Comparative Phytochemical Profiles and Bioactivity-Constituent Relationships in Seven Pandanus Species From Vietnam

The genus Pandanus comprises numerous tropical plant species that are widely used in traditional medicine and local diets, yet comprehensive comparative studies linking their phytochemical composition to biological activities remain limited, particularly for underexplored species. In this study, forty-five methanolic extracts obtained from seven Pandanus species (Pandanus tectorius, Pandanus amaryllifolius, Pandanus odoratissimus, Pandanus affinis, Pandanus nanofrutex, Pandanus humilis, and Pandanus tonkinensis) collected in Vietnam were systematically evaluated for their phytochemical profiles and bioactivities. Total phenolic (TPC), flavonoid (TFC), saponin (TSC), and alkaloid (TAC) contents were quantified, and antioxidant activities (DPPH and hydroxyl radical scavenging) together with α-amylase inhibitory effects were assessed. Pronounced interspecific variation, together with selected exploratory organ-related patterns, was observed, with P. tectorius exhibiting consistently high phenolic, flavonoid, and saponin contents and the strongest antioxidant activities, while P. amaryllifolius was distinguished by exceptionally high alkaloid levels. To elucidate the relationships between chemical constituents and bioactivities, partial least squares regression (PLSR) and Spearman's correlation analyses were applied. The PLSR models showed strong explanatory and predictive performance (Q ² = 0.889), indicating that phenolic content showed the strongest association with free radical scavenging activities, whereas saponin content was most strongly associated with α-amylase inhibition. These patterns were consistent with the Spearman correlation analysis and the PLS biplot. Overall, this study provides an integrated phytochemical-bioactivity framework for Pandanus species, highlights distinct associations between metabolite classes and the measured bioactivities, and identifies underexplored taxa as promising candidates for future phytochemical and pharmacological investigations.