Summary:
In the present study, byproducts of pomegranate, peach, Bosnian and black pine,
eucalyptus and juniper deriving from agro-industrial wastes were exploited, in
order to be used as potential source of valuable compounds with application to
cosmetic industry and crop protection.
Totally, twenty extracts and four hydrosols were prepared and investigated for
their antioxidant (DPPH and ABTS methods) and whitening activity (tyrosinase
inhibition), as well as their total phenolic content (TPC). Moreover, they were
examined for their antibacterial activity against 17 phytopathogenic bacteria
and one phytopathogenic fungus (disk diffusion and agar dilution assay,
respectively).
All the extracts of pomegranate and eucalyptus revealed remarkable antioxidant
activity and particularly high phenolic content. Moreover, the pomegranate
extracts inhibited remarkably the growth of Pseudomonas corrugata, Erwinia
carotovora subsp. atroseptica and all the tested species of Xanthomonas and
Acidovorax, while the eucalyptus extracts showed good control against X.
campestris pv. campestris. Additionally, the same extracts presented strong
antifungal activity against P. nicotianae. The ethanolic extracts of
pomegranate and eucalyptus were investigated by LC-HRMS/MS for the
identification of their major constituents.
The hydroalcoholic extract and the hydrosol of P. nigra revealed strong
antioxidant activity. Moreover, the hydroalcocholic extract of P. heldreichii
presented significant antioxidant activity as well as the highest whitening
activity.
Concerning their phytochemical analysis, the following procedures were carried
out: a Centrifugal Partition Chromatography , a Chromatography of molecular
exclusion and a Preparative Thin layer Chromatography. As a result, 9
metabolites from the extracts of P. heldreichii were isolated, as well as five
metabolites from P. nigra. All the isolated molecules were identified through
NMR (1D & 2D) spectroscopy and LC-HRMS.
The fractions of the P. heldreichii extracts were examined for their whitening
activity, in order to detect the active metabolites. The main bioactive
compound was found to be pinosylvin.
Keywords:
By-products, Agrochemical, Antioxidant, Whitening, Antimicrobial
