 3% - 5% olive and apple extracts), and stored at 4°C for 7 days. Survivors were enumerated at days 0, 3, 5, and 7. Cinnamon oil at 0.5% and olive extract at 3% induced a 1.0 and a 0.9 log CFU/g (from 6-log CFU/g initial inoculum) reduction, respectively, at day 7. At 3%, olive extract showed a 1.06 log CFU/g maximum reduction of Salmonella from a 4-log CFU/g initial inoculum. Pork samples containing oregano oil and apple extract did not show a significant reduction compared to the control without the antimicrobials. The results indicate that cinnamon oil and olive extract can potentially be applied at consumer-acceptable concentrations against low levels of S. Typhimurium DT104 in ground pork.

Anti-Fertility Effects and Mechanism of the Plant Extract Shikonin on Mice

Controlling fertility of rodent pests has become an effective means of controlling the population of grassland rodents in China. Recently, research has focused on how to select environmentally-friendly sterilants without pollution effects, and to realize sustainable control of pest rodent populations. Sterilants from plant extracts have been mainly selected. In this study, mice were used as the experimental subjects for research on the anti-fertility effects of plant extracts of shikonin and the anti-fertility mechanism of shikonin extract was determined. The mice were divided into four groups, including one control group and three experimental groups. There were three applications of shikonin extract in different concentrations (5 mg·kg-1, 20 mg·kg-1 and 50 mg·kg-1). The mice gavage experiments indicated that a shikonin concentration of 50 mg·kg-1 had the expected anti-fertility effects. Mice copulation experiments showed that the 50 mg·kg-1 shikonin treatment had significant anti-fertility effects on both female-treatment and female-male-treatment groups. The results of the PCR analysis on the AgRP and ghrelin mRNA from female ovaries and male testicles indicated that shikonin could control mice reproduction by regulating the pituitary gonadal axis. Shikonin, as plant source sterile agent, would have more ideal effects for functioned both sexes sterility.

Preliminary Study on Antifungal Activities of 30 Kinds of Plant Extracts

[Objective]The paper was to screen the plant extracts with strong antifungal activity. [Method] With R. solani as the test object, the antifungal activities of 30 kinds of plant extracts were carried out primary screening by mycelial growth rate method. [Result] Twelve kinds of plant extracts including Pinus yunnanensis （leaf）, Phryma leptostachya （stem and leaf）, Pueraria peduncularis （root, stem and leaf）, Pinus armandiifruit （fruit）, Aconitum brachypodum （stem and leaf）, Phellodendron amurense （stem and leaf）, Rhaponticum uniflorum （root）, Alnus cremastogyne （leaf）, Rehmannia glutinosa （root）, Cryptomeria fortunei （stem and leaf） and Berberis pruinosa （stem and leaf） had strong activities against R. solani with growth inhibition rates over 80% as the concentration was 10 mg/ml,among which the extracts of P. yunnanensis （leaf）, P. leptostachya （stem and leaf）, P. peduncularis （root, stem and leaf） and P. armandiifruit （fruit） showed the inhibition rate above 95%, significantly higher than other plant extracts. The secondary screening results of antifungal activities of the above 12 plant extracts were consistent with the primary screening. [Conclusion] The study laid foundation for further development of high efficient, safe and environmental-friendly new fungicides.

Effects of Spraying Plant Extract Mixture on Growth and Development and Diseases of Flue-cured Tobacco

[Objective]The paper was to study the effects of plant extract mixture on growth and development,photosynthetic indexes and disease control of flue-cured tobacco.[Method]Using field test method,a total of five treatments were designed in the test,including T1(control,conven-tional pesticide control),T2(conventional pesticide control+spraying plant extract mixture at 15 and 30 d post transplanting),T3(conventional pesticide control+spraying plant extract mixture at 15,30 and 45 d post transplanting),T4(conventional pesticide control+spraying plant extract mixture at 15,30,45 and 60 d post transplanting),and T5(conventional pesticide control+spraying plant extract mixture at 15,30,45,60 and 75 d post transplanting).In addition,flue-cured tobacco in treatments T2-T5 were sprayed with antiviral agent once at 30 d post transplanting,and sprayed with quality promoting agent at 30 and 75 d post transplanting,respectively.[Result]The agronomic traits and photosynthetic indexes of all treatments were improved by spraying plant extract mixture,and those in T5 treatment were the best.Spraying plant extract mixture had significant control effect on brown spot;the disease index in T5 treatment was the lowest,and the control effect was the best.The results showed that spraying plant extract mixture promoted the growth and development of flue-cured tobacco,reduced the disease index of brown spot,and improved the quality of tobacco leaves.[Conclusion]Spraying plant extract mixture has positive effect on growth and development and disease control of flue-cured tobacco.

Treatment Effect of Various Concentration of Plant Extracts on Murine Norovirus

Noroviruses are positive-sense, single-stranded, non-enveloped RNA virus that measures approximately 27 - 35 nm in diameter. It affects humans of all ages and races causing most cases of viral gastroenteritis worldwide. Infection results from ingestion of contaminated food or water as well as causing diarrhea and vomiting in humans. Extracts from plants are known to have antioxidant, anti-inflammatory, and adhesive properties which are associated with barrier functions. The aim of this study was to elucidate whether plaque reduction was due to an effect of methanolic plant extract directly on the virus, whether the extract affects viral replication, and lastly, whether the extract disrupts the cell surface binding with the virus. The plant extracts of interest were the calyces of Hibiscus sabdariffa (HS) and the seeds of Zanthoxylum armatum (ZA). Antiviral activities of these extracts were determined against murine norovirus. The logarithmic viral reduction per plaque-forming unit was (22 log10) PFU/ml (control), (15 log10) PFU/ml (treated HS), and (12 log10) PFU/ml (treated ZA) with a significant reduction (68% and 55% respectively) when compared with the control for the direct effect on the virus. The role of extracts on virus replication showed (25 log10) PFU/ml (control) as against the HS treated-virus-infected cells (9 log10) PFU/ml and ZA treated-virus-infected cells (5 log10) PFU/ml (36% and 20% respectively). Finally, effect of the extract on the viral attachment showed (31 log10) PFU/ml (control), (12 log10) (HS-treated) and (9 log10) PFU/ml (ZA-treated), (39% and 29% respectively. Extract treatment with HS and ZA has shown evidence of a reduced number of plaques formation with the latter having fewer plaques. Both extracts have proven potential to reduce the viral multiplication process by interfering with the replication process. This study shows that Hibiscus sabdariffa (calyces) and Zanthoxylum armatum (seed) extracts disrupt murine norovirus from consistent viral replication.

A review: effect and mechanism of plant extracts rich in polyphenols on reducing uric acid activity

Hyperuricemia is a metabolic condition caused by the increase of uric acid level in the body,which can lead to gout,kidney disease,cardiovascular disease,hypertension and diabetes.In recent years,the incidence rate of hyperuricemia has been increasing and gradually becoming younger.Allopurinol and febuxostat are commonly used drugs to reduce the level of uric acid in the body.Although these drugs have good curative effect,they can produce adverse reactions.Therefore,it has been the focus of attention to find appropriate treatment and new drugs to reduce serum uric acid level.Natural plants have become the source of new drugs for their multiple biological activities,strong efficacy and minimal side effects.More and more studies have shown that natural plant extracts rich in phenols,flavonoids and other active components can significantly reduce the level of uric acid,and improve the complications caused by high uric acid.In this paper,hyperuricemia related diseases,functional plants rich in polyphenols with the effect of reducing uric acid and the mechanism of their active components were reviewed.

Teucrium polium plant extract provokes significant cell death in human lung cancer cells

Lung cancer is the first common malignancy worldwide;in view of the limited success of available treatment modalities for this cancer, alternative and complementary strategies need to be developed. On the other hand, Teucrium polium (TP) is a medicinal plant that has been used for more than two thousand years for treating many diseases such as abdominal pain, indigestion and diabetes in the Middle East. However, the effect of TP plant extract on hu-man non-small cell lung cancer (NSCLC) has not been investigated yet. In this study, we exam-ined the effects of TP extract on cell prolifera-tion, cell cycle progression and cell death in H322 and A549 lung cell lines. Our results show that TP plant extract inhibits cell proliferation and deregulates cell cycle progression. More importantly, TP plant extract causes a dramatic cell death in both cell lines in comparison with untreated cells. Our data suggest that this plant extract could have an important therapeutic role in the treatment of human NSCLC.

Antibacterial activity of eight Iranian plant extracts against methicillin and cefixime restistant Staphylococcous aureus strains

Objective:To assess the antibacterial activity of eight Iranian plant extracts against Staphylococcus aureus(S.aureus) strains which were isolated from infected patients.Methods: The studied strains were isolated from urine,stool,blood and wound of infected patients and identified by biochemical tests.In further,the antibacterial activity of 8 ethanolic local plant extracts including Querqus brantii(Q.brantii),Ziziphus spina-christi(Z.spina-christi),Peganum harmala(P.harmala),Oliveira decumbens(O.decumbens),Galium tricornutum(G.tricornutum), Vitex pseudo negundo(Vi.pseudo negundo),Salvia officinalis(S.officinalis),Vaccaria pyramidata (V.pyramidata) were then evaluated using agar disc diffusion method.Results:A total of 9 isolates were isolated and identified as S.aureus.Antibacterial profile of the strains showed that the strains were resistant to methicillin and cefixime.The highest antibacterial activity against the studied strains were belong to Q.brantii,P.harmala,Z.spina-christi and O.decumbens vent extracts with 11-40 mm,15-28 mm,8-26 mm and 10-20 mm of diameters,respectively. Intermediate antibacterial activity was exhibited by G.tricornutum and Vi.pseudo negundo against some of the studied strains with 7-20 mm and 7-13 mm of diameters,respectively. Noteworthy,out of 9 studied strains;6 and 2 of them were resistant to the G.tricornutum and Vi. pseudo negundo extracts,respectively.The S.officinalis and Va.pyramidata,however,showed no antibacterial activity against the studied strains.Conclusions:The Q.brantii,P.harmala,Z. spina-christi and O.decumbens extracts were shown to possess strong antibacterial activity against methicillin and cefixime resistant S.aureus strains and can be considered as the promising natural antibiotics for treating the studied strains.

Effect of plant extracts on activity of some defense enzymes of apple fruit in interaction with Botrytis cinerea

The efficacy of seven plant extracts(neem,fennel,lavender,thyme,pennyroyal,salvia and asafetida) in controlling postharvest of apple(caused by Botrytis cinerea) was evaluated in vitro and in vivo.In vitro,all plant extracts treatments inhibited spore germination.Inhibitory rates of pore germination was 17.41 and 20.83% for neem extract treatment(methanolic and aqueous extracts,respectively) with significant difference compared to control(73.6 and 85.33%) for aqueous and methanol extracts.In the storage conditions,the application of aqueous extract of neem(at concentration of 25%) resulted in 89.11% reduction of disease severity compared with the untreated control.Results of enzymes activity showed the plant extracts can increase the activity of peroxidase,phenylalanine ammonia-lyase,β-1,3-glucanase and polyphenol oxidase in the presence of pathogens,in apple fruits.However,the results of this research revealed that application of neem extracts was more effective than the application of other plant extracts.According to this study,it could be concluded that plant extracts may be useful to control postharvest disease as a safe alternative option to chemical fungicides.

Larvicidal and repellent activity of medicinal plant extracts from Eastern Ghats of South India against malaria and filariasis vectors

Objective:To evaluate the larvicidal and repellent activities of ethyl acetate and methanol extracts of Acacia concinna（A.concinna）,Cassia siamea（C.siamea）.Conundrum sativum（C. sativum）,Cuminum cyminum（C.cyminum）,Lantana camma（L.camara）,Nelumbo nucifera （N.nucifera） Phyllanlhus amarus（P.amarus）.Piper nigrum（P.nigrum） and Trachyspermum ammi（T.ammi） against Anopheles stephensi（An.stephensi） and Culex quinquefasciatus（Cx. quinquefasciatus）.Methods:The larvicidal activity of medicinal plant extracts were tested against earl) fourth-instar larvae of malaria and filariasis vectors.The mortality was observed 24 h and 48 h after treatment,data were subjected to probit analysis to determine the lethal concentrations(LC50 and LC90) to kill 50 and 90 per cent of the treated larvae of the tested species. The repellent efficacy was determined against two mosquito species at five concentrations（31.25. 62.50.125.00.250.00,and 500.00 ppm） under the laboratory conditions.Results:All plant extracts showed moderate effects after 24 h and 48 h of exposure;however,the highest activity was observed after 24 h in the leaf methanol extract ol N.nucifera.seed ethyl acetate and methanol extract of P.nigrum against the larvae of An.Stephensi(LC50 = 34.76.24.54 and 30.20 ppm) and against Cx.quinquefasciatus(LC50= 37.49.43.94 and 57.39 ppm),respectively.The toxic effect of leaf methanol extract of C.siamea,seed methanol extract of C.cyminum,leaf ethyl acetate extract of N.nucifera.leaf ethyl acetate and methanol extract of P.amarus and seed methanol extract of T.ammi were showed 100%mortality against An.stephensi and Cx.quinquefasciatus alter 48 h exposer.The maximum repellent activity was observed at 500 ppm in methanol extracts of N. nucifera.ethyl acetate and methanol extract of P.nigrum and methanol extract of T.ammi and the mean complete protection time ranged from 30 to 150 min with the different extracts tested. Conclusions:These results suggest that the leaf and seed extracts of C.siamea.N.nucifera.P. amarus.P.nigrum and T.ammi have the potential to be used as an ideal ecofriendly approach for the control of the An.stephensi and Cx.quinquefasciatus.

Total phenolic content,in vitro antioxidant activity and chemical composition of plant extracts from semiarid Mexican region

Objective:To determine the extraction suitable conditions of total phenolic content(TPC) by heat-reflux system,antioxidant activities and HPLC characterization of the aqueous-ethanolic extracts of Jatropha dioica(J.dioica)(Dragon's blood).Flourensia cernua(F.cernua)(Tar bush).Eucalyptus camaldulensis(E.camaldulensis)(Eucalyptus) and Turnera diffusa(T.diffusa)(Damiana).Methods:TPC was evaluated by the well-known colorimetric assay using FolinCiocalteu reagent.The antioxidant activities were assayed by three methods based on scavenging of DPPH,ABTS and by lipid oxidation inhibition.The chemical composition of the extracts obtained was subject to HPLC analysis.Results:TPC in the plant extracts ranged from 2.3 to14.12 mg gallic acid equivalents/g for J.dioica and E.camaldulensis,respectively.The plant extracts of F.cernua,E.camaldulensis and T.diffusa showed similar strong antioxidant activities on scavenging of DPPH and lipid oxidation inhibition.In contrast,J.dioica extracts had lowest potential antioxidant in three assays used.HPLC assay showed the presence of several phenolic compounds in the extracts used.Conclusions:The results obtained suggest that F.cernua,E.camaldulensis and T.diffusa are potential sources to obtain bioactive phenolic compounds with high antioxidant properties which can be used in the factories as antioxidant agents or for treatments in diseases.

Synergistic effects of plant extracts and antibiotics on Staphylococcus aureus strains isolated from clinical specimens

Objective:This study has been done to evaluate the interaction between water extracts of Psidium guajava, Rosmarinus officinalis,Salvia fruticosa,Majorana syriaca,Ocimum basilucum,Syzygium aromaticum,Laurus nobilis,and Rosa damascena alone and then synergy testing of these extracts with known antimicrobial agents including oxytetracycline HCl,gentamicin sulfate,penicillin G,cephalexin and enrofloxacin.This study was conducted against five S.aureus isolates;one is Methicillin -resistant Staphylococcus aureus(MRSA) and 4 Methicillin - sensitive Staphylococcus aureus(MSSA).Methods:Evaluation of the interaction between plant extracts and different antimicrobial agents has been done using well - diffusion and microdilution methods. Results:The results of the conducted experiments using well - diffusion method demonstrate that these plants showed in vitro interactions between antimicrobial agents and plant extracts were additive,while using microdilution method showed synergistic effects with significant reduction in the MICs of the test antibiotics against these strains of S.aureus.This change in MIC was noticed in all plant extracts against test antibiotics including these plants showed weak antibacterial activity by well diffusion method.Synergism effect was occurred in both sensitive and resistant strains but the magnitude of minimum fold reduction of inhibitory concentration in resistant strains especially MRSA strain was higher than the sensitive strains.Coclusion:This study probably suggests the possibility of concurrent use of these antimicrobial drugs and plant extracts in combination in treating infections caused by S.aureus strains or at least the concomitant administration may not impair the antimicrobial activity of these antibiotics.

Efficacy of Selected Plant Extracts against <i>Pyricularia grisea</i>, Causal Agent of Rice Blast Disease

Rice blast disease, caused by a seed-borne fungus Pyricularia grisea, is an important and serious disease of rice (Oryza sativa L.) worldwide. The disease has been reported to cause yield losses of up to 40% in Tanzania. Studies were conducted to determine the effect of aqueous extracts of Aloe vera, Allium sativum, Annona muricata, Azadirachta indica, Bidens pilosa, Camellia sinensis, Chrysanthemum coccineum, processed Coffee arabica, Datura stramonium, Nicotiana tabacum and Zingiber officinalis for control of rice blast disease (Pyricularia grisea) in-vitro and in-vivo. The results indicate that processed C. arabica at 10% and 25% (v/v) had the highest (81.12%) and (89.40%) inhibitory effect, respectively, against P. grisea. Aqueous extract from N. tabacum at 10% concentration ranked third (80.35%) in inhibiting P. grisea. These were followed by extracts from 25% A. vera (79.45%) and 25% C. coccineum flower (78.83%). The results also indicate that, extracts from A. indica, A. vera, A. sativum, C. arabica, D. stramonium, C. sinensis, Z. officinalis and N. tabacum did not have any phytotoxic effect on seed germination, shoot height, root length, dry weight, seedling growth and seedling vigour index. These plant extracts can thus be used for rice seed treatment to manage rice blast disease.

Evaluation of larvicidal activity of medicinal plant extracts against three mosquito vectors

Objective:To evaluate the mosquito larvicidal activity of plant extracts.Methods:The hexane,chloroform,ethyl acetate,acetone,and methanol leaf,flower and seed extracts of Abrus precatorius（A.precatorius）,Croton bonplandianum（C.bonplandianum）,Cynodon dactylon （C.dactylon）,Musa paradisiaca（M.paradisiaca） and Syzygium aromaticum（S.aromaticum） were tested against fourth instar larvae of Anopheles vagus（An.vagus）,Armigeres subalbatus （Ar.subalbatus） and Culex vishnui（Cx.vishnui）.Results:The highest larval mortality was found in seed ethyl acetate extracts of A.precatorius and leaf extracts of C.bonplandianum, flower chloroform and methanol extracts of M.paradisiaca,and flower bud hexane extract of S. aromaticum against An.vagus with LC50 values of 19.31,39.96,35.18,79.90 and 85.90μg/mL;leaf ethyl acetate and methanol extracts of C.dactylon,flower methanol extract of M.paradisiaca, flower bud methanol extract of S.aromaticum against Ar.subalbatus with LC50 values of 21.67, 32.62,48.90 and 78.28μg/mL,and seed methanol of A.precatorius,flower methanol extract of M.paradisiaca,flower bud hexane extract of S.aromaticum against Cx.vishnui with LC50 values of 136.84,103.36 and 149.56μg/mL,respectively.Conclusions:These results suggest that the effective plant crude extracts have the potential to be used as an ideal ecofriendly approach for the control of disease vectors.This study provides the first report on the larvicidal activity of crude solvent extracts of different mosquitoes.