Plant-mediated effects on mosquito capacity to transmit human malaria

The ecological context in which mosquitoes and malaria parasites interact has received little attention, compared to the genetic and molecular aspects of malaria transmission. Plant nectar and fruits are important for the nutritional ecology of malaria vectors, but how the natural diversity of plant-derived sugar sources affects mosquito competence for malaria parasites is unclear. To test this, we infected Anopheles coluzzi, an important African malaria vector, with sympatric field isolates of Plasmodium falciparum, using direct membrane feeding assays. Through a series of experiments, we then examined the effects of sugar meals from Thevetia neriifolia and Barleria lupilina cuttings that included flowers, and fruit from Lannea microcarpa and Mangifera indica on parasite and mosquito traits that are key for determining the intensity of malaria transmission. We found that the source of plant sugar meal differentially affected infection prevalence and intensity, the development duration of the parasites, as well as the survival and fecundity of the vector. These effects are likely the result of complex interactions between toxic secondary metabolites and the nutritional quality of the plant sugar source, as well as of host resource availability and parasite growth. Using an epidemiological model, we show that plant sugar source can be a significant driver of malaria transmission dynamics, with some plant species exhibiting either transmission-reducing or -enhancing activities

Detection of cantharidin-related compounds in Mylabris impressa (Coleoptera: Meloidae)

Cantharidin is mainly found in the beetle families Meloidae and Oedemeridae (Insecta: Coleoptera) which are the natural producers of this terpene anhydride. Most studies to date have focused on cantharidin distribution in blister beetles, with few reports on recently found cantharidin-related compounds (CRCs). Using gas chromatography-mass spectrometry (GC-MS), the present work reported cantharidin and two CRCs, palasonin and cantharidinimide from Mylabris impressa stillata (Baudi, 1878) which was collected from Toyserkan county, Hamedan Province, Iran. Ionization provided mass spectra with characteristic fragments of cantharidin at m/z 96 and 128, demethylcantharidin at m/z 82 and 114, and cantharidinimide at m/z 70, 96 and 127. This is the first time that cantharidin and the two CRCs are found in the genus Mylabris which in turn is new to the field of venomous insects

Origin, transfer and distribution of cantharidin-related compounds in the blister beetle Hycleus scabiosae

Cantharidin provides chemical protection for the coleopteran families Meloidae and Oedemeridae. In the present study, it was observed that cantharidin concentration in Hycleus scabiosae was slightly decreased from mated females (mean = 0.011 mg/mg of dry weight) to males (mean = 0.010 mg/mg) and considerably diminished in relation to virgin females (mean = 0.005 mg/mg). Significant concentrations of palasonin (21.69 ng/mg among virgins and 17.49 ng/mg in mated females) and palasoninimide (14.62 ng/mg in virgins and 9.17 ng/mg in mated females) were found in H. scabiosae. Palasonin, palasoninimide and cantharidinimide content of eggs were measured as 5.61, 7.69 and 7.80 ng/mg respectively. Surprisingly, males showed no trace of cantharidin-related compounds (CRCs); therefore CRCs in H. scabiosae could not be transferred from males to females and based on experiments employing its deuterated form, cantharidin is probably independently synthesized in females from the male nuptial transfer. An inseminated female incorporates about 38.5 ng of cantharidin (0.34% of the maternal content), 196.35 ng of palasonin (91.82% of maternal content) and 269.15 ng of palasoninimide (96.70% maternal content) into each egg mass during oviposition. It seems that eggs of this meloid species exploit a different array of protective chemicals by increasing the ratio of CRCs versus cantharidin. CRCs are less toxic than cantharidin; therefore, such compounds might have been deposited in eggs as a safer substitute for cantharidin to provide effective protection, but does not simultaneously harm the susceptible embryo

A novel approach to the quantitation of coeluting cantharidin and deuterium labelled cantharidin in blister beetles (Coleoptera: Meloidae)

Blister beetles (Coleoptera: Meloidae) are the main natural source of cantharidin, but the compound titre is depended on several factors including, age, sex and mating status of the insects. In order to eliminate such uncertainty factors in physiological and chemical studies deuterium labelled cantharidin (D(2)C) with no natural abundance is normally introduced into the beetles' body to use it as a model for studying the cantharidin behaviour in vivo. Experiments were achieved on Mylabris quadripunctata (Col.: Meloidae) from Southern France and the beetles were exposed to an artificial diet containing a defined amount of D(2)C. On the other hand, because of the high similarity between the two compounds they cannot be well quantified by gas chromatography. In order to remove the burden, MRM technique was used for the first time which could successfully create well-defined cantharidin and D(2)C peaks and hence a precise measurement. MRM technique was examined using a GC-MS Varian Saturn which collected MS/MS data of more than one compound in the same time window of the chromatogram. It is especially useful when coeluting compounds have different parent ions, i.e. m/z 84 for D(2)C (coeluting isotopically-labelled compound) and m/z 82 for cantharidin (beetle-originated compound). Using the routine GC-MS runs, measurement accuracy may be significantly reduced because the D(2)C peak is covered by the cantharidin huge peak while MRM could reveal the two coincided peaks of cantharidin and D(2)C. Therefore MRM is hereby introduced as the method of choice to separate cantharidin from D(2)C with high sensitivity and thus provide a precise base of quantitation

Intraspecific transfer of cantharidin within selected members of the family Meloidae (Insecta: Coleoptera)

The use of deuterium-labelled cantharidin (CAN-D-2) to study details of cantharidin transfer in blister beetles indicates that the dynamics of organ-selective cantharidin accumulation may differ over time. Although the accessory glands absorb a high am

Carvacrol as a Potential Neuroprotective Agent for Neurological Diseases: A Systematic Review Article

BACKGROUND AND OBJECTIVE: Neurological diseases are becoming a significant problem worldwide, with the elderly at a higher risk of being affected. Several researchers have investigated the neuroprotective effects of Carvacrol (CAR) (5-isopropyl-2-methyl phenol). This review systematically surveys the existing literature on the impact of CAR when used as a neuroprotective agent in neurological diseases. METHODS: The systematic review involved English articles published in the last ten years obtained from PubMed, Google Scholar, and Scopus databases. The following descriptors were used to search the literature: "Carvacrol" Title AND "neuroprotective (neuroprotection)" Title OR "stroke, traumatic brain injury, Alzheimer's disease, Parkinson's disease, seizure, epilepsy Title. RESULTS: A total of 208 articles were retrieved during the search process, but only 20 studies met the eligibility criteria and were included for review. A total of 20 articles were identified, in which the efficacy of CAR was described in experimental models of stroke, traumatic brain injury, Parkinson's disease, Alzheimer's disease, epilepsy, and seizure, through motor deficits improvements in neurochemical activity, especially antioxidant systems, reducing inflammation, oxidative stress and apoptosis as well as inhibition of TRPC1 and TRPM7. CONCLUSION: The data presented in this study support the beneficial impact of CAR on behavioural and neurochemical deficits. CAR benefits accrue because of its anti-apoptotic, antioxidant, and anti- inflammatory properties. Therefore, CAR has emerged as an alternative treatment for neurological disorders based on its properties. Copyright© Bentham Science Publishers; For any queries, please email at [email protected]