Saw palmetto fruit from diverse geographical locations, ecotypes and developmental stages exhibit differential fatty acid accumulation

Saw palmetto (Serenoa repens) fruit extract is a popular dietary supplement used as a therapy for benign prostatic hyperplasia and associated lower urinary tract symptoms in men. The United States Pharmacopeia has defined the quality determinant of saw palmetto fruit extract by its lipido-sterolic fingerprint characterized by ≥80% total fatty acid (FA) content with specific FA ratios relative to lauric acid and minor portions of phytosterols (0.25-0.5 %). A comprehensive understanding of post-anthesis saw palmetto fruit development comparing saw palmetto forms, in addition to the impact of geographical adaptation on fruit phytochemical profiles is lacking. We characterized the morphology and development of saw palmetto fruit from green form (Serenoa repens Bartram) and silver form (S. repens forma glauca) collected from varied geographical locations in Florida, and analyzed the fruit phytochemicals focusing on FA content and composition using GC-MS. Notably, silver form fruits exhibited a longer fruit development period of 25 weeks after anthesis (WAA), where anthesis was defined by fully opened flowers, compared to 19WAA in green form leading to larger fruit with higher fatty acid content. In both ecotypes, the major FAs in mature fruit extracts were oleic acid (C18:1 n- 9, 35-60%) and lauric acid (C12:0, 16-20%). The lauric-to-oleic acid ratio was 0.46 in the green form and 0.34 in the silver form. In both saw palmetto forms, the optimal harvest period corresponding to the highest FA accumulation was at yellow/orange fruit ripening stage, which occurred 3 weeks prior to fruits turning black. The present study provides new insights into the developmental FA profiling of saw palmetto fruit based on the form and geographical location which has practical implications in guiding saw palmetto berry harvest for nutraceutical applications. • Saw palmetto berries from southern regions of FL had higher fatty acid accumulation. • Silver and green saw palmetto berries varied in fatty acids profiles • Silver form berries had longer development, larger size, and higher fatty acid content. • Oleic acid and lauric acid are the major fatty acids in ripe fruit of saw palmetto • Peak fatty acid accumulation occurred three weeks before fruit fully ripened