Natural products are an important source of therapeutically effective compounds
throughout the world. Since ancient times, a huge amount of both plant extracts and isolated
compounds have been largely employed in treatment and prevention of human disorders and,
currently, more than 60% of the world’s population trusts on plant medicaments as demonstrated
by the increasing quantity of herbal therapeutics in the market.
Unfortunately, several promising natural molecules for the treatment of the most diverse ailments
are characterized by extremely unfavourable features, such as low water solubility and
poor/irregular bioavailability, which hinder their clinical use. To overcome these limitations
and to make herbal therapy more effective, different formulative approaches have been employed.
Among the different strategies for increasing drug solubility, nanocrystals can be considered
one of the most interesting and successful approaches. Drug nanocrystals are nanosized drug
particles usually formulated as nanosuspensions, namely submicron dispersions in liquid media
where surfactants, polymers, or a mixture of both act as stabilisers.
In this review, we described the most significant results and progresses concerning drug
nanocrystal formulations for the delivery of natural compounds with a significant pharmacological
activity. The text is organized in nine sections, each focusing on a specific poorly water-
soluble natural compound (apigenin, quercetin, rutin, curcumin, baicalin and baicalein,
hesperetin and hesperidin, resveratrol, lutein, silybin).
To foster the clinical translation of these natural nanomedicines, our opinion is that future research
should pair the essential pharmacokinetic studies with carefully designed pre-clinical
experiments, able to prove the formulation efficacy in relevant animal models in vivo.