Determination of phytochemicals and antioxidant activity of methanol extracts obtained from the fruit and leaves of Tunisian Lycium intricatum Boiss

Abstract

A comparative analysis of methanol extracts from fruit and leaves of Lycium intricatum Boiss., a Solanaceous shrubbery with the potential to become a high-value crop, was performed by means of liquid chromatography with photodiode array and electrospray ionisation mass spectrometric detection (LC/PDA/ESI-MS). The total phenolic (TPC), anthocyanin (TAC) and flavonoid (TFC) contents as well as the antioxidant capacity measured by four complementary methods were performed for each sample. The results showed the tested extracts to be rich sources of phenolics; in leaves polyphenols and flavonoids dominate, while in fruit anthocyanins dominate. Nineteen phenolic compounds were detected and fifteen were identified or tentatively characterised based on Photodiode-array ultraviolet visible (PDA) UV-Vis spectra, ESI-MS spectrometric data and spiking experiments with authentic standards. Rutin and chlorogenic acid are the major constituents of the leaves and fruit, respectively. Results obtained in this study have revealed that leaves exhibit better performance in all antioxidant assays. From these results it has been shown that extracts of L. intricatum have great potential as a source of phenolics for natural health products.

Keywords: 2-Coumaroylquinic acid (PubChem CID: 57351087); 3,4-Dicaffeoylquinic acid (PubChem CID: 5459216); 3-Caffeoylquinic acid (PubChem CID: 327-97-9); 4-p-Coumaroylquinic acid (PubChem CID: 5281766); Antioxidant activity; Flavonoids; Isoquercitrin (PubChem CID: 5280804); Isorhamnetin 3-glucoside (PubChem CID: 44258009); Kaempferol-3-O-rutinoside (PubChem CID: 20055286); LC/PDA/ESI-MS; Lycium intricatum; Phenolic acids; Quercetrin (PubChem CID: 5280459); Rutin (PubChem CID: 5280805).