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.

Anti-sickling Activity of Ursolic Acid Isolated from the Leaves of Ocimum gratissimum L.(Lamiaceae)

The present study reports in vitro anti-sickling activity and phytochemical analyses of the leaves of Ocimum gratissimum.Biological testing revealed that the plant extracts possess antisickling effects.The combination of spectroscopic techniques:1D-NMR,2D-NMR and MS revealed that ursolic acid is the major biologically active compound of O.gratissimum(Silva et al.in Molecules 13:2482–2487,2008;Kedar et al.J Food Drug Anal 20:865–871,2012).This study is the first report of the antisickling activity of ursolic acid isolated from O.gratissimum.The pharmaceutical relevance of findings from this study derives from the possibility of integrating O.gratissimum as an antisickling plant in the pharmacopoeia of Democratic Republic of the Congo.The identification of the active principle could enhance the standardization of antisickling recipe.

Chemical Fingerprint and Anti-Sickling Activity of Rosmarinic Acid and Methanolic Extracts from Three Species of Ocimum from DR Congo

The aim of this study was to characterize the polyphenolic composition by determination of chemical fingerprints of Methanolic extracts of Ocimum canum Sims, Ocimum basilicum L. and Ocimum gratissimum L. from Democratic Republic of Congo and to compare their antisickling activity of that of rosmarinic acid, the major compound to those of methanolic extracts. Phytochemical analysis performed by TLC and HPLC analysis, showed that rosmarinic acid is the most abundant phenolic acid in these Ocimum species according to the following order O. basilicum L., O. gratissimum L. and O. canum Sims. Methanolic extracts of these three species and pure rosmarinic acid showed significant antisickling activities with minimal concentration of normalization values of 0.18 ± 0.03, 0.23 ± 0.04, 0.26 ± 0.04 and 0.31 ± 0.05 mg/mL for rosmarinic acid, O. basilicum L., O. gratissimum L. and O. canum Sims methanolic extracts respectively. The antisickling activity order is the same as that of the rosmarinic acid content, indicating that this polyphenolic acid would be among the main active molecules in these extracts.