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    Cola caricifolia (G.Don) K. Schum and Crotalaria retusa L. from Ivory Coast as sources of bioactive constituents
    (Elsevier B.V., 2020) Sut S.; Dall'Acqua S.; Ibrahime Sinan K.; Bene K.; Kumar G.; Fawzi Mahomoodally M.; Picot-Allain C.
    Cola caricifolia (G.Don) K. Schum and Crotalaria retusa L. are important plants in African traditional medicine used against a plethora of human ailments. In this study, phytochemical characterization and enzyme inhibitory assays were performed to assess the potential usefulness of C. caricifolia and C. retusa leaves extracts as source of bioactive constituents for potential industrial applications. The flavonoid content of C. caricifolia (22.27 mg rutin equivalent (RE)/g) was significantly higher (p<0.05) than C. retusa (12.45 mg RE/g) methanol extract. Inhibitory activity against acetylcholinesterase, butyrylcholinesterase, and tyrosinase were evaluated for all the extracts (ethyl acetate, methanol, and water), whereby the best activity recorded for the methanol extracts. Additionally, the methanol extracts of C. caricifolia and C. retusa showed significant antioxidant activity in the phosphomolybdenum, metal chelating, reducing power, and radical scavenging assays. Flavonoid glycosides and caffeoyl derivatives were the most abundant constituents in C. caricifolia. Crotalaria retusa contained several flavonoid glycosides with structures not described previously. One new compound, kaempferol-6-C-?-glucopyranoside-3-O-?-glucopyranosil-6-O-caffeoyl ester has been elucidated using spectroscopic method in the current study. Derivatives present in minor amount were tentatively identified as kaempferol glycosides. Overall phytochemical investigations allowed the identification of flavonoid O and C glycosides, caffeic acid derivatives, and phytosterols from both plant extracts while pyrrolizidine alkaloids were identified in C. retusa. Structural characteristics of the new isolated compounds along with the most abundant constituents of the two extracts were elucidated allowing the observation of some structural moieties related to the observed activity. These observations highlighted the potential use of these plants as a source of multi-directional biological agents that could lead to bioproducts development. © 2020 Elsevier B.V.
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    An insight into Cochlospermum planchonii extracts obtained by traditional and green extraction methods: Relation between chemical compositions and biological properties by multivariate analysis
    (Elsevier B.V., 2020) Dall'Acqua S.; Kumar G.; Sinan K.I.; Sut S.; Ferrarese I.; Mahomoodally M.F.; Seebaluck-Sandoram R.
    In African traditional medicine Cochlospermum planchonii is used to manage various diseases such as malaria, diarrhoea, jaundice, infections and inflammation, hence presents the potential to be a good source of bioactive compounds. In this study, traditional and green extraction techniques have been used namely green extraction (homogenizer assisted extraction (HAE) and Sonication (SON)) and conventional extraction (Maceration (MAC), and Soxhlet (SOX)). Extracts prepared from aerial parts were studied for the total phenolic, flavonoids, total antioxidant and enzyme inhibitory properties also relating their biological properties and chemical content by multivariate analysis. The total phenolic contents obtained were in the order of HAE (221.78 mg gallic acid equivalent (GAE)/g) > SON (202.64 mg GAE/g) > SOX (190.28 mg GAE/g) > MAC (187.45 mg GAE/g). The highest flavonoid content (rutin equivalent (RE)) was obtained by SOX (65.67 ± 0.43 mg rutin equivalent (RE)/g). The highest antioxidant activity was recorded for HAE. C. planchonii extracts showed inhibitory activity against acetylcholinesterase (8.46–8.56 mg galantamine equivalent (GALAE)/g), tyrosinase (165.76–171.10 mg kojic acid equivalent (KAE)/g) and ?-amylase (1.18–1.30 mmol acarbose equivalent (ACAE)/g) enzymes. It was found that the observed enzyme inhibitory properties was dependent on the type of extraction methods. Only SOX extract presented ?-glucosidase inhibition (21.26 mmol ACAE/g) suggesting potential studies of this extract as antidiabetic. Liquid chromatography coupled to diode array detection and electrospray ionization tandem mass spectrometry (LC-DAD-ESI-MSn) was used for the qualitative analysis of the samples, allowing the quantification of gallic acid, prodelphynidins and flavonol derivatives. Based on multivariate analysis, green extraction techniques (HAE and SON) were different from conventional techniques (MAC and SOX). Results showed the usefulness of green extraction techniques for obtaining bioactive enriched fractions and tend to highlight the need for additional investigations to fully explore the potential usefulness of C. planchonii as source of antioxidant, antidiabetic and whitening agent as well as cholinesterase inhibitors. © 2020 Elsevier B.V.