Aloe barbadensis: how a miraculous plant becomes reality

Aloe barbadensis Miller is a plant that is native to North and East Africa and has accompanied man for over 5,000 years. The aloe vera plant has been endowed with digestive, dermatological, culinary and cosmetic virtues. On this basis, aloe provides a range of possibilities for fascinating studies from several points of view, including the analysis of chemical composition, the biochemistry involved in various activities and its application in pharmacology, as well as from horticultural and economic standpoints. The use of aloe vera as a medicinal plant is mentioned in numerous ancient texts such as the Bible. This multitude of medicinal uses has been described and discussed for centuries, thus transforming this miracle plant into reality. A summary of the historical uses, chemical composition and biological activities of this species is presented in this review. The latest clinical studies involved in vivo and in vitro assays conducted with aloe vera gel or its metabolites and the results of these studies are reviewed

Antioxidant and Antimicrobial Activities of Flavonoid Glycosides from Dennettia Tripetala G. Baker Leaf Extract

Dennettia tripetala a Nigerian medicinal plant widely employed in the management of oxidative stress related diseases and infections was investigated for its active constituents. A DPPH (1,1-diphenyl-2-picrylhydrazine) guided fractionation was used to target and isolate the antioxidant constituents of the ethyl acetate solvent fraction of a 20% aqueous methanol leaf extract. Two flavonoid glycosides were isolated and identified by spectral data (1H, and 13C NMR, along with ESI-TOF-MS spectrometry) as: quercetin-3-O-arabinofuranoside, avicularin (1) and vitexin-2'’-O-rhamnoside (2). In the qualitative antioxidant assay, the compounds instantly bleached the DPPH purple colour indicating free radical scavenging potential (antioxidant activity). In the micro-well dilution assay, Compound (1) was the most active with MIC values of 0.081 mg/mL against Staphylococcus aureus NCTC 6571 and 2.50 mg/mL against Escherichia coli NCTC 8196 compared to the standard drug streptomycin which had MICs of 0.039 mg/mL and 0.156 mg/mL respectively against the two organisms. None of the compounds was able to inhibit the growth of the fungi strain used at the tested concentrations. Isolation of these antioxidant and antimicrobial compounds could provide rationale for the ethnomedicinal use of this plant in traditional medicine in the management of the oxidative stress related diseases and infections

Isolation and Characterization of Antioxidative Constituents of Ceiba Pentandra (Kapok) Leaves Extract

Ceiba pentandra widely employed in the management of inflammatory conditions, infections and oxidative stress related diseases was investigated for its active constituents. A DPPH-directed fractionation of the ethyl acetate solvent fraction of a 20% aqueous methanol leaves extract of Ceiba pentandra afforded a clovamide derivative, N-trans-caffeoyl-DOPA-methyl ester (1) together with a flavonoid, acacetin-7-O-rutinoside, Linarin (2) and 3,4- dihydroxybenzoic acid, protocatechuic acid (3). Structure elucidation of the isolated compounds was carried out using spectroscopic techniques: mass spectrometry (ESI-TOF-MS), 1D NMR (1H, 13C and DEPT) as well as 2D experiments (GCOSY, GHSQC and GHMBC). In the qualitative antioxidant assay, compounds 1- 3 bleached the DPPH purple colour indicating free radical scavenging potential (antioxidant activity). Isolation of these antioxidant compounds could provide rationale for the use of this plant in traditional medicine in the management of the oxidative stress related diseases and  infections.Keywords: Ceiba Pentandra, Bombacaceae, Clovamide, Antioxidan

Photosynthetic adaptation of two semi-arid species of <I>Gethyllis</I> (Kukumakranka) to drought-and-shade stress

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The carbon and nitrogen cost associated with the growth, reproductive and dormant phases of two South African semi-arid geophytic species of Gethyllis (Amaryllidaceae)

Gethyllis multifolia L.Bolus and G. villosa Thunb. (Family: Amaryllidaceae) are deciduous and bulbous geophytes that occur in the succulent Karoo biome of South Africa. Both species occupy the same natural habitat, but G. multifolia is threatened and G. villosa not. Both G. multifolia and G. villosa require seasonal bulb reserves for initial vegetative and reproductive growth. In spite of G. villosa having smaller bulbs than G. multifolia, both species produce similar flower sizes and weights. The aim of the present study was to determine the carbon and nitrogen costs of vegetative and reproductive growth during the phases of growth, senescence, reproduction and dormancy of these bulbous species. The rates, costs and efficiencies of biomass production during various growth phases of the two species were determined in a comparative experiment. The results show that in spite of a significantly smaller bulb, G. villosa produced more leaves per unit bulb mass and invested more carbon and nitrogen resources into the bulbs during senescence. G. villosa also had a higher flower production, relative to bulb weight, than did G. multifolia. These physiological responses suggest that G. villosa may be more efficient at carbon and nitrogen resource utilisation