Natural Products Journal, The - Volume 8, Issue 3, 2018

Background: Cistus genus is widespread in the Mediterranean regions with several species and is traditionally known as a natural remedy, but few previous phytochemical researches have been conducted on Cistus species growing in Sardinia. The aim of this study is to characterize the phenolic composition and to evaluate antimicrobial activities of the extracts of C. creticus subspecies growing in Sardinia. Methods: The fresh aerial parts of the plants were extracted using acidified methanol. HPLC-DADESI- MS was employed to identify the polyphenols in the obtained extracts. Antimicrobial activity was determined as Minimum Inhibitory Concentration by using an agar macrodilution method. Results: The obtained results allowed the detection of 52 phenolic compounds including phenolic acids, monomeric and dimeric flavan-3-ols, flavonol glycosides. The phenolic profiles of the three subspecies were observed to be similar, even if the relative percentages were quite different. The extracts did not exhibit any pronounced differences in their antimicrobial activities; however, it was revealed that Gram-positive bacteria are more sensitive to the Cistus extracts than Gram-negative bacteria. None of the extracts showed any noticeable action against Candida species. Conclusion: We can affirm that some differences are evident between the chemical profile of polyphenols in the C. creticus subsp. creticus and the other two subspecies; however, it appears to be clear that the secondary metabolites are similar. The present study permits us to obtain preliminary information on the antibacterial and antifungal activity of methanol extracts of Cistus creticus subspecies from Sardinia.

Background: Protozoal infection is endemic to the tropical regions of the world including West Africa, where high disease burden and associated deaths are reported annually. There is still a high reliability on traditional and herbal medication for the management of such diseases. Method: In this study, a total of 66 extracts of different polarity were prepared from 22 Nigerian medicinal plants belonging to 16 different families, and evaluated for antitrypanosomal, antileishmanial and antiplasmodial activities. Results: Methanol extracts of the leaves and stem of Securinega virosa and Japtropha curcas showed strong antiplasmodial activity with IC50 values generally less than 20 μg/mL. Chloroform fractions of the leaves extract of Datura metel and Calotropis procera, hexane fractions of the whole plant of Hymenocardia acida with the leaves of Morinda lucida and the methanol fractions of the leaves and stem of Nymphea odorata showed significant activity against Trypanosoma brucei brucei blood stage trypamastigotes with IC50 (μg/ml) values generally less than 5 μg/mL. No significant activity was observed in vitro against Leishmania donovani (promastigotes, axenic amastigotes and intracellular amastigotes in THP1 cells) except for the methanol and chloroform fractions of the extract from the leaves of Datura metel. Conclusion: This work partly supports the ethno-medicinal use of some of the selected medicinal plants and further research into the putative active constituents may be desirable.

Objectives: Erythroxylum cuneatum is a plant that belongs to the family of Erythroxylaceae. It is locally known as “Chinta mula” and found around Southeast Asia. This study identified the active phytochemicals and antioxidant properties in various extracts derived from dried leaves of Erythroxylum cuneatum. Methods: The tests of phytochemical screening included extracts of ethanol, acetone, hexane and aqueous. The antioxidant activity was determined by measuring total phenolic content, 2,2- diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and hydrogen peroxide scavenging activity. Results: The phytochemical screening of Erythroxylum cuneatum dried leaves revealed the presence of phenolic compounds namely flavonoids, tannins and total phenols. Alkaloids and saponins were also detected. The antioxidant activity of the examined extracts varies depending on the solvent used. Generally, acetone extract showed highest total phenolic content with a value of 2228 μg GAE/g and highest DPPH radical scavenging activity with IC50 of 1020.00 μg/ml compared to the standard ascorbic acid of 304.44 μg/ml. Ethanol extract exhibited high hydrogen peroxide activity with IC50 of 83.09 μg/ml. Conclusion: This study showed that acetone extract contains highest phenolic compounds and both ethanol and acetone extracts are a potential source of natural antioxidants.

Background: Protein extraction from plant tissues is a great challenge since they contain low amount of proteins and rich in proteases, secondary metabolites and oxidative enzymes. Besides, dealing with limited amount of starting material would pose another challenge in getting high protein yield. The aim of this study is to determine the best protein extraction protocol for recalcitrant tissues of banana (Musa sp.) specific for non-reducing one dimensional SDS-PAGE analysis. Methods: Three protein extraction protocols were compared which include TCA-acetone, phenol and phosphate buffer saline (PBS) using small amount of starting material. Modifications were done to each protocol to suit non-reducing SDS-PAGE analysis and subsequent downstream processes. Results: Of the three protocols compared, TCA-acetone protocol gave the highest yield and quality of protein extract from only a small amount of starting material based on protein quantification and non-reducing one dimensional SDS-PAGE analysis compared to phenol and phosphate buffer saline (PBS) protocol. Conclusion: Even though various protein extraction protocols have been developed to date, there is no one-size-fits-all when it comes to different types of plant tissues from varieties of plant species. TCA-acetone protocol was found to be most effective in extracting protein from banana shoot and root tissues even for small amount of starting material in absence of reducing agent.

Background: Lupeol, a pentacyclic triterpenoid is found in the stem-bark of Walsura trifoliate. Derivatives of lupeol are associated with a broad range of biological activities. Objective: To synthesis a series of Lupeol-benzylidine derivatives and evaluate their antimicrobial and antiproliferative acitivities. Method: Lupeol was isolated from the bark of Walsura trifoliate. The ring A at C2 position of Lupeol was modified by claisens Schmidt condentation to produce Lupeol-benzylidine derivatives. Antimicrobial assay was performed by broth dilution technique. Results: All the structures were confirmed by 1HNMR, 13CNMR and IR spectroscopic techniques. Compounds 3c and 3h exhibited the highest activity. Conclusion: In conclusion, a series of different benzylidine derivatives from natural product Lupeol have been synthesized. All the tested compounds are found to be as antimicrobial and antiproliferative agents.

Background: In this work, a series of benzoxazole derivatives has been synthesized using 1,2-diols and 2-aminophenols in the presence of lead tetraacetate. This one pot cyclocondensation involves the breaking of a C-C bond and formation of C-O and C-N bonds in a single synthetic operation. Methods: The synthesis of benzoxazole derivatives is developed through the reaction of 1,2-diols and 2-aminophenols in the presence of lead tetraacetate in ethanol under reflux conditions. Results: A series of benzoxazole derivatives was synthesized in good yields (82-96%) under reflux for 2-3.5 hours in ethanol solvent. The structural assignments of these compounds were made on the basis of elemental analysis and spectroscopic data. Conclusion: This domino reaction implies oxidation, condensation, cyclization and dehydrogenation. This procedure is an alternative to the existing procedures for the synthesis of these compounds.

Background: The genus Senecio (Asteraceae) is widely distributed all over the world (except in Antarctica and Amazonas) and includes more than 3000 species. Senecio filaginoides DC, one of the 270 species which occur in Argentina, grows from Jujuy to Santa Cruz provinces, also called Charcao, is a native species that grows spontaneously near Comodoro Rivadavia, Chubut Province, in the southeast of Argentina.Its small white flowers gather in bundles at the end of the branches. By the end of November at flowering, it concentrates a great number of insects. Methods: To better understand the chemistry of this plant and identify taxonomic markers, in the present study, we isolated a terpenoid from this genus and characterized a sesquiterpene with eremophilenolide skeleton from the fresh aerial parts of S. filaginoides. The structure of this compound was elucidated mainly by advanced NMR experiments, including inverse techniques such us, HSQC, HMBC, COSY and NOESY. The essential oil and the isolated compound, 8-hydroxy-9- keto-10αH-eremophil-7(11)-en-8,12-olide, were tested for their antimicrobial activities. Results: In the present study, P. aeruginosa strains were highly susceptible to the dilutions from 1/125 to 1/1000, whereas S. aureus showed sensitivity to two dilutions tested: 1/125 and 1/250.All species of Candida sp had biological activity from dilutions: 1/125 and 1/2000. Conclusion: The compound isolated was active against E. coli and P. aeruginosa with a MIC of 250 μg/mL, and active against E.faecalis with a value of 100 μg/mL. This is the first report about eremophilane isolated from the essential oil species of Senecio from East Central Area of Patagonia.

Background: Mentha suaveolens Ehrh. which belongs to the Lamiaceae is commonly used in Morocco for the treatment of diabetes. Objective: The present work aimed to evaluate the antidiabetic and the plasma lipid profile of the aqueous extract of aerial part of Mentha suaveolens. Method: The effect of a single and repeated (15 days of treatment) oral administration of the aqueous extract of aerial part of Mentha suaveolens (AEAPMS) on glucose and lipid profile was evaluated in normal and streptozotocin-induced diabetic rats. Furthermore, preliminary phytochemical screening, quantification of phenolic and flavonoid contents as well as histopathological examination of pancreas and liver according to the Hematoxylin-Eosin method were carried out. Results: The results showed that the extract exhibited a significant hypoglycemic and lowering serum lipids (Total cholesterol and triglycerides) effects in both normal and diabetic rats. In addition, an important influence on glucose tolerance was also noticed after AEAPMS treatment. Moreover, AEAPMS has been demonstrated to act positively on histopathological tissues of liver and pancreas. In another hand, a potential in vitro antioxidant of AEAPMS has been shown while no significant effect was observed on serum lipoproteins (HDL and LDL). Conclusion: In conclusion, the study demonstrates that AEAPMS possesses a beneficial effect on glucose and lipid metabolism.

Background: Surfactants as catalysts have found extensive utility in developing environmentally benign reaction conditions by reducing the resultant organic waste and the recyclability of the catalysts has made great advantages over other catalysts. The vital catalytic action can be attributed to its ability to solubilize insoluble substrate by forming colloidal mixtures. Objective: In this concern, we hypothesized, to develop a green protocol using micellar catalysts in aqueous media. Primarily expecting the reaction components should be ideally soluble at room temperature conditions under suitable catalysts. Method: Herein a highly efficient, one-pot four-component reaction involving thiobarbituric acid, hydrazine hydrate, ethyl acetoacetate and aromatic aldehydes for the synthesis of 7- thioxopyrazolopyrano- pyrimidinone derivatives has been accomplished using SDS (sodium dodecyl sulphate) as a catalyst. The procedure offers the advantages of green solvent, easy work-up avoiding the chromatographic separation and use of inexpensive, biodegradable, reusable catalyst. Results: These novel 7-thioxo-pyrazolopyrano-pyrimidinone derivatives were screened for antimicrobial and antioxidant activities. It was found that 3-methyl-4-(2,4-dichlorophenyl)-6,8-diethyl- 7-thioxo- 4,6,7,8-tetra-hydropyrazolo[4',3':5,6]pyrano[2,3-d]pyrimidin-5(1H)-one (5b) has shown high anti- fungal and anti-bacterial activities against the tested fungi and bacteria, which may be due to the presence of chlorine atoms. Four compounds, 5a, 5b, 5i and 5j were found to show high antioxidant activities. Conclusion: The thioxo-pyrazolo-pyranopyrimidinone motifs synthesized via the condensation protocol under micellar catalysis are found to be highly biological active entities. These series of novel compounds accounted for unique in-vitro assays.

Background: To find out the biological activities of thrombolytic, membrane stabilizing activity, as well as quantification of total phenol content in vitro model from the leaves extract of Butea monosperma (B. monosperma). Method: The collected leaves were dried and grinded. The grinded powder was kept in 2500 ml of 90% methanol for several days followed by filtered. At reduced temperature of 40°C, the volume of filtrated crude methanolic extract was reduced by a vacuum rotary evaporator under reduced pressure. Following the concentrated aqueous methanol extract was partitioned into petroleum ether, carbon tetrachloride, chloroform and aqueous soluble fractions respectively by the Kupchan methods, Then all extracts were subjected to evaluate in vivo thrombolytic by Daginawala, membrane stabilizing properties by Okoli and Omale method and total phenol content followed by the method of Wolfe et al. Results: In thrombolytic assay among the extractives, petroleum soluble fraction showed the highest percentage clot lysis (27.36 ± 0.10%) activity as compared with standard streptokinase (65.15 ± 0.16%). In case of membrane stabilizing activity, crude methanolic extract profoundly inhibited the lysis of erythrocytes (65.79 ± 0.40%) induced by osmosis, whereas reference standard acetyl salicylic acid resulted in (83.147 ± 0.39%) inhibition of lysis. On the other hand, aqueous soluble fraction showed slightly higher level of membrane stabilizing activity in the heat-induced hemolysis (75.3 ± 0.39). In the total phenolic content test, petroleum soluble fraction found significant level of phenolic (249.06 mg of GAE/gm). Conclusion: This study was conducted to legalize the B. monosperma leaves used as a folk medicine (for the ailment of thrombosis, inflammation) such as, thrombolytic, and membrane stabilizing.