I-V Curves of an Apigenin Dye and Their Analysis by a New Parabolic Function.

A new parabolic function for I-V curves' analysis has been proposed. The new "analytical tool" provides a simple way to describe photophysical processes at an approximately monolayer surface of a dye-sensitized solar cell. It may now be possible to estimate factors such as hole-electron recombination, surface defects, and electron diffusion at the semiconductor layer. The theoretical approach that was previously reported by our group for predicting the photovoltaic performance of potential dye sensitizers has also been validated. The experimental photovoltaic and DFT/TD-DFT data of apigenin and those of the highly rated black dyes were used for the validation.

Isolation and Cytotoxic Investigation of Flacourtin from Oncoba spinosa.

Background:Oncoba spinosa, an endangered medicinal plant whose secondary metabolites have not been extensively profiled, and which is hitherto yet to be examined for cytotoxicity, is being investigated in this study. Methods: Leaves of Oncoba spinosa (800 g) were extracted with 95% aqueous methanol. The crude extract was partitioned with n-hexane and the resultant defatted extract was extensively chromatographed on silica gel to yield compound 1 which was subjected to spectroscopic analysis. A brine shrimps lethality test was used to establish the cytotoxicity potentials of the isolated compound and the plant extracts. Results: Compound 1 was elucidated as flacourtin, 3-hydroxy-4-hydroxymethylphenyl-6-O-benzoyl-ß-d-glucopyranoside. The LD50 values obtained were less than 1000 µg/mL for flacourtin and the plant extracts. Conclusion: Flacourtin is being reported for the first time in the O. spinosa. The preliminary toxicity assay indicated that flacourtin and the plant extracts were not cytotoxic; thus, the tradomedicinal uses of the plant may portend no danger.