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A chemical study on the stems and leaves of Melodinus cochinchinensis resulted in the isolation and identification of a new monoterpenoid indole alkaloid, melodicochine A ( 1 ), together with seven known monoterpenoid indole alkaloids ( 2 - 8 ). The chemical structure of 1 was elucidated on the basis of extensive spectral data analyses and the known compounds were identified by comparing their experimental spectral data with the reported data in the literature. All isolated indole alkaloids were evaluated for their neuroprotective effects against 6-hydroxydopamine induced cell death in human neuroblastoma SH-SY5Y cells in vitro . Monoterpenoid indole alkaloids 1 - 8 exhibited notable neuroprotective effects with EC 50 values in range of 0.72 ± 0.06 to 17.89 ± 0.16  μ M.[Formula: see text].

The floral scents of three forms of cultivated Plumeria rubra L. were evaluated through mass flowering phenology using the dynamic headspace adsorption method and were identified with coupled gas chromatography and mass spectrometry. The forms P. rubra f. acutifolia and P. rubra f. lutea had white and yellow flower petals, respectively, and the flower petals of P. rubra f. rubra were red. Although 68 components of the flower scents of the three forms were recorded in different proportions, only 14 chemical compounds were identified with statistically significance. The main volatile compounds in the red form of P. rubra L. were fatty acid derivatives (56.75%). The main compounds in the white and yellow forms of P. rubra L. were benzenoid and terpene, with proportions of 48.38% and 33.33% in P. rubra f. acutifolia and proportions of 42.30% and 47.43% in P. rubra f. lutea , respectively. These differences in the flower scents might be one result of the minor genetic differences between these forms, similar to the role of genetic differences in the flower color combinations of the three forms. We conclude that petal color traits can, to some extent, reflect differences in floral scent compositions and that minor genetic differences of different plant forms exert impacts not only on flower color but also on the phytochemistry of floral scents. • Floral color and scent are the major components that attract pollinator insects. • Ecologists have long sought to explain how these combinations can support deceptive pollination behavior. • We show here the floral scent properties of three forms of Plumeria rubra L. and confirm that (1) there are significant intrinsic relationships between floral color traits and scent compositions: (2) floral color traits can reflect the differences of scent compositions to some extent; and: (3) both color traits of petals and floral scents might play a role in the evolution of the deceptive pollination syndrome of Plumeria rubra L. [ABSTRACT FROM AUTHOR]