Effect of prolonged administration of sublethal concentrations of aridanin isolated from Tetrapleura tetraptera and bayluscide on the glycogen and protein content of Biomphalaria glabrata

The effect of chronic application of sublethal concentrations of aridanin isolated from Tetrapleura tetraptera (0.25-0.125 ppm) and of bayluscide (0.05-0.025 ppm) on the glycogen and protein content of Biomphalaria glabrata was determined. Aridanin and bayluscide produced significant reductions in the glycogen content of B. glabrata, but a significant decrease in the protein content of the snails was not apparent until after 4 weeks of continuous exposure. The results indicate that the molluscicides may exert their primary molluscicidal action on the carbohydrate metabolism of the snail.     

Analgesic and anticonvulsant properties of Tetrapleura tetraptera (Taub) (Fabaceae) fruit aqueous extract in mice

Previous studies in our laboratories and elsewhere have shown that the fruit of Tetrapleura tetraptera (Taub) (family: Fabaceae) is widely used in African traditional medicine for the management and/or control of an array of human ailments, including schistosomiasis, asthma, epilepsy, hypertension and so on. The present study was designed to investigate the analgesic and anticonvulsant effects of Tetrapleura tetraptera (Taub) fruit aqueous extract (TTE) in mice. Morphine (MPN, 10 mg/kg i.p.), diclofenac (DIC, 100 mg/kg i.p.), phenobarbitone (20 mg/kg i.p.) and diazepam (0.5 mg/kg i.p.) were used, respectively, as reference analgesic and anticonvulsant agents for comparison. T. tetraptera fruit aqueous extract (TTE, 50-800 mg/kg i.p.) produced dose-dependent, significant (p < 0.05-0.001) analgesic effects against thermally and chemically induced pain in mice. Like the standard anticonvulsant agents (phenobarbitone and diazepam) used, T. tetraptera fruit aqueous extract (TTE, 50-800 mg/kg i.p.) significantly (p < 0.05-0.001) delayed the onset of, and antagonized, pentylenetetrazole (PTZ)-induced seizures. Aqueous extract of the fruit (TTE, 50-800 mg/kg i.p.) also profoundly antagonized picrotoxin (PCT)-induced seizures, but only partially and weakly antagonized bicuculline (BCL)-induced seizures. However, the results of this experimental animal study indicate that Tetrapleura tetraptera (Taub) fruit aqueous extract (TTE) possesses analgesic and anticonvulsant properties. These findings lend pharmacological support to the suggested folkloric uses of the plant's fruit in the management and/or control of painful, arthritic inflammatory conditions, as well as for the management and/or control of epilepsy and childhood convulsions in some tropical African countries.     

Subchronic exposure of Biomphalaria glabrata eggs to aridanin and niclosamide

Treatment of 3-day-old Biomphalaria glabrata eggs with aridanin caused a knock-down effect on the prehatch snails, making this group the most susceptible. The development and hatching of 0- to 1-day-old eggs could not be prevented but was prolonged by continuous exposure to aridanin (0.5-10 mg/l). Prehatch snails were less susceptible than juvenile and adult snails. Niclosamide (0.625-0.35 mg/l) arrested the development of B. glabrata. The results predict a poor action of aridanin as an ovicidal agent in the control of snail intermediate hosts of schistosomiasis.     

Evaluation of the molluscicidal properties of Myrtus communis L. (Myrtaceae)

Crude water extract and a flavonoid fraction of Myrtus communis were found to possess molluscicidal activity against the aquatic snail Biomphalaria glabrata involved in the transmission of schistosomiasis.     

Ethnopharmacological survey of plants used for the treatment of schistosomiasis in Niono District, Mali

In Mali the use of traditional medicine is a wide spread phenomenon, not only because of its cultural importance, but also as the majority of people cannot afford the western drugs or medicines. In Mali, the Office du Niger area constitutes the main zone of schistosomiasis transmission where both Schistosoma mansoni and Schistosoma haematobium are encountered. An ethnopharmacological survey, using questionnaire, was conducted in the Office du Niger area of the Niono District to determine the plants used against schistosomiasis amongst traditional healers. Forty healers from 21 villages of six different health areas were interviewed. All interviewed healers knew about urinary schistosomiasis, while only six knew about the intestinal form. The presence of blood in urine was reported as the main symptom of urinary schistosomiasis. Fifty-five plants belonging to 30 families were reported to be used alone for treating urinary and intestinal schistosomiasis, while nine combinations of plants were used against the urinary form of the disease. Cissus quadrangularis and Stylosanthes erecta were the plants most frequently used and were reported for the first time, to be used against schistosomiasis in Mali.     

Schistosomiasis in China: an update

A study tour in China provided information on the current status of schistosomiasis. Although many counties have been cleared of Oncomelania snails, problem areas still exist in the lakes region of the central Yangtze Valley, in hilly or mountainous terrain, and where water level cannot be controlled. In the central Yangtze area the main reservoir of infection is now considered to be cattle. It was estimated that the prevalence of schistosomiasis in 1983 was about 2.4 million cases, mostly light. Considerable effort is being made to develop immunodiagnostic methods to identify the relatively few and often subclinical cases that occur in sparsely endemic areas. Nationwide eradication does not seem feasible at present, necessitating continued surveillance to maintain and consolidate progress and prevent reintroduction of the parasite or its host snails in areas freed from the disease.     

Effect of active molluscicidal component of spices on different enzyme activities and biogenic amine levels in the nervous tissue of Lymnaea acuminata

In vivo exposure of Lymnaea acuminata to thymol and [6]-gingerol (active molluscicidal components of Trachyspermum ammi and Zingiber officinale, respectively) indicates that they significantly alter acetylcholinesterase, lactic dehydrogenase, succinic dehydrogenase and cyto-oxidase activity in the nervous -tissue of snails. In vitro exposure showed that, except for acetylcholinesterase and lactic dehydrogenase, no significant changes were observed in cyto-oxidase and succinic dehydrogenase activity in the nervous tissue of L. acuminata. Sublethal exposure to thymol and [6]-gingerol reduced the levels of 5-hydroxytryptamine (5-HT) and dopamine (DA) in the nervous tissue of L. acuminata. There was, however, no significant change in the level of 5-hydroxy indol acetic acid (5-HIAA). Thymol and [6]-gingerol thus affects all the known neurotransmission mechanisms in the snail either separately or through a complex interaction between the different neurotransmitters. This may account for their toxicity to snails.     

Evaluation of aridanin, a glycoside, and Aridan, an aqueous extract of Tetrapleura tetraptera fruit, on Schistosoma mansoni and S. bovis

Experiments were conducted on different stages of Schistosoma mansoni and S. bovis using various concentrations of aridanin and Aridan. Aridanin and Aridan were active against Schistosoma mansoni and S. bovis miracidia. A low concentration of aridanin (0.25 micrograms/ml) reduced the production of cercariae by snails already shedding cercariae. Aridanin and Aridan also produced profound reduction in the worm recovery of mice infected with pretreated cercariae of S. mansoni and S. bovis. Higher concentrations of the molluscicides were biocidal to the cercariae of these schistosomes. These results indicate that the molluscicides are capable of reducing the transmission of schistosomiasis at different stages of the schistosome development and suggest that a similar effect may occur under field conditions.     

Anthelmintic activity of the latex of Ficus species.

The latex of some species of Ficus (Moraceae) has been traditionally used as vermifuge in Central and South America. It has been accepted that anthelmintic activity is due to a proteolytic fraction called ficin. In the present study, the anthelmintic activity of the latex of Ficus insipida Willd. and Ficus carica L. has been investigated in NIH mice naturally infected with Syphacia obvelata, Aspiculuris tetraptera and Vampirolepis nana. The latex of F. insipida, administered by intragastric route in doses of 4 ml/kg/day during three consecutive days, were effective in the removal of 38.6% of the total number of S. obvelata, being inexpressive in the removal of A. tetraptera (8.4%) and segments of V. nana (6.3%). The latex of F. carica, administered in doses of 3 ml/kg/day, during three consecutive days, was effective in the removal of S. obvelata (41.7%) and it did not produce significant elimination of A. tetraptera (2.6%) and V. nana (8.3%). The observed high acute toxicity with hemorrhagic enteritis, in addition to a weak anthelmintic efficacy, do not recommend the use of these lattices in traditional medicine.     

具有杀灭钉螺活性的植物源天然产物研究进展

钉螺(oncomelania)是日本血吸虫Schistosoma japonicum的唯一中间寄主,是血吸虫病传播过程中不可缺少的环节。目前用于杀灭钉螺的化学药物存在生产成本高、严重污染环境、钉螺耐药性和对非靶体生物的毒性等诸多问题,这使人们将研究兴趣转向从植物中寻找天然灭螺药物。从结构类型、作用机制和构效关系等方面入手,对具有杀灭钉螺活性的植物源天然产物进行归纳总结,以期为新型植物源灭螺剂的开发提供参考。     

Evaluation of the effects of low concentrations of aridanin isolated from Tetrapleura tetraptera Taub. (Mimosaceae) on the growth and egg production of Biomphalaria glabrata say and Lymnaea columella say

The effects of low concentrations of aridanin (0.125, 0.25, 0.5, and 1.0 ppm) on the growth and egg production of Biomphalaria glabrata and Lymnaea columella were compared with the effects of low concentrations of niclosamide (0.025, 0.05, and 0.10 ppm). Aridanin and niclosamide caused significant reduction in the egg production and growth of B. glabrata and L. columella, indicating that aridanin has a potential use in schistosomiasis control if used in slow-release formulations. The poor chemical stability of aridanin in dear water suggests that its effectiveness as a molluscicide in the field will depend on the speed of its destructive action on snails.     

Molluscicidal metabolites from an assemblage of Palmyra Atoll cyanobacteria

Molluscicides can play an important role in the control of schistosomiasis because snails of the genus Biomphalaria act as intermediate hosts for the parasite. Schistosomiasis is one of 13 neglected tropical diseases with high morbidity and mortality that collectively affect one billion of the world's poorest population, mainly in developing countries. Thiopalmyrone (1) and palmyrrolinone (2), metabolites isolated from extracts of a Palmyra Atoll environmental assemblage of two cyanobacteria, cf. Oscillatoria and Hormoscilla spp., represent new and potent molluscicidal chemotypes against Biomphalaria glabrata (LC50=8.3 and 6.0 μM, respectively). A slight enhancement in molluscicidal effect (LC50=5.0 μM) was observed when these two natural products were utilized as an equimolar binary mixture.     

Molluscicidal activity of some Saudi Arabian euphorbiales against the snail Biomphalaria pfeifferi

The comparative susceptibility of the snail vector of intestinal schistosomiasis, Biomphalaria pfeifferi to the action of extracts from Saudi Arabian Euphorbiales has been determined. Methanol and chloroform extracts of the plants tested (Jatropha glauca, Euphorbia helioscopia and Euphorbia schimperiana) were the most promising from the molluscicidal point of view with LD(50) values in the range 10-100 ppm.     

Efficiency of traditionally used South African plants against schistosomiasis

Urinary schistosomiasis is treated traditionally by means of herbal remedies. Forty-eight South African plant species were identified as possible antischistosomic plants. Twenty-one of these plant species were collected in order to investigate their antischistosomal properties. Crude extracts of the plant materials were screened against the schistosomula of the species Schistosoma haematobium. Cercariae were obtained from Bulinus africanus snails through an in vitro technique. By subjecting the cercariae to a sheering stress, they were transformed into schistosomula. The schistosomula were placed into a culture medium to which the plant extracts were added. The results obtained indicated that the plant extracts from Berkheya speciosa (Asteraceae), Euclea natalensis (Ebenaceae) and Trichilia emetica (Meliaceae) are lethal to the schistosomula.     

Antimalaria activity of ethanolic extract of Tetrapleura tetraptera fruit

The in vivo antiplasmodial activity of the ethanol fruit extract of Tetrapleura tetraptera used as spice and in the treatment of various ailment in Niger Delta region of Nigeria was evaluated in Plasmodium berghei infected mice. Tetrapleura tetraptera (300-900 mg/kg day) exhibited significant (P < 0.05) blood schizonticidal activity both in 4-day early infection test and in established infection with a considerable mean survival time comparable to that of the standard drug, chloroquine, 5 mg/kg day. The fruit extract possesses significant (P < 0.05) antiplasmodial activity with may have contributed to the immune status of the Nigerians against malaria in addition to its nutritive value.     

Aqueous degradation of isoflavonoids in an extract of Millettia thonningii (Leguminosae) which is larvicidal towards schistosomes

A chloroform extract of the seeds of the West African legume Millettia thonningii has been shown to kill the snails which transmit the schistosomiasis and also the larvae of the parasite itself. This study examines the bioactivity of the chloroform extract of M. thonningii in aqueous non-sterile conditions. Suspensions of the extract in water maintained larvicidal activity for long periods. HPLC analysis showed that over a period of 4 weeks in aqueous suspension, degradation of two of the compounds present, the isoflavonoids alpinumisoflavone and 4′-methylalpinumisoflavone, occurred and bioactivity was eventually lost, indicating that these compounds are probably responsible for the bioactivity. These isoflavonoids are thought to act via inhibition of electron transport.     

Environmental impact evaluation of the stem bark extract of Maesa lanceolata used in Democratic Republic of Congo

This study has been carried out in order to evaluate new chemical drugs from plants for biocidal activity before use to avoid noxious effect on human beings and animals or plants and also to prevent the worsing of environment. In fact, many natural products endowed with biological active principles are obtained from plant material used in the holistic medicines. Presently, scientists pay attention to the study of plant extracts hoping to discover cheaper and efficient new drugs for health care and for pest control. On this point of view, the safety tests of extract from Maesa lanceolata (Myrsinaceae) candidate for snails control in the Democratic Republic of Congo, were undertaken. Portion of powdered steam barks was extracted with EtOH to obtain saponins that were submitted to tests. Saponins were fractionated by using TLC techniques and biocidal activity tests were performed on fishes, molluscs and mousquitoes. Saponins exhibited powerful biocidal activity against aquatic adult insects (Aeschnidae, Coenagrionidae, Hydrobidae), moustiquitoes (Anopheles gambiae, Anopheles funestus, Culex sp), snails (Biomphalaria pfeiffeiri and Lymnae natalensis), furcocercariae of Schistosoma mansoni and fish (Haplochromis sp, Oreochromis nilotica and Oreochromis macrochi)r. As results, Maesa lanceolata (Myrsinaceae) contains a saponin-mixture endowed with molluscicidal activity at a dose of 1mg/l. It may be a real candidate for snail control programs but it is harmful to aquatic biota. Attention must be paid to its utilization to avoid the ecological disturbance in the environment, especially when indigenous populations use it for fishing during the dry season.     

Millettia thonningii molluscicide: A rapid knockdown cercaricide for schistosome cercariae

Suspensions of ground seed material from the West African legume, Millettia thonningii, have previously been shown to be molluscicidal to schistosome-transmitting snails and thus potentially useful as a control agent for schistosomiasis. It is demonstrated here that Millettia seed suspensions, in addition to their molluscicidal action, show considerable toxicity towards the infective cercarial stage of Schistosoma mansoni, a causative agent of human intestinal schistosomiasis. This toxicity consists of a rapid knockdown effect on the cercariae, producing unresponsive immobility in times from 11 to 42 min in a concentration range from 500 to 100 parts per million. Filtering reduced the speed of this effect. Cercaricidal activity of the suspensions is also demonstrated in a range of unfiltered suspension concentrations, with 100% mortality occurring from 120 to 310 min after exposure. This potent action will add to the potential effectiveness of a Millettia molluscicide preparation when used as a control agent for schistosomiasis.     

A study of the larvicidal and molluscicidal activities of some medicinal plants from northeast Brazil

In a search for natural products that could be used to control the vectors of tropical diseases, 23 extracts of medicinal plants from the northeast of Brazil have been tested for molluscicidal activity against egg masses and adults of the snail Biomphalaria glabrata, for larvicidal activity against the larvae of the mosquito Aedes aegypti, and for general toxicity against the larvae of the brine shrimp Artemia salina. Of these extracts, two were active against the adult snail, one against snail egg masses, eight against the larvae of the mosquito, and 16 showed toxicity towards the brine shrimp. Chemical tests indicated that a wide variety of natural product classes were present in those extracts that showed significant activities in the bioassays.     

斑点追踪技术对2型糖尿病患者心肌收缩异常及其与C肽水平相关性研究

目的:观察2型糖尿病患者心肌运动异常,检测其血清C肽水平,探讨糖尿病患者心功能异常改变与C肽之间的关系。方法:选取2型糖尿病患者60例,对照组60例,应用经胸二维超声、获取受检者左心室心尖四腔心、两腔心、长轴切面二维图像,测定左心室内外膜心肌纵向收缩期峰值应变。检测2型糖尿病患者空腹及餐后2h血清C肽水平。结果:①糖尿病组与正常对照组各常规超声心动图参数均无显著性差异(P>0.05);②与正常对照组比较,糖尿病组的左室长轴内膜心肌纵向峰值应变均明显减低(P<0.05),而外膜心肌只有后壁、下壁及后间隔纵向峰值应变明显减低(P<0.05)。③糖尿病组内膜心肌整体纵向应变峰值与空腹及餐后2h血清C肽水平呈正相关(r=0.45,0.62,P<0.05),外膜心肌整体纵向峰值应变仅与餐后2h血清C肽水平呈正相关(r=0.46,P<0.05)。左心室射血分数(EF)、左心室内径缩短率(FS)等与空腹及餐后2h血清C肽均没有相关性。结论:二维超声斑点追踪技术能够发现常规超声心动图难以发现的糖尿病患者左心室心肌收缩功能异常,且与血清C肽尤其是餐后2hC肽水平密切相关。