Effect Of Plant Extracts Research Articles

Anti-inflammatory effects of aqueous extract of Mangifera indica in Wistar rats.

Recent studies in standard laboratories have indicated that a typical mango stem bark aqueous extract (Magnifera indica Linn) possess anti-malaria and anti-fever properties. Recent information also exists in the literature, suggesting its potency as a very effective anti-inflammatory plant extract. This study will therefore contribute immensely to the systemic search for a useful, less toxic and natural bioactive medicinal compound. This study investigated the anti-inflammatory effects of the aqueous extract of Mangifera indica (MI) in a carrageenin-induced rat paw oedema model of acute inflammation. Rats (n=5) were treated orally with MI (50, 100 and 200 mg/kg), acetylsalicylic acid (100 mg/kg) or distilled water (3 mL). Thirty minutes later, acute inflammation was induced with a sub-plantar injection of 0.1 mL of 1% carrageenin solution into the right hind paw of the rats. The paw oedema sizes were measured with the aid of a Vernier calliper over a period of 3 hours. The aqueous extract of MI (50-200 mg/kg, p.o.) produced a dose-dependent and significant inhibition of the acute inflammation induced by the carrageenin in rats when compared with controls. The percentage inhibition of oedema formation produced by MI (200 mg/kg, p.o.) was similar to that elicited by acetylsalicylic acid (100 mg/kg, p.o.). The results of this preliminary investigation suggest that MI contains active compounds with an anti-inflammatory activity. However, more detailed studies using additional models are necessary to further characterise the effects of MI in inflammatory disorders.

Antifungal activity using medicinal plant extracts against pathogens of coffee tree

Generally, the medicinal plants have antifungal substances that can be used for the plant protection against phytopathogens. The objective of this study was to know the efficiency of aqueous extracts from medicinal plants against the major etiological agents of coffee tree. The aqueous extracts used were extracted from bulbs of Allium sativum, leaves of Vernonia polysphaera, Cymbopogon citratus, Cymbopogon nardus, Cordia verbenacea, Eucalyptus citriodora, Ricinus communis, Azadirachta indica, Piper hispidinervum and flower buds of Syzygium aromaticum. The etiological agents considered for this study were Cercospora coffeicola, Colletotrichum gloeosporioides, Fusarium oxysporum, Phoma tarda, Rhizoctonia solani and Hemileia vastatrix. The screening for harmful extracts was done based on mycelial growth and conidial germination inhibition. All experiments performed were in vitro conditions. The inhibition of mycelial growth was performed mixing the extracts with the PDA. This mixture was poured in Petri dishes. On the center of the dishes was added one PDA disc with mycelium. It was incubated in a chamber set to 25ºC. The evaluation was done daily by measuring the mycelial growth. The germination assessment was also performed with Petri dishes containing agar-water medium at 2%. These were incubated at 25ºC for 24 hours. After this period the interruption of germination was performed using lactoglycerol. The experiments were conducted in a completely randomized design. The most effective plant extracts against the micelial growth and conidial germination were V. polysphaera, S. aromaticum and A. sativum.

Effects of aqueous extract of some herbal plant leaves on seed germination and seedling growth of bean (Lablab niger) and borboti (Vigna unguiculata)

An experiment was conducted on aqueous extracts of leaves of some herbal plants viz., bohera (Terminalia belirica), horitoki (Terminalia chebula), tulsi (Ocimum gratissmum) and arjun (Terminalia arjuna) for investigating the presence of biologically active substance. The seeds of two vegetable crop such as, country bean (Lablab niger) and borboti (Vigna unguiculata), were testing for germination and seedling growth treating with aqueous extract of four herbal plant leaves. The chemical investigation on effective plant extract was also attempted. The aqueous extract of horitoki significantly reduced and delayed germination, growth of shoot length and root length of country bean, and borboti seeds compared with control whereas, bohera increased and enhanced germination, growth of shoot length and root length of these same vegetable crops. The maximum germination was in country bean, and borboti seeds within 4 and 3.77days respectively, treated with the leaves extract of bohera compared with control. Shoot lengths were 15.63 and 15.83 cm and root length were 8.44 and 8.65 cm for country bean, and borboti seedlings, respectively, due to the presence of growth regulator. The aqueous extract of horitoki showed the lowest and late germination at 5 and 4.77days and minimum shoot length were 12.01 and 12.76 cm, and root length were 5.56 and 5.82 cm for country bean, and borboti seedlings, respectively, due to the presence of growth inhibiting substances or toxic compounds. The growth promoting effect of bohera leaves extract on the tested vegetable crops seemed due might be the presence of biologically active substances. The thin layer chromatography (TLC) examination of chloroform extract of bohera leaves showed four distinct compounds at Hexane: Ethyl acetate (3:1, v/v) while horitoki leaves showed three distinct compounds at Hexane: Ethyl acetate (5:1, v/v).

Antimicrobial potential of Pakistani medicinal plants against multi-drug resistance Staphylococcus aureus

Objective: To determine resistance patterns of Staphylococcus aureus (S. aureus) isolated from different areas of Pakistan and to identify antimicrobial agents against multi-drug resistant S. aureus strains. Methods: A total of 67 samples (sewerage, nasal and milk) were collected from different farm areas of Pakistan to identify local strains of S. aureus. Sixteen out of 67 samples were positive for S. aureus. Only 6 out of 16 S. aureus strains showed resistance to antibiotics. Then the antibacterial effect of 29 medicinal plants was evaluated on these S. aureus isolates and a standard S. aureus strain ATCC 25923. The solvents used for the extraction of plants were acetone, dimethyl sulfoxide and methanol. The in vitro antibacterial activity was performed using agar disc diffusion method. Moreover, minimum inhibitory concentration of effective medicinal plant extracts was identified through micro-dilution method to find out their 50% inhibitory concentration. Results: Plant extracts of 5 medicinal plants (Psidium guajava, Nigella sativa, Piper nigrum, Valeriana jatamansi, and Cucurbita pepo) exhibited antibacterial activity against locally isolated multidrug resistant strains of S. aureus. The minimum inhibitory concentration of these extracts was ranged from 0.328 to 5.000 mg/mL. Conclusions: Plant extracts of Psidium guajava, Piper nigrum seed, Valeriana jatamansi, Cucurbita pepo and Nigella sativa showed significant in vitro antibacterial activity and thus, such findings may serve as valuable contribution in the treatment of infection and may contribute to the development of potential antimicrobial agents against multi drug resistant strains of S. aureus. Peer reviewer

Bioassay of different extract of clerodendruminfortunatum on some vegetables seeds with their chemical investigation

An experiment was conducted on bioassay of different extracts of Clerodendrum infortunatum leaves for each vegetable crop such as, swamp cabbage, ladies finger, and yard long bean with the attempt for chemical investigation on effective plant extract. The chloroform extract of Clerodendrum infortunatum has significantly increased and enhanced the germination, growth of shoot length and root length of yard long bean and swamp cabbage whereas, reduced and delayed the germination, growth of shoot length and root length of lady’s finger seeds compared with control. The study revealed that different extract of Clerodendrum infortunatum contains growth regulatory active compounds. Among the extracts, chloroform extracts showed better performances in terms of percent germination and growth of shoot and root length of yard long bean and swamp cabbage. To find out effective compound from chloroform extracts, thin layer chromatography was done which showed five distinct compounds. These compounds were separated by preparative Thin Layer Chromatography. Further study is needed to determine structure for finding growth regulatory compound in Agricultural usage.

Antifertility activity of Artemisia vulgaris leaves on female Wistar rats

AimTo evaluate the antifertility activity of Artemisia vulgaris leaves on female Wistar rats. MethodThe plant extract was tested for its effect on implant formation at two dose levels, 300 and 600 mg·kg−1, respectively. The effective methanolic plant extract was further studied for estrogenic potency on ovariectomised immature female Wistar rats. ResultsThe data presented in this study demonstrate the antifertility potential of Artemisia vulgaris methanolic leaf extract, which shows a strong and significant decrease in implant formation (100%), and a strong estrogenic effect resulting in a significant increase in uterine weight in immature ovariectomised rats. These observations suggest that the methanolic extract of Artemisia vulgaris leaves has strong anti-implantation activity and estrogenic activity. ConclusionThe methanolic plant extract of A. vulgaris has antifertility activity.

In-vitro studies of some selected botanicals and baubiofungicide on mycelial growth and conidial germination of Cercospora arachidicola and Cercosporidium personatum

Efforts have been made to assess some plant extracts namely, Lycopersicon esculentum, Tagetus patula, Achras sapota, Azadirachta indica, Datura metel, Cymbopogon citrates, Polyalthia longifolia, Allium sativum and Allium cepa in vitro for the management of leaf spot (tikka) disease of groundnut cultivar Dhaka-1 caused by Cercospora arachidicola and Cercosporidium personatum. Results indicated that all the tested plant extracts and BAUBiofungicide suppressed the growth of mycelium and inhibition of conidial germination of C. arachidicola and C. personatum. Among the treatments, the leaf extracts of L. esculentum showed the most effective followed by leaf extract of D. metel, A. indica and BAU-Biofungicide in case of mycelial growth and conidial germination. Other plant extracts also had inhibitory effects. In case of conidial germination and germination inhibition, the least effective plant extract was C. citrates. Leaf extract of A. sapota was the least effective in case of mycelial growth. DOI: http://dx.doi.org/10.3329/ijarit.v3i2.17842 Int. J. Agril. Res. Innov. & Tech. 3 (2): 36-40, December, 2013

Can Standardized Plant Extracts Induce Complete Remission in Patients with Metastatic Tumors?

Background: The prognostic significance of malignant tumor-induced imbalance in the innate immune system is well known. The innate system uses a limited number of Pattern Recognition Receptors (PRR) to recognize conserved Pathogenic Associated Molecular Pattern (PAMP) structures expressed by microbes but not by host. PRR engagement often leads to the activation of natural immune cells which are important in the tumor defense. Growing evidence supports the hypothesis that similar to microbes various plant extracts can also contain PAMP-like structures which can activate cellular immune functions. Since the chemical production of PAMP structures is hardly accomplishable, the phytotherapy may be promising for the future tumor therapy. Objectives: The aim of this article is to present and discuss several favorable clinical responses of tumor patients treated with immunologically effective and standardized plant extracts (containing PAMP-like structures) as an addition to the conventional oncologic therapy. Course of therapy and results: Two standardized plant preparations based on lectin-sugar interactions were the patients given. The dose of the active sugar-binding mistletoe lectin (ML), applied subcutaneously by standardized mistletoe extract (ME) preparations, was between 0.5 and 1.0 ng/kg and the dose of arabinoxylan (given by standardized rice bran preparation, MGN-3/Biobran) was between 12 and 45mg/kg twice a week. In addition, wheat germ extract (WGE) standardized for 2, 6-dimethoxy-p-benzoquinone (50-80 mg/kg Avemar four times a week) was also given which can sensitize tumor cells against natural immune effector cells. Case reports gave an account of complete or nearly complete remissions in patients with sarcoma or with hepatic metastases treated with these standardized plant immunomodulators with and without conventional oncologic therapy. Conclusion: Standardized plant extracts (such as ME/ML, MGN-3 and WGE) seem to be potent candidates to be regarded as a supportive therapy of metastatic tumors

Efficacy of Selected Chemotherapeutic and Medicinal Plants on Fungal Fish Pathogens

Studies were conducted to examine the efficacy of selected chemotherapeutic and medicinal plants against common fungal fish pathogens. Four different doses of available fungicidal agents viz., lime + salt, brilliant green, malachite green and methylene blue were applied to the fresh culture of newly isolated fish pathogenic fungi (Aphanomyces invadans, Saprolegnia sp. and Achlya sp.) under in-vitro condition and minimum inhibitory dose (MID) was determined. Based on in-vitro results, chemotherapeutic were applied to the experimental infection of fish (Barbonymus gonionotus). Salt + lime, brilliant green and malachite green offered better results in reducing the rate of infection followed by medium effective methylene blue. Medicinal plants were selected on the basis of previous studies. Crude extracts were prepared from various parts (leaves and bulb) of neem (Azadirachta indica), turmeric (Curcuma longa) and shoti (C. zedoaria) and four different doses were applied to the fresh culture of above mentioned fungal pathogens under in-vitro condition to determine MID. Treatment trial was performed using the MID of the highly effective plant extracts (viz., tumeric, shoti, neem + tumeric and neem + shoti) on experimental infection of fish. Turmeric and neem + tumeric were found to be the most effective ones. Thus, medicinal plants would be an effective and alternative control measure along with selected chemotherapeutic against fungal diseases of fish.DOI: http://dx.doi.org/10.3329/pa.v19i1.17361 Progress. Agric. 19(1): 105 - 116, 2008

In vitro Antifungal Activity of Three Geophytic Plant Extracts against Three Post-harvest Pathogenic Fungi

Plant extracts appear to be one of the most effective alternative methods of plant diseases control which are less harmful to human beings and environment. In vitro antifungal activity of methanolic extracts of three promising wild geophytic plants against three post-harvest pathogenic fungi using radial growth technique was conducted. These extracts included the shoot system (S) and underground parts (R) of Asparagus stipularis, Cyperus capitatus and Stipagrostis lanata. The tested fungi were Alternaria solani, Aspergillus niger and Rhizopus stolonifer. The results exhibited that, all plant extracts had antifungal activity against the tested fungi. The antifungal activity greatly varied depending on plant parts and/or plant species. R. stolonifer was the most susceptible fungus to the tested plant extracts followed by A. niger and then A. solani. On the other hand, the most effective plant extracts against tested fungi were S. lanata (S) and A. stipularis (R). The most effective plant extracts against R. stolonifer were S. lanata (R) and C. capitatus (S). While, the extracts of A. stipularis (R) and S. lanata (S) were the most effective against A. niger. The extracts of C. capitatus (S) and S. lanata (S) exhibited the highest antifungal activity against A. solani. The results demonstrated that, the methanolic extracts of A. stipularis, C. capitatus and S. lanata had potential antifungal activity against A. solani, A. niger and R. stolonifer.

Inhibitory effects of some invasive alien species leaf extracts against tomato (Lycopersicon esculentum Mill.) bacterial wilt (Ralstonia solanacearum)

The inhibitory activity of selected invasive alien species leaf extracts against tomato bacterial wilt was studied in vitro and greenhouse. In vitro inhibitory activity was undertaken in a disc diffusion sensitivity test. Furthermore, aqueous extracts of Eichhorina crassipes, Mimosa diplotricha and Lantana camara and methanolic extract of Prosopis juliflora which showed better inhibitory effect in vitro were evaluated against R. solanacearum in greenhouse on tomato. The plant extracts were applied and evaluated at three different times of application (at the time of inoculation; two days before pathogen inoculation; and two days after pathogen inoculation). The result showed that most of the treatment combinations significantly reduce disease incidence and area under disease progress curve and increase biomass of tomato plants, but the effectiveness of tested plant species depends on the type of plant species and application time. The application of plant extracts at the time of pathogen inoculation resulted in highest reduction of disease development on tomato plants. Aqueous extract of E. crassipes was found to be the most effective plant extract in disease suppression and increase above-ground biomass compared to inoculated control. The study revealed that the tested plant species have a potential of inhibiting the development of bacterial wilt on tomato.

Plant extracts abated pathogenic Fusarium species of millet seedlings

Millet is an important crop threatened by soil-borne pathogenic fungi worldwide, but the position of these soil-borne fungi most especially Fusarium has not been evaluated in south-western Nigeria alongside their biocontrol using plant extracts. This study investigates the effects (in vitro and in vivo) of Moringa oleifera, Manihot esculenta (peels) and Senna alata at 5, 10 and 15% g/ml concentrations on Fusarium anthophilum, Fusarium verticillioides, Fusarium oxysporum and Fusarium scirpi. The in vivo experimental layout was arranged in a completely randomised design and all obtained data, both in vitro and in vivo, were statistically analysed using Minitab version 15. The extract of Moringa oleifera, Manihot esculenta (peels) and S. alata at 5, 10 and 15% g/ml concentrations showed significant (p < 0.05) antagonistic effect in vitro and in vivo on F. anthophilum, F. verticillioides and F. oxysporum. Moringa oleifera and S. alata at 5 and 10% g/ml significantly (p < 0.05) reduced the disease incidence and disease severity of F. scirpi on millet seedlings. Thus, Moringa oleifera appears to be the most effective extract followed by Manihot esculenta, while S. alata was the least effective plant extract. Hence, the effectiveness of plant extracts on pathogenic Fusarium of millet justified their management strategy geared towards sustainable millet growth in Nigeria.

Fungicidal activities of certain methanolic plant extracts against tomato phytopathogenic fungi

The fungicidal activity of five methanolic plant extracts from Lantana camara, Salvadora persica, Thymus vulgaris, Zingiber officinale and Ziziphus spina-christi were evaluated for their antifungal efficiency on tomato phytopathogenic fungi, Fusarium oxysporum, Pythium aphanidermatum and Rhizoctonia solani, the causative agents of tomato damping-off diseases. Three of five plant extracts were effective against thees phytopathogenic fungi. T. vulgaris and Z. officinale extracts were strongly active and showed fungistatic and fungicidal activities against the phytopathogenic fungi with minimal inhibitory concentration (MIC of 4 mg ml-1 and minimal fungicidal concentrations (MFC) of 8 mg ml-1 except F. oxysporum which was less sensitive and its MFC reached to 16 mg ml-1 of Z. officinale extract. On the other hand, S. persica extract showed a moderate antifungal activity while L. camara and Z. spina-christi were not effective against tomato phytopathogenic fungi except P. aphanidermatum which was completely inhibited at 10 mg ml-1 of L. camara extract. Carbendazim fungicide was more effective than all methanolic plant extracts inhibiting mycelial growth of all phytopathogenic fungi at 8 ppm and a huge concentration reached to 8 mg ml-1 of the effective plant extract was required to attain the same effect. Analysis of the effective plant extracts by GC/MS revealed that T. vulgaris extract was mainly composed by thymol (38.73%), carvacrol (19.31%), β-cimene (10.13%) and α-terpinolene (5.94%) while Z. officinale was mainly composed by Gingerol (46.85%), cedrene (8.39%), zingiberene (7.41%) and α-curcumene (7.32%) respectively. These effective plant extracts may contribute to development of potentially effective and environmentally safer alternative fungicide to control tomato damping- off phytopathogenic fungi. Key words: Fungicides, plant extracts, fungitoxic properties

Case Reports of Cancer Patients with Hepatic Metastases Treated by Standardized Plant Immunomodulatory Preparations

Background:Metastatic hepatocellular carcinoma often has a multifocal tumor pattern with markedly depressed hepatic function. Hepatic resection in many cases results in no long-term benefit. After a chemotherapy hepatic tumors rarely disappear completely and the duration of responses is short. In the last decades growing evidence suggested that a disturbed balance in the innate system can also play a role in the poor prognosis of hepatic tumors. Objectives:The aim of this article is to present and discuss several favorable clinical responses of patients with hepatic metastases who parallel to conventional oncologic therapy, were treated with immunologically effective and standardized plant extracts. Course of Therapy and Results: In accordance with the bell-shaped dose-response relationship of mistletoe lectins (MLs), the patients were treated with a fermented mistletoe extract (ME) preparation, standardized for the active sugar-binding lectin contents. Thus, an optimal dose between 0.5 and 1.0ng/kg MLs was given twice a week subcutaneously. In addition to ML therapy, a heteropolysaccharide rice bran preparation standardized for arabinoxylan (12-45mg/kg MGN-3/BiobranR twice a week) and wheat germ extract (WGE) standardized for 2, 6-dimethoxy-p-benzoquinone (50-80mg/kg AvemarR four times a week) was also given. In these case reports the clinical progress of seven patients showed a complete or nearly complete remission of hepatic metastases. Conclusion:ML, MGN-3 and WGE seem to be potent candidates to be regarded as a supportive therapy to surgery, hormone treatment or chemotherapy for patients with hepatic metastases. These case reports require further clinical studies.

Seed Germination and Seedling Growth of Two Vegetables in Responses to Aqueous Extract of Four Herbal Plant Leaves

An experiment was conducted on aqueous extracts of leaves of some herbal plants viz., Beleric myrobalan; bohera (Terminalia belirica), Chebulic myrobalan; horitoki (Terminalia chebula), Sweet basil; tulsi (Ocimum gratissmum) and arjunaa myrobalan; arjun (Terminalia arjuna) for investigating the presence of biologically active substance. The seeds of two vegetable crops such as, swamp cabbage (Impoea aquatica) and okra (Hibiscus esculentus) were tested for germination and seedling growth treating with aqueous extract of four herbal plant leaves. The chemical investigation on effective plant extract was also attempted. The aqueous extract of bohera leaves increased germination of seeds tested and enhanced the growth of shoot length and root length of swamp cabbage (Impoea aquatica) and okra (Hibiscus esculentus) whereas the aqueous extract of horitoki significantly reduced and delayed germination, growth of shoot length and root length of swamp cabbage seeds compared with control; water. The maximum germination was in okra and swamp cabbage seeds within 5 and 4.8 days respectively, treated with the leaves extract of bohera. Shoot lengths were 16.2 and 16.43 cm and root length were 8.74 and 8.91 cm for okra and swamp cabbage seedlings, respectively. The aqueous extract of horitoki showed the lowest rate and late germination at 6 and 5.8 days and minimum shoot lengths were 13.13 and 13.36 cm, and root lengths were 5.91 and 6.08 cm for okra and swamp cabbage seedlings, respectively. The thin layer chromatography (TLC) examination of chloroform extract of bohera leaves showed four distinct compounds at Hexane: Ethyl acetate (3:1, v/v) while horitoki leaves showed three distinct compounds at Hexane: Ethyl acetate (5:1, v/v). DOI: http://dx.doi.org/10.3329/jesnr.v5i1.11569 J. Environ. Sci. &amp; Natural Resources, 5(1): 141-150, 2012

Growth Regulatory Activities of Different Extracts of Tinospora Cordifolia on Some Vegetable Seeds with their Chemical Investigation

An experiment was conducted to investigate the growth regulatory activities of different extracts of Tinospora cordifolia on radish (Raphanus sativus), swamp cabbage (Impoea aquatica) and lady’s finger (Hibiscus esculentus) with the attempt for chemical investigation of effective plant extract. The chloroform extract of Tinospora cordifolia significantly increased and enhanced germination, growth of shoot length and root length of radish and lady’s finger whereas and delayed germination, growth of shoot length and root length of swamp cabbage seeds compared with control. In the same way, ethanol extract of Tinospora cordifolia significantly increased germination, growth of shoot length and root length of swamp cabbage followed by control and chloroform extract. Our study reveals that different extracts of Tinospora cordifolia contain growth regulatory active principle. Among the extracts, chloroform extract was shown better performance in terms of percent germination, growth of shoot and root length of radish and lady’s finger. To find out effective compound from chloroform extract, thin layer chromatography was done and showed five distinct compounds. Further study is needed to determine structure for finding growth regulatory compound for agricultural usage. DOI: http://dx.doi.org/10.3329/jesnr.v5i1.11568 J. Environ. Sci. &amp; Natural Resources, 5(1): 133 - 140, 2012

Larvicidal and repellent effect of some Tribulus terrestris L., (Zygophyllaceae) extracts against the dengue fever mosquito, Aedes aegypti (Diptera: Culicidae)

Aedes aegypti transmits etiologic agents of yellow fever and dengue. Vaccine for dengue virus is not available and vector control is essential to minimize dengue incidence. The larvicidal and repellent effect of the crude ethanol, acetone and petroleum ether extract leaves of Tribulus terrestris, against 3rd instar larvae and adults of mosquito, Ae. aegypti the vector of dengue fever was evaluated. The efficacy of petroleum ether extract seemed to be more effective with LC50 64.6ppm followed by acetone extract with LC50 173.2ppm and finally ethanolic extract with LC50 376.4ppm. Moreover, the acetone and petroleum ether extracts exerted a highly delayed toxic effect on the pupae and adults resulted from treated larvae, where the pupal mortality was 57.1% and 100% at concentrations 400 and 100ppm, respectively. Also, the petroleum ether and acetone extracts showed reduction effects on adult emergence. The repellent action of the plant extracts tested was varied depending on the solvent used in extraction and the dose of the extract. The most effective plant extract that evoked 100% repellency or biting deterrence was petroleum ether extract at a dose of 1.5mg/cm2 compared with 100% repellency for commercial formulation, N,N-diethyl-3-methylbenzamide (DEET) at the same dose. Hence, these extracts can be used as an effective alternative to the existing synthetic pesticides for the control of Ae. aegypti.

Insecticidal activities of ethanol extracts from thirty Chinese medicinal plants against Spodoptera exigua (Lepidoptera: Noctuidae)

Chinese medicinal plants extracts of a group of 30 species from 20 different botanical families, were screened for contact toxicity and antifeedant activities against Spodoptera exigua. The extracts from eight of the Chinese medicinal plants showed strong activity against the insect. The most effective plant extracts were from Litsea cubeba (Lour.) Pers., Brucea javanica (L.) Merr. and Artemisia argyi Levl. et Vant. Three of the extracts exerted strong antifeedant activity to the insect. Key words: Plant extract, contact toxicity, antifeedant activity, Spodoptera exigua Hubner.

Screening the methanolic extracts of some plants for tyrosinase inhibitory activity

Melanin is responsible for pigmentation of skin and hair. It protects the skin from the harmful effects of UV radiation; however, its abnormal production may lead to different diseases such as hyper-pigmentation or vitiligo. Tyrosinase is a key enzyme in melanin production, therefore inhibitors of this enzyme should have broad application. Due to the adverse effects of synthetic inhibitors currently being used, the search for new inhibitors, especially natural ones, is needed. The methanolic extracts of 80 plants were tested for their tyrosinase inhibitory activities by spectrophotometry at 492 nm. The inhibition mode of effective plant extracts was determined using the Lineweaver-Burk plots. Among these plant extracts, Alhagi camelorum (camel thorn), Camelia sinensis (green tea), Cuminum cyminum (Cumin), Lawsonia inermis (henna), Quercus infectoria (masso), and Vaccinium arctostaphylos (Caucasian whortleberry) were identified as tyrosinase inhibitors with inhibitory effect of more than 50% at concentrations of 1.14 g L−1. The inhibition mode of four newly found effective plant extracts showed that A. camelorum and V. arctostaphylos inhibit the enzyme in a competitive manner whereas L. inermis and Q. infectoria have mixed inhibitory effect. To recommend these plant extracts for hyper-pigmentation disorders and other applications, further in vitro and in vivo studies are needed.

Efficacy of Some Botanical Extracts againstTrogoderma granariumin Wheat Grains with Toxicity Evaluation

In an attempt to find alternative control methods for stored products insects, extracts of seven plant species (Cassia senna, Caesalpinia gilliesii, Thespesia populnea var. acutiloba, Chrysanthemum frutescens, Euonymus japonicus, Bauhinia purpurea, and Cassia fistula) were evaluated under laboratory conditions for their ability to protect wheat (Triticum spp.) grains against Trogoderma granarium insect. Moreover, gas chromatography-mass spectrometry (GC-MS) analysis was carried to identify the chemical components of the most effective plant extract against T. granarium. Furthermore, the safety of the most effective plant extract was evaluated with respect to biochemical and histological changes in treated rats relative to control. The results revealed that, the tested botanical extracts showed high efficiency against T. granarium with respect to mortality and progeny of the adults. C. senna was the most effective botanical extract against T. granarium. The GC-MS analysis of the most effective plant extract showed the presence of different bioactive compounds that is known by its insecticidal activity. The most effective plant extract showed no toxicity on treated rats relative to control with respect to biochemical and histological changes. The results suggest the ability of using these plant extracts for wheat grains protection as a safe alternative to insecticides.