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.

Seasonal variation and correlation with environmental factors of photosynthesis and water use efficiency of Juglans regia and Ziziphus jujuba.

Both the photosynthetic light curves and CO(2) curves of Juglans regia L. and Ziziphus jujuba Mill. var. spinosa in three seasons were measured using a LI-6400 portable photosynthesis system. The maximal net photosynthetic rate (A(max)), apparent quantum efficiency(phi), maximal carboxylation rate (V(cmax)) and water use efficiency (WUE) of the two species were calculated based on the curves. The results showed that A(max) of J. regia reached its maximum at the late-season, while the highest values of A(max) of Z. jujuba occurred at the mid-season. The A(max) of J. regia was more affected by relative humidity (RH) of the atmosphere, while that of Z. jujuba was more affected by the air temperature. Light saturation point (LSP) and Light compensation point (LCP) of J. regia had a higher correlation with RH of the atmosphere, those of Z. jujuba, however, had a higher correlation with air temperature. V(cmax) of both J. regia and Z. jujuba had negative correlation with RH of the atmosphere. WUE of J. regia would decrease with the rise of the air temperature while that of Z. jujuba increased. Thus it could be seen that RH, temperature and soil moisture had main effect on photosynthesis and WUE of J. regia and Z. jujuba. Incorporating data on the physiological differences among tree species into forest carbon models will greatly improve our ability to predict alterations to the forest carbon budgets under various environmental scenarios such as global climate change, or with differing species composition.