蚊虫驱避剂及其剂型的研究进展

植物源驱避剂,具有安全、环保、毒副作用小等特点,目前对其研究重点在于筛选高驱避活性成分。本文通过查阅近年来的文献资料,对蚊虫驱避剂剂型的研究进展进行综述,为蚊虫驱避剂剂型的研究开发提供科学依据。     

茶树油乳液对水蛭驱避作用的研究

水蛭叮咬后通常流血较多,真皮组织被破坏形成终生疤痕,若水蛭进入人体腔道会更危险,因此亟需研发水蛭驱避剂。本研究以茶树油为主药,魔芋葡甘聚糖、乙基纤维素为主要辅料制备水包油型茶树油乳液。通过滤纸圈法、水中驱避法确定其驱避效率,评价茶树油乳液对水蛭的驱避作用。所有动物实验经军事科学院军事医学研究院伦理委员会批准且实验均按照相关指导原则和规定进行。以体内乙酰胆碱酯酶、谷胱甘肽S-转移酶和羧酸酯酶活性为评价指标,阐明茶树油乳液对水蛭的驱避机制。本研究成功制备了均一稳定的茶树油乳液,亲水性优良,可有效驱避水蛭,该乳液的驱避时间延长,可避免茶树油挥发,为类似挥发油用于长效、高效驱避提供了新思路。     

驱蚊宁(驱蚊剂42号)

【化学名】对-(艹孟)烯8(9)-二醇(1.2)。【结构式】【作用特点】本品为我国创制的新型广谱涂抹驱避剂,对蚊、蠓、山蚂蝗等吸血昆虫均有较好的驱避作用,对蚊有4～5小时驱避效果;对山蚂蝗亦有3个小时以上的效果。本品与国外广泛使用的DETA(N,N-二乙基-间-甲基苯甲酰胺)相比毒副作用较小。【适应症】涂抹于皮肤后,对蚊、蠓、山蚂蝗等吸血昆虫有驱避作用,可用作对人的个体防护。     

避蚊胺微球载药量的HPLC测定

避蚊胺(DEET,1)化学名为N,N-二乙基-间甲苯酰胺,是目前应用最广泛的广谱蚊虫驱避剂,通过自然挥发或借助载体挥发气味,使吸血昆虫产生忌避而难以接近人体[1,2].1具有驱避效果好、毒性小等优点,但现有制剂作用时间短、皮肤用量大、吸收较多,可能引发皮炎及心血管疾病等[3].我院采用溶剂挥发法,制备了用于皮肤给药的1乙基纤维素(EC)微球[4].本研究建立了HPLC法测定微球的载药量.     

应用几丁聚糖提高避蚊胺驱蚊效果的实验观察

避蚊胺(delphene)是一种常用的高效、广谱、安全的驱避剂。30%避蚊胺酊剂在北方一次涂抹对蚊虫驱避时间仅为3～5h,对野外工作人员来说显得短了些。为延长避蚊胺对蚊虫的驱避时间,我们选用了大分子量的几丁聚糖(chitosan)作为避蚊胺的缓释成膜剂,将避蚊胺的驱蚊虫效果提高了一倍多。现将实验观察结果报告如下。 1 材料与方法 1.1 实验用药 1.1.1 避蚊胺酊剂由本队提供,用上皿天平称取避蚊胺结晶体1.2g,溶于95%乙醇10ml     

植物挥发油抗炎作用研究进展

机体受到感染或损伤后触发的一种自身防御机制称为炎症。作为一种常见的防御机制，炎症在临床上十分多见。如果得不到及时治疗还有可能导致多种更加严重的疾病。目前临床上大多通过化学合成的药物进行抗感染治疗，但其不良反应不可忽视，这已经成为一个临床亟待解决的问题。植物挥发油是一种从芳香植物中提取的天然化合物，具有抵抗炎症的作用。本文通过植物挥发油对于炎症病原菌的有效成分、作用机制、协同作用以及安全性等方面进行阐述，为以后植物挥发油的科研方向提供一定借鉴。     

抗菌植物挥发油及其递送系统研究进展

挥发油是从植物中获得的一种挥发性芳香物质，具有良好的抗菌活性，但当遇到氧气、光线及高温时，挥发油成分易挥发、易氧化分解及易变质。将水凝胶、微囊、脂质体、纳米乳、皮克林乳液和环糊精包合物等载药系统运用于挥发油组分时，可有效提高挥发油的稳定性、降低刺激性，同时可提高挥发油的抗菌作用及延长作用时间，扩大其临床应用范围。综述植物挥发油的提取方法、抗菌作用及载药系统的研究进展，以期为更合理有效地利用挥发油组分提供参考。     

天然植物成分抗真菌研究新进展

查阅近年来有关天然植物成分抗真菌研究的国内外文献,并对其进行分析、归纳和总结,综述了天然植物成分抗真菌研究的新进展。天然植物以提取物和活性成分的形式发挥抗真菌作用,或作为抗真菌药物的增效剂和增敏剂,与抗真菌药物联合应用。研究的深入为筛选天然植物抗真菌活性成分和先导化合物提供了有利条件。     

中草药挥发油类透皮吸收促进作用研究进展

20世纪90年代以来,中草药挥发油类及其活性成分透皮吸收促进作用的研究报告日益增多,并已展示出广阔的临床应用前景.文献报道较多的这类促进剂包括薄荷油、柠檬油、桉油、丁香油、蛇床子油、当归挥发油、松节油等.其主要促渗活性成分多为单萜和倍半萜类化合物.该类天然促渗剂具有促渗作用强、起效快、不良反应小等特点.它们主要通过改变皮肤角质层细胞的有序排列、"拉动"效应以及增强皮肤角质层水合作用等机制发挥促渗作用.该类促渗荆的化学结构和理化性质、促渗剂的浓度以及促渗剂的联合应用均可影响其促渗作用.现综述近年来国内外该类透皮吸收促进剂的作用特点、机制及其影响因素方面的研究进展.     

驱蚊剂研究概况

蚊、蠓等吸血性医学昆虫对人类的危害相当严重。驱蚊剂研究,从第二次世界大战迄今已历四十几年。通过从天然植物来源发掘、人工合成和配方研究,得到了一系列有效的驱蚊剂。同时,构效关系的研究取得了成果,驱避机理的研究亦有了良好的开端。本文就驱蚊剂研究概况作一介绍。     

Microencapsulation and testing of the agricultural animal repellent, Daphne

The microencapsulated animal repellent Daphne was prepared by in situ polymerization of melamine-formaldehyde prepolymer with styrene-maleic acid anhydride copolymer as a modifying agent. Pure Daphne (a mixture of essential oils and other volatile compounds) and Daphne (45 wt%) diluted with isopropylmyristate (55 wt%) were used as core materials. Three types of formulations were prepared: (1) aqueous suspension concentrates, to be diluted for spraying, (2) thickened pastes with microcapsules for coating tree bark, and (3) textile, paper and metal strips, coated or impregnated with microcapsules. In field testing, all formulations with microcapsules showed a prolonged effect in comparison with non-encapsulated Daphne. The repelling effect on animals was stronger in summer and weaker in winter, when the pressure of the animals was much more intense, and diffusion of repellent from the microcapsules was reduced due to low temperatures. However, pastes for the bark and non-woven textile strips impregnated with microencapsulated Daphne showed good repelling effect against deer and rabbits in the winter period.     

Patent literature on mosquito repellent inventions which contain plant essential oils--a review

Bites Bites of mosquitoes belonging to the genera Anopheles Meigen, Aedes Meigen, Culex L. and Haemagogus L. are a general nuisance and are responsible for the transmission of important tropical diseases such as malaria, hemorrhagic dengue and yellow fevers and filariasis (elephantiasis). Plants are traditional sources of mosquito repelling essential oils (EOs), glyceridic oils and repellent and synergistic chemicals. A Chemical Abstracts search on mosquito repellent inventions containing plant-derived EOs revealed 144 active patents mostly from Asia. Chinese, Japanese and Korean language patents and those of India (in English) accounted for roughly 3/4 of all patents. Since 1998 patents on EO-containing mosquito repellent inventions have almost doubled about every 4 years. In general, these patents describe repellent compositions for use in topical agents, cosmetic products, incense, fumigants, indoor and outdoor sprays, fibers, textiles among other applications. 67 EOs and 9 glyceridic oils were individually cited in at least 2 patents. Over 1/2 of all patents named just one EO. Citronella [Cymbopogon nardus (L.) Rendle, C.winterianus Jowitt ex Bor] and eucalyptus (Eucalyptus L?Hér. spp.) EOs were each cited in approximately 1/3 of all patents. Camphor [Cinnamomum camphora (L.) J. Presl], cinnamon (Cinnamomum zeylanicum Blume), clove [Syzygium aromaticum (L.) Merr. & L.M. Perry], geranium (Pelargonium graveolens L?Hér.), lavender (Lavandula angustifolia Mill.), lemon [Citrus × limon (L.) Osbeck], lemongrass [Cymbopogon citratus (DC.) Stapf] and peppermint (Mentha × piperita L.) EOs were each cited in > 10% of patents. Repellent chemicals present in EO compositions or added as pure “natural” ingredients such as geraniol, limonene, p-menthane-3,8-diol, nepetalactone and vanillin were described in approximately 40% of all patents. About 25% of EO-containing inventions included or were made to be used with synthetic insect control agents having mosquito repellent properties such as pyrethroids, N,N-diethyl-m-toluamide (DEET), (±)-p-menthane-3,8-diol (PMD) and dialkyl phthalates. Synergistic effects involving one or more EOs and synthetic and/or natural components were claimed in about 10% of all patents. Scientific literature sources provide evidence for the mosquito repellency of many of the EOs and individual chemical components found in EOs used in patented repellent inventions.     

Antibacterial and antifungal properties of essential oils

In recent years there has been an increasing interest in the use of natural substances, and some questions concerning the safety of synthetic compounds have encouraged more detailed studies of plant resources. Essential oils, odorous and volatile products of plant secondary metabolism, have a wide application in folk medicine, food flavouring and preservation as well as in fragrance industries. The antimicrobial properties of essential oils have been known for many centuries. In recent years (1987-2001), a large number of essential oils and their constituents have been investigated for their antimicrobial properties against some bacteria and fungi in more than 500 reports. This paper reviews the classical methods commonly used for the evaluation of essential oils antibacterial and antifungal activities. The agar diffusion method (paper disc and well) and the dilution method (agar and liquid broth) as well as turbidimetric and impedimetric monitoring of microorganism growth in the presence of tested essential oils are described. Factors influencing the in vitro antimicrobial activity of essential oils and the mechanisms of essential oils action on microorganisms are reported. This paper gives an overview on the susceptibility of human and food-borne bacteria and fungi towards different essential oils and their constituents. Essential oils of spices and herbs (thyme, origanum, mint, cinnamon, salvia and clove) were found to possess the strongest antimicrobial properties among many tested.     

Phytotoxic potential of selected essential oils against Ailanthus altissima (Mill.) Swingle,an invasive tree

Ailanthus altissima (Mill.) Swingle, tree of heaven, is an exotic tree introduced as a horticultural tree in Europe and America in 18th Century. Now it is aggressively invading ecosystems. This study was aimed to estimate phytotoxic potential of essential oils (EOs) from fourteen industrial, aromatic and medicinal crops, such as Thymus sp., Pinus sp., Origanum sp. etc. against this invasive species. The phytotoxic potential was assessed through three different doses of EOs by a germination bioassay and the effects on seedling growth. Analysis of seedling growth revealed that seven EOs (Petasites hybridus, Thymus serpyllum, Thymus vulgaris, Rosmarinus officinalis, Helichrysum italicum, Matricaria chamomilla, Origanum vulgare) exhibit high phytotoxic effect resulting in 95–100% seedling mortality. Moreover, detailed GC-MS analysis of these oils showed that they are mostly comprised either of oxygenated monoterpenes or sesquiterpene hydrocarbons, which are already known as compounds with allelopathic effects. Presented results indicate these essential oils might be used as natural herbicides by foliar application of oils on young plants of Ailanthus altissima.     

A review on recent research results on bio-effects of plant essential oils against major Coleopteran insect pests

Upfront problems about the use of synthetic insecticides such as damage to the environment and human health and pests’ resistance have brought about interest in natural compounds. In the last few years, more studies have been published for the insecticidal effects of essential oils from several plant families such as Apiaceae, Asteraceae, Cupressaceae, Lamiaceae, Lauraceae, Myrtaceae, Poaceae, Piperaceae, Rutaceae and Zingiberaceae. The present article emphases on the effects of essential oils against Coleopteran insect pests by highlighting on their extraction, chemical insecticidal properties, mode of action on insect, commercialization and safety.     

Essential oils—their antimicrobial activity against Escherichia coli and effect on intestinal cell viability

Essential oils are known to possess antimicrobial activity against a wide spectrum of bacteria. The main objective of this study was to evaluate possible harmful effects of four commonly used essential oils and their major components on intestinal cells. Antimicrobial activity of selected plant extracts against enteroinvasive Escherichia coli was dose dependent. However, doses of essential oils with the ability to completely inhibit bacterial growth (0.05%) showed also relatively high cytotoxicity to intestinal-like cells cultured in vitro. Lower doses of essential oils (0.01%) had only partial antimicrobial activity and their damaging effect on Caco-2 cells was only modest. Cell death assessment based on morphological and viability staining followed by fluorescence microscopy showed that essential oils of cinnamon and clove and their major component eugenol had almost no cytotoxic effect at lower doses. Although essential oil of oregano and its component carvacrol slightly increased the incidence of apoptotic cell death, they showed extensive antimicrobial activity even at lower concentrations. Relatively high cytotoxicity was demonstrated by thyme oil, which increased both apoptotic and necrotic cell death incidence. In contrast, its component thymol showed no cytotoxic effect as well as greatly-reduced ability to inhibit visible growth of the chosen pathogen in the doses used. On the other hand, the addition of all essential oils and their components at lower doses, with the exception of thyme oil, to bacterial suspension significantly reduced the cytotoxic effect of E. coli on Caco-2 cells after 1 h culture. In conclusion, it is possible to find appropriate doses of essential oils showing both antimicrobial activity and very low detrimental effect on intestinal cells.     

Chemical composition and antimicrobial action of the essential oils of Salvia desoleana and S. sclarea

The chemical composition of the essential oils of Salvia desoleana Atzei & Picci and Salvia sclarea L. from Sardinia (Italy) was analysed by GC and GC/MS. S. desoleana oil had a high content of monoterpenic esters (linalyl acetate and alpha-terpinyl acetate) and a lower amount of the corresponding alcohols while S. sclarea oil was characterised by a higher content of alcohols and lower quantity of esters. We studied the antimicrobial activity of these oils concerning their use in pharmaceutical preparations for local application. Only weak microbiostatic inhibitory activity was seen against S. aureus, E. coli, S. epidermidis and C. albicans, but since inhibition increased progressively with contact time, better results could be obtained by using these oils in bioadhesive formulations that would also have anti-inflammatory and peripheral analgesic action at a local level, as demonstrated in experimental animals following systemic application.     

Qualitative and quantitative composition of essential oils: A literature-based database on contact allergens used for safety assessment

The risks related to the use of essential oils are difficult to ascertain at present, due in part to the large number of different oils available on the market, making it difficult for the risk assessor. Essential oils may contain skin allergens in significant amounts, and could thus pose a risk to the consumer. The aim of our study was to collect as much qualitative and quantitative data as possible on allergens present in essential oils. 11 types of essential oils, with 25 respective subspecies, were taken into account based on a previous survey. Based on the literature, 517 dosages were recorded from 112 publications, providing precious information for probabilistic exposure assessment purposes. 22 substances recognized as established allergens were found in the essential oils we included. Of these, 11 are also found in cosmetics as fragrance components. These results are of major importance regarding co-exposure to fragrance allergens. Moreover, this could lead to regulatory measures for essential oils in the future, as it is the case for cosmetic products, in order to better protect consumers against skin allergy.     

Anti-inflammatory activities of essential oils and their constituents from different provenances of indigenous cinnamon (Cinnamomum osmophloeum) leaves

Context: Cinnamomum osmophloeum Kaneh. (Lauraceae) is one of the indigenous tree species in Taiwan. This tree species has been of interest to researchers because the chemical constituents of its essential oil are similar to those of Cinnamomum cassia Presl. bark oil, known as cinnamon oil, which is commonly used in foods and beverages.

Objective: The anti-inflammatory activities of the leaf essential oils and their major compounds from seven provenances of C. osmophloeum are investigated here for the first time.

Materials and methods: Chemical compositions of hydrodistilled essential oils obtained from C. osmophloeum leaves were analyzed by gas chromatography-mass spectrometry (GC-MS), and the effects of essential oils on nitric oxide (NO) production in lipopolysaccharide (LPS)-activated RAW 264.7 macrophages were investigated.

Results: The leaf essential oils of cinnamaldehyde type and mixed type strongly inhibited NO production, with IC₅₀ values ranging from 9.7-15.5?μg/mL. Furthermore, trans-cinnamaldehyde is responsible for the inhibitory activity of cinnamaldehyde type, and T-cadinol and α-cadinol are responsible for the inhibitory activity of mixed type.

Discussion and conclusion: These findings demonstrate that the leaf essential oils and their constituents of C. osmophloeum have excellent anti-inflammatory activities and thus have great potential as a source for natural health products.     

Biological effects of essential oils--a review.

Since the middle ages, essential oils have been widely used for bactericidal, virucidal, fungicidal, antiparasitical, insecticidal, medicinal and cosmetic applications, especially nowadays in pharmaceutical, sanitary, cosmetic, agricultural and food industries. Because of the mode of extraction, mostly by distillation from aromatic plants, they contain a variety of volatile molecules such as terpenes and terpenoids, phenol-derived aromatic components and aliphatic components. In vitro physicochemical assays characterise most of them as antioxidants. However, recent work shows that in eukaryotic cells, essential oils can act as prooxidants affecting inner cell membranes and organelles such as mitochondria. Depending on type and concentration, they exhibit cytotoxic effects on living cells but are usually non-genotoxic. In some cases, changes in intracellular redox potential and mitochondrial dysfunction induced by essential oils can be associated with their capacity to exert antigenotoxic effects. These findings suggest that, at least in part, the encountered beneficial effects of essential oils are due to prooxidant effects on the cellular level.