Scientific Study

Polyphenolic compounds (present in different parts of the plant) have beneficial properties such as antioxidant and inhibition of key enzymes. In this research, antioxidant and anti-lipase activity of pistachio green hull (PGH) extract was investigated. Fractionation of PGH on Sephadex LH-20 furnished a tannin enriched fraction with higher antioxidant activity respect to that of the extract and of the non-tannin fraction. UHPL/MS2 analyses showed the presence of phenolic compounds including galloyl-O-hexoside, galloyl-shikimic acid, galloylquinic acid, and gallic acid in tannin fraction. PGH-extract was an un-competitive inhibitor against porcine pancreatic lipase so that its IC50 value was 2.26 mg/ml. In the same phenol amount (490 µg), anti-lipase activity of the tannin fraction was also more than non-tannin fraction and crude PGH-extract. This is probably due to the presence of some active polyphenolic compounds such as gallic acid. PRACTICAL APPLICATIONS: Pistachio is native to the arid regions of Central and West Asia including Iran. The green hull is main by-product of pistachio industry that has numerous phenolic compounds. Our results showed that the pistachio green hull extract has antioxidant and anti-lipase activity and these activities in its tannin fraction were higher than non-tannin fraction. Therefore, the PGH extract and its tannin fraction can be used as potential substitutes of anti-obesity drugs. This allows the use of pistachio processing waste and reduces the amount of waste.