Chemo-type of essential oil of Ocimum basilicum L.from DR Congo and relative in vitro antioxidant potential to the polarity of crude extracts

Objective:To carry out a phyto-chemical characterization of essential oil from Ocimum basilicum L.(O.basilicum) harvested in DR Congo and to assess the antioxidant potential of crude extracts with respect to the polarity for comparison reason.Methods:The phyto-chemical characterization of essential oil produced by hydrodistillation was performed by coupled gas chromatography-mass spectrometer analysis and the antioxidant potential evaluation by in vitro 2,2-diphenyl-1-picrylhydrazyl free radical scavenging activity method.Results:A previously weighed amount of fresh leaves of O.basilicum produced 0.65%of essential oil that led to the identification of a set of 84.44%out of 99.98%as major compounds(> 1.5%).The chemo-type of this essential oil was linalool-methyl chavicol.Chemical components of oil were characterized by oxygenated aromatic hydrocarbons(46.00%) and oxygenated monoterpenes(26.75%).With respect to the amount of components,methyl chavicol also known as estragole(35.72%) constituted the very large quantity afterward linalool(21.25%) and then epi-α-cadinol(8.02%),α-bergamotene(6.56%),eugenol(4.60%),1,8-cineole(4.04%),germacrene D(2.06%),thymol(1.64%),and(E)-citral(1.55%),respectively.Essential oil exhibited antioxidant potential and IC_(50) =(1.180 ± 0.015) mg/mL.Non-polar crude extracts yields were low compared to the one of polar extracts.Only methanol and ethyl acetate had considerably manifested antioxidant potential with IC_(50) values equal to(0.025 ± 0.013) mg/mL and(0.085 ± 0.012) mg/mL,respectively.As concerns to IC50 values,essential oil was less active than methanol and ethyl acetate extracts.The methanol crude extract exhibited the highest activity.Non-polar extracts showed insignificant radical scavenging ability that did not allow assessing IC50 values.These results highlighted the occurrence of antioxidant potential compounds in polar media.Conclusions:Essential oil and crude extracts of O.basilicum growing in DR Congo can be advocated as natural sources of antioxidant potential compounds not only in food but also in pharmaceutical industries.The high antioxidant potential of polar crude extracts highlights antioxidant character of its composition particularly butyl stearate and rosmarinic acid we isolated and identified,respectively in the methanol crude extract.

A two-stage CO-PSO minimum structure inversion using CUDA for extracting IP information from MT data

The study of induced polarization （IP） information extraction from magnetotelluric （MT） sounding data is of great and practical significance to the exploitation of deep mineral, oil and gas resources. The linear inversion method, which has been given priority in previous research on the IP information extraction method, has three main problems as follows： 1） dependency on the initial model, 2） easily falling into the local minimum, and 3） serious non-uniqueness of solutions. Taking the nonlinearity and nonconvexity of IP information extraction into consideration, a two-stage CO-PSO minimum structure inversion method using compute unified distributed architecture （CUDA） is proposed. On one hand, a novel Cauchy oscillation particle swarm optimization （CO-PSO） algorithm is applied to extract nonlinear IP information from MT sounding data, which is implemented as a parallel algorithm within CUDA computing architecture; on the other hand, the impact of the polarizability on the observation data is strengthened by introducing a second stage inversion process, and the regularization parameter is applied in the fitness function of PSO algorithm to solve the problem of multi-solution in inversion. The inversion simulation results of polarization layers in different strata of various geoelectric models show that the smooth models of resistivity and IP parameters can be obtained by the proposed algorithm, the results of which are relatively stable and accurate. The experiment results added with noise indicate that this method is robust to Gaussian white noise. Compared with the traditional PSO and GA algorithm, the proposed algorithm has more efficiency and better inversion results.

GC-MS Analysis of Low-polar Components and Antioxidant Activities of Vernonia divergens

[Objective]This study aimed to analyze the low-polar components and antioxidant activities of Vernonia divergens.[Method]After extraction,the relative contents of various components were calculated with peak area normalization method.In addition,V.divergens were extracted with n-hexane,ethyl acetate and n-butanol,respectively;DPPH scavenging capacity and reducing capacity of these three extracts were analyzed and compared with that of vitamin C.[Result]A total of 29 compounds were identified that accounted for 88.30%of the total amount of low-polar chemical components.The results indicated that n-butanol extract exhibited higher DPPH scavenging capacity and reducing capacity than ethyl acetate extract and n-hexane extract.[Conclusion]This study provided a theoretical basis for the development and utilization of V.divergens.

In vitro C ytotoxic Properties of Crude Polar Extracts of Plants Sourced from Australia

Background:Numerous commercial pharmaceuticals-including anticancer,antiviral,and antidiabetic drugs have been developed from traditional plant-derived medicines.There are approximately 25,000 species of flora occurring in Australia,which are adapted to a range of harsh environments,and hence a plethora of novel compounds are still awaiting research in the context of their medicinal properties.Objective:The current study therefore aimed to develop a systematic protocol for screening plants with potential cytotoxicity.Many studies have found polar compounds such as to be the bioactive components responsible for the therapeutic effects.Methods:The total phenolic content(TPC)and antioxidant capacity(FRAP)of methanolic extracts of selected plants was first determined.A high correlation between the TPC values and FRAP values of the plant polar extracts were evident.Cell viability of the cancer cell lines were assessed using the MTS assay.Results:Cells subjected to Pittosporum angustifolium Lodd.Extracts at concentration of 250μg/mL showed no viable cells,comparable to cisplatin(a chemotherapy medication)used as a positive control(10μg/mL).Some promising inhibitory effects were also seen with Murrya koenigii flower and leaves at concentration of 250μg/mL,with only 43.46%and 63.88%cell viability,respectively.In contrast,extracts of Citrus hystrix(leaves)and Sygyz-ium australe(stamen)showed higher percentage cell viabilities(around 82-93%)at same concentrations.The phenolic profile of P.angustifolium B extracts demonstrating greater peak intensity and dominant peaks were tentatively identified as chlorogenic acid,p-coumaric acid,caffeic acid,t-ferulic acid and rutin.Conclusion:The Australian species P.angustifolium extract was the most cytotoxic against HeLa and HT29 cells comparing to the other plant extracts tested.A HPLC profile of the P.angustifolium extract also showed an array of promising therapeutic phenolic compounds.Future work will aim to fractionate and isolate novel compounds from this species and test their bioactivity.