Antioxidant, Anti-Inflammatory, and Antidiabetic Activities of Leaves and Stems of Uapaca bojeri Bail.(EUPHORBIACEAE), an Endemic Plant of Madagascar

Uapaca bojeri is an endemic Malagasy plant used by the local population. This work aimed to evaluate antioxidant, anti-inflammatory, and antidiabetic activities of the methanol extracts of U. bojeri leaves and stems and to report their total phenolic content and the bioactive compound content by HPLC methods. Antioxidant capacity was determined by DPPH and ferric reducing antioxidant power (FRAP) assays. An in vivo carrageenan-induced paw oedema and acetic acid-induced writhing test in mice were used for anti-inflammatory activity evaluation. An oral glucose tolerance test was performed in mice to evaluate antidiabetic activity. The total bioactive compound content of leaves was higher than that of stems. Stem methanol extract inhibited the free radical DPPH more than the leaf methanol extract. Leaf methanol extract inhibited, in a dose-dependent manner, the carrageenan-induced paw oedema more than the stem extract, but their inhibition of the pain symptoms caused an acetic acid-induced decrease similar to the number of writhes in the dose-dependent case. The leaf and stem methanol extracts significantly reduced blood glucose levels after 30 min of glucose loading in mice compared to the control group blood glucose reduction. The presence of several bioactive compounds in U. bojeri contributed to the different biological activities, but isolation and identification of these bioactive molecules are necessary to confirm these pharmacological properties

Insights into an endemic medicinal plant species of Madagascar and Comoros: The case of Famelona (Chrysophyllum boivinianum (Pierre) Baehni, Sapotaceae family)

Abstract Chrysophyllum boivinianum (Pierre) Baehni is an endemic plant of Madagascar and Comoros. In Madagascar, it is known by the local name "famelona". The wood of C. boivinianum is exploited for carpentry as material for building houses and ships. Its leaves are used in traditional medicine to treat fever, muscle pain and scorpion bites as well as to heal wounds. In Madagascar, it is widely used by the local population to treat many diseases. Thus, a deeper assessment of its valorisation strategy is becoming ever more crucial. The objective of this study was to determine the phenolic and organic compounds in the leaves and stems of C. boivinianum in relation to their biological activities and local uses. Solvents composed of methanol, water and chloridric acid were used for leaf and stem extractions. The two extracts were then compared with leaf infusions and stem decoctions by spectrophotometric and chromatographic analysis in order to determine phytochemical composition, and antioxidant and antimicrobial activities. The results showed that the leaf extracts contained the highest amount of total polyphenolic compounds (TPC) (805.16 ± 1.08 mgGAE/100 gDW), followed by leaf infusions at 477.87 ± 38.49 mgGAE/100 gDW. The stem extracts and stem decoctions had lower TPC than did the leaf extracts, with 249.12 ± 7.11 mgGAE/100 gDW and 191.66 ± 14.88 mgGAE/100 gDW, respectively. The leaf infusions showed much higher antioxidant activity (49.67 ± 0.45 mmol Fe2 +/kgDW) than did leaf extracts (27.60 ± 0.32 mmol Fe2 +/kgDW). This activity was influenced by high amounts of chlorogenic acid and caffeic acid, at 217.08 ± 2.89 mgGAE/100 gDW and 13.02 ± 0.15 mgGAE/100 gDW, respectively. The leaf infusions were also rich in gallic acid (15.19 ± 1.63 mgGAE/100 gDW). The stem extracts and stem decoctions also had lower antioxidant activity, at 19.86 ± 7.35 mmol Fe2 +/kgDW and 12.53 ± 0.15 mmol Fe2 +/kgDW, respectively. The leaves of C. boivinianum showed a higher content of bioactive compounds than the stems, and the infusions represented the best method for extracting biomolecules with high amounts of healthy properties and antioxidant activity. Regarding antimicrobial activities, leaf extracts had higher antimicrobial activity against Salmonella typhii, Escherichia coli and Candida albicans than did stem extracts. This activity was influenced by the high rates of polyphenols in the leaves

Antihypertenseur, Activité Vasorelaxant De Rouppelinia Boivinni (Apocynaceae) Et Etude De Relation Structure-Activité Des Alcaloïdes Indoliques Isolées

In the southern and south-western regions of Madagascar, traditional medicine plays an important role in society. Ethnobotanical surveys carried out in these regions have revealed that the plant known under the vernacular name "Feka (nom Mahafaly, Masikoro); Fekambato (Nom Antandroy); Fekakely (Nom Sakalava)" is used by the local population to treat hypertension. The results of biological tests (in-vivo and in-vitro) carried out on the alkaloid extract show improved vasorelaxant activity. These results justify their therapeutic virtues. Bioguided fractionation of the alkaloid extract from the aerial part of this plant resulted in the isolation of two pure products, PX-1 and PX-2. The chemical structures of these two pure products were isolated using spectral analysis methods. The ultraviolet spectrum of the PX-1 molecule recorded by LHPC-UV-DAD shows an absorption maximum at 240nm and 317nm, indicating the presence of an acylindole chromophore in PX-1. The peak at Tr= 2.9min corresponds to the molecular ion peak at m/z =355.20141 [M+H]+, corresponding to the empirical formula C21H26N2O3. Product PX-2 has a molecular weight of m/z = 352.17896 [M+H]+, corresponding to the molecular formula C21H24N2O3, and its UV spectrum recorded by HPLC-UV-DAD shows absorption maxima at 240nm and 317nm consistent with the 2-acyl indole chromophore. Analysis by nuclear magnetic resonance spectroscopy (1D and 2D NMR) confirms that the basic structures of PX-1 and PX-2 are attributed to indole alkaloids. Analysis of the pharmacological mechanism of this plant's vasorelaxant activity shows that the relaxant activity may result from blockade of calcium influx through vascular smooth muscle cells, as the contraction produced by CaCl2 on the aorta in a calcium-free depolarizing medium was inhibited by the alkaloid extract in a concentration-dependent manner with EC50= 0.061±0.0056mg/ml at n=7. Preliminary acute and chronic toxicity studies carried out on the alkaloid extract of this plant showed no significant toxic signs. In perspective, the study of the plant used in medicine to treat TAH enables the isolation of two indole-type alkaloids and the discovery of their mechanisms of pharmacological activity. It's time for researchers to turn to traditional medicine as an inexhaustible source of scientific discovery

Chemical composition of the essential oils from the aerialparts of two Malagasy endemic species (Apiaceae): Billburttiacapensoides Sales & Hedge and Billburttia vaginoides Sales &Hedge

International audienc

Chemical composition of the essential oils from the aerial parts of two Malagasy endemic species (Apiaceae): <i>Billburttia capensoides</i> Sales & Hedge and <i>Billburttia vaginoides</i> Sales & Hedge

<p>The chemical composition of twenty-five essential oil samples from the aerial parts of two Malagasy endemic species <i>Billburttia capensoides</i> Sales & Hedge and <i>B. vaginoides</i> Sales & Hedge, were investigated for the first time. Based on chromatographic profiles, three selected samples were investigated using GC(RI), GC-MS and ¹³C NMR. The content of the main components varied drastically from sample to sample: <i>p</i>-mentha-1,3,8-triene (0.2–52.7%), terpinolene (2.8–40.7%) and dill apiole (0.0–22.2%). Statistical analysis of the 25 oil compositions allowed the distinction of two well-differentiated groups. Samples of group I contained mainly <i>p</i>-mentha-1,3,8-triene while the Group II was dominated by terpinolene and dill apiole.</p