Colorimetric and HPLC-DAD and bioactivity of Goji phytocomplex components

Lycium barbarum L, commonly known as Goji, is originally cultivated in China and Tibet and represents a medicinal plant in the Traditional Chinese Medicine. Several Goji cultivars from Italy and Romania, coming from different harvesting dates and seasons, were submitted, after a simple homogenization, to colorimetric CieLab analysis. The obtained organic and hydroalcoholic extracts were characterized in their quali-quantitative profile of carotenoid or polyphenolic components by HPLC-DAD analysis. Total phenolic content, total flavonoid content, antioxidant and scavenger anti-Candida and anti-tyrosinase activity were evaluated. Samples belonging to “Polonia” and “Wild” varieties harvested in three different dates in 2015 and in two different dates in 2016 at Fondi, (Lazio, Italy) samples belonging to “Sweet” and “Big” varieties harvested in two different dates in 2017 at Subiaco (Lazio, Italy) and to “Erma” and “Biglifeberry” varieties coming from Romania were evaluated. HPLC-DAD analyses, TPC, TFC, antioxidant, scavenging, anti-Candida and anti-tyrosinase activity were performed according to previously described methods. (1,2,3) CIELAB parameters (L*, a*, b*, C*ab and hab) were recorded on a Colorimeter X-Rite SP-62 (D65 illuminant, observer angle of 10°) equipped with an integration sphere to determine the color reflectance. (4) A double phase extraction from the homogenized fruits allows to simultaneously separate an organic and hydroalcoholic phase, containing the carotenoid and the phenolic components submitted to HPLC-DAD analysis. Zeaxanthin dipalmitate, rutin and carvacrol were the most represented molecules and were quantified by calibration curves. HPLC-DAD analyses confirm that Goji berries represent an exceptional source of zeaxanthin, and a good source of rutin and carvacrol. Both TPC and TFC showed a good correlation with the HPLC data and the antioxidant and scavenging activity. A correlation was attempted among carvacrol content and anti-Candida activity. Colorimetric analyses show that different homogenization techniques influence the distribution of pigments in the matrix, so that the purees resulting color is different also if pigment content should be the same. A good correlation was found among color expressed by simple homogenized samples and carotenoid content of the related extracts, showing that colorimetric measurement can represent a crucial point in the design of a processing flow chart for juices preparation. Preliminary encouraging results about the tested activities on polyphenolic fraction need to be carefully evaluated in order to assess the Goji berry potential use in food suppliers. 1) Boutaoui, Zaiter, Benayache, Benayache, Carradori, Cesa, ... & Locatelli, M. (2018), Molecules, 23(2), 463. 2) Mocan, Moldovan, Zengin, Bender, Locatelli, Simirgiotis, ... & Crișan, G. (2018). Food and Chemical Toxicology,115, 414-424 3) Simonetti, D’Auria, Mulinacci, Milella, Antonacci, Innocenti, & Pasqua, (2017). Phenolic content and in vitro antifungal activity of unripe grape extracts from agro-industrial wastes. Natural Product Research, 1-5. 4) Patsilinakos, Ragno, Carradori, Petralito, Cesa, (2018). Food Chemistry.