Ommochromes from the Compound Eyes of Insects: Physicochemical Properties and Antioxidant Activity.

The objective of this study was screening of ommochromes from the compound eyes of insects and comparison of their antioxidant properties. Ommochromes were isolated in preparative quantities from insects of five different families: Stratiomyidae, Sphingidae, Blaberidae, Acrididae, and Tenebrionidae. The yield of ommochromes (dry pigment weight) was 0.9-5.4% of tissue wet weight depending on the insect species. Isolated pigments were analyzed by high-performance liquid chromatography and represented a mixture of several ommochromes of the ommatin series. The isolated ommochromes displayed a pronounced fluorescence with the emission maxima at 435-450 nm and 520-535 nm; furthermore, the emission intensity increased significantly upon ommochrome oxidation with hydrogen peroxide. The ommochromes produced a stable EPR signal consisting of a singlet line with g = 2.0045-2.0048, width of 1.20-1.27 mT, and high concentration of paramagnetic centers (> 1017 spin/g dry weight). All the investigated ommochromes demonstrated high antiradical activity measured from the degree of chemiluminescence quenching in a model system containing luminol, hemoglobin, and hydrogen peroxide. The ommochromes strongly inhibited peroxidation of the photoreceptor cell outer segments induced by visible light in the presence of lipofuscin granules from the human retinal pigment epithelium, as well as suppressed iron/ascorbate-mediated lipid peroxidation. The obtained results are important for understanding the biological functions of ommochromes in invertebrates and identifying invertebrate species that could be used as efficient sources of ommochromes for pharmacological preparations to prevent and treat pathologies associated with the oxidative stress development.

Paramagnetics melanin and Mn2+ in black soldier fly Hermetia illucens.

Larva, prepupa (last instar larva), pupa, and an empty shell of pupa after hatching of the black soldier fly Hermetia illucens contain eumelanin, an active synthesis of which is observed at the prepupal stage, which is probably due to the release of prepupa from the feed substrate thickness to the open space for pupation. It was shown for the first time that prepupa contains high quantities of the magnetically active form of manganese Mn2+. This fact indicates that Mn2+ stimulates the copper-containing tyrosinase-the key enzyme in the synthesis of melanin in the period of migration and adaptation of the insect to the solar radiation.

Characteristics of lipid fractions of larvae of the black soldier fly Hermetia illucens.

The lipid fraction of larvae of the black soldier fly Hermetia illucens was shown to contain lauric acid (38.43 wt %) and its esters, azelaic and sebacic acids, and azelaic acid dibutyl ester. The dominant compound in the group of identified glycerides was lauric acid monoglyceride (0.70 wt %). Glycerides were also represented by triglycerides and diglycerides of lauric acid. Sterols were represented primarily by phytosterols (over 75%), the major of which was alpha-sitosterol (45%). The identified lipid complex composition is apparently determined by the biological characteristics of the fly Hermetia illucens and ensures antibacterial defence of larvae and stability of lipids at changing ambient temperature.

[BLOCKING SENSORIMOTOR DISORDERS IN STRIATIC DOPAMINERGIC DEFICIENT MICE BY THE EXTRACTS OF "REMEDY BEETLE" ALPHITOBIUS DIAPERINUS].

Five groups of C57Bl/6JSto mice (groups 1-5) were tested on a vertical pole 2 weeks since subcutaneous administration of proneurotoxin MPTP (40 mg per kg b. w.) to groups 2-5. Group 1 served as control. It is known that this MPTP dosage forms within 2 weeks sensorimotor disturbances similar to the initial stage of Parkinson's disease. One week before MPTP injection and during all the period after it (2 weeks) animals of groups 3-5 got one of the three extracts of biomass homogenate of the «remedy beetle¼ Alphitobius diaperinus as an additive to their food (8 g per 1 kg of food). The extracts were as follows: water (N 1), water-methanol (N 2) and water-methanol one after solid-phase extraction (N 3). All extracts were immobilized on a phytocarrier. Animals of groups 1 & 2 used ordinary food. Sensorimotor disturbances which could be clearly seen in the 2nd group of mice (MPTP) were absent in group 1 (control) as well as groups 3-5 which received an «antidote¼ with their food as one of the extracts of homogenate of the beetle biomass. The extract N 3 demonstrated maximal efficiency of all.