Antisickling activity of anthocyanins from Bombax pentadrum, Ficus capensis and Ziziphus mucronata: photodegradation effect.

AIM OF THE STUDY: A survey was conducted in Lubumbashi city (Democratic Republic of Congo) in order to: (a) identify medicinal plants used by traditional healers in the management of sickle cell anaemia, (b) verify their antisickling activity in vitro, (c) determine the most active plants, and (d) verify if anthocyanins are responsible of the bioactivity and study their photodegradation effect. MATERIALS AND METHODS: The Emmel test was used in vitro, for the antisickling activity assays of aqueous and ethanolic extracts of different parts of these plants when a UV lamp and solar irradiations were used to induce the photodegradation effect. RESULTS: The survey revealed that 13 medicinal plants are used in the treatment of drepanocytosis among which 12 plants exhibited the in vitro antisickling activity for at least one of the used parts or extracts. These plants are Bombax pentadrum, Bougainvillea sp., Byarsocarpus orientalis, Dalberigia bochmintaub, Diplorrhynbchus condolocarpus, Euphorbia heterophylla, Ficus capensis, Harungana madagascariensis, Parinari mobola, Pothmania witfchidii, Syzygium guineense, Temnocalys verdickii and Ziziphus mucronata of which four (Bombax pentadrum, Ficus capensis, Parinari mobola and Ziziphus mucronata) revealed a high antisickling activity. The biological activity of three of these plants is due to anthocyanins. The antisickling activity and photodegradation effect of anthocyanins extracts were studied and minimal concentration of normalization determined. The biological activity of Bombax pentadrum anthocyanins decreased to half of its value after 40 min of irradiation under a lamp emitting at a wavelength of 365 nm and after about 10h of solar irradiation. For Ziziphus mucronata and Ficus capensis, the antisickling activity decreased to half after about 6h under a lamp exposition and after about 50h of solar exposition. CONCLUSION: In vitro Antisickling activity justifies the use of these plants by traditional healers and this activity would be due to anthocyanins. But these natural pigments are instable towards UV-Visible irradiations. The conservation of these plants should then be performed in a shield from the sun radiation.

Fluorescence energy transfer on erythrocyte membranes.

Stationary and time-dependent fluorescence were measured for a donor/ acceptor (DA) pair bound to membrane proteins of bovine erythrocyte ghosts. The donor N-(p-(2-benzoxazolyl)phenyl)-maleimide (BMI) and the acceptor fluram bind to SH- and NH2-residues, respectively. The fluorescence spectra and the time-dependent emission were consistent with radiationless fluorescence energy transfer (RET). Band3 protein is the only membrane spanning protein with accessible SH-groups for the coupling of BMI molecules, and therefore only acceptor binding sites on the same band3 protein were counted by the RET measurements performed. A density of RET-effective acceptor binding sites c = 0.072 nm-2 was calculated on the basis of the two-dimensional Förster-kinetics.

WITHDRAWN: Ethno-botanical survey and ecological study of anti-pathogenic organisms medicinal plants species used in the Congolese folk medicine.

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Ancistroealaines A and B, two new bioactive naphthylisoquinolines, and related naphthoic acids from Ancistrocladus ealaensis.

Two new 5,8'-coupled naphthylisoquinoline alkaloids, ancistroealaines A (1) and B (2), eleutherolic acid (3), and two naphthoic acids, ancistronaphthoic acid A (4) and B (5), have been isolated from Ancistrocladus ealaensis. Their structures were determined by spectroscopic, chemical, and chiroptical methods. Ancistroealaine A (1) exhibited activity against Leishmania donovani and Trypanosoma cruzi in vitro.

Ancistrolikokines A-C: new 5,8'-coupled naphthylisoquinoline alkaloids from Ancistrocladus likoko.

Three new naphthylisoquinoline alkaloids, ancistrolikokines A-C (1-3), have been isolated and structurally assigned from Ancistrocladus likoko, as well as the known compound korupensamine A (4). Their 5,8'-coupling hints at a close biogenetic relationship of A. likoko to other Central African Ancistrocladus species. Compounds 1-4 showed good to moderate antimalarial activities when evaluated in vitro against the NF54 and K1 strains of Plasmodium falciparum.