Fatty acids profile and anticholinesterase activity of fish lipids from Brazilian Northeast

Acetylcholine deficiency is a neurochemical characteristic of patients with clinical diagnosis of Alzheimer´s disease. Substances that inhibit the enzyme acetylcholinesterase, increasing levels of acetylcholine in the brain, are a promising form of treatment. Studies relate the use of omega-3 fatty acids in the treatment and prevention of Alzheimer's disease. The Northeast Region of Brazil has an enormous biological diversity and a wide variety of fish species. In this work, the oils of eleven species of marine fish found on the coast of Ceará, Brazil, were analyzed in relation to the fatty acid profile and the inhibitory activity of the enzyme acetylcholinesterase. Total lipids were extracted from fish samples by Folch metodology. The lipid extracts of the fish and industrialized fish oil, used for comparison, were esterified and fatty acid profiles were analyzed. The acetylcholinesterase inhibitory activity was measured quantitatively. The oils presented a high percentage of saturated fatty acids, which is a general characteristic of tropical fish. Oleic acid was the highest monounsaturated fatty acid. Oils of Scomberomorus cavalla, Lutjanus synagris and Haemulon plumieri presented expressive percentages of polyunsaturated fatty acids and the most potent anticholinesterase activities. This research showed the oils of S. cavalla, L. synagris and H. plumieri may be promising functional food products of active fatty acids as new therapies to treatment or prevention of Alzheimer's disease. The expressive concentration of unsaturated and polyunsaturated fatty acids together with their relevant anticholinesterase activity are characteristics of the importance of these fish oils.

Development of Synergy-Based Combination for Learning and Memory Using in vitro, in vivo and TLC-MS-Bioautographic Studies

The present study is aimed at developing a synergistic combination to enhance learning and memory in Alzheimer’s patients with the help of eight common medicinal plants used in the AYUSH system. Aqueous and hydroalcoholic extracts of eight medicinal plants from the AYUSH system of medicine were prepared. These were subjected to in vitro anticholinesterase activity, to find out the combination index of synergistic combination. The synergistic combination and their individual extracts were subjected to total phenol, flavonoid and antioxidant activity estimation. Further, in vivo neurobehavioral studies in rats were carried out followed by TLC-MS-bioautographic identification of bioactive metabolites. Out of the sixteen extracts, aqueous extracts of Withania somnifera (L.) Dunal (WSA) and Myristica fragrans (L.) Dunal (MFA) were selected for the development of synergistic combination based on their IC50 value in vitro anticholinesterase assay. The synergistic combination inhibited the anticholinesterase activity significantly as compared to the individual extracts of WSA and MFA. The synergistic combination also showed more phenolic and flavonoid contents with potential antioxidant activity. The TLC-bioautography showed four white spots in WSA, signifying sitoindosides VII, VIII, quercetin, isopelletierine and Withanolide S as AChE inhibitory compounds while showing five white spots of anti-cholinesterase active metabolites identified as eugenol, methyl eugenol, myristic acid, galbacin and β-sitosterol in MFA. The observation of neurocognitive behavior in amnesia induced subjects manifested that both the synergistic combinations showed comparable results to that of standard piracetam, though the synergistic combination containing a higher concentration of WSA showed more appreciable results in ameliorating dementia in rats. The study suggests that the synergy based combination successfully enhanced memory and learning by abating free radical and acetylcholine levels, and increased learning and memory in rats, providing a strong rationale for its use in the treatment of dementia and Alzheimer’s disease.

Bioactivity of Wild Hop Extracts against the Granary Weevil, Sitophilus granarius (L.)

The use of bioinsecticides, rather than synthetic compounds, appears a goal to be pursued in pest control, especially for species such as Sitophilus granarius (L.) which attack stored products. Since Humulus lupulus (L.) is a remarkable source of bioactive compounds, this study investigated the bioactivity of hop flower extracts against S. granarius adults by evaluating toxic (contact, inhalation, and ingestion), repellent, antifeedant, and nutritional effects as well as their anticholinesterase activity and olfactory sensitivity. Hop extracts were obtained by soaking dried and ground hop cones in solvents of decreasing polarity: methanol, acetone, and n-hexane. Dried crude extracts were resuspended in each solvent, and used in topical application, ingestion, and fumigation toxicity assays, as well as in contact and short-range repellency tests, in vitro anticholinesterase activity evaluation, and electroantennographic tests. No inhalation toxicity for the extracts was found. On the contrary, all extracts showed adult contact toxicity 24 h after treatment (LD50/LD90 16.17/33.20, 25.77/42.64, and 31.07/49.48 µg/adult for acetone, n-hexane, and methanol extracts, respectively); negligible variations for these values at 48 h were found. The anticholinesterase activity shown by all extracts suggested that the inhibition of this enzyme was one of the mechanisms of action. Interestingly, flour disk bioassays revealed a significant ingestion toxicity for the acetone extract and a lower toxicity for the other two extracts. Moreover, all extracts affected insect nutritional parameters, at the highest dose checked. Filter paper and two-choice pitfall bioassays showed repellent activity and a strong reduction of insect orientation to a highly attractive food odor source, with minor differences among extracts, respectively. Finally, the presence of volatile compounds in the different extracts that are perceived by insect antennae was confirmed by electroantennography. All these findings strongly suggest a possible use of hop cone extracts against S. granarius, thus further confirming this plant as an interesting species for pest control.

Phytochemical, physicochemical, microbiological study and anticholinesterase activity of Ginkgo biloba L. and Bacopa monnieri L. used in phytotherapy

Herbal medicines based on Ginkgo biloba L. and Bacopa monnieri L. are used to improve memory and cognitive function. The quality control and anticholinesterase activity of the herbal medicines prepared from G. biloba and B. monnieri were evaluated which are commercialized in handling pharmacies. Samples of herbal medicines based on G. biloba and B. monnieri were obtained from handling pharmacies in Teresina-PI, submitted to labeling analysis and anticholinesterase activity. The phytochemical study was performed by preliminary prospecting, TLC and HPLC. The tests physicochemical and microbiological analyses were made according to the Pharmacopoeia 2010. It was observed that the labeling, foreign material, disintegration, and microbiological parameters were in accordance with ANVISA standards. The colorimetric tests were uniform in the samples of B. monnieri and variable of G. biloba. The average weight evaluation shows that the G1 and B3 samples have capsular content above that described in the labeling and presented pH values ​​different. Among the thermogravimetric profiles, the mass losses of samples G1 and B3 showed values ​​with high ash content, suggesting adulterations. Phytochemical prospecting showed flavonoids as common secondary metabolites in both species, corroborating with TLC and HPLC analysis, which identified the compounds chlorogenic acid, rutin, myricetin and quercetin. The samples G4, B2 and B5 present metabolites capable of inhibiting the enzyme acetylcholinesterase with IC50 of 0.8540 mg/mL, 0.9650 mg/mL and 1.8221×10-5 mg/mL, respectively. The samples G1 and B3 of G. biloba and B. monnieri, did not obey some parameters of quality control for herbal medicines according to the criteria of the Brazilian Pharmacopeia.