Abstract:
The fruit pulp of palmyrah (Borassus flabellifer) contains
flabelliferins which are glycosides of p-sitosterol. Naturally bound to
flabelliferins is an UV active compound, phytofluene, which affects
biological activity. This UV active compound shows intense blue
fluorescence and can be dissociated from flabelliferins.
The objectives of this study were to determine the main carotenoid
binder to flabelliferin- II (F-II, a tetraglycoside) in a sample of PFP
from Kalpitiya,Sri Lanka by HPLC and some of the chemical features
of this complex (F-II+ carotenoid binder).
HPLC studies showed that the major binder to F-II in a sample ofPFP
from Kalpitiya was phytofluene.
No correlation was found between the stoichiometry of binding of
phytofluene and F-Il (r2= 0.406) as well as for Fb (r2=0.007)
indicating that the binding ratios of phytofluene with F-UJ()r Fb are not
constant in different PFP samples tested.
Computational calculations (-~~Hf /KJ mol") suggest that binding is
a less stable between F-II and phytofluene compared to the other
flabelliferins tested. This was probably due to phytofluene distorting
the conformation of the carbohydrate moiety of F-II. Computer
modeling provided confirmatory evidence for this assumption.
