Unleashing the power of nature: Investigating the effects of storage on plant-based pigments and bioactivities in tropical Ficus spp. extracts

Abstract

The phytochemical composition and antioxidant activities of tropical Ficus trees: Ficus benjamina (FB), Ficus racemosa (FRa) and Ficus religiosa (FRe) were analysed in this study. The bark and leaf samples of these species were subjected to solvent extraction using absolute methanol and analysed for their total chlorophyll (TCC), total carotenoid (TXc) and total anthocyanin (TAC) contents. The TPC, TFC and antioxidant potential of the extracts were also determined. The stability of the extracts during storage at different temperatures (4 °C, − 20 °C and − 80 °C) was investigated at weeks 0, 4 and 8. The results showed that the bark of F. racemosa and leaves of F. benjamina contained the highest amounts of phenolic content, with significantly higher antioxidant properties. PLSR analysis revealed that the secondary metabolite composition strongly influenced the antioxidant activities differently with Ficus trees. VIP scores were also computed to determine the most important factors that contributed to the ABTS and FRAP activities in the extracts from each species. Specifically, TPC, TFC, TXc, TCC, chlorophyll a, and chlorophyll b contents were the most important variables for F. benjamina. Meanwhile, TPC, TAC, TFC and chlorophyll b were the most important factors for F. racemosa, and only TAC, TPC and chlorophyll b were the most important factors for F. religiosa. Long term storage (8 weeks) of the extracts at 4 °C was observed to cause the highest percentage of metabolite degradation (up to 88.56% in TXc, 66.86% in TPC and 81.93% in TFC). Storage at − 80 °C was found to be the most suitable for retaining the secondary metabolites content and bioactivities of the samples. Taken together, F. religiosa leaf was identified as the best source of pigments and antioxidants. The findings of this study highlight the huge potential of plant extracts as both natural pigments and antioxidants in the food industry. These extracts can serve as a source of colorants while also improving the nutritional quality of food products, which aligns with the growing demand for clean-label and sustainable food options that can replace synthetic food additives.