Toona sinensis, popularly known as Chinese toon or
Chinese mahogany, is a perennial deciduous arbor belonging to the
genus Toona in the Meliaceae family,
which is widely distributed and cultivated in eastern and southeastern
Asia. Its fresh young leaves and buds have been consumed as a very
popular nutritious vegetable in China and confirmed to display a wide
variety of biological activities. To investigate the chemical constituents
and their potential health benefits from the fresh young leaves and
buds of T. sinensis, a phytochemical
study on its fresh young leaves and buds was therefore undertaken.
In our current investigation, 16 limonoids (1–16), including four new limonoids, toonasinenoids A–D
(1–4), and a new naturally occurring
limonoid, toonasinenoid E (5), were isolated and characterized
from the fresh young leaves and buds of T. sinensis. The chemical structures and absolute configurations of limonoids 1–5 were elucidated by comprehensive spectroscopic
data analyses. All known limonoids (6–16) were identified via comparing their experimental spectral data
containing mass spectrometry data, 1H and 13C nuclear magnetic resonance data, and optical rotation values to
the data reported in the literature. All known limonoids (6–16) were isolated from T. sinensis for the first time. Furthermore, the neuroprotective effects of
all isolated limonoids 1–16 against
6-hydroxydopamine-induced cell death in human neuroblastoma SH-SY5Y
cells were assessed in vitro. Limonoids 1–16 exhibited notable neuroprotective activities,
with EC50 values in the range from 0.27 ± 0.03 to
17.28 ± 0.16 μM. These results suggest that regular consumption
of the fresh young leaves and buds of T. sinensis might prevent the occurrence and development of Parkinson’s
disease (PD). Moreover, the isolation and characterization of these
limonoids that exhibit notable neuroprotective activities from the
fresh young leaves and buds of T. sinensis could be very significant for researching and developing new neuroprotective
drugs used for the prevention and treatment of PD.
Artocarpus heterophyllus (jack tree) is an evergreen
fruit tree belonging to the genus Artocarpus (Moraceae),
which is widely distributed in subtropical and tropical regions of
Asia. Its fruits (jackfruit), well-known as the world’s largest
tree-borne fruit, are being consumed in our daily diets as a very
popular tropical fruit throughout the world and have been confirmed
to hold various health benefits. In this study, five new prenylated
chromones, artocarheterones A–E (1–5), as well as seven known prenylated chromones (6–12) were purified and isolated from the ripe
fruits of A. heterophyllus (jackfruit). Their chemical
structures were determined through comprehensive spectroscopic methods.
This is the first report on prenylated chromones isolated from A. heterophyllus. The anti-HIV-1 effects of all isolated
chromones were assessed in vitro. As a result, prenylated
chromones (1–12) showed remarkable
anti-HIV-1 effects with EC50 values ranging from 0.09 to
9.72 μM. These research results indicate that the isolation
and characterization of these prenylated chromones with remarkable
anti-HIV-1 activities from the ripe fruits of A. heterophyllus could be significant to the discovery and development of new anti-HIV-1
drugs.
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