Phytochemical analysis, in-vitro biological activities and Pearson correlation of total polyphenolic content with antioxidant activities of Ziziphus mauritiana fruit pulp and seed during different ripening stages

Ziziphus mauritiana is widely used in folkfore medicine to cure constipation, urinary problems, insomnia, chronic bronchitis, liver diseases and depression. The fruit of Z. mauritiana Pak white (PW) growing in Bahawalpur, Punjab, Pakistan, is not only tasteful but also famous for its maximum pulp, high yield and biological properties. It was therefore, selected for investigation of phytochemical content, antioxidant, antibacterial and anti-inflammatory activities at three different stages of the fruit (FZM 1–3) and seed (SZM 1–3) ripening. The fruit (FZM1) and seed (SZM2) extracts expressed highest phenolic and flavonoid content with the calculated values 3.61 mgGAE/g and 53.5 mgQE/g respectively. In antioxidant assays, SZM1 and SZM3 extracts depicted maximum total antioxidant capacity (TAC) and ferric reducing antioxidant power (FRAP) activity as measured 128 mgAA/g and 0.05 ± 0.001 absorbance respectively. Both seed and fruit extracts also had significant DPPH and metal chelating activities which increase as the fruit matures. Concentration dependent antibacterial activity of the extracts shown that fruit FZM1 is more potent than seeds with maximum clearance zone of 19 mm and 17 mm against S. Aureus and E. coli respectively. The fruit FZM1 exhibited highest anti-inflammatory activity i. e. 44.03% at a concentration of 500 µg/mL. Pearson correlation study manifested a strong correlation of total phenolics with the DPPH and anti-bacterial activities and total flavonoid with FRAP and TAC which provides additional affirmation to our activity results. It was observed that at different stages of fruit ripening, variations in phytochemical content resulted in a change in antioxidant and therapeutic potential of the fruit. Conclusively, these results suggested that fruit and seeds of Z. mauritiana can be developed into effective antioxidant, antibacterial and anti-inflammatory agents at specific ripening stages using a renewable natural source.