Medicinal plants and malaria

OBJECTIVE To carry out a literature survey on medicinal plants documented for use in malaria,and to create a comprehensive database documenting the usage and preparation of these medicinal plants for malaria.METHODS A search was done through Scopus,ScienceDirect,and PubMed,on all ethnobotanical surveys that were specifically done on medicinal plants used in malaria using the keywords″ethnobotanical″,″survey″,″ethnopharmacological″,and″malaria″.In addition,Dr Duke′s Phytochemical and Ethnobotanical Database,and books on medicinal plants from the Library of Botany and Horticulture,Singapore Botanic Gardens,and the Medical and Science Libraries,National University of Singapore,were used in the search.Plants used specifically as quinine substitutes were also included.Plants that were reported to be used solely for fever(other than malarial fever),external application,or insect repelling property,were excluded.Data collected were analyzed according to family,genus,location of use,method of preparation,part used,and indication(treatment and/or prevention).RESULTS A total of 1739 plants from 185 families and 973 genera were reportedly used for malaria globally,with 59 plantsused in three or more continents.Of these,11 were used in four continents for malaria,and 7of these can be found in Singapore.Anti-malarial plants from the family Fabaceae and the genus Vernoniawere the most commonly reported.Most of the plants are prepared as decoctions,followed by infusions.Leaves were most frequently used,followed by roots,and bark.97.8% of the plants are used solely for curative purposes,1.8% of the plants are both curative and prophylactic,while 0.4% are solely prophylactic.Priority of plants for further research could either focus on geographical extent of use,plant family,or genus.CONCLUSION An extensive database documenting the medicinal plants used for malaria has been compiled.Sustained interest in anti-malarial medicinal plant research is evident over the past decade.Promising plants for further research is presented.     

Medicinal plants and cancer chemoprevention

Cancer is the second leading cause of death worldwide. Although great advancements have been made in the treatment and control of cancer progression, significant deficiencies and room for improvement remain. A number of undesired side effects sometimes occur during chemotherapy. Natural therapies, such as the use of plant-derived products in cancer treatment, may reduce adverse side effects. Currently, a few plant products are being used to treat cancer. However, a myriad of many plant products exist that have shown very promising anti-cancer properties in vitro, but have yet to be evaluated in humans. Further study is required to determine the efficacy of these plant products in treating cancers in humans. This review will focus on the various plant-derived chemical compounds that have, in recent years, shown promise as anticancer agents and will outline their potential mechanism of action.     

Pesticide stress on plants negatively affects parasitoid fitness through a bypass of their phytophage hosts

Pesticides taken up by plants from the soil or interstitial (pore) water can cascade to higher trophic levels, which are expected to be more affected due to cumulative bottom-up effects. Knowledge about the impact of indirect exposure to pesticides on non-target terrestrial trophic chains, however, is still lacking. Therefore, we examined the direct and indirect effects of three concentrations of the herbicide 2,6-dichlorobenzonitrile (DCBN) and an insecticide with a similar molecular structure (1,4-dichlorobenzene, DCB) on the fitness traits of a tritrophic system: the wheat plant Triticum aestivum, the aphid Sitobion avenae and its specialist parasitoid Aphidius rhopalosiphi. To mimic exposure via interstitial water the toxicants were added to the growth medium of the plant. Passive dosing between the medium and a silicon layer was used to achieve constant exposure of the poorly soluble pesticides. Wheat plants exposed to both pesticides grew smaller and had reduced biomasses. Negative effects on the reproductive rate, biomass and the number of aphids were only observable at the highest concentration of DCBN. Overall parasitism rate decreased when exposed to both pesticides and parasitoid attack rates decreased at lower concentrations of DCBN and at the highest DCB concentration. The parasitoid sex ratio was extremely male-biased in the presence of DCBN. Our results demonstrate that pesticides can alter the performance of higher trophic levels by sublethal effects, through a bypass of the second trophic level. In addition, the novel test system used was suitable for detecting such carryover effects on non-target organisms.     

Medicinal plants with inhibitory properties against snake venoms

Envenomations due to snake bites are commonly treated by parenteral administration of horse or sheep-derived polyclonal antivenoms aimed at the neutralization of toxins. However, despite the widespread success of this therapy, it is still important to search for different venom inhibitors, either synthetic or natural, that could complement or substitute for the action of antivenoms. Several plants have been utilized in folk medicine as antiophidian. However, only a few species have been scientifically investigated and still less had their active components isolated and characterized both structurally and functionally. This article presents a review of plants showing neutralizing properties against snake venoms which were assayed in research laboratories, correlating them with ethnopharmacological studies, as (i) the part of the plant used as antidote, (ii) its respective genus and family and (iii) inhibition of the main pharmacological, toxic and enzymatic activities of snake venoms and isolated toxins. Protective activity of many of these plants against the lethal action of snake venoms has been confirmed by biological assays. Compounds in all of them belong to chemical classes capable of interacting with macromolecular targets (enzymes or receptors). Popular culture can often help to guide scientific studies. In addition, biotechnological application of these inhibitors, as helpful alternative or supplemental treatments to serum therapy, and also as important models for synthesis of new drugs of medical interest, needs to be better oriented and scientifically explored.     

Medicinal plants for insomnia: a review of their pharmacology, efficacy and tolerability

A number of medicinal plants are traditionally endowed with anxiolytic or sedative properties and, in the context of this revue, both indications are considered since the former may induce a mood conducive to the latter. For any sleep-inducing drug to be effective, a tranquil ambience needs to be established a priori. Thus, physical ailments (i.e. pain), factors interfering with sleep (i.e. noise), psychological conditions causing stress, psychiatric illnesses (i.e. depression) and other drugs that interfere with sleep (i.e. caffeine) need to be controlled, if possible. Kava-kava is a well-established hypnotic drug, with a rapid onset of effect, adequate duration of action and minimal morning after-effects. However, reports of serious hepatotoxicity with this preparation have led to it being banned in most countries worldwide. On the other hand, side-effects with valerian would appear to be bland indeed. However, it's slow onset of effect (2-3 weeks) renders it unsuitable for short-term use (i.e. 'jet-lag'), but it does have profound beneficial effects on sleep architecture (augments deep sleep) that may make it particularly suitable for long-term use and for the elderly. In a personal trial (not double-blind) in stress-induced insomnia, both kava and valerian improved sleep and the ill-effects of stress, and the combination of the two was even more effective for the control of insomnia. Aromatherapy (lavender, chamomile, Ylang-Ylang) would appear to improve sleep, but how practical a form of treatment this may be remains to be determined. The only other plant drug that may have some effect on sleep is melissa, but reports are too scanty to form any opinion about this. Based on animal experiments, passion flower (passiflora) may have a sedative action, but the sedative action of hops has not been investigated in any detail. In conclusion, there is a need for longer-term controlled studies with some of these compounds (particularly valerian). Aromatherapy constitutes a tantalising possibility. In the interpretation of this review, it should be borne in mind that the evidence on which it is based is often incomplete or missing, but that is all that is available. Consequently some conjecture on the part of the author is inevitable and should be appreciated as such.     

Medicinal plants and primary health care: part 2

The WHO Programme on Traditional Medicine has joined WHO's global program on drug management and policies because there is a need for recognition that an adequate technological infrastructure must be in place to maximize plants for their medicinal value, especially in the context of primary health care (PHC). PHC places traditional medicine high on its list of priorities and emphasizes the availability and use of appropriate drugs. For example, countries should distribute seeds or plants to be cultivated in home or community gardens and taken as infusions. Scientists have not studied most medicinal plants which can be a rich potential resource for developing countries. Countries should apply known and effective technologies to meet health needs in a culturally acceptable manner and to promote self reliance. They must 1st strengthen data gathering and analysis capabilities needed for economic mapping of medicinal flora, then develop data centers on medicinal plants and plant derived products, such as the WHO Collaborating Center in Chicago. Clinical research should focus on the safety and efficacy of herbal medicines used by traditional health practitioners and on developing antiinfective agents. For example, 2 WHO agencies are collaborating on identifying, preparing, and testing extracts for medicinal plants for antiHIV capabilities. WHO favors developing the knowledge and skills of traditional health practitioners within the framework of PHC. Further, interregional workshops promote selection and use of traditional medicine in national PHC programs. Since there continue to be much public interest in medicinal plants, accurate information must be disseminated to the public and health professionals so they can know both the potential benefits and harmful effects of these remedies.     

Medicinal plants as potential sources of lead compounds with anti-platelet and anti-coagulant activities

Medicinal plants are potential sources of lead compounds which can be further developed or optimised into novel therapeutics. This paper gives an overview of drug discovery from plants and an up-to-date and comprehensive review of plants and phytoconstituents reported to have anti-platelet and anti-coagulant activities.     

Medicinal plants for the prevention and treatment of bacterial infections

Infectious diseases are a significant cause of morbidity and mortality worldwide, accounting for approximately 50% of all deaths in tropical countries and as much as 20% of deaths in the Americas. Despite the significant progress made in microbiology and the control of microorganisms, sporadic incidents of epidemics due to drug resistant microorganisms and hitherto unknown disease-causing microbes pose an enormous threat to public health. These negative health trends call for a global initiative for the development of new strategies for the prevention and treatment of infectious disease. For over 100 years chemical compounds isolated from medicinal plants have served as the models for many clinically proven drugs, and are now being re-assessed as antimicrobial agents. The reasons for this renaissance include a reduction in the new antibacterial drugs in the pharmaceutical pipeline, an increase in antimicrobial resistance, and the need of treatments for new emerging pathogens. Literally thousands of plant species have been tested against hundreds of bacterial strains in vitro and many medicinal plants are active against a wide range of gram positive and gram negative bacteria. However, very few of these medicinal plant extracts have been tested in animal or human studies to determine safety and efficacy. This review focuses on the medicinal plants and bacteria for which there is significant published in vitro, in vivo and clinical data available. The examples provided in this review indicate that medicinal plants offer significant potential for the development of novel antibacterial therapies and adjunct treatments (i.e. MDR pump inhibitors).     

致病微生物和宿主相互作用的研究进展

新老传染病的流行和再现,病原微生物的变异和致病机制更加复杂和多样化.因此,迫切需要我们从更深层次去了解和研究它们,为临床治疗中寻找更灵、敏特异的诊断分型手段,发展高效的基因工程疫苗及筛选新型药物提供了线索和保障.感染性疾病是病原体与宿主相互作用的结果.转录组学和蛋白质组学已经发展成为两种成熟的方法,并广泛地运用于致病微生物感染宿主细胞的致病机制的研究.对宿主细胞基因表达谱的研究,可以了解宿主是如何抵抗致病微生物的入侵.传统蛋白质组学研究方法,采用亚细胞蛋白质组学来分析特异性的细菌入侵过程.两种方法相互补充,结合功能基因组学技术,如RNA干扰技术,为进一步阐明致病微生物-宿主相互作用的机制奠定基础.     

复方氟米松软膏不同用法对神经性皮炎患者治疗效果分析

目的 观察复方氟米松软膏不同使用次数、间隔时间对神经性皮炎患者疗效及复发率的影响.方法 将入选的229例神经性皮炎患者随机分为治疗组1(57例)、治疗组2(62例)、治疗组3(58例)和对照组(52例),4组患者均给予复方氟米松软膏每日2次早晚外用,共2周;之后治疗组1仍给予每日2次早晚外用,治疗组2给予每日晚1次外用,治疗组3仅给予每周末2天每日2次外用,治疗时间均2周,对照组直接停药.观察治疗第2周末、第4周末、第8周末4组疗效、不良反应及复发率情况.结果 治疗组1在治疗第2周、4周、8周末的有效率为77.19％、91.23％、89.47％,治疗组2在治疗第2周、4周、8周末的有效率为77.42％、88.71％、87.10％,治疗组3在治疗第2周、4周、8周末的有效率为74.14％、75.86％、74.14％,对照组在治疗第2周、4周、8周末的有效率为80.77％、75％、71.15％,治疗组1与治疗组2在治疗第4周末和8周末的有效率均显著高于治疗组3和对照组(P＜0.05),治疗后治疗组1和治疗组2有效率差异均无统计学意义(P＞0.05).4组患者在第8周复发率分别为7.02％、9.68％、13.79％、21.75％,差异无统计学意义(P＞0.05).结论 复方氟米松软膏治疗神经性皮炎起效迅速、有效,安全性好,其中治疗方法1和2治愈率相对最好.改变氟米松的使用次数和使用时间并不能短期内减少神经性皮炎的复发率,但减少激素的使用量对降低激素不良反应是有意义的.     

Nitrogen-containing flavonoid and their analogs with diverse B-ring in acetylcholinesterase and butyrylcholinesterase inhibition

In this study, a series of new flavones (2-phenyl-chromone), 2-naphthyl chromone, 2-anthryl-chromone, or 2-biphenyl-chromone derivatives containing 6 or 7-substituted tertiary amine side chain were designed, synthesized, and evaluated in acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) inhibition. The results indicated that the alteration of aromatic ring connecting to chromone scaffold brings about a significant impact on biological activity. Compared with flavones, the inhibitory activity of 2-naphthyl chromone, 2-anthryl-chromone derivatives against AChE significantly decreased, while that of 2-biphenyl chromone derivatives with 7-substituted tertiary amine side chain is better than relative flavones derivatives. For all new synthesized compounds, the position of tertiary amine side chain obviously influenced the activity of inhibiting AChE. The results above provide great worthy information for the further development of new AChE inhibitors. Among the newly synthesized compounds, compound 5a is potent in AChE inhibition (IC₅₀ = 1.29 ± 0.10 μmol/L) with high selectivity for AChE over BChE (selectivity ratio: 27.96). An enzyme kinetic study of compound 5a suggests that it produces a mixed-type inhibitory effect against AChE.